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Nessipkhan A, Matsuda N, Takamura N, Oriuchi N, Ito H, Kiguchi M, Nishihara K, Tamaru T, Awai K, Kudo T. Occupational radiation exposure among medical personnel in university and general hospitals in Japan. Jpn J Radiol 2024:10.1007/s11604-024-01579-3. [PMID: 38705937 DOI: 10.1007/s11604-024-01579-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 04/20/2024] [Indexed: 05/07/2024]
Abstract
OBJECTIVE This study aimed to compare the occupational radiation exposure of medical workers between general hospitals and university hospitals. METHODS Radiation exposure data from three hospitals in Hiroshima city, including one university hospital and two general hospitals, were collected using personal dosimeters. Monthly radiation doses were analyzed, and the annual sum of radiation exposure dose was calculated for 538 subjects in general hospitals and 1224 subjects in the university hospital. To assess the impact of locality, additional data from Nagasaki University Hospital and Fukushima Medical University Hospital were included for comparative analysis. Professional affiliations, such as doctors, nurses, and radiological technologists, were considered in the evaluation. RESULTS The study revealed slight but significant differences in radiation doses between general and university hospitals. In general hospitals, except for radiological technologists, a slightly higher radiation dose was observed compared to university hospitals. Despite the annual increase in the use of medical radiation, the majority of hospital workers in both settings adhered to safety guidelines, with occupational radiation exposure remaining below the limit of detection (LOD). Workers who involved in fluoroscopic procedure, whether at university or general hospitals, had higher radiation doses than those who did not. CONCLUSION The study's primary conclusion is that workers in general hospitals experience a slight but significantly higher radiation dose and a lower percentage below the LOD compared to university hospitals. The observed difference is attributed to the greater workload at general hospitals than at university hospitals, and also may be due to the different nature of university hospital and general hospital. University hospitals, characterized by greater academic orientation, tend to benefit from comprehensive support systems, specialized expertise, and advanced technology, leading to more structured and regulated radiation control. These findings provide a basis for targeted interventions, improved safety protocols.
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Affiliation(s)
- Arman Nessipkhan
- Department of Radioisotope Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki University, Sakamoto 1-12-4, Nagasaki, 852-8523, Japan.
| | - Naoki Matsuda
- Department of Radiation Biology and Protection, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
| | - Noboru Takamura
- Department of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
| | - Noboru Oriuchi
- Advanced Clinical Research Center, Fukushima Global Medical Science Center, Fukushima Medical University, Fukushima, Japan
| | - Hiroshi Ito
- Department of Radiology, Faculty of Medicine, Fukushima Medical University, Fukushima, Japan
| | - Masao Kiguchi
- Department of Clinical Support, Hiroshima University Hospital, Hiroshima, Japan
| | - Kiyoto Nishihara
- Department of Radiological Technology, Hiroshima City Hiroshima Citizens Hospital, Hiroshima, Japan
| | - Takayuki Tamaru
- Department of Radiology, JA Hiroshima General Hospital, Hiroshima, Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Takashi Kudo
- Department of Radioisotope Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
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Masuda T, Kiguchi M, Fujioka C, Oku T, Ishibashi T, Katsunuma Y, Yoshitake T, Abe S, Awai K. Impact of beam collimation of z-overscanning on dose to the lens and thyroid gland in paediatric thoracic computed tomography imaging. Pediatr Radiol 2024; 54:758-763. [PMID: 38308740 DOI: 10.1007/s00247-024-05862-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 01/17/2024] [Accepted: 01/19/2024] [Indexed: 02/05/2024]
Abstract
BACKGROUND Adaptive collimation reduces the dose deposited outside the imaged volume along the z-axis. An increase in the dose deposited outside the imaged volume (to the lens and thyroid) in the z-axis direction is a concern in paediatric computed tomography (CT). OBJECTIVE To compare the dose deposited outside the imaged volume (to the lens and thyroid) between 40-mm and 80-mm collimation during thoracic paediatric helical CT. MATERIALS AND METHODS We used anthropomorphic phantoms of newborns and 5-year-olds with 40-mm and 80-mm collimation during helical CT. We compared the measured dose deposited outside the imaged volume using optically stimulated luminescence dosimeters (OSLD) at the surfaces of the lens and thyroid and the image noise between the 40-mm and 80-mm collimations. RESULTS There were significant differences in the dose deposited outside the imaged volume (to the lens and thyroid) between the 40-mm and 80-mm collimations for both phantoms (P < 0.01). CONCLUSION Compared with that observed for 80-mm collimation in helical CT scans of the paediatric thorax, the dose deposited outside the imaged volume (to the lens and thyroid) was significantly lower in newborns and 5-year-olds with 40-mm collimation.
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Affiliation(s)
- Takanori Masuda
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, Matsushima, Kurashiki, Okayama, 288701-0193, Japan.
| | - Masao Kiguchi
- Department of Radiology, Hiroshima University, Hiroshima, Japan
| | - Chikako Fujioka
- Department of Radiology, Hiroshima University, Hiroshima, Japan
| | - Takayuki Oku
- Department of Radiological Technologist, Tsuchiya General Hospital, Hiroshima, Japan
| | - Toru Ishibashi
- Department of Radiological Technologist, Tsuchiya General Hospital, Hiroshima, Japan
| | - Yasushi Katsunuma
- Department of Radiological Technology, Tokai University Oiso Hospital, Kanagawa, Japan
| | | | - Shuji Abe
- Department of Radiological Technology, Osaka College of High Technology, Osaka, Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Hiroshima University, Hiroshima, Japan
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Kitera N, Fujioka C, Higaki T, Nishimaru E, Yokomachi K, Matsumoto Y, Kiguchi M, Ohashi K, Kasai H, Awai K. [Validation of Optimal Imaging Conditions for Coronary Computed Tomography Angiography Using High-definition Mode and Deep Learning Image Reconstruction Algorithm]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2024:2024-1353. [PMID: 38508756 DOI: 10.6009/jjrt.2024-1353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
PURPOSE To verify the optimal imaging conditions for coronary computed tomography angiography (CCTA) examinations when using high-definition (HD) mode and deep learning image reconstruction (DLIR) in combination. METHOD A chest phantom and an in-house phantom using 3D printer were scanned with a 256-row detector CT scanner. The scan parameters were as follows - acquisition mode: ON (HD mode) and OFF (normal resolution [NR] mode), rotation time: 0.28 s/rotation, beam coverage width: 160 mm, and the radiation dose was adjusted based on CT-AEC. Image reconstruction was performed using ASiR-V (Hybrid-IR), TrueFidelity Image (DLIR), and HD-Standard (HD mode) and Standard (NR mode) reconstruction kernels. The task-based transfer function (TTF) and noise power spectrum (NPS) were measured for image evaluation, and the detectability index (d') was calculated. Visual evaluation was also performed on an in-house coronary phantom. RESULT The in-plane TTF was better for the HD mode than for the NR mode, while the z-axis TTF was lower for DLIR than for Hybrid-IR. The NPS values in the high-frequency region were higher for the HD mode compared to those for the NR mode, and the NPS was lower for DLIR than for Hybrid-IR. The combination of HD mode and DLIR showed the best value for in-plane d', whereas the combination of NR mode and DLIR showed the best value for z-axis d'. In the visual evaluation, the combination of NR mode and DLIR showed the best values from a noise index of 45 HU. CONCLUSION The optimal combination of HD mode and DLIR depends on the image noise level, and the combination of NR mode and DLIR was the best imaging condition under noisy conditions.
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Affiliation(s)
- Nobuo Kitera
- Department of Radiology, Hiroshima University Hospital
| | | | - Toru Higaki
- Graduate School of Advanced Science and Engineering, Hiroshima University
| | | | | | | | - Masao Kiguchi
- Department of Radiology, Hiroshima University Hospital
| | - Kazuya Ohashi
- Department of Radiology, Nagoya City University Hospital
| | - Harumasa Kasai
- Department of Radiology, Nagoya City University Hospital
| | - Kazuo Awai
- Graduate School of Biomedical and Health Sciences, Hiroshima University
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Hayashi A, Fukui R, Kamioka S, Yokomachi K, Fujioka C, Nishimaru E, Kiguchi M, Shiraishi J. Task-based assessment of resolution properties of CT images with a new index using deep convolutional neural network. Radiol Phys Technol 2024; 17:83-92. [PMID: 37930564 DOI: 10.1007/s12194-023-00751-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Revised: 09/28/2023] [Accepted: 10/09/2023] [Indexed: 11/07/2023]
Abstract
In this study, we propose a method for obtaining a new index to evaluate the resolution properties of computed tomography (CT) images in a task-based manner. This method applies a deep convolutional neural network (DCNN) machine learning system trained on CT images with known modulation transfer function (MTF) values to output an index representing the resolution properties of the input CT image [i.e., the resolution property index (RPI)]. Sample CT images were obtained for training and testing of the DCNN by scanning the American Radiological Society phantom. Subsequently, the images were reconstructed using a filtered back projection algorithm with different reconstruction kernels. The circular edge method was used to measure the MTF values, which were used as teacher information for the DCNN. The resolution properties of the sample CT images used to train the DCNN were created by intentionally varying the field of view (FOV). Four FOV settings were considered. The results of adapting this method to the filtered back projection (FBP) and hybrid iterative reconstruction (h-IR) images indicated highly correlated values with the MTF10% in both cases. Furthermore, we demonstrated that the RPIs could be estimated in the same manner under the same imaging conditions and reconstruction kernels, even for other CT systems, where the DCNN was trained on CT systems produced by the same manufacturer. In conclusion, the RPI, which is a new index that represents the resolution property using the proposed method, can be used to evaluate the resolution of a CT system in a task-based manner.
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Affiliation(s)
- Aiko Hayashi
- Department of Radiology, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan.
- Graduate School of Health Sciences, Kumamoto University, 4-24-1 Kuhonji, Kumamoto, 862-0976, Japan.
| | - Ryohei Fukui
- Department of Radiological Technology, Faculty of Health Sciences, Okayama University, 2-5-1 Shikatacho, Okayama, 700-8558, Japan
| | - Shogo Kamioka
- Department of Radiology, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan
| | - Kazushi Yokomachi
- Department of Radiology, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan
| | - Chikako Fujioka
- Department of Radiology, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan
| | - Eiji Nishimaru
- Department of Radiology, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan
| | - Masao Kiguchi
- Department of Radiology, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan
| | - Junji Shiraishi
- Faculty of Life Sciences, Kumamoto University, 4-24-1 Kuhonji, Chuo-ku, Kumamoto, 862-0976, Japan
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Masuda T, Kiguchi M, Fujioka C, Oku T, Ishibashi T, Katsunuma Y, Yoshitake T, Abe S, Awai K. Effectiveness of low tube voltage scan in the exposure dose for lenses during paediatric thoracic CT examination: anthropomorphic phantoms study. Radiat Prot Dosimetry 2024; 200:143-148. [PMID: 37987195 DOI: 10.1093/rpd/ncad284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 10/04/2023] [Accepted: 10/30/2023] [Indexed: 11/22/2023]
Abstract
To determine whether using lower-tube voltage reduces the scattered dose for the lens during paediatric thoracic computed tomography (CT). Two paediatric anthropomorphic phantoms (ATOM Phantom, CIRS, Norfolk, Virginia, USA) representing a newborn and 5-year-old were placed on the gantry of CT scanner, and optically stimulated luminescence dosemeters were placed on the left and right lenses, in front of the left and right thyroid glands, in front of the left and right mammary glands, and in front of and behind the mammary gland level and we measured scattered dose of the optically stimulated luminescence dosemeter was compared for each phantom between 80 and 120 kVp. Significant differences were observed in the scatter doses for the lens between 80 and 120 kVp (p < 0.01). Compared with the 120 kVp scan, the scatter doses for the lens were ~15-40% lower in newborn and 5-year-olds using the 80 kVp scan during paediatric CT.
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Affiliation(s)
- Takanori Masuda
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Masao Kiguchi
- Department of Radiology, Hiroshima University, 2-3, Kasumi, Minami-ku, Hiroshima 734-0037, Japan
| | - Chikako Fujioka
- Department of Radiology, Hiroshima University, 2-3, Kasumi, Minami-ku, Hiroshima 734-0037, Japan
| | - Takayuki Oku
- Department of Radiological Technologist, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima 730-8655, Japan
| | - Toru Ishibashi
- Department of Radiological Technologist, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima 730-8655, Japan
| | - Yasushi Katsunuma
- Department of Radiological Technology, Tokai University Oiso Hospital, 143, Shimokasuya, Iseharashi, Kanagawa 259-1193, Japan
| | - Takayasu Yoshitake
- TOWCAR WORKS Co., Ltd Hoashi 233-1, Kusu-machi, Kusugun, Oita 879-4403, Japan
| | - Shuji Abe
- Department of Radiological Technologist, Osaka College of High Technology, 1-2-43, Miyahara, Yogogawa-ku, Osaka 532-0003, Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Hiroshima University, 2-3, Kasumi, Minami-ku, Hiroshima 734-0037, Japan
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Tamura M, Kawamoto T, Ishifuro M, Tamura T, Masumoto Y, Kenjo M, Kiguchi M, Awai K, Nagata Y. Radio Frequency Identification Gate System to Identify Misused Personal Dosimeters. J Med Syst 2023; 47:107. [PMID: 37851155 DOI: 10.1007/s10916-023-02002-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 10/03/2023] [Indexed: 10/19/2023]
Abstract
The use of two personal dosimeters, one worn over and one worn under a protective apron, provides the best estimate of effective dose. However, inappropriate positioning of dosimeters is a common occurrence, resulting in abnormally high or low radiation exposure records. Although such incorrect positioning can be identified by radiation exposure records, doing so is time-consuming and labor-intensive for administrators. Therefore, a system that can identify incorrect locations of dosimeters without burdening administrators must be developed. In this study, we developed a radio frequency identification (RFID) gate system that can differentiate between two RFID-tagged dosimeters placed over and under a metal apron and identify misused dosimeters. To simulate the position of the RFID-tagged dosimeters, we designed four dosimeter-wearing classes, including "proper use" and three types of "misuse" (i.e., "reversed," "both under," and "both over"). When the system predicts "misuse" based on the tag reading, the worker is alerted with lights and alarms. The system performance was evaluated using a confusion matrix, with an overall accuracy of 97.75%, demonstrating high classification performance. The safety of the system against life support devices was also investigated, demonstrating that they were not affected by the electric field at 0.3 m or more from the antenna of the system under any transmit powers tested. This RFID gate system is highly capable of identifying incorrectly positioned dosimeters, enabling real-time monitoring of dosimeters to manage their positioning.
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Affiliation(s)
- Megumi Tamura
- Department of Clinical Support, Hiroshima University Hospital, Hiroshima, Japan.
| | | | - Minoru Ishifuro
- Department of Radiological Technology, Faculty of Medical Technology, Niigata University of Health and Welfare, Niigata, Japan
- Department of Orthopaedic Surgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Takayuki Tamura
- Department of Clinical Radiology, Faculty of Health Sciences, Hiroshima International University, Higashi-Hiroshima, Japan
| | - Yoshifumi Masumoto
- Department of Clinical Support, Hiroshima University Hospital, Hiroshima, Japan
| | - Masahiro Kenjo
- Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan
| | - Masao Kiguchi
- Department of Clinical Support, Hiroshima University Hospital, Hiroshima, Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Hiroshima University Hospital, Hiroshima, Japan
| | - Yasushi Nagata
- Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan
- Department of Radiation Oncology, Hiroshima University, Hiroshima, Japan
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Matsumoto Y, Fujioka C, Yokomachi K, Kitera N, Nishimaru E, Kiguchi M, Higaki T, Kawashita I, Tatsugami F, Nakamura Y, Awai K. Evaluation of the second-generation whole-heart motion correction algorithm (SSF2) used to demonstrate the aortic annulus on cardiac CT. Sci Rep 2023; 13:3636. [PMID: 36869155 PMCID: PMC9984533 DOI: 10.1038/s41598-023-30786-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 03/01/2023] [Indexed: 03/05/2023] Open
Abstract
The main purpose of pre-transcatheter aortic valve implantation (TAVI) cardiac computed tomography (CT) for patients with severe aortic stenosis is aortic annulus measurements. However, motion artifacts present a technical challenge because they can reduce the measurement accuracy of the aortic annulus. Therefore, we applied the recently developed second-generation whole-heart motion correction algorithm (SnapShot Freeze 2.0, SSF2) to pre-TAVI cardiac CT and investigated its clinical utility by stratified analysis of the patient's heart rate during scanning. We found that SSF2 reconstruction significantly reduced aortic annulus motion artifacts and improved the image quality and measurement accuracy compared to standard reconstruction, especially in patients with high heart rate or a 40% R-R interval (systolic phase). SSF2 may contribute to improving the measurement accuracy of the aortic annulus.
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Affiliation(s)
- Yoriaki Matsumoto
- Department of Radiology, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan.
| | - Chikako Fujioka
- Department of Radiology, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan
| | - Kazushi Yokomachi
- Department of Radiology, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan
| | - Nobuo Kitera
- Department of Radiology, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan
| | - Eiji Nishimaru
- Department of Radiology, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan
| | - Masao Kiguchi
- Department of Radiology, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan
| | - Toru Higaki
- Department of Diagnostic Radiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan
| | - Ikuo Kawashita
- Department of Diagnostic Radiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan
| | - Fuminari Tatsugami
- Department of Diagnostic Radiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan
| | - Yuko Nakamura
- Department of Diagnostic Radiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan
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Masuda T, Funama Y, Nakaura T, Sato T, Urayama K, Kiguchi M, Oku T, Yoshida M, Arao S, Ono A, Hiratsuka J, Awai K. Usefulness of large beam-shaping filters at different tube voltages of newborn chest CT. Phys Eng Sci Med 2023; 46:289-293. [PMID: 36633769 DOI: 10.1007/s13246-023-01217-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/10/2022] [Accepted: 01/03/2023] [Indexed: 01/13/2023]
Abstract
BACKGROUND To investigate optimizing the use of different beam shaping filters (viz. small, medium and large) when using different tube voltages during the newborn chest computed tomography (CT) on a GE Lightspeed VCT scanner. METHODS We used pediatric anthropomorphic phantoms with a 64 detector-row CT scanner while scanning the chest. A real-time skin dosimeter (RD - 1000; Trek Corporation, Kanagawa, Japan) was positioned into the phantom center of the body, the surface of the body back, and the right and left mammary glands. We performed and compared six scan protocols using small, medium, and large beam shaping filters at 80 and 120 kVp protocols. RESULT There were no significant differences in the image noise for the chest scan among the different beam shaping filters. By using the large beam shaping filter at 80 kVp, it was possible to reduce the exposure dose by 5% in comparison with the small beam shaping filter, and by 10% in comparison with the medium beam shaping filter. By using the large beam shaping filter at 120 kVp, it was possible to reduce the exposure dose by 15% in comparison with the small beam shaping filter and by 20% in comparison with the medium beam shaping filter (p < 0.01). CONCLUSION The large beam shaping filter had the most dose reduction effect during newborn chest CT on a GE Lightspeed VCT scanner. The additional copper filtration being present in the large bowtie filter of the GE Lightspeed CT scanner when using different tube voltages is more effective in reducing radiation exposure in children.
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Affiliation(s)
- Takanori Masuda
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, 701-0193, Kurashiki-city, Okayama, Japan.
| | - Yoshinori Funama
- Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, 1-1-1 Honjo, 860-8556, Kumamoto, Japan
| | - Takeshi Nakaura
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, 860-8556, Kumamoto, Japan
| | - Tomoyasu Sato
- Department of Diagnostic Radiology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, 730-8655, Hiroshima, Japan
| | - Kotaro Urayama
- Department of Pediatric cardiology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, 730-8655, Hiroshima, Japan
| | - Masao Kiguchi
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Kasumi 1-2-3 Minami-ku, 734-8551, Hiroshima, Japan
| | - Takayuki Oku
- Department of Radiological technologist, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, 730-8655, Hiroshima, Japan
| | - Masato Yoshida
- Department of Radiological technologist, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, 730-8655, Hiroshima, Japan
| | - Shinichi Arao
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, 701-0193, Kurashiki-city, Okayama, Japan
| | - Atsushi Ono
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, 701-0193, Kurashiki-city, Okayama, Japan
| | - Junichi Hiratsuka
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, 701-0193, Kurashiki-city, Okayama, Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Kasumi 1-2-3 Minami-ku, 734-8551, Hiroshima, Japan
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Tamura M, Kawamoto T, Kenjo M, Nakashima T, Kawano R, Tamura T, Ishifuro M, Kiguchi M, Awai K, Nagata Y. Evaluation of Inappropriate Positioning of Dosimeters in Medical Workers Based on Dose Equivalent Hp(10). Health Phys 2023; 124:10-16. [PMID: 36331308 DOI: 10.1097/hp.0000000000001619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
This report presents a new method to characterize the inappropriate positioning of dosimeters based on the dose equivalent Hp(10). The Hp(10) values of medical workers were measured monthly for 12 mo using two personal dosimeters. Using the ratio between the values of Hp(10) recorded from dosimeters worn over and under protective aprons [Hp(10) over and Hp(10) under , respectively], 670 pairs of dosimeter readings were categorized into a proper use group [Hp(10) over /Hp(10) under ≥ 5] and a misuse group [Hp(10) over /Hp(10) under < 5]. Following personal interviews, the readings in the misuse group were classified into the following six subgroups: "reversed," "sometimes reversed," "both under," "both over," "without apron," and "not specified." Ultimately, the scatter plot of "Hp(10) over - Hp(10) under " vs. Hp(10) over was identified as the most promising tool for clarifying the misuse patterns of dosimeters, as individual readings were mapped to the locations of the corresponding subgroups in the obtained graphs. Our results are expected to facilitate efficient and accurate usage of dosimeters by medical workers.
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Affiliation(s)
- Megumi Tamura
- Department of Clinical Support, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Takeshi Kawamoto
- Writing Center, Hiroshima University, 1-2-2 Kagamiyama, Higashi-Hiroshima 739-8512, Japan
| | - Masahiro Kenjo
- Hiroshima High-Precision Radiotherapy Cancer Center, 1-2-3 Futabanosato, Higashi-ku, Hiroshima 732-0057, Japan
| | - Takeo Nakashima
- Department of Clinical Support, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Reo Kawano
- Clinical Research Center in Hiroshima, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Takayuki Tamura
- Department of Clinical Support, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Minoru Ishifuro
- Faculty of Human Sciences, University of Human Arts and Sciences, 1288 Magome, Iwatsuki-ku, Saitama 339-8539, Japan; formerly at Department of Clinical Support, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Masao Kiguchi
- Department of Clinical Support, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Yasushi Nagata
- Department of Radiation Oncology, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
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10
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Masuda T, Funama Y, Nakaura T, Sato T, Urayama K, Kiguchi M, Oku T, Arao S, Ono A, Hiratsuka J, Awai K. COMPARISON OF PEDIATRIC LENS DOSE MEASUREMENTS BETWEEN AXIAL SCAN MODE WITHOUT ACTIVE COLLIMATOR AND HELICAL SCAN MODE WITH ACTIVE COLLIMATOR BY USING A 64 DETECTOR-ROW COMPUTED TOMOGRAPHY SCANNER. Radiat Prot Dosimetry 2022; 198:1522-1527. [PMID: 36193882 DOI: 10.1093/rpd/ncac196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 08/11/2022] [Accepted: 09/06/2022] [Indexed: 06/16/2023]
Abstract
To investigate the pediatric eye lens entrance surface dose for both axial scan modes without an active collimator and helical scan modes with an active collimator on 64 detector-row computed tomography (CT) scanner. We used three pediatric anthropomorphic phantoms with axial and helical scan modes from the superior orbitomeatal line to the crown of the head. We compared the measured dose values of the real-time skin dosemeter at the surfaces of the lens and the image noise at different scan modes. The median measured dose values for the lens of newborn, 1-year-old and the 5-year-old phantom were 31.3, 0.97 and 0.65 mGy, respectively, in the axial scan mode and 0.89, 1.21 and 0.71 mGy, respectively, in the helical scan mode. Compared with helical scans with an active collimators, axial scans can reduce the lens dose by ∼10% during head CT on 64 detector-row CT scanner without deterioration of image noise.
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Affiliation(s)
- Takanori Masuda
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Yoshinori Funama
- Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, Kumamoto, 1-1-1 Honjo, Kumamoto 860-8556, Japan
| | - Takeshi Nakaura
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan
| | - Tomoyasu Sato
- Department of Diagnostic Radiology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima 730-8655, Japan
| | - Kotaro Urayama
- Department of Pediatric Cardiology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima 730-8655, Japan
| | - Masao Kiguchi
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Kasumi 1-2-3 Minami-ku, Hiroshima 734-8551, Japan
| | - Takayuki Oku
- Department of Radiological Technologist, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima 730-8655, Japan
| | - Shinichi Arao
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Atsushi Ono
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Junichi Hiratsuka
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Kasumi 1-2-3 Minami-ku, Hiroshima 734-8551, Japan
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11
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Masuda T, Funama Y, Nakaura T, Sato T, Tahara M, Takei Y, Yamashita Y, Oku T, Masuda S, Kiguchi M, Awai K. USE OF VACUUM MATTRESSES CAN REDUCE THE ABSORBED DOSE DURING PEDIATRIC CT. Radiat Prot Dosimetry 2021; 194:201-207. [PMID: 34227663 DOI: 10.1093/rpd/ncab102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 05/10/2021] [Accepted: 06/12/2021] [Indexed: 06/13/2023]
Abstract
To evaluate and compare the absorbed dose and image quality when applying a commercially produced fixation device (group A) and a vaccum mattress fixation device to pediatric patients (group B). We compared the absorbed dose and image noise between the groups at the phantom and clinical study. For phantom study, the measurement absorbed dose for a real time skin dosimeter was 3.0 mGy at the group A and 1.9 mGy at the group B (p < 0.05). For clinical study, computed tomography dose index product, dose-length and effective radiation dose were significantly lower with the group B compared to the group A, (3.4 mGy, 27.0 mGy-cm, and 2.2 mSv vs 4.4 mGy, and 36.7 mGy-cm, and 3.0 mSv), p < 0.05 for all comparisons. Compared to the commercially produced fixation device, the vaccum mattress fixation device composed of a less absorptive material enabled a reduction in the absorbed dose while maintaining the image quality during pediatric CT examinations.
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Affiliation(s)
- Takanori Masuda
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Yoshinori Funama
- Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, Kumamoto, 1-1-1 Honjo, Kumamoto 860-8556, Japan
| | - Takeshi Nakaura
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan
| | - Tomoyasu Sato
- Department of Diagnostic Radiology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima 730-8655, Japan
| | - Masahiro Tahara
- Department of Pediatric cardiology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima 730-8655, Japan
| | - Yasutaka Takei
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Yukari Yamashita
- Department of Radiological Technology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima 730-8655, Japan
| | - Takayuki Oku
- Department of Radiological Technology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima 730-8655, Japan
| | - Shouko Masuda
- Department of Radiological Technology, kawamura clinic, Otemachi, Naka-ku, Hiroshima 730-0051, Japan
| | - Masao Kiguchi
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Kasumi 1-2-3 Minami-ku, Hiroshima 734-8551, Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Kasumi 1-2-3 Minami-ku, Hiroshima 734-8551, Japan
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12
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Masuda T, Funama Y, Nakaura T, Sato T, Muraoka Y, Okimoto T, Yamashita Y, Oku T, Matsumoto Y, Masuda S, Kiguchi M, Awai K. The combined application of the contrast-to-noise index and 80 kVp for cardiac CTA scanning before atrial fibrillation ablation reduces radiation dose exposure. Radiography (Lond) 2021; 27:840-846. [PMID: 33549491 DOI: 10.1016/j.radi.2021.01.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 12/26/2020] [Accepted: 01/13/2021] [Indexed: 11/27/2022]
Abstract
INTRODUCTION To compare the radiation dose, diagnostic accuracy, and the resultant ablation procedures using 80 and 120-kVp cardiac computed tomography angiography (CCTA) protocols with the same contrast-to-noise ratio in patients scheduled for atrial fibrillation (AF) ablation. METHODS This retrospective study was performed following institutional review board approval. We divided 140 consecutive patients who had undergone CCTA using a 64-MDCT scanner into two equal groups. Standard deviation (SD) of the CT number was set at 25 Hounsfield units (HU) for the 120-kVp protocol. To facilitate a reduction in radiation dose it was set at 40 HU for the 80 kVp protocol. We compared the two protocols with respect to the radiation dose, the diagnostic accuracy for detecting left atrial appendage (LAA) thrombi, matching for surface registration, and the resultant ablation procedures. RESULTS At 120 kVp, the dose length product (DLP) was 2.2 times that at 80 kVp (1269.0 vs 559.0 mGy cm, p < 0.01). The diagnostic accuracy for thrombus detection was 100% using both protocols. There was no difference between the two protocols with respect to matching for surface registration. The protocols did not differ with respect to the subsequent time required for the ablation procedures and the ablation fluoroscopy time, and the radiation dose (p = 0.54, 0.33, and 0.32, respectively). CONCLUSION For the same CNR, the DLP at 80 kVp (559.0 mGy cm) was 56% of that delivered at 120 kVp (1269.0 mGy cm). There was no reduction in diagnostic accuracy. IMPLICATIONS FOR PRACTICE Maintaining CNR allows for a reduction in the radiation dose without reducing the image quality.
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Affiliation(s)
- T Masuda
- Department of Radiological Technology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima, 730-8655, Japan; Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
| | - Y Funama
- Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - T Nakaura
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto, 860-8556, Japan
| | - T Sato
- Department of Diagnostic Radiology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima 730-8655, Japan
| | - Y Muraoka
- Department of Cardiovascular Internal Medicine, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima 730-8655, Japan
| | - T Okimoto
- Department of Cardiovascular Internal Medicine, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima 730-8655, Japan
| | - Y Yamashita
- Department of Radiological Technology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima, 730-8655, Japan
| | - T Oku
- Department of Radiological Technology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima, 730-8655, Japan
| | - Y Matsumoto
- Department of Radiological Technology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima, 730-8655, Japan
| | - S Masuda
- Department of Radiological Technology, Kawamura Clinic, Otemachi, Naka-ku, Hiroshima, 730-0051, Japan
| | - M Kiguchi
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - K Awai
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
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13
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Kobayashi S, Kaneko S, Kiguchi M, Tsukagoshi K, Nishino T. Tolerance to Stretching in Thiol-Terminated Single-Molecule Junctions Characterized by Surface-Enhanced Raman Scattering. J Phys Chem Lett 2020; 11:6712-6717. [PMID: 32619093 DOI: 10.1021/acs.jpclett.0c01526] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We investigated the change in the metal-molecule interaction in a 1,4-benzenedithiol (BDT) single-molecule junction using a combination of surface-enhanced Raman scattering spectra and current-voltage curves. During the stretching process, the conductance of the junction systematically decreased, accompanied by an increase in the vibrational energy of the CC stretching mode. By analyzing the current-voltage curves and Raman spectra, we found that the interaction between the π orbital of BDT and the electronic states of Au was diminished by the orientation change of BDT during the stretching process. A comparison with a 4,4'-bipyridine single-molecule junction revealed that the reduction of coupling of the Au-S contacts was smaller than that of Au-pyridine contacts. Therefore, the electronic states originating from the contact geometry are responsible for the tolerance to the stretching of thiol-terminated molecular junctions.
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Affiliation(s)
- S Kobayashi
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
| | - S Kaneko
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
- JST PRESTO, 4-1-8 Honcho, Kawaguchi 332-0012, Japan
| | - M Kiguchi
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
| | - K Tsukagoshi
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Tsukuba, Ibaraki 305-0044, Japan
| | - T Nishino
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
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14
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Kitera N, Matsubara K, Fujioka C, Yokomachi K, Nishimaru E, Kiguchi M, Morimoto A, Ishifuro M, Awai K. [Organ-based Tube-current Modulation Applied on Different MDCT Scanners: Reduction in the Radiation Dose to the Eye Lens at Head CT]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2020; 76:366-374. [PMID: 32307364 DOI: 10.6009/jjrt.2020_jsrt_76.4.366] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE Organ-based tube current modulation (OB-TCM) techniques, which are provided by three vendors, reduces the radiation dose to the lens of the eyes by decreasing the tube current, when the X-ray tube passes over the anterior surface of critical organs. However, the characteristics of dose modulation of these techniques are different. The purpose of this study was to understand the performance characteristics of OB-TCM technique of each computed tomography (CT) vendor at head CT. METHODS We used three CT scanners (SOMATOM Definition Flash; Siemens Healthcare, Revolution CT; GE Healthcare, and Aquilion ONE Genesis Edition; Canon Medical Systems). We measured the radiation dose to the lens surface as evaluation of radiation dose reduction and measured the image noise as index of image quality. We measured the radiation dose rate in the air for analysis of the characteristics of dose modulation in each OB-TCM. RESULTS When applying OB-TCM, the radiation doses for the lens surface were decreased by 28%, 22%, and 25% for Siemens, GE, and Canon CT scanners, respectively, and the image noise level was increased by 5.6%, 8.5%, and 15.1% for Siemens, GE, and Canon CT scanners, respectively. The characteristics of dose modulation in each OB-TCM were also confirmed by measured the radiation dose rate. CONCLUSION We confirmed that each OB-TCM has different influence on image quality and radiation doses for lens surface, due to the different characteristics of dose modulation for each CT vendor.
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Affiliation(s)
- Nobuo Kitera
- Department of Radiology, Hiroshima University Hospital.,Graduate School of Medical Science, Kanazawa University
| | - Kosuke Matsubara
- Department of Quantum Medical Technology, Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University
| | | | | | | | - Masao Kiguchi
- Department of Radiology, Hiroshima University Hospital
| | | | | | - Kazuo Awai
- Department of Diagnostic Radiology, Hiroshima University Hospital
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15
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Masuda T, Nakaura T, Funama Y, Sato T, Higaki T, Matsumoto Y, Yamashita Y, Imada N, Kiguchi M, Baba Y, Yamashita Y, Awai K. Contrast enhancement on 100- and 120 kVp hepatic CT scans at thin adults in a retrospective cohort study: Bayesian inference of the optimal enhancement probability. Medicine (Baltimore) 2019; 98:e17902. [PMID: 31764788 PMCID: PMC6882564 DOI: 10.1097/md.0000000000017902] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To assess the probability of achieving optimal contrast enhancement in 100 kVp and 120 kVp-protocol on hepatic computed tomography (CT) scans. MATERIALS AND METHODS We enrolled 200 patients in a retrospective cohort study. Hundred patients were scanned with 120 kVp setting, and other 100 patients were scanned with 100 kVp setting. We measured the CT number in the abdominal aorta and hepatic parenchyma on unenhanced scans and hepatic arterial phase (HAP)-, and portal venous phase (PVP). The aortic enhancement at HAP and the hepatic parenchymal enhancement at PVP were compared between the two scanning protocols. Bayesian inference was used to assess the probability of achieving optimal contrast enhancement in each protocol. RESULTS The Bayesian analysis indicated that when 100 kVp-rotocol was used, the probability of achieving optimal aortic enhancement (>280 HU) was 98.8% ± 0.6%, whereas it was 88.7% ± 2.5% when 120 kVp-protocol was used. Also, the probability of achieving optimal hepatic parenchymal enhancement (>50 HU) was 95.3% ± 1.5%, whereas it was 64.7% ± 3.8% when 120 kVp-protocol was used. CONCLUSION Bayesian inference suggested that the post-test probability of optimal contrast enhancement at hepatic dynamic CT was lower under the 120 kVp than the 100 kVp-protocol.
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Affiliation(s)
- Takanori Masuda
- Department of Radiological Technology, Tsuchiya General Hospital, 3-30 Nakajima-cho, Naka-ku, Hiroshima
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Takeshi Nakaura
- Department of Diagnostic Radiology, Graduate School of Medical Sciences
| | - Yoshinori Funama
- Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto
| | - Tomoyasu Sato
- Department of Diagnostic Radiology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku
| | - Toru Higaki
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Yoriaki Matsumoto
- Department of Radiological Technology, Tsuchiya General Hospital, 3-30 Nakajima-cho, Naka-ku, Hiroshima
| | - Yukari Yamashita
- Department of Radiological Technology, Tsuchiya General Hospital, 3-30 Nakajima-cho, Naka-ku, Hiroshima
| | - Naoyuki Imada
- Department of Radiological Technology, Tsuchiya General Hospital, 3-30 Nakajima-cho, Naka-ku, Hiroshima
| | - Masao Kiguchi
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Yasutaka Baba
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | | | - Kazuo Awai
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
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16
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Aiba A, Koizumi R, Tsuruoka T, Terabe K, Tsukagoshi K, Kaneko S, Fujii S, Nishino T, Kiguchi M. Investigation of Ag and Cu Filament Formation Inside the Metal Sulfide Layer of an Atomic Switch Based on Point-Contact Spectroscopy. ACS Appl Mater Interfaces 2019; 11:27178-27182. [PMID: 31276618 DOI: 10.1021/acsami.9b05523] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The atomic switches have attracted wide attention owing to their applications in nonvolatile electric devices. The atomic switch is operated by the formation and dissipation of a metallic filament inside a metal sulfide film, which is controlled by a solid electrochemical reaction. Although the metallic filament is considered to consist of metal atoms, the chemical species of the metallic filament are difficult to be identified due to challenges in observing the metallic filament inside the solid. In this study, we report the investigation on the metallic filament in the atomic switch with metal sulfide based on point-contact spectroscopy (PCS). By cooling the atomic switch, the switch voltage increased to 1 V, which allowed for the PCS measurement. The PCS revealed that the metallic filament was composed of Ag atoms in the case of the Pt/Ag2S/Ag atomic switch. We applied this technique to the Pt/Cu2S/Ag and Pt/Ag2S/Cu atomic switches to uncover the formation process of the metallic filament. In both atomic switches, the chemical species of the metallic filament were Ag. The metal atoms were supplied from both the metal electrode and the sulfide layer.
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Affiliation(s)
- A Aiba
- Department of Chemistry, School of Science , Tokyo Institute of Technology , 2-12-1 W4-10 Ookayama , Meguro-ku, Tokyo 152-8551 , Japan
| | - R Koizumi
- Department of Chemistry, School of Science , Tokyo Institute of Technology , 2-12-1 W4-10 Ookayama , Meguro-ku, Tokyo 152-8551 , Japan
| | - T Tsuruoka
- International Center for Materials Nanoarchitectonics (WPI-MANA) , National Institute for Materials Science (NIMS) , 1-1 Tsukuba , Ibaraki 305-0044 , Japan
| | - K Terabe
- International Center for Materials Nanoarchitectonics (WPI-MANA) , National Institute for Materials Science (NIMS) , 1-1 Tsukuba , Ibaraki 305-0044 , Japan
| | - K Tsukagoshi
- International Center for Materials Nanoarchitectonics (WPI-MANA) , National Institute for Materials Science (NIMS) , 1-1 Tsukuba , Ibaraki 305-0044 , Japan
| | - S Kaneko
- Department of Chemistry, School of Science , Tokyo Institute of Technology , 2-12-1 W4-10 Ookayama , Meguro-ku, Tokyo 152-8551 , Japan
| | - S Fujii
- Department of Chemistry, School of Science , Tokyo Institute of Technology , 2-12-1 W4-10 Ookayama , Meguro-ku, Tokyo 152-8551 , Japan
| | - T Nishino
- Department of Chemistry, School of Science , Tokyo Institute of Technology , 2-12-1 W4-10 Ookayama , Meguro-ku, Tokyo 152-8551 , Japan
| | - M Kiguchi
- Department of Chemistry, School of Science , Tokyo Institute of Technology , 2-12-1 W4-10 Ookayama , Meguro-ku, Tokyo 152-8551 , Japan
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17
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Koizumi R, Aiba A, Kaneko S, Fujii S, Nishino T, Kiguchi M. Investigation on the formation process of metal atomic filament for metal sulfide atomic switches by electrical measurement. Nanotechnology 2019; 30:125202. [PMID: 30620940 DOI: 10.1088/1361-6528/aafc79] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We have studied the formation process of the metal atomic filament for metal sulfide atomic switches by electrical measurement. The switching between ON and OFF states of the atomic switch is controlled by the application of the bias voltage for the atomic switches. The SET (OFF → ON) and RESET (ON → OFF) voltages were investigated for the atomic switch where the Ag2S or Cu2S layer were sandwiched between the Pt and Ag or Cu electrodes. The SET and RESET voltages of the Ag/Cu2S/Pt and Cu/Ag2S/Pt were close to those of the Ag/Ag2S/Pt atomic switch, and different from those of the Cu/Cu2S/Pt atomic switch. These results indicated that the dominant chemical species of the making and breaking part of the metal filament was Ag, and that the source of the metal filament was both the sulfide layer and the metal electrode.
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Affiliation(s)
- R Koizumi
- Department of Chemistry, School of Science, Tokyo Institute of Technology, Japan
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18
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Kobayashi S, Kaneko S, Fujii S, Nishino T, Tsukagoshi K, Kiguchi M. Stretch dependent electronic structure and vibrational energy of the bipyridine single molecule junction. Phys Chem Chem Phys 2019; 21:16910-16913. [DOI: 10.1039/c9cp01442j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Change in the molecular orbital energy and vibrational energy of the bipyridine single molecule junction as a function of stretch distance.
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Affiliation(s)
- S. Kobayashi
- Department of Chemistry
- Tokyo Institute of Technology
- Meguro-ku
- Japan
| | - S. Kaneko
- Department of Chemistry
- Tokyo Institute of Technology
- Meguro-ku
- Japan
| | - S. Fujii
- Department of Chemistry
- Tokyo Institute of Technology
- Meguro-ku
- Japan
| | - T. Nishino
- Department of Chemistry
- Tokyo Institute of Technology
- Meguro-ku
- Japan
| | - K. Tsukagoshi
- International Center for Materials Nanoarchitectonics (WPI-MANA)
- National Institute for Materials Science
- Tsukuba
- Japan
| | - M. Kiguchi
- Department of Chemistry
- Tokyo Institute of Technology
- Meguro-ku
- Japan
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Masuda T, Nakaura T, Funama Y, Sato T, Higaki T, Kiguchi M, Matsumoto Y, Yamashita Y, Imada N, Awai K. Development and Validation of Generalized Linear Regression Models to Predict Vessel Enhancement on Coronary CT Angiography. Korean J Radiol 2018; 19:1021-1030. [PMID: 30386134 PMCID: PMC6201979 DOI: 10.3348/kjr.2018.19.6.1021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 04/24/2018] [Indexed: 11/25/2022] Open
Abstract
Objective We evaluated the effect of various patient characteristics and time-density curve
(TDC)-factors on the test bolus-affected vessel enhancement on coronary computed
tomography angiography (CCTA). We also assessed the value of generalized linear
regression models (GLMs) for predicting enhancement on CCTA. Materials and Methods We performed univariate and multivariate regression analysis to evaluate the effect of
patient characteristics and to compare contrast enhancement per gram of iodine on test
bolus (ΔHUTEST) and CCTA (ΔHUCCTA). We developed GLMs to predict
ΔHUCCTA. GLMs including independent variables were validated with 6-fold
cross-validation using the correlation coefficient and Bland–Altman analysis. Results In multivariate analysis, only total body weight (TBW) and ΔHUTEST maintained
their independent predictive value (p < 0.001). In validation
analysis, the highest correlation coefficient between ΔHUCCTA and the prediction
values was seen in the GLM (r = 0.75), followed by TDC
(r = 0.69) and TBW (r = 0.62). The lowest
Bland–Altman limit of agreement was observed with GLM-3 (mean difference,
−0.0 ± 5.1 Hounsfield units/grams of iodine [HU/gI]; 95% confidence
interval [CI], −10.1, 10.1), followed by ΔHUCCTA (−0.0 ± 5.9
HU/gI; 95% CI, −11.9, 11.9) and TBW (1.1 ± 6.2 HU/gI; 95% CI,
−11.2, 13.4). Conclusion We demonstrated that the patient's TBW and ΔHUTEST significantly affected
contrast enhancement on CCTA images and that the combined use of clinical information
and test bolus results is useful for predicting aortic enhancement.
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Affiliation(s)
- Takanori Masuda
- Department of Radiological Technology, Tsuchiya General Hospital, Hiroshima 730-8655, Japan.,Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Takeshi Nakaura
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan
| | - Yoshinori Funama
- Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, Kumamoto 860-0811, Japan
| | - Tomoyasu Sato
- Department of Diagnostic Radiology, Tsuchiya General Hospital, Hiroshima 730-8655, Japan
| | - Toru Higaki
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Masao Kiguchi
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Yoriaki Matsumoto
- Department of Radiological Technology, Tsuchiya General Hospital, Hiroshima 730-8655, Japan
| | - Yukari Yamashita
- Department of Radiological Technology, Tsuchiya General Hospital, Hiroshima 730-8655, Japan
| | - Naoyuki Imada
- Department of Radiological Technology, Tsuchiya General Hospital, Hiroshima 730-8655, Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8553, Japan
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Masuda T, Funama Y, Nakaura T, Tahara M, Yamashita Y, Kiguchi M, Imada N, Sato T, Awai K. Radiation Dose Reduction with a Low-Tube Voltage Technique for Pediatric Chest Computed Tomographic Angiography Based on the Contrast-to-Noise Ratio Index. Can Assoc Radiol J 2018; 69:390-396. [DOI: 10.1016/j.carj.2018.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Revised: 03/08/2018] [Accepted: 05/16/2018] [Indexed: 10/28/2022] Open
Abstract
Introduction The aim of this study was to evaluate the radiation dose and image quality at low tube-voltage pediatric chest computed tomographic angiography (CTA) that applies the same contrast-to-noise ratio (CNR) index as the standard tube voltage technique. Materials and Methods Contrast-enhanced chest CTA scans of 100 infants were acquired on a 64-row multidetector computed tomography (MDCT) scanner. In the retrospective study, we evaluated 50 images acquired at 120 kVp; the image noise level was set at 25 Hounsfield units. In the prospective study, we used an 80-kVp protocol; the image noise level was 40 Hounsfield units because the iodine contrast was 1.6 times higher than on 120-kVp scans; the CNR was as in the 120-kVp protocol. We compared the CT number, image noise, CT dose index volume (CTDIvol), and the dose-length product on scans acquired with the 2 protocols. A diagnostic radiologist and a pediatric cardiologist visually evaluated all CTA images. Results The mean CTDIvol and the mean dose-length product were 0.5 mGy and 7.8 mGy-cm for 80- and 1.2 mGy and 20.8 mGy-cm for 120-kVp scans, respectively ( P < .001). The mean CTDIvol was 42% lower at 80 kVp than at 120 kVp, and there was no significant difference in the visual scores assigned to the CTA images ( P = .28). Conclusions With the CNR index being the same at 80-kVp and 120-kVp imaging, the radiation dose delivered to infants subjected to chest CTA can be reduced without degradation of the image quality.
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Affiliation(s)
- Takanori Masuda
- Department of Radiological Technology, Tsuchiya General Hospital, Hiroshima, Japan
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Yoshinori Funama
- Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Takeshi Nakaura
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Masahiro Tahara
- Department of Pediatric Cardiology, Tsuchiya General Hospital, Hiroshima, Japan
| | - Yukari Yamashita
- Department of Radiological Technology, Tsuchiya General Hospital, Hiroshima, Japan
| | - Masao Kiguchi
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Naoyuki Imada
- Department of Radiological Technology, Tsuchiya General Hospital, Hiroshima, Japan
| | - Tomoyasu Sato
- Department of Diagnostic Radiology, Tsuchiya General Hospital, Hiroshima, Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
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21
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Kaichi Y, Tatsugami F, Nakamura Y, Baba Y, Iida M, Higaki T, Kiguchi M, Tsushima S, Yamasaki F, Amatya VJ, Takeshima Y, Kurisu K, Awai K. Improved differentiation between high- and low-grade gliomas by combining dual-energy CT analysis and perfusion CT. Medicine (Baltimore) 2018; 97:e11670. [PMID: 30095624 PMCID: PMC6133561 DOI: 10.1097/md.0000000000011670] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The purpose of this study was to investigate the value of the cerebral blood volume (CBV) obtained with perfusion computed tomography (CT) and the electron density (ED) measured by dual-energy CT for differentiating high- from low-grade glioma (HGG, LGG).The CBV and ED were obtained in 9 LGG and 7 HGG patients. The CBV and ED of LGGs and HGGs were compared. Receiver operating characteristic (ROC) curves were generated for CBV, ED, and CBV plus ED. The correlation between CBV, ED, and the MIB-1 labeling index of the tumors was examined. All of these analyses were also performed using relative CBV (rCBV) and ED (rED) (the value of tumors/the value of contralateral white matter).The mean CBV, ED, rCBV, and rED values were significantly higher in HGG than LGG (P < .05). By ROC analysis, the combination of rCBV plus rED as well as CBV plus ED were more accurate than CBV, ED, rCBV, rED alone. There was a significant correlation between ED and MIB-1 (P = .04).ED improved diagnostic accuracy of perfusion CT for differentiating HGG from LGG.
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Affiliation(s)
| | | | | | | | | | | | - Masao Kiguchi
- Department of Radiology, Hiroshima University, Minami-ku, Hiroshima
| | - So Tsushima
- Canon Medical Systems Corporation, Otawara, Tochigi
| | | | - Vishwa Jeet Amatya
- Department of Pathology, Institute of Biomedical and Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Yukio Takeshima
- Department of Pathology, Institute of Biomedical and Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Kaoru Kurisu
- Department of Neurosurgery, Graduate School of Biomedical Sciences
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22
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Masuda T, Nakaura T, Funama Y, Sato T, Higaki T, Kiguchi M, Yamashita Y, Imada N, Awai K. Effect of Patient Characteristics on Vessel Enhancement at Lower Extremity CT Angiography. Korean J Radiol 2018. [PMID: 29520184 PMCID: PMC5840055 DOI: 10.3348/kjr.2018.19.2.265] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Objective To evaluate the effect of patient characteristics on popliteal aortic contrast enhancement at lower extremity CT angiography (LE-CTA) scanning. Materials and Methods Prior informed consent to participate was obtained from all 158 patients. All were examined using a routine protocol; the scanning parameters were tube voltage 100 kVp, tube current 100 mA to 770 mA (noise index 12), 0.5-second rotation, 1.25-mm detector row width, 0.516 beam pitch, and 41.2-mm table movement, and the contrast material was 85.0 mL. Cardiac output (CO) was measured with a portable electrical velocimeter within 5 minutes of starting the CT scan. To evaluate the effects of age, sex, body size, CO, and scan delay on the CT number of popliteal artery, the researchers used multivariate regression analysis. Results A significant positive correlation was seen between the CT number of the popliteal artery and the patient age (r = 0.39, p < 0.01). A significant inverse correlation was observed between the CT number of the popliteal artery and the height (r = −0.48), total body weight (r = −0.52), body mass index (r = −0.33), body surface area (BSA) (r = −0.56), lean body weight (r = −0.56), and CO (r = −0.35) (p < 0.001 for all). There was no significant correlation between the enhancement and the scan delay (r = 0.06, p = 0.47). The BSA, CO, and age had significant effects on the CT number (standardized regression: BSA −0.42, CO −0.22, age 0.15; p < 0.05, respectively). Conclusion The BSA, CO, and age are significantly correlated with the CT number of the popliteal artery on LE-CTA.
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Affiliation(s)
- Takanori Masuda
- Department of Radiological Technology, Tsuchiya General Hospital, Hiroshima 730-8655, Japan.,Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-0037, Japan
| | - Takeshi Nakaura
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan
| | - Yoshinori Funama
- Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
| | - Tomoyasu Sato
- Department of Diagnostic Radiology, Tsuchiya General Hospital, Hiroshima 730-8655, Japan
| | - Toru Higaki
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-0037, Japan
| | - Masao Kiguchi
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-0037, Japan
| | - Yukari Yamashita
- Department of Radiological Technology, Tsuchiya General Hospital, Hiroshima 730-8655, Japan
| | - Naoyuki Imada
- Department of Radiological Technology, Tsuchiya General Hospital, Hiroshima 730-8655, Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-0037, Japan
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23
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Abstract
We have investigated the electric conductance and atomic structure of single molecular junctions of pyrazine (Py), 4,4′-bipyridine (BiPy), fullerene (C60), and 1,4-diaminobutane (DAB).
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Affiliation(s)
- Y. Isshiki
- Department of Chemistry
- Tokyo Institute of Technology
- Tokyo
- Japan
| | - S. Fujii
- Department of Chemistry
- Tokyo Institute of Technology
- Tokyo
- Japan
| | - T. Nishino
- Department of Chemistry
- Tokyo Institute of Technology
- Tokyo
- Japan
| | - M. Kiguchi
- Department of Chemistry
- Tokyo Institute of Technology
- Tokyo
- Japan
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24
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Nakamura Y, Kawaoka T, Higaki T, Fukumoto W, Honda Y, Iida M, Fujioka C, Kiguchi M, Aikata H, Chayama K, Awai K. Hepatocellular carcinoma treated with sorafenib: Arterial tumor perfusion in dynamic contrast-enhanced CT as early imaging biomarkers for survival. Eur J Radiol 2017; 98:41-49. [PMID: 29279169 DOI: 10.1016/j.ejrad.2017.10.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 07/27/2017] [Accepted: 10/24/2017] [Indexed: 12/18/2022]
Abstract
OBJECTIVES To investigate whether hepatic perfusion CT yields early imaging biomarkers predictive of the prognosis of hepatocellular carcinoma (HCC) patients treated with sorafenib. METHODS We evaluated 36 HCC patients who underwent hepatic perfusion CT before- and one week after sorafenib therapy. We measured arterial and portal perfusion in the hepatic tumor and liver parenchyma [(AP)(PP)tumor], [(AP)(PP)liver]. The perfusion ratio was calculated by dividing the post- by the pre-sorafenib value. The effect of each value on the overall survival rate was analyzed with the Cox proportional hazards model; statistically significant parameters were subjected to receiver operating characteristic analysis based on median survival after sorafenib administration to determine the overall survival rate with the Kaplan-Meier method. RESULTS Pre-APtumor was significantly associated with the overall survival rate (hazard ratio (HR) and 95% confidence interval (CI), 0.16 and 0.02-0.84, p=0.03). The APtumor ratio tended to be associated with the overall survival rate (HR and 95% CI, 2.94 and 0.94-7.88, p=0.06). The overall survival rate was higher in patients with pre-APtumor>71.7mL/min/100mL, and with APtumor ratio≦1.1 (p<0.01 and 0.03, respectively, in Kaplan-Meier method with log-rank). CONCLUSION Hepatic perfusion CT yields early imaging biomarkers for predicting overall survival in HCC patients treated with sorafenib.
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Affiliation(s)
| | - Tomokazu Kawaoka
- Department of Medicine and Molecular Science, Hiroshima University, Japan; Hiroshima Liver Research Project Center, Japan.
| | - Toru Higaki
- Diagnostic Radiology, Hiroshima University, Japan.
| | | | - Yukiko Honda
- Diagnostic Radiology, Hiroshima University, Japan.
| | - Makoto Iida
- Diagnostic Radiology, Hiroshima University, Japan.
| | - Chikako Fujioka
- Department of Radiology, Hiroshima University Hospital, Japan.
| | - Masao Kiguchi
- Department of Radiology, Hiroshima University Hospital, Japan.
| | - Hiroshi Aikata
- Department of Medicine and Molecular Science, Hiroshima University, Japan; Hiroshima Liver Research Project Center, Japan.
| | - Kazuaki Chayama
- Department of Medicine and Molecular Science, Hiroshima University, Japan; Hiroshima Liver Research Project Center, Japan.
| | - Kazuo Awai
- Diagnostic Radiology, Hiroshima University, Japan.
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25
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Masuda T, Funama Y, Kiguchi M, Osawa K, Suzuki S, Oku T, Sugisawa K, Shouji T, Awai K. Relationship between the radiation doses at nonenhanced CT studies using different tube voltages and automatic tube current modulation during anthropomorphic phantoms of young children. J Appl Clin Med Phys 2017; 18:232-243. [PMID: 28984023 PMCID: PMC5689931 DOI: 10.1002/acm2.12192] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 07/10/2017] [Accepted: 08/10/2017] [Indexed: 11/14/2022] Open
Abstract
To compare the radiation dose and image noise of nonenhanced CT scans performed at 80, 100, and 120 kVp with tube current modulation (TCM) we used anthropomorphic phantoms of newborn, 1‐year‐old, and 5‐year‐old children. The noise index was set at 12. The image noise in the center of the phantoms at the level of the chest and abdomen was measured within a circumscribed region of interest. We measured the doses in individual tissues or organs with radio‐photoluminescence glass dosimeters for each phantom. Various tissues or organs were assigned and the radiation dose was calculated based on the international commission on radiological protection definition. With TCM the respective radiation dose at tube voltages of 80, 100, and 120 was 29.71, 31.60, and 33.79 mGy for the newborn, 32.00, 36.79, and 39.48 mGy for the 1‐year‐old, and 32.78, 38.11, and 40.85 mGy for the 5‐year‐old phantom. There were no significant differences in the radiation dose among the tube voltages and phantoms (P > 0.05). Our comparison of the radiation dose using anthropomorphic phantoms of young children showed that the radiation dose of nonenhanced CT performed at different tube voltages with TCM was not significantly different.
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Affiliation(s)
- Takanori Masuda
- Department of Radiological Technology, Tsuchiya General Hospital, Naka-ku, Japan.,Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Yoshinori Funama
- Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Masao Kiguchi
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Kazuaki Osawa
- Department of Radiological Technology, Saiseikai Chuwa Hospital, Nara, Japan
| | - Syouichi Suzuki
- Department of Diagnostic Radiology, Fujita Health University School of Health Science, Aichi, Japan
| | - Takayuki Oku
- Department of Radiological Technology, Tsuchiya General Hospital, Naka-ku, Japan
| | - Koichi Sugisawa
- Department of Diagnostic Radiology, Keio University School, Tokyo, Japan
| | - Tomokazu Shouji
- Department of Radiology, Jikei University Kashiwa Hospital, Chiba, Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
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26
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Tatsugami F, Higaki T, Sakane H, Fukumoto W, Kaichi Y, Iida M, Baba Y, Kiguchi M, Kihara Y, Tsushima S, Awai K. Coronary Artery Stent Evaluation with Model-based Iterative Reconstruction at Coronary CT Angiography. Acad Radiol 2017; 24:975-981. [PMID: 28214228 DOI: 10.1016/j.acra.2016.12.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 11/23/2016] [Accepted: 12/12/2016] [Indexed: 12/27/2022]
Abstract
RATIONALE AND OBJECTIVES This study aims to compare the image quality of coronary artery stent scans on computed tomography images reconstructed with forward projected model-based iterative reconstruction solution (FIRST) and adaptive iterative dose reduction 3D (AIDR 3D). MATERIALS AND METHODS Coronary computed tomography angiography scans of 23 patients with 32 coronary stents were used. The images were reconstructed with AIDR 3D and FIRST. We generated computed tomography attenuation profiles across the stents and measured the width of the edge rise distance and the edge rise slope (ERS). We also calculated the stent lumen attenuation increase ratio (SAIR) and measured visible stent lumen diameters. Two radiologists visually evaluated the image quality of the stents using a 4-point scale (1 = poor, 4 = excellent). RESULTS There was no significant difference in the edge rise distance between the two reconstruction methods (P = 0.36). The ERS on FIRST images was greater than the ERS on AIDR 3D images (325.2 HU/mm vs 224.4 HU/mm; P <0.01). The rate of the visible stent lumen diameter compared to the true diameter on FIRST images was higher than that on AIDR 3D images (51.4% vs 47.3%, P <0.01). The SAIR on FIRST images was lower than the SAIR on AIDR 3D images (0.19 vs 0.30, P <0.01). The mean image quality scores for AIDR 3D and FIRST images were 3.18 and 3.63, respectively; the difference was also significant (P <0.01). CONCLUSION The image quality of coronary artery stent scans is better on FIRST than on AIDR 3D images.
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27
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Ziatdinov M, Lim H, Fujii S, Kusakabe K, Kiguchi M, Enoki T, Kim Y. Chemically induced topological zero mode at graphene armchair edges. Phys Chem Chem Phys 2017; 19:5145-5154. [PMID: 28140409 DOI: 10.1039/c6cp08352h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electronic and magnetic properties of chemically modified graphene armchair edges are studied using a combination of tight-binding calculations, first-principles modelling, and low temperature scanning tunneling microscopy (STM) experiments. The atomically resolved STM images of the hydrogen etched graphitic edges suggest the presence of localized states at the Fermi level for certain armchair edges. We demonstrate theoretically that the topological zero-energy edge mode may emerge at armchair boundaries with asymmetrical chemical termination of the two outermost atoms in the unit cell. We particularly focus our attention on armchair edges terminated by various combinations of the hydrogen (H, H2) and methylene (CH2) groups. The inclusion of the spin component in our calculations reveals the appearance of π-electron-based magnetism at the armchair edges under consideration.
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Affiliation(s)
- M Ziatdinov
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan.
| | - H Lim
- Surface and Interface Science Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - S Fujii
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan.
| | - K Kusakabe
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
| | - M Kiguchi
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan.
| | - T Enoki
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan.
| | - Y Kim
- Surface and Interface Science Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
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28
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Awai K, Higaki T, Tatsugami F, Nakamura Y, Baba Y, Iida M, Fujioka C, Yokomachi K, Kiguchi M. [Clinical Application of Iterative Reconstruction at CT]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2017; 73:1261-1269. [PMID: 29269622 DOI: 10.6009/jjrt.2017_jsrt_73.12.1261] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Affiliation(s)
- Kazuo Awai
- Diagnostic Radiology, Graduate School of Biomedical and Health Sciences, Hiroshima University
| | - Toru Higaki
- Diagnostic Radiology, Graduate School of Biomedical and Health Sciences, Hiroshima University
| | - Fuminari Tatsugami
- Diagnostic Radiology, Graduate School of Biomedical and Health Sciences, Hiroshima University
| | - Yuko Nakamura
- Diagnostic Radiology, Graduate School of Biomedical and Health Sciences, Hiroshima University
| | - Yasutaka Baba
- Diagnostic Radiology, Graduate School of Biomedical and Health Sciences, Hiroshima University
| | - Makoto Iida
- Diagnostic Radiology, Graduate School of Biomedical and Health Sciences, Hiroshima University
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29
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Masuda T, Funama Y, Kiguchi M, Imada N, Oku T, Sato T, Awai K. Radiation dose reduction based on CNR index with low-tube voltage scan for pediatric CT scan: experimental study using anthropomorphic phantoms. Springerplus 2016; 5:2064. [PMID: 27995041 PMCID: PMC5133217 DOI: 10.1186/s40064-016-3715-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 11/21/2016] [Indexed: 12/13/2022]
Abstract
Background To figure out the relationship between image noise and contrast noise ratio (CNR) at different tube voltages, using anthropomorphic new-born and 1-year-old phantoms, and to discuss the feasibility of radiation dose reduction, based on the obtained CNR index from image noise. We performed helical scans of the anthropomorphic new-born and 1-year-old phantoms. The CT numbers of the simulated aorta and image noise of the simulated mediastinum were measured; then CNR was calculated on 80, 100, and 120-kVp images reconstructed with filtered back projection (FBP) and iterative reconstruction (IR). We also measured the center and surface dose in the case of CNR of 14 using radio-photoluminescence glass dosimeters. Results The CT number of the simulated aorta was increased with decreasing tube voltage from 120 to 80 kVp (362.5–535.1 HU for the new-born, 358.9–532.6 HU for the 1-year-old). At CNR of 14, the center dose was 0.4, 0.6 and 0.9 mGy at FBP and 0.5, 0.6 and 0.9 mGy at IR and with the new-born phantom acquired at 80, 100 and 120 kVp, respectively. The center dose for FBP image was reduced by 56% at 80 kVp, 34% at 100 kVp for the new-born and 36% at 80 kVp, 22% at 100 kVp for the 1-year-old compared with that at 120 kVp. We obtained a relationship between image noise and CNR at different tube voltages using the anthropomorphic new-born and 1-year-old phantoms. Conclusion The use of index of CNR with low-tube voltage may achieve further radiation dose reduction in pediatric CT examination.
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Affiliation(s)
- Takanori Masuda
- Department of Radiological Technology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima, 730-8655 Japan ; Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Yoshinori Funama
- Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Masao Kiguchi
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Naoyuki Imada
- Department of Radiological Technology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima, 730-8655 Japan
| | - Takayuki Oku
- Department of Radiological Technology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima, 730-8655 Japan
| | - Tomoyasu Sato
- Department of Diagnostic Radiology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima, 730-8655 Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
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Shimonobo T, Funama Y, Utsunomiya D, Nakaura T, Oda S, Kiguchi M, Masuda T, Sakabe D, Yamashita Y, Awai K. Low-tube-voltage selection for non-contrast-enhanced CT: Comparison of the radiation dose in pediatric and adult phantoms. Phys Med 2016; 32:197-201. [DOI: 10.1016/j.ejmp.2015.12.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Revised: 11/30/2015] [Accepted: 12/11/2015] [Indexed: 11/30/2022] Open
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31
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Takasu M, Yamagami T, Nakamura Y, Komoto D, Kaichi Y, Tani C, Date S, Kiguchi M, Awai K. Multidetector computed tomography-based microstructural analysis reveals reduced bone mineral content and trabecular bone changes in the lumbar spine after transarterial chemoembolization therapy for hepatocellular carcinoma. PLoS One 2014; 9:e110106. [PMID: 25329933 PMCID: PMC4199685 DOI: 10.1371/journal.pone.0110106] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 09/16/2014] [Indexed: 11/19/2022] Open
Abstract
PURPOSE It is well recognized that therapeutic irradiation can result in bone damage. However, long-term bone toxicity associated with computed tomography (CT) performed during interventional angiography has received little attention. The purpose of this study was to determine the prevalence of osteoporosis and trabecular microstructural changes in patients after transarterial chemoembolization (TACE) for hepatocellular carcinoma therapy using an interventional-CT system. MATERIALS AND METHODS Spinal microarchitecture was examined by 64-detector CT in 81 patients who underwent TACE, 35 patients with chronic hepatitis, and 79 controls. For each patient, the volumetric CT dose index (CTDIv) during TACE (CTDIv (TACE)), the dose-length product (DLP) during TACE (DLP (TACE)), and CTDIv and DLP of routine dynamic CT scans (CTDIv (CT) and DLP (CT), respectively), were calculated as the sum since 2008. Using a three dimensional (3D) image analysis system, the tissue bone mineral density (tBMD) and trabecular parameters of the 12th thoracic vertebra were calculated. Using tBMD at a reported cutoff value of 68 mg/cm3, the prevalence of osteoporosis was assessed. RESULTS The prevalence of osteoporosis was significantly greater in the TACE vs. the control group (39.6% vs. 18.2% for males, P<0.05 and 60.6% vs. 34.8% for females, P<0.01). Multivariate regression analysis demonstrated that sex, age, and CTDIv (CT) significantly affected the risk of osteoporosis. Of these indices, CTDIv (CT) had the highest area under the curve (AUC) (0.735). Correlation analyses of tBMD with cumulative radiation dose revealed weak correlations between tBMD and CTDIv (CT) (r2 = 0.194, P<0.001). CONCLUSION The prevalence of osteoporosis was significantly higher in post TACE patients than in control subjects. The cumulative radiation dose related to routine dynamic CT studies was a significant contributor to the prevalence of osteoporosis.
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Affiliation(s)
- Miyuki Takasu
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Takuji Yamagami
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Yuko Nakamura
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Daisuke Komoto
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Yoko Kaichi
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Chihiro Tani
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Shuji Date
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Masao Kiguchi
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
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Yokomachi K, Nishimaru E, Fujioka C, Kiguchi M, Ishifuro M, Funama Y, Awai K. [Effects of differences in head holder on image quality and radiation dose in head CT]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2014; 70:1166-1172. [PMID: 25327427 DOI: 10.6009/jjrt.2014_jsrt_70.10.1166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
PURPOSE For emergency or pediatric head CT scans, a simplified pillow made of hard sponge instead of a dedicated head holder may be used if it is difficult to immobilize the head. However, the radiation dose when using a simplified head holder may be increased due to radiation absorption by the patient couch if the automatic exposure control (AEC) system is used. In this phantom study, we compared the radiation dose delivered when using a dedicated and a simplified head holder. MATERIALS AND METHODS We used a dedicated-type and a pillow-type head holder made of hard sponge (simplified head holder). We placed a 20 cm-diameter cylindrical phantom made of water-equivalent material and an anthropomorphic head phantom in the head holders and then scanned them five times with a 64-detector CT scanner (VCT, GE Healthcare). We performed step-and-shoot and helical scanning with AEC; the noise index was set to 2.8. We measured the radiation dose using fluorescent glass dosimeters in the head phantom and the image noise at five sites in the cylindrical phantom. All values were averaged. RESULTS With step-and-shoot scans, the mean image noise with the dedicated and the simplified head holder was 3.30 ± 0.05 [SD] and 3.20 ± 0.05, respectively. With helical scans they were 3.00 ± 0.09 and 2.88 ± 0.03, respectively. There was no statistically significant difference (p = 0.02 and 0.04, Student's t-test). The radiation doses with the dedicated and the simplified head holder were 58.6 and 70.4 mGy, respectively, for step-and-shoot scanning and 41.8 and 49.0 mGy, respectively, for helical scanning. The doses were thus significantly higher with the simplified head holder for both step-and-shoot and helical scanning (p < 0.01 and < 0.01). CONCLUSION We recommend the use of a dedicated head holder for head scanning with AEC since the radiation dose was lower than with the simplified head holder.
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Kajihara K, Nakano Y, Hirai Y, Ogi H, Oda N, Suenari K, Makita Y, Sairaku A, Tokuyama T, Motoda C, Fujiwara M, Watanabe Y, Kiguchi M, Kihara Y. Variable procedural strategies adapted to anatomical characteristics in catheter ablation of the cavotricuspid isthmus using a preoperative multidetector computed tomography analysis. J Cardiovasc Electrophysiol 2014; 24:1344-51. [PMID: 23875907 PMCID: PMC4229059 DOI: 10.1111/jce.12231] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Revised: 06/14/2013] [Accepted: 06/26/2013] [Indexed: 11/30/2022]
Abstract
Objectives This study aimed to investigate the anatomical characteristics complicating cavotricuspid isthmus (CTI) ablation and the effectiveness of various procedural strategies. Methods and Results This study included 446 consecutive patients (362 males; mean age 60.5 ± 10.4 years) in whom CTI ablation was performed. A total of 80 consecutive patients were evaluated in a preliminary study. The anatomy of the CTI was evaluated by multidetector row-computed tomography (MDCT) prior to the procedure. A multivariate logistic regression analysis revealed that the angle and mean wall thickness of the CTI, a concave CTI morphology, and a prominent Eustachian ridge, were associated with a difficult CTI ablation (P < 0.01). In the main study, 366 consecutive patients were divided into 2 groups: a modulation group (catheter inversion technique for a concave aspect, prominent Eustachian ridge, and steep angle of the CTI or increased output for a thicker CTI) and nonmodulation group (conventional strategy). The duration and total amount of radiofrequency energy delivered were significantly shorter and smaller in the modulation group than those in the nonmodulation group (162.2 ± 153.5 vs 222.7 ± 191.9 seconds, P < 0.01, and 16,962.4 ± 11,545.6 vs 24,908.5 ± 22,804.2 J, P < 0.01, respectively). The recurrence rate of type 1 atrial flutter after the CTI ablation in the nonmodulation group was significantly higher than that in the modulation group (6.3 vs 1.7%, P = 0.02). Conclusion Changing the procedural strategies by adaptating them to the anatomical characteristics improved the outcomes of the CTI ablation.
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Affiliation(s)
- Kenta Kajihara
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences
- Address for correspondence: Kenta Kajihara, M.D., Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan. Fax: +81-82-257-5169; E-mail:
| | - Yukiko Nakano
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences
| | - Yukoh Hirai
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences
| | - Hiroshi Ogi
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences
| | - Noboru Oda
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences
| | - Kazuyoshi Suenari
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences
| | - Yuko Makita
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences
| | - Akinori Sairaku
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences
| | - Takehito Tokuyama
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences
| | - Chikaaki Motoda
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences
| | - Mai Fujiwara
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences
| | - Yoshikazu Watanabe
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences
| | - Masao Kiguchi
- Department of Radiology, Hiroshima University HospitalHiroshima, Japan
| | - Yasuki Kihara
- Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences
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He BJ, Nolte G, Nagata K, Takano D, Yamazaki T, Fujimaki Y, Maeda T, Satoh Y, Heckers S, George MS, Lopes da Silva F, de Munck JC, Van Houdt PJ, Verdaasdonk RM, Ossenblok P, Mullinger K, Bowtell R, Bagshaw AP, Keeser D, Karch S, Segmiller F, Hantschk I, Berman A, Padberg F, Pogarell O, Scharnowski F, Karch S, Hümmer S, Keeser D, Paolini M, Kirsch V, Koller G, Rauchmann B, Kupka M, Blautzik J, Pogarell O, Razavi N, Jann K, Koenig T, Kottlow M, Hauf M, Strik W, Dierks T, Gotman J, Vulliemoz S, Lu Y, Zhang H, Yang L, Worrell G, He B, Gruber O, Piguet C, Hubl D, Homan P, Kindler J, Dierks T, Kim K, Steinhoff U, Wakai R, Koenig T, Kottlow M, Melie-García L, Mucci A, Volpe U, Prinster A, Salvatore M, Galderisi S, Linden DEJ, Brandeis D, Schroeder CE, Kayser C, Panzeri S, Kleinschmidt A, Ritter P, Walther S, Haueisen J, Lau S, Flemming L, Sonntag H, Maess B, Knösche TR, Lanfer B, Dannhauer M, Wolters CH, Stenroos M, Haueisen J, Wolters C, Aydin U, Lanfer B, Lew S, Lucka F, Ruthotto L, Vorwerk J, Wagner S, Ramon C, Guan C, Ang KK, Chua SG, Kuah WK, Phua KS, Chew E, Zhou H, Chuang KH, Ang BT, Wang C, Zhang H, Yang H, Chin ZY, Yu H, Pan Y, Collins L, Mainsah B, Colwell K, Morton K, Ryan D, Sellers E, Caves K, Throckmorton S, Kübler A, Holz EM, Zickler C, Sellers E, Ryan D, Brown K, Colwell K, Mainsah B, Caves K, Throckmorton S, Collins L, Wennberg R, Ahlfors SP, Grova C, Chowdhury R, Hedrich T, Heers M, Zelmann R, Hall JA, Lina JM, Kobayashi E, Oostendorp T, van Dam P, Oosterhof P, Linnenbank A, Coronel R, van Dessel P, de Bakker J, Rossion B, Jacques C, Witthoft N, Weiner KS, Foster BL, Miller KJ, Hermes D, Parvizi J, Grill-Spector K, Recanzone GH, Murray MM, Haynes JD, Richiardi J, Greicius M, De Lucia M, Müller KR, Formisano E, Smieskova R, Schmidt A, Bendfeldt K, Walter A, Riecher-Rössler A, Borgwardt S, Fusar-Poli P, Eliez S, Schmidt A, Sekihara K, Nagarajan SS, Schoffelen JM, Guggisberg AG, Nolte G, Balazs S, Kermanshahi K, Kiesenhofer W, Binder H, Rattay F, Antal A, 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E, Ball J, Eich-Höchli D, Brandeis D, Salisbury DF, Murphy TK, Butera CD, Mathalon DH, Fryer SL, Kiehl KA, Calhoun VC, Pearlson GD, Roach BJ, Ford JM, McGlashan TH, Woods SW, Volpe U, Merlotti E, Vignapiano A, Montefusco V, Plescia GM, Gallo O, Romano P, Mucci A, Galderisi S, Mingoia G, Langbein K, Dietzek M, Wagner G, Smesny, Scherpiet S, Maitra R, Gaser C, Sauer H, Nenadic I, Gonzalez Andino S, Grave de Peralta Menendez R, Grave de Peralta Menendez R, Sanchez Vives M, Rebollo B, Gonzalez Andino S, Frølich L, Andersen TS, Mørup M, Belfiore P, Gargiulo P, Ramon C, Vanhatalo S, Cho JH, Vorwerk J, Wolters CH, Knösche TR, Watanabe T, Kawabata Y, Ukegawa D, Kawabata S, Adachi Y, Sekihara K, Sekihara K, Nagarajan SS, Wagner S, Aydin U, Vorwerk J, Herrmann C, Burger M, Wolters C, Lucka F, Aydin U, Vorwerk J, Burger M, Wolters C, Bauer M, Trahms L, Sander T, Faber PL, Lehmann D, Gianotti LRR, Pascual-Marqui RD, Milz P, Kochi K, Kaneko S, Yamashita S, Yana K, Kalogianni K, Vardy AN, Schouten AC, van der Helm FCT, Sorrentino A, Luria G, Aramini R, Hunold A, Funke M, Eichardt R, Haueisen J, Gómez-Aguilar F, Vázquez-Olvera S, Cordova-Fraga T, Castro-López J, Hernández-Gonzalez MA, Solorio-Meza S, Sosa-Aquino M, Bernal-Alvarado JJ, Vargas-Luna M, Vorwerk J, Magyari L, Ludewig J, Oostenveld R, Wolters CH, Vorwerk J, Engwer C, Ludewig J, Wolters C, Sato K, Nishibe T, Furuya M, Yamashiro K, Yana K, Ono T, Puthanmadam Subramaniyam N, Hyttinen J, Lau S, Güllmar D, Flemming L, Haueisen J, Sonntag H, Vorwerk J, Wolters CH, Grasedyck L, Haueisen J, Maeß B, Freitag S, Graichen U, Fiedler P, Strohmeier D, Haueisen J, Stenroos M, Hauk O, Grigutsch M, Felber M, Maess B, Herrmann B, Strobbe G, van Mierlo P, Vandenberghe S, Strobbe G, Cárdenas-Peña D, Montes-Restrepo V, van Mierlo P, Castellanos-Dominguez G, Vandenberghe S, Lanfer B, Paul-Jordanov I, Scherg M, Wolters CH, Ito Y, Sato D, Kamada K, Kobayashi T, Dalal SS, Rampp S, Willomitzer F, Arold O, Fouladi-Movahed S, Häusler G, Stefan H, Ettl S, Zhang S, Zhang Y, Li H, Kong X, Montes-Restrepo V, Strobbe G, van Mierlo P, Vandenberghe S, Wong DDE, Bidet-Caulet A, Knight RT, Crone NE, Dalal SS, Birot G, Spinelli L, Vulliémoz S, Seeck M, Michel CM, Emory H, Wells C, Mizrahi N, Vogrin SJ, Lau S, Cook MJ, Karahanoglu FI, Grouiller F, Caballero-Gaudes C, Seeck M, Vulliemoz S, Van De Ville D, Spinelli L, Megevand P, Genetti M, Schaller K, Michel C, Vulliemoz S, Seeck M, Genetti M, Tyrand R, Grouiller F, Vulliemoz S, Spinelli L, Seeck M, Schaller K, Michel CM, Grouiller F, Heinzer S, Delattre B, Lazeyras F, Spinelli L, Pittau F, Seeck M, Ratib O, Vargas M, Garibotto V, Vulliemoz S, Vogrin SJ, Bailey CA, Kean M, Warren AE, Davidson A, Seal M, Harvey AS, Archer JS, Papadopoulou M, Leite M, van Mierlo P, Vonck K, Boon P, Friston K, Marinazzo D, Ramon C, Holmes M, Koessler L, Rikir E, Gavaret M, Bartolomei F, Vignal JP, Vespignani H, Maillard L, Centeno M, Perani S, Pier K, Lemieux L, Clayden J, Clark C, Pressler R, Cross H, Carmichael DW, Spring A, Bessemer R, Pittman D, Aghakhani Y, Federico P, Pittau F, Grouiller F, Vulliémoz S, Gotman J, Badier JM, Bénar CG, Bartolomei F, Cruto C, Chauvel P, Gavaret M, Brodbeck V, van Leeuwen T, Tagliazzuchi E, Melloni L, Laufs H, Griskova-Bulanova I, Dapsys K, Klein C, Hänggi J, Jäncke L, Ehinger BV, Fischer P, Gert AL, Kaufhold L, Weber F, Marchante Fernandez M, Pipa G, König P, Sekihara K, Hiyama E, Koga R, Iannilli E, Michel CM, Bartmuss AL, Gupta N, Hummel T, Boecker R, Holz N, Buchmann AF, Blomeyer D, Plichta MM, Wolf I, Baumeister S, Meyer-Lindenberg A, Banaschewski T, Brandeis D, Laucht M, Natahara S, Ueno M, Kobayashi T, Kottlow M, Bänninger A, Koenig T, Schwab S, Koenig T, Federspiel A, Dierks T, Jann K, Natsukawa H, Kobayashi T, Tüshaus L, Koenig T, Kottlow M, Achermann P, Wilson RS, Mayhew SD, Assecondi S, Arvanitis TN, Bagshaw AP, Darque A, Rihs TA, Grouiller F, Lazeyras F, Ha-Vinh Leuchter R, Caballero C, Michel CM, Hüppi PS, Hauser TU, Hunt LT, 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van Assche M, Goldstein R, van der Meulen M, Vuilleumier P, Richiardi J, Van De Ville D, Assal F, Wozniak-Kwasniewska A, Szekely D, Harquel S, Bougerol T, David O, Bracht T, Jones DK, Horn H, Müller TJ, Walther S, Sos P, Klirova M, Novak T, Brunovsky M, Horacek J, Bares M, Hoschl C C, Fellhauer I, Zöllner FG, Schröder J, Kong L, Essig M, Schad LR, Arrubla J, Neuner I, Hahn D, Boers F, Shah NJ, Neuner I, Arrubla J, Hahn D, Boers F, Jon Shah N, Suriya Prakash M, Sharma R, Kawaguchi H, Kobayashi T, Fiedler P, Griebel S, Biller S, Fonseca C, Vaz F, Zentner L, Zanow F, Haueisen J, Rochas V, Rihs T, Thut G, Rosenberg N, Landis T, Michel C, Moliadze V, Schmanke T, Lyzhko E, Bassüner S, Freitag C, Siniatchkin M, Thézé R, Guggisberg AG, Nahum L, Schnider A, Meier L, Friedrich H, Jann K, Landis B, Wiest R, Federspiel A, Strik W, Dierks T, Witte M, Kober SE, Neuper C, Wood G, König R, Matysiak A, Kordecki W, Sieluzycki C, Zacharias N, Heil P, Wyss C, Boers F, Arrubla J, Dammers J, Kawohl W, Neuner I, Shah NJ, Braboszcz C, Cahn RB, Levy J, Fernandez M, Delorme A, Rosas-Martinez L, Milne E, Zheng Y, Urakami Y, Kawamura K, Washizawa Y, Hiyoshi K, Cichocki A, Giroud N, Dellwo V, Meyer M, Rufener KS, Liem F, Dellwo V, Meyer M, Jones-Rounds JD, Raizada R, Staljanssens W, Strobbe G, van Mierlo P, Van Holen R, Vandenberghe S, Pefkou M, Becker R, Michel C, Hervais-Adelman A, He W, Brock J, Johnson B, Ohla K, Hitz K, Heekeren K, Obermann C, Huber T, Juckel G, Kawohl W, Gabriel D, Comte A, Henriques J, Magnin E, Grigoryeva L, Ortega JP, Haffen E, Moulin T, Pazart L, Aubry R, Kukleta M, Baris Turak B, Louvel J, Crespo-Garcia M, Cantero JL, Atienza M, Connell S, Kilborn K, Damborská A, Brázdil M, Rektor I, Kukleta M, Koberda JL, Bienkiewicz A, Koberda I, Koberda P, Moses A, Tomescu M, Rihs T, Britz J, Custo A, Grouiller F, Schneider M, Debbané M, Eliez S, Michel C, Wang GY, Kydd R, Wouldes TA, Jensen M, Russell BR, Dissanayaka N, Au T, Angwin A, O'Sullivan J, Byrne G, Silburn P, Marsh R, Mellic G, Copland D, Bänninger A, Kottlow M, Díaz Hernàndez L, Koenig T, Díaz Hernàndez L, Bänninger A, Koenig T, Hauser TU, Iannaccone R, Mathys C, Ball J, Drechsler R, Brandeis D, Walitza S, Brem S, Boeijinga PH, Pang EW, Valica T, Macdonald MJ, Oh A, Lerch JP, Anagnostou E, Di Lorenzo G, Pagani M, Monaco L, Daverio A, Verardo AR, Giannoudas I, La Porta P, Niolu C, Fernandez I, Siracusano A, Shimada T, Matsuda Y, Monkawa A, Monkawa T, Hashimoto R, Watanabe K, Kawasaki Y, Matsuda Y, Shimada T, Monkawa T, Monkawa A, Watanabe K, Kawasaki Y, Stegmayer K, Horn H, Federspiel A, Razavi N, Bracht T, Laimböck K, Strik W, Dierks T, Wiest R, Müller TJ, Walther S, Koorenhof LJ, Swithenby SJ, Martins-Mourao A, Rihs TA, Tomescu M, Song KW, Custo A, Knebel JF, Murray M, Eliez S, Michel CM, Volpe U, Merlotti E, Vignapiano A, Montefusco V, Plescia GM, Gallo O, Romano P, Mucci A, Galderisi S, Laimboeck K, Jann K, Walther S, Federspiel A, Wiest R, Strik W, Horn H. Abstracts of Presentations at the International Conference on Basic and Clinical Multimodal Imaging (BaCI), a Joint Conference of the International Society for Neuroimaging in Psychiatry (ISNIP), the International Society for Functional Source Imaging (ISFSI), the International Society for Bioelectromagnetism (ISBEM), the International Society for Brain Electromagnetic Topography (ISBET), and the EEG and Clinical Neuroscience Society (ECNS), in Geneva, Switzerland, September 5-8, 2013. Clin EEG Neurosci 2013; 44:1550059413507209. [PMID: 24368763 DOI: 10.1177/1550059413507209] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- B J He
- National Institutes of Health, Bethesda, MD, USA
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Nishimaru E, Ichikawa K, Hara T, Terakawa S, Yokomachi K, Fujioka C, Kiguchi M, Ishifuro M. [Novel method of noise power spectrum measurement for computed tomography images with adaptive iterative reconstruction method]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2012; 68:1637-43. [PMID: 23257594 DOI: 10.6009/jjrt.2012_jsrt_68.12.1637] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Adaptive iterative reconstruction techniques (IRs) can decrease image noise in computed tomography (CT) and are expected to contribute to reduction of the radiation dose. To evaluate the performance of IRs, the conventional two-dimensional (2D) noise power spectrum (NPS) is widely used. However, when an IR provides an NPS value drop at all spatial frequency (which is similar to NPS changes by dose increase), the conventional method cannot evaluate the correct noise property because the conventional method does not correspond to the volume data natures of CT images. The purpose of our study was to develop a new method for NPS measurements that can be adapted to IRs. Our method utilized thick multi-planar reconstruction (MPR) images. The thick images are generally made by averaging CT volume data in a direction perpendicular to a MPR plane (e.g. z-direction for axial MPR plane). By using this averaging technique as a cutter for 3D-NPS, we can obtain adequate 2D-extracted NPS (eNPS) from 3D NPS. We applied this method to IR images generated with adaptive iterative dose reduction 3D (AIDR-3D, Toshiba) to investigate the validity of our method. A water phantom with 24 cm-diameters was scanned at 120 kV and 200 mAs with a 320-row CT (Acquilion One, Toshiba). From the results of study, the adequate thickness of MPR images for eNPS was more than 25.0 mm. Our new NPS measurement method utilizing thick MPR images was accurate and effective for evaluating noise reduction effects of IRs.
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Fujioka C, Funama Y, Kiguchi M, Ishifuro M, Kihara Y, Nagata Y, Awai K. Coronary artery calcium scoring on different 64-detector scanners using a low-tube voltage (80 kVp). Acad Radiol 2012; 19:1402-7. [PMID: 22925933 DOI: 10.1016/j.acra.2012.07.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2012] [Revised: 06/05/2012] [Accepted: 07/07/2012] [Indexed: 12/22/2022]
Abstract
PURPOSE The aim of this study was to compare the calcium score and reproducibility of coronary artery calcium scores obtained on the four kinds of 64-detector computed tomography (CT) scanners using standard (120 kVp) and low tube voltage (80 kVp) scan techniques. MATERIALS AND METHODS We scanned 80 and 120 kVp on all scanners. We calculated Agatston, volume, and mass scores for coronary artery calcium scoring on each scanner and compared the coefficients of variation of the calcium scores to evaluate reproducibility of among CT scanners. RESULTS The averages of the total mean Agatston score, total mean volume score, and total mean mass score at 80 kVp/120 kVp were 798.9/683.8, and 627.2/567.3, and 157.1/156.7, respectively. The total mean mass score was almost constant irrespective of the tube voltage. The total mean coefficients of variation for the four CT scanners were lower at 80 than 120 kVp (4.1% vs. 10.2% [total mean Agatston score], 3.2% vs. 9.6% [total mean volume score], and 3.2% vs. 9.4% [total mean mass score]). CONCLUSION Use of the low tube voltage technique can reduce variations in the coronary artery calcium scores obtained on different CT scanners.
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Kiguchi M, Atsumori H, Fukasaku I, Kumagai Y, Funane T, Maki A, Kasai Y, Ninomiya A. Note: wearable near-infrared spectroscopy imager for haired region. Rev Sci Instrum 2012; 83:056101. [PMID: 22667665 DOI: 10.1063/1.4704456] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A wearable optical topography system was developed that is based on near-infrared spectroscopy (NIRS) for observing brain activity noninvasively including in regions covered by hair. An avalanche photo diode, high voltage dc-dc converter, and preamplifier were placed in an electrically shielded case to be safely mounted on the head. Rubber teeth and a glass rod were prepared to clear away hair and reach the scalp. These devices realized for the first time a wearable NIRS imager for any region of the cortex. The activity in the motor cortex during finger tapping was successfully observed.
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Affiliation(s)
- M Kiguchi
- Central Research Laboratory, Hitachi, Ltd., Hatoyama, Saitama 350-0395, Japan
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Takasu M, Tani C, Ishikawa M, Date S, Horiguchi J, Kiguchi M, Tamura A, Sakai A, Asaoku H, Nango N, Awai K. Multiple Myeloma: Microstructural Analysis of Lumbar Trabecular Bones in Patients without Visible Bone Lesions—Preliminary Results. Radiology 2011; 260:472-9. [DOI: 10.1148/radiol.11101746] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Horiguchi J, Kiura Y, Tanaka J, Fukuda H, Kiguchi M, Fujioka C, Kurisu K, Awai K. Feasibility of extended-coverage perfusion and dynamic computer tomography (CT) angiography using toggling-table technique on 64-slice CT. J Neuroradiol 2011; 38:156-60. [PMID: 21211838 DOI: 10.1016/j.neurad.2010.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Revised: 10/11/2010] [Accepted: 10/13/2010] [Indexed: 11/25/2022]
Abstract
PURPOSE The major drawbacks of brain computed tomography (CT) perfusion are limited coverage in the z-axis, radiation exposure and the use of contrast medium, all of which increase when CT angiography (CTA) is performed with double acquisitions. The purpose of this study was to investigate the feasibility of the 'toggling-table' technique using a 40-mm detector. MATERIALS AND METHODS The clinical usefulness of CT perfusion and 4D-CTA (time-resolved 3D-CTA), as well as the time taken and radiation exposure, were assessed in 14 non-ischemic patients clinically indicated for CT perfusion and CTA. RESULTS A perfusion map and 4D-CTA was successfully achieved in all patients. The total time needed for scanning and processing was approximately 30 min per examination. The 80-mm CT perfusion coverage and 4D-CTA images were advantageous for analyses of the anatomy and widely distributed lesions. The estimated effective radiation dose was 2.22 mSv, and the amount of contrast media was 40 mL. CONCLUSION The 'toggling-table' technique acts as a 'one-stop-shop' protocol for perfusion mapping and 4D-CTA over a wide area, following a single contrast injection and scan.
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Affiliation(s)
- Jun Horiguchi
- Department of Radiology, Hiroshima Kyoritsu Hospital, 2-19-6, Nakasu, Asaminami-ku, Hiroshima, 731-0121, Japan.
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Horiguchi J, Yamamoto H, Arie R, Kiguchi M, Fujioka C, Ohtaki M, Kihara Y, Awai K. Is it possible to predict heart rate and range during enhanced cardiac CT scan from previous non-enhanced cardiac CT? J Digit Imaging 2010; 24:688-93. [PMID: 20824301 DOI: 10.1007/s10278-010-9333-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The effect of heart rate and variation during cardiac computed tomography (CT) on the examination quality. The purpose of this study is to investigate whether it is possible to predict heart rate and range during enhanced cardiac computed CT scan from previous non-enhanced cardiac CT scan. Electrocardiograph (ECG) files from 112 patients on three types of cardiac 64-slice CT (non-enhanced, prospective ECG-triggered and retrospective ECG-gated enhanced scans) were recorded. The mean heart rate, range (defined as difference between maximal and minimal heart rates) and the range ratio (defined as maximal heart rate divided by minimal heart rate) during the scans were compared. Scan time was 4.8, 4.6, and 7.3 s on non-enhanced, prospective ECG-triggered and retrospective ECG-gated scans, respectively (p < 0.0001). The heart rates were not significantly different (60 ± 9 beats per minute (bpm), 60 ± 9 and 61 ± 10 bpm; p = 0.64). Heart rate on the enhanced scan markedly correlated with that of the non-enhanced scan (r = 0.78 and 0.74). In contrast, the ranges of heart rate were 2 ± 5, 4 ± 8, and 8 ± 21 bpm, with different range ratios (1.04, 1.07, and 1.14; p < 0.0001). Correlation of heart rate ranges between non-enhanced scan versus prospective ECG-triggered scan was low (r = 0.27) and that between non-enhanced scan versus retrospective ECG-gated scan negligible (r = -0.027).Heart rate on enhanced cardiac CT, in most cases, can be predicted from a non-enhanced scan. Heart rate range on enhanced cardiac CT, however, is hard to predict from the non-enhanced scan.
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Affiliation(s)
- Jun Horiguchi
- Department of Clinical Radiology, Hiroshima University Hospital, Minami-ku, Hiroshima, Japan.
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Fujii S, Yabe K, Kimura Y, Ito Y, Rokukawa M, Furukawa M, Ito K, Matsuura M, Kiguchi M. Syndactyly lethal: new mutation with multiple malformations occurring in Sprague Dawley rats. Congenit Anom (Kyoto) 2009; 49:262-8. [PMID: 20021486 DOI: 10.1111/j.1741-4520.2009.00244.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
We previously found newborns exhibiting syndactyly of both fore- and hindlimbs in a litter from a pair of Sprague Dawley rats. Continuous breeding of the parental animals yielded pups with the same anomaly in following litters, suggesting that the syndactyly was genetic in origin. In the present study, as all the syndactylous pups died on postnatal day 0, we conducted genetic analyses using 30 phenotypically normal female progeny and the sire. The females were subjected to caesarean section on day 20 of gestation and the fetuses were examined for the phenotypes. The results of the mating experiments suggest that the mutant phenotype is caused by a single autosomal recessive gene at a homozygous condition. As homozygous mutants are lethal at the neonatal stage, the mutant gene was named syndactyly lethal, gene symbol syl. The mutant rats have multiple abnormalities, such as syndactyly, micrognathia, fused/absent/small lung lobes, absent kidney and ureter, small spleen, small uterus, fused phalanges, sternoschisis, absent/detached rib, and splitting/fused/absent/small thoracic vertebra, some of which must be the cause of death on postnatal day 0. This mutant is considered to be useful for investigating the mechanisms and/or pathogenesis of syndactyly, as well as the accompanying malformations.
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Affiliation(s)
- Sakiko Fujii
- Safety Research Division, Safety Research Institute for Chemical Compounds, Co., Ltd., Sapporo, Japan.
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Horiguchi J, Fujioka C, Kiguchi M, Yamamoto H, Shen Y, Kihara Y. In vitro measurement of CT density and estimation of stenosis related to coronary soft plaque at 100 kV and 120 kV on ECG-triggered scan. Eur J Radiol 2009; 77:294-8. [PMID: 19716249 DOI: 10.1016/j.ejrad.2009.08.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Accepted: 08/03/2009] [Indexed: 11/27/2022]
Abstract
PURPOSE The purpose of the study was to compare 100 kV and 120 kV prospective electrocardiograph (ECG)-triggered axial coronary 64-detector CT angiography (64-MDCTA) in soft plaque diagnosis. MATERIALS AND METHODS Coronary artery models (n = 5) with artificial soft plaques (-32 HU to 53 HU at 120 kV) with three stenosis levels (25%, 50% and 75%) on a cardiac phantom (mimicking slim patient's environment) were scanned in heart rates of 55, 60 and 65 beats per minute (bpm). Four kinds of intracoronary enhancement (205 HU, 241 HU, 280 HU and 314 HU) were simulated. The soft plaque density and the measurement error of stenosis (in percentage), evaluated by two independent observers, were compared between 100 kV and 120 kV. The radiation dose was estimated. RESULTS Interobserver correlation of the measurement was excellent (density; r = 0.95 and stenosis measure; r = 0.97). Neither the density of soft plaque nor the measurement error of stenosis was different between 100 kV and 120 kV (p = 0.22 and 0.08). The estimated radiation doses were 2.0 mSv and 3.3 mSv (in 14 cm coverage) on 100 kV and 120 kV prospective ECG-triggered axial scans, respectively. CONCLUSION The 100 kV prospective ECG-triggered coronary MDCTA has comparable performance to 120 kV coronary CTA in terms of soft plaque densitometry and measurement of stenosis, with a reduced effective dose of 2 mSv.
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Affiliation(s)
- Jun Horiguchi
- Department of Clinical Radiology, Hiroshima University Hospital, 1-2-3 Kasumi-cho, Minami-ku, Hiroshima 734-8551, Japan.
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Horiguchi J, Matsuura N, Yamamoto H, Kiguchi M, Fujioka C, Kitagawa T, Ito K. Effect of heart rate and body mass index on the interscan and interobserver variability of coronary artery calcium scoring at prospective ECG-triggered 64-slice CT. Korean J Radiol 2009; 10:340-6. [PMID: 19568461 PMCID: PMC2702042 DOI: 10.3348/kjr.2009.10.4.340] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Accepted: 02/19/2009] [Indexed: 11/28/2022] Open
Abstract
Objective To test the effects of heart rate, body mass index (BMI) and noise level on interscan and interobserver variability of coronary artery calcium (CAC) scoring on a prospective electrocardiogram (ECG)-triggered 64-slice CT. Materials and Methods One hundred and ten patients (76 patients with CAC) were scanned twice on prospective ECG-triggered scans. The scan parameters included 120 kV, 82 mAs, a 2.5 mm thickness, and an acquisition center at 45% of the RR interval. The interscan and interobserver variability on the CAC scores (Agatston, volume, and mass) was calculated. The factors affecting the variability were determined by plotting it against heart rate, BMI, and noise level (defined as the standard deviation: SD). Results The estimated effective dose was 1.5 ± 0.2 mSv. The mean heart rate was 63 ± 12 bpm (range, 44-101 bpm). The patient BMIs were 24.5 ± 4.5 kg/m2 (range, 15.5-42.3 kg/m2). The mean and median interscan variabilities were 11% and 6%, respectively by volume, and 11% and 6%, respectively, by mass. Moreover, the mean and median of the algorithms were lower than the Agatston algorithm (16% and 9%, respectively). The mean and median interobserver variability was 10% and 4%, respectively (average of algorithms). The mean noise levels were 15 ± 4 Hounsfield unit (HU) (range, 8-25 HU). The interscan and interobserver variability was not correlated with heart rate, BMI, or noise level. Conclusion The interscan and interobserver variability of CAC on a prospective ECG-triggered 64-slice CT with high image quality and 45% of RR acquisition is not significantly affected by heart rate, BMI, or noise level. The volume or mass algorithms show reduced interscan variability compared to the Agatston scoring (p < 0.05).
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Affiliation(s)
- Jun Horiguchi
- Department of Clinical Radiology, Hiroshima University Hospital, Minami-ku, Hiroshima, Japan.
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Horiguchi J, Fujioka C, Kiguchi M, Yamamoto H, Kitagawa T, Kohno S, Ito K. Prospective ECG-triggered axial CT at 140-kV tube voltage improves coronary in-stent restenosis visibility at a lower radiation dose compared with conventional retrospective ECG-gated helical CT. Eur Radiol 2009; 19:2363-72. [DOI: 10.1007/s00330-009-1419-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2008] [Accepted: 03/19/2009] [Indexed: 12/01/2022]
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Horiguchi J, Matsuura N, Yamamoto H, Kiguchi M, Fujioka C, Kitagawa T, Kohno N, Ito K. Coronary artery calcium scoring on low-dose prospective electrocardiographically-triggered 64-slice CT. Acad Radiol 2009; 16:187-93. [PMID: 19124104 DOI: 10.1016/j.acra.2008.05.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2008] [Revised: 05/13/2008] [Accepted: 05/13/2008] [Indexed: 10/21/2022]
Abstract
RATIONALE AND OBJECTIVES The purpose of this prospective study was to assess image noise and variability in repeated coronary artery calcium (CAC) scoring on low-dose prospective electrocardiographically-triggered 64-slice multidetector computed tomography. MATERIALS AND METHODS Patients (n = 115) suspected of having coronary artery disease were scanned twice, using a tube current of 10 x body mass index mA. The standard deviation (SD) of the computed tomographic value in the ascending aorta and (mean + 2 x SD) were obtained. Repeated CAC scores (Agatston, volume, and mass) were measured by two observers, and the interscan and interobserver variability were determined. RESULTS The mean tube current used was 246 +/- 36 mA. The mean tube current-time product and mean estimated effective dose were 57 +/- 8 mA and 0.9 +/- 0.2 mSv, respectively. The SD and (mean + 2 x SD) computed tomographic values in the ascending aorta were 16 +/- 3 and 75 +/- 10 Hounsfield units, respectively. Repeated CAC scores were correlated (r(2) = 0.995-0.998). The interscan variability for observer 1 and observer 2, respectively, were 13% and 13% for Agatston score, 12% and 11% for volume, and 11% and 11% for mass. The interobserver variability for scan 1 and scan 2, respectively, were 3% and 3% for Agatston score, 5% and 3% for volume, and 3% and 3% for mass. CONCLUSION Low-dose prospective electrocardiographically-triggered 64-slice multidetector computed tomography shows low interscan and interobserver variability on CAC scoring while maintaining low image noise.
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Teragawa H, Ueda K, Okuhara K, Kuwashima R, Fukuda Y, Kiguchi M, Taniguchi K, Higashi Y, Oshima T, Yoshizumi M, Chayama K. Coronary vasospasm produces reversible perfusion defects observed during adenosine triphosphate stress myocardial single-photon emission computed tomography. Clin Cardiol 2008; 31:310-6. [PMID: 18636477 DOI: 10.1002/clc.20217] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Adenosine triphosphate stress thallium-201 single-photon emission computed tomography (ATP-SPECT) is useful for diagnosing coronary artery disease (CAD), although sometimes false positive results are observed. It has not been established whether a coronary spasm is responsible for the false positive findings during ATP-SPECT. HYPOTHESIS We investigated whether coronary spasm is one of the factors which produces reversible defects on ATP-SPECT. METHODS Eighty-six patients (mean age: 62 y; 58 men) who underwent both spasm-provocation testing by coronary angiography and ATP-SPECT, were selected for the study. Patients with coronary narrowing (>30%), myocardial infarction, or heart failure were excluded. Patients were divided into 2 groups based on whether the spasm-provocation test result was positive (vasospastic angina [VSA] group, n = 46) or negative (non-VSA group, n = 39). RESULTS The body mass index was lower in the VSA group than in the non-VSA group (p = 0.005). On ATP-SPECT imaging, any type of reversible defect was observed more frequently in the VSA group (68%) than in the non-VSA group (36%, p = 0.0027). Logistic regression analysis demonstrated that the presence of reversible defects was one of the factors accounting for the presence of coronary vasospasm (p = 0.0022, R2 = 0.172). CONCLUSIONS The findings suggest that reversible defects on ATP-SPECT imaging are frequently present in patients with coronary vasospasm. Coronary spasm may be considered as 1 of the factors, which produce reversible defects on ATP-SPECT, observed in patients with chest symptoms and angiographically normal coronary arteries.
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Affiliation(s)
- Hiroki Teragawa
- Department of Medicine and Molecular Science, Hiroshima University Hospital, Hiroshima, Japan.
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Hirai N, Horiguchi J, Fujioka C, Kiguchi M, Yamamoto H, Matsuura N, Kitagawa T, Teragawa H, Kohno N, Ito K. Prospective versus Retrospective ECG-gated 64-Detector Coronary CT Angiography: Assessment of Image Quality, Stenosis, and Radiation Dose. Radiology 2008; 248:424-30. [PMID: 18574140 DOI: 10.1148/radiol.2482071804] [Citation(s) in RCA: 252] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Nobuhiko Hirai
- Department of Clinical Radiology, Hiroshima University Hospital, Hiroshima, Japan
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Kiguchi M, Tal O, Wohlthat S, Pauly F, Krieger M, Djukic D, Cuevas JC, van Ruitenbeek JM. Highly conductive molecular junctions based on direct binding of benzene to platinum electrodes. Phys Rev Lett 2008; 101:046801. [PMID: 18764352 DOI: 10.1103/physrevlett.101.046801] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2008] [Indexed: 05/26/2023]
Abstract
Highly conductive molecular junctions were formed by direct binding of benzene molecules between two Pt electrodes. Measurements of conductance, isotopic shift in inelastic spectroscopy, and shot noise compared with calculations provide indications for a stable molecular junction where the benzene molecule is preserved intact and bonded to the Pt leads via carbon atoms. The junction has a conductance comparable to that for metallic atomic junctions (around 0.1-1G0), where the conductance and the number of transmission channels are controlled by the molecule's orientation at different interelectrode distances.
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Affiliation(s)
- M Kiguchi
- Kamerlingh Onnes Laboratory, Leiden University, Leiden, The Netherlands
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Kiguchi M, Sekiguchi N, Murakoshi K. In-situ preparation of a single molecular junction with mechanically controllable break junctions in vacuum. ACTA ACUST UNITED AC 2008. [DOI: 10.1088/1742-6596/100/5/052059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Kiguchi M, Kitagawa Y, Fujioka C, Ishifuro M, Yamaguchi T, Ikeda T, Furukawa T. [Evaluation of improvement of the detection of interstitial lung diseases by using the dual-energy subtraction radiography method of a flat-panel detector system]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2007; 63:1362-1369. [PMID: 18310996 DOI: 10.6009/jjrt.63.1362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We investigated and evaluated the detection of simulated lesions in various interstitial lung diseases using the dual-energy subtraction radiography method and flat-panel detector (FPD) images. We obtained a FPD system (GE Revolution XR/d), and employed dual-energy 60 kV and 130 kV exposure techniques. Three types of lung lesions, namely, micro-nodule, ground-glass, and honeycomb patterns were simulated with interstitial lung disease on a chest phantom. Chest images with and without simulated lesions were exposed and compared with standard images and subtraction images. We carried out evaluations with and without subtraction images and performed the analysis by using receiver operating characteristic (ROC) analysis of detection. Results showed that the detection of interstitial lung diseases was significantly improved by the use of subtraction images. The area under the ROC curve (AUC) values of micro-nodule images obtained with and without subtraction images were 0.768 and 0.963, ground-glass images 0.670 and 0.917, and honeycomb images 0.768 and 0.996, respectively. A significant difference of p<0.05 was accepted. The use of dual-energy subtraction radiography with a FPD improved diagnostic accuracy in detecting cases of multiple interstitial lung diseases and was considered useful.
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Affiliation(s)
- Masao Kiguchi
- Department of Radiology, Hiroshima University Hospital
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