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Yap LPP, Sani FM, Chung E, Gowdh NFM, Ng WL, Wong JHD. Customised weight-based volume contrast media protocol for multiphase abdominal computed tomography. Singapore Med J 2024:00077293-990000000-00085. [PMID: 38305361 DOI: 10.4103/singaporemedj.smj-2021-461] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 10/19/2022] [Indexed: 02/03/2024]
Abstract
INTRODUCTION Multiphase computed tomography (CT) using fixed volume contrast media may lead to high radiation exposure and toxicity in patients with low body weight. We evaluated a customised weight-based protocol for multiphase CT in terms of radiation exposure, image quality and cost savings. METHODS A total of 224 patients were recruited. An optimised CT protocol was applied using 100 kV and 1 mL/kg of contrast media dosing. The image quality and radiation dose exposure of this CT protocol were compared to those of a standard 120 kV, 80 mL fixed volume protocol. The radiation dose information and CT Hounsfield units were recorded. The signal-to-noise ratio, contrast-to-noise ratio (CNR) and figure of merit (FOM) were used as comparison metrics. The images were assessed for contrast opacification and visual quality by two radiologists. The renal function, contrast media volume and cost were also evaluated. RESULTS The median effective dose was lowered by 16% in the optimised protocol, while the arterial phase images achieved significantly higher CNR and FOM. The radiologists' evaluation showed more than 97% absolute agreement with no significant differences in image quality. No significant differences were found in the pre- and post-CT estimated glomerular filtration rate. However, contrast media usage was significantly reduced by 1,680 mL, with an overall cost savings of USD 421 in the optimised protocol. CONCLUSION The optimised weight-based protocol is cost-efficient and lowers radiation dose while maintaining overall contrast enhancement and image quality.
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Affiliation(s)
- Lilian Poh Poh Yap
- Department of Biomedical Imaging, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
- Department of Biomedical Imaging, Universiti Malaya Medical Centre, Lembah Pantai, Kuala Lumpur, Malaysia
| | - Fadhli Mohamed Sani
- Department of Biomedical Imaging, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
- Department of Biomedical Imaging, Universiti Malaya Medical Centre, Lembah Pantai, Kuala Lumpur, Malaysia
| | - Eric Chung
- Department of Biomedical Imaging, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
- Department of Biomedical Imaging, Universiti Malaya Medical Centre, Lembah Pantai, Kuala Lumpur, Malaysia
| | - Nadia Fareeda Muhammad Gowdh
- Department of Biomedical Imaging, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
- Department of Biomedical Imaging, Universiti Malaya Medical Centre, Lembah Pantai, Kuala Lumpur, Malaysia
| | - Wei Lin Ng
- Department of Biomedical Imaging, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
- Department of Biomedical Imaging, Universiti Malaya Medical Centre, Lembah Pantai, Kuala Lumpur, Malaysia
| | - Jeannie Hsiu Ding Wong
- Department of Biomedical Imaging, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
- Department of Biomedical Imaging, Universiti Malaya Medical Centre, Lembah Pantai, Kuala Lumpur, Malaysia
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Radaideh K, Al-radaideh A, Ramli RM, Saleh A, Alshayeb R. Establishment of national diagnostic dose reference levels (DRLs) for routine computed tomography examinations in Jordan. Polish Journal of Medical Physics and Engineering 2023; 29:26-34. [DOI: 10.2478/pjmpe-2023-0003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Abstract
Background: Dose reference levels (DRLs) are used as indicators as well as guidance for dose optimization and to ensure justification of appropriate dose for a given clinical indication. The main aims of this study were to establish local DRLs for each CT imaging protocol as a reference point to evaluate the radiation dose indices and to compare our DRLs with those established in other countries and against the internationally reported guidelines.
Materials and methods: 2000 CT dose reports of different adult imaging protocols from January 2021 until April 2022 were collected retrospectively at different hospitals in Jordan. Data were collected from CT scans that were performed using different types and models of CT scanners and included four adult non-enhanced, helical CT imaging protocols; Head, Chest, Abdomen-Pelvis, and Chest-Abdomen-Pelvis.
Results: The average doses of CTDIvol, DLP, and effective dose were (65.11 mGy, 1232.71 mGy·cm, 2.83 mSv) for the head scan, (16.6 mGy, 586.6 mGy·cm, 8.21 mSv) for the chest scan, (17.91 mGy, 929.9 mGy·cm, 13.9 mSv) for the abdomen-pelvis scan, and (19.3 mGy, 1152 mGy·cm, 17.25 mSv) for the chest-abdomen-pelvis scan. In comparison with results from different international studies, DLP values measured in the present study were lower for the chest-abdomen-pelvis and abdomen-pelvis CT scans, and higher for the head CT and chest CT scans.
Conclusions: It is very important that each country establishes its own DRLs and compares them with those reported by other countries, especially the developed ones. It is also important that these levels are regularly updated.
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Alashban Y, Shubayr N. Establishing diagnostic reference levels for CT examinations in the south region of Saudi Arabia. Radiat Phys Chem Oxf Engl 1993 2022; 201:110407. [DOI: 10.1016/j.radphyschem.2022.110407] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Jusoh II, Abdullah KA, Ali MH. DIAGNOSTIC REFERENCE LEVELS FOR COMMON CT EXAMINATIONS: RESULTS FROM A STATEWIDE DOSE SURVEY. Radiat Prot Dosimetry 2022; 198:1417-1423. [PMID: 36093894 DOI: 10.1093/rpd/ncac182] [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: 07/26/2021] [Revised: 08/09/2022] [Accepted: 08/17/2022] [Indexed: 06/15/2023]
Abstract
The aim of this study was to investigate the current radiation doses for CT examinations throughout a state in Malaysia and, based on this data, to propose local diagnostic reference levels (DRLs) for the most common CT examinations. A study was conducted in three of the four hospitals that have provided CT services throughout the state. A survey booklet was designed to facilitate collection of pertinent CT scan data. The following information were extracted and recorded for each study: tube voltage, tube current, number of scans phases, CT dose index volume (CTDIvol) and dose length product (DLP). Proposed local DRLs of CT brain and thorax were up to 12% lower than the current national DRLs. However, an increase of DLP (median value) for CT abdomen was also found as compared to the 75th percentile of national DRLs. Therefore, considerable optimisation should be made to achieve a better dose reduction.
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Affiliation(s)
- Irwan Iskandar Jusoh
- School of Medical Imaging, Faculty of Health Sciences, Universiti Sultan Zainal Abidin, Kuala Nerus, Terengganu 21300, Malaysia
| | - Kamarul Amin Abdullah
- School of Medical Imaging, Faculty of Health Sciences, Universiti Sultan Zainal Abidin, Kuala Nerus, Terengganu 21300, Malaysia
| | - Mohd Hanafi Ali
- Discipline of Medical Imaging Science, Sydney School of Health Sciences, Faculty of Medicine and Health, Level 7, University of Sydney, D18 Susan Wakil Health Building, Western Avenue, Camperdown, NSW 2006, Australia
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Karim M, Harun H, Kayun Z, Aljewaw O, Azizan S, Rafiz N, Muhammad N. Paediatric radiation dose and cancer risk associated with body effective diameter during CT thorax examination. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2021.109685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Harun H, Karim M, Abbas Z, Sabarudin A, Muniandy S, Razak H, Ng K. The influence of iterative reconstruction level on image quality and radiation dose in CT pulmonary angiography examinations. Radiat Phys Chem Oxf Engl 1993 2021; 178:108989. [DOI: 10.1016/j.radphyschem.2020.108989] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Harun HH, Abdul Karim MK, Abd Rahman MA, Abdul Razak HR, Che Isa IN, Harun F. Establishment of CTPA Local Diagnostic Reference Levels with Noise Magnitude as a Quality Indicator in a Tertiary Care Hospital. Diagnostics (Basel) 2020; 10:E680. [PMID: 32916913 DOI: 10.3390/diagnostics10090680] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/12/2020] [Accepted: 08/14/2020] [Indexed: 12/16/2022] Open
Abstract
This study aimed to establish the local diagnostic reference levels (LDRLs) of computed tomography pulmonary angiography (CTPA) examinations based on body size with regard to noise magnitude as a quality indicator. The records of 127 patients (55 males and 72 females) who had undergone CTPAs using a 128-slice CT scanner were retrieved. The dose information, scanning acquisition parameters, and patient demographics were recorded in standardized forms. The body size of patients was categorized into three groups based on their anteroposterior body length: P1 (14–19 cm), P2 (19–24 cm), and P3 (24–31 cm), and the radiation dose exposure was statistically compared. The image noise was determined quantitatively by measuring the standard deviation of the region of interest (ROI) at five different arteries—the ascending and descending aorta, pulmonary trunk, and the left and right main pulmonary arteries. We observed that the LDRL values were significantly different between body sizes (p < 0.05), and the median values of the CT dose index volume (CTDIvol) for P1, P2, and P3 were 6.13, 8.3, and 21.40 mGy, respectively. It was noted that the noise reference values were 23.78, 24.26, and 23.97 HU for P1, P2, and P3, respectively, which were not significantly different from each other (p > 0.05). The CTDIvol of 9 mGy and dose length product (DLP) of 329 mGy∙cm in this study were lower than those reported by other studies conducted elsewhere. This study successfully established the LDRLs of a local healthcare institution with the inclusion of the noise magnitude, which is comparable with other established references.
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Muhammad NA, Abdul Karim MK, Abu Hassan H, Ahmad Kamarudin M, Ding Wong JH, Ng KH. Diagnostic Reference Level of Radiation Dose and Image Quality among Paediatric CT Examinations in A Tertiary Hospital in Malaysia. Diagnostics (Basel) 2020; 10:E591. [PMID: 32823818 PMCID: PMC7460376 DOI: 10.3390/diagnostics10080591] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [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: 07/09/2020] [Revised: 07/22/2020] [Accepted: 07/22/2020] [Indexed: 01/27/2023] Open
Abstract
Pediatrics are more vulnerable to radiation and are prone to dose compared to adults, requiring more attention to computed tomography (CT) optimization. Hence, diagnostic reference levels (DRLs) have been implemented as part of optimization process in order to monitor CT dose and diagnostic quality. The noise index has recently been endorsed to be included as a part of CT optimization in the DRLs report. In this study, we have therefore set local DRLs for pediatric CT examination with a noise index as an indicator of image quality. One thousand one hundred and ninety-two (1192) paediatric patients undergoing CT brain, CT thorax and CT chest-abdomen-pelvis (CAP) examinations were analyzed retrospectively and categorized into four age groups; group 1 (0-1 year), group 2 (1-5 years), group 3 (5-10 years) and group 4 (10-15 years). For each group, data such as the volume-weighted CT dose index (CTDIvol), dose-length product (DLP) and the effective dose (E) were calculated and DRLs for each age group set at 50th percentile were determined. Both CT dose and image noise values between age groups have differed significantly with p-value < 0.05. The highest CTDIvol and DLP values in all age groups with the lowest noise index value reported in the 10-15 age group were found in CT brain examination. In conclusion, there was a significant variation in doses and noise intensity among children of different ages, and the need to change specific parameters to fit the clinical requirement.
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Affiliation(s)
- Nor Azura Muhammad
- Department of Physics, Faculty of Science, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (N.A.M.); (M.A.K.)
| | - Muhammad Khalis Abdul Karim
- Department of Physics, Faculty of Science, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (N.A.M.); (M.A.K.)
- Centre of Diagnostic Nuclear Imaging, Faculty of Medicine, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia
| | - Hasyma Abu Hassan
- Department of Imaging, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia;
| | - Mazliana Ahmad Kamarudin
- Department of Physics, Faculty of Science, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (N.A.M.); (M.A.K.)
| | - Jeannie Hsiu Ding Wong
- Department of Biomedical Imaging, University Malaya Medical Centre, Petaling Jaya 59100, Kuala Lumpur, Malaysia; (J.H.D.W.); (K.H.N.)
| | - Kwan Hoong Ng
- Department of Biomedical Imaging, University Malaya Medical Centre, Petaling Jaya 59100, Kuala Lumpur, Malaysia; (J.H.D.W.); (K.H.N.)
- Department of Medical Imaging and Radiological Sciences, College of Health Sciences, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
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Harun HH, Karim MKA, Abbas Z, Sabarudin A, Muniandy SC, Ibahim MJ. Effect of iterative reconstruction algorithm levels on noise index and figure-of-merit in CT pulmonary angiography examinations. J Xray Sci Technol 2020; 28:893-903. [PMID: 32741801 DOI: 10.3233/xst-200699] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
PURPOSE To evaluate the influence of iterative reconstruction (IR) levels on Computed Tomography (CT) image quality and to establish Figure of Merit (FOM) value for CT Pulmonary Angiography (CTPA) examinations. METHODS Images of 31 adult patients who underwent CTPA examinations in our institution from March to April 2019 were retrospectively collected. Other data, such as scanning parameters, radiation dose and body habitus information from the subjects were also recorded. Six different levels of IR were applied to the volume data of the subjects. Five circles of the region of interest (ROI) were drawn in five different arteries namely, pulmonary trunk, right pulmonary artery, left pulmonary artery, ascending aorta and descending aorta. The mean Signal-to-noise ratio (SNR) was obtained, and the FOM was calculated in a fraction of the SNR2 divided by volume-weighted CT dose index (CTDIvol) and SNR2 divided by the size-specific dose estimates (SSDE). RESULTS Overall, we observed that the mean value of CTDIvol and SSDE were 13.79±7.72 mGy and 17.25±8.92 mGy, respectively. Notably, SNR values significantly increase with increase of the IR level (p < 0.05). There are also significant differences (p < 0.05) in the FOM for both SNR2/SSDE and SNR2/CTDIvol attained in different IR levels. CONCLUSION We successfully evaluate the value of radiation dose and image quality performance and set up a figure of merit for both parameters to further verify scanning protocols by radiology personnel.
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Affiliation(s)
- H H Harun
- Department of Physics, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - M K A Karim
- Department of Physics, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Z Abbas
- Department of Physics, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - A Sabarudin
- Department of Diagnostic & Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysiainstitution>
| | - S C Muniandy
- Department of Radiology, Hospital Kuala Lumpur, Jalan Pahang, Kuala Lumpur, Malaysia
| | - M J Ibahim
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Universiti Teknologi MARA, Sungai Buloh, Selangor, Malaysia
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Karim MKA, Sabarudin A, Muhammad NA, Ng KH. A comparative study of radiation doses between phantom and patients via CT angiography of the intra-/extra-cranial, pulmonary, and abdominal/pelvic arteries. Radiol Phys Technol 2019; 12:374-381. [PMID: 31468370 DOI: 10.1007/s12194-019-00532-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [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: 02/18/2019] [Revised: 08/09/2019] [Accepted: 08/10/2019] [Indexed: 10/26/2022]
Abstract
This study aimed to evaluate effective dose and size-specific dose estimate (SSDE) of computed tomography angiography (CTA) examination using an anthropomorphic phantom. We included three CTA examination protocols to evaluate the intra- and extra-cranial arteries, pulmonary artery (CTPA), and abdominal vessels. Patient SSDEs were measured retrospectively to estimate patient dose, relative to the bodyweight of the patient and volume CT dose index (CTDIvol). Our findings revealed that the highest dose was absorbed by the left lobe of the thyroid gland during intra-/extra-cranial CTA and CTPA, that is, 14.11 ± 0.24 mGy and 16.20 ± 3.95 mGy, respectively. However, the highest absorbed dose in abdominal/pelvic CTA was the gonads (8.98 ± 0.30 mGy), while other radiosensitive organs in intra- and extra-cranial CTA, CTPA, and abdominal/pelvic CTA did not demonstrate significant differences between organs/structures with p value 0.88, 0.11, and 0.54, respectively. The estimated effective dose in intra-/extra-cranial CTA was lower in patients (0.80 ± 0.60 mSv) than in the phantom (0.83 mSv), but it was the opposite for CTPA, with the effective dose being higher in patients (7.54 ± 3.09 mSv) than in the phantom (6.68 mSv). Similar to the effective dose, only CTPA SSDEs were significantly higher in men than in women (19.74 ± 4.79 mGy versus 7.9 mGy). Effective dose and SSDE are clinically relevant parameters that can help estimate a more accurate patient dose based on a patient's size.
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Affiliation(s)
- M K A Karim
- Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
| | - A Sabarudin
- Programme of Diagnostic Imaging and Radiotherapy, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, 56000, Kuala Lumpur, Malaysia
| | - N A Muhammad
- Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
| | - K H Ng
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
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Lin HC, Lai TJ, Tseng HC, Wang CH, Tseng YL, Chen CY. Radiation doses with various body weights of phantoms in brain 128-slice MDCT examination. J Radiat Res 2019; 60:466-475. [PMID: 31197311 PMCID: PMC6640898 DOI: 10.1093/jrr/rrz029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 04/15/2019] [Indexed: 06/09/2023]
Abstract
The effective dose (HE) and organ or tissue equivalent dose (HT) for use in brain computed tomography (CT) examinations with various body weights were evaluated. Thermoluminescent dosimeters (TLD-100H) were inserted into Rando and five anthropomorphic phantoms. These phantoms were made of polymethylmethacrylate (PMMA), according to the specifications of ICRU 48, with masses from 10 to 90 kg. Brain CT examinations were conducted, scanning the maxillae from the external auditory meatus to the parietal bone using a 128-slice multi-detector CT (MDCT) scanner. To reduce errors, three independent trials were conducted. Calculated HE,TLD, based on the weighting factor recommended by ICRP 103, was 1.72 ± 0.28 mSv, which slightly exceeds the HE,DLP of 1.70 mSv, that was calculated from the dose-length product (DLP) of the Rando phantom. This experiment yielded HE,TLD values of ICRP 103 from the highest 1.85 ± 0.28 (90 kg) to the lowest 1.47 ± 0.22 (10 kg) mSv. HE,TLD (mSv) = 5.45×10-3 W(kg) + 1.361, with an R2 of 0.87667. Using the DLP protocol, HE,DLP was estimated from CTDIvol that was recorded directly from the console display of the CT unit and multiplied by the conversion coefficient (k) recommended by the ICRP 103. Finally, the experimental results obtained herein are compared with those in the literature. Physicians should choose and adjust protocols to prevent the exposure of patients to unnecessary radiation, satisfying the as low as reasonably achievable (ALARA) principle. These findings will be valuable to patients, physicians, radiologists and the public.
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Affiliation(s)
- Hung-Chih Lin
- Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan, Republic of China
- Department of Radiology, Lukang Christian Hospital of Changhua Christian, Medical Foundation, Lukang, Taiwan, Republic of China
| | - Te-Jen Lai
- Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan, Republic of China
- Department of Psychiatry, Chung Shan Medical University Hospital, Chung Shan Medical University, Taichung, Taiwan, Republic of China
| | - Hsien-Chun Tseng
- School of Medicine, Chung Shan Medical University, Taichung, Taiwan, Republic of China
- Department of Radiation Oncology, Chung Shan Medical University Hospital, Chung Shan Medical University, Taichung, Taiwan, Republic of China
| | - Ching-Hsiang Wang
- Department of Radiology, Lukang Christian Hospital of Changhua Christian, Medical Foundation, Lukang, Taiwan, Republic of China
| | - Yen-Ling Tseng
- Department of Radiology, Lukang Christian Hospital of Changhua Christian, Medical Foundation, Lukang, Taiwan, Republic of China
| | - Chien-Yi Chen
- Department of Radiation Oncology, Chung Shan Medical University Hospital, Chung Shan Medical University, Taichung, Taiwan, Republic of China
- Department of Medical Imaging and Radiological Sciences, Chung Shan Medical University, Taichung, Taiwan, Republic of China
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Khoramian D, Sistani S, Hejazi P. Establishment of diagnostic reference levels arising from common CT examinations in Semnan County, Iran. Polish Journal of Medical Physics and Engineering 2019; 25:51-5. [DOI: 10.2478/pjmpe-2019-0008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Objective: The literature has approved that the use of the concept of diagnostic reference level (DRL) as a part of an optimization process could help to reduce patient doses in diagnostic radiology comprising the Computed Tomography (CT) examinations. There are four public/governmental CT centers in the province (Semnan, Iran) and, to our knowledge, after about 12 years since the launch of the first CT scanner in the province there is no dosimetry information on those CT scanners. The aim of this study was to evaluate CT dose indices with the aim of the establishment of the DRL for head, chest, cervical spine, and abdomen-pelvis examinations.
Methods: Scan parameters of 381 patients were collected during two months from 4 CT scanners. The CT dose index (CTDI) was measured using a calibrated ionization chamber on two cylindrical poly methyl methacrylate (PMMA) phantoms. For each sequences, weighted CTDI (CTDIw), volumetric CTDI (CTDIv) and dose length product (DLP) were calculated. The 75th percentile was proposed as the criterion for DRL values.
Results: Proposed DRL (CTDIw, CTDIv, DLP) for the head, chest, cervical spine, and abdomen-pelvis were (46.1 mGy, 46.1 mGy, 723 mGy × cm), (13.8 mGy, 12.0 mGy, 377 mGy × cm), (40.0 mGy, 40.0 mGy, 572 mGy × cm) and (14.9 mGy, 12.1 mGy, 524 mGy × cm), respectively.
Conclusion: Comparison with the others results from the other countries indicates that the head, chest and abdomen-pelvis scans in our region are lower or in the range of the other studies investigated in terms of dose. In the case of cervical spine scanning it’s necessary to review and regulate scan protocols to reach acceptable dose levels.
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Isa INC, Rahmat SMS, Dom SM, Kayun Z, Karim MKA. The effects of mis-centering on radiation dose during CT head examination: A phantom study. J Xray Sci Technol 2019; 27:631-639. [PMID: 31205011 DOI: 10.3233/xst-190491] [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] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
There are several factors that may contribute to the increase in radiation dose of CT including the use of unoptimized protocols and improper scanning technique. In this study, we aim to determine significant impact on radiation dose as a result of mis-centering during CT head examination. The scanning was performed by using Toshiba Aquilion 64 slices multi-detector CT (MDCT) scanner and dose were measured by using calibrated ionization chamber. Two scanning protocols of routine CT head; 120 kVp/ 180 mAs and 100 kVp/ 142 mAs were used represent standard and low dose, respectively. As reference measurement, the dose was first measured on standard cylindrical polymethyl methacrylate (PMMA) phantom that positioned at 104 cm from the floor (reference isocenter). The positions then were varied to simulate mis-centering by 5 cm from isocenter, superiorly and inferiorly at 109 cm, 114 cm, 119 cm, 124 cm and 99 cm, 94 cm, 89 cm, 84 cm, respectively. Scanning parameter and dose information from the console were recorded for the radiation effective dose (E) measurement. The highest mean CTDIvol value for MCS and MCI were 105.06 mGy (at +10 cm) and 105.51 mGy (at - 10 cm), respectively which differed significantly (p < 0.05) as compared to the isocenter. There were large significant different (p < 0.05) of mean Dose Length Product (DLP) recorded between isocenter to the MCS (85.8 mGy.cm) and MCI (93.1 mGy.cm). As the low dose protocol implemented, the volume CTDI (CTDIvol) were significantly increase (p < 0.05) for MCS (at +10 cm) and MCI (at - 10 cm) when compared to the isocenter. The phantom study revealed a noticeable different in radiation dose between isocenter and experimental groups due to degradation of the bowtie filter performance. It is anticipated that these noteworthy findings may emphasize the importance of accurate patient centering at the isocenter of CT gantry, so that CT optimization practice can be achieved.
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Affiliation(s)
- I N C Isa
- Diagnostic Imaging & Radiotherapy Program, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - S M S Rahmat
- Department of Radiology, National Cancer Institute, Putrajaya, Malaysia
- Faculty of Health Sciences, Universiti Teknologi MARA, Puncak Alam, Selangor, Malaysia
| | - S M Dom
- Faculty of Health Sciences, Universiti Teknologi MARA, Puncak Alam, Selangor, Malaysia
| | - Z Kayun
- Department of Physics, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - M K A Karim
- Department of Physics, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
- Center for Diagnostic Nuclear Imaging, Faculty of Medicine, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
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Karim MKA, Rahim NA, Matsubara K, Hashim S, Mhareb MHA, Musa Y. The effectiveness of bismuth breast shielding with protocol optimization in CT Thorax examination. J Xray Sci Technol 2019; 27:139-147. [PMID: 30584178 DOI: 10.3233/xst-180397] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
BACKGROUND Numerous techniques had been proposed to reduce radiation exposure in computed tomography (CT) including the use of radiation shielding. OBJECTIVE This study aims to evaluate efficacy of using a bismuth breast shield and optimized scanning parameter to reduce breast absorbed doses from CT thorax examination. METHODS Five protocols comprising the standard CT thorax clinical protocol (CP1) and four modified protocols (CP2 to CP5) were applied in anthropomorphic phantom scans. The phantom was configured as a female by placing a breast component on the chest. The breast component was divided into four quadrants, where 2 thermoluminescence dosimeters (TLD-100) were inserted into each quadrant to measure the absorbed dose. The bismuth shield was placed over the breast component during CP4 and CP5 scans. RESULTS The pattern of absorbed doses in each breast and quadrant were approximately the same for all protocols, where the 4th quadrant > 3rd quadrant > 2nd quadrant > 1st quadrant. The mean absorbed dose value in CP3 was reduced to almost 34% of CP1's mean absorbed dose. It was reduced even lower to 15% of CP1's mean absorbed dose when the breast shield was used in CP5. CONCLUSION This study showed that CT radiation exposure on the breast could be reduced by using a bismuth shield and low tube potential protocol without compromising the image quality.
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Affiliation(s)
- M K A Karim
- Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - N A Rahim
- Department of Radiology, National Cancer Institute, Precint 7, 62250 Putrajaya, Malaysia
| | - K Matsubara
- Department of Quantum Medical Technology, Faculty of Health Sciences, Kanazawa University, Japan
| | - S Hashim
- Department of Physics, Faculty of Science, Universiti Teknologi Malaysia Johor Baru, Malaysia
| | - M H A Mhareb
- Department of Physics, College of Science, Imam Abdurrahman Bin Faisal University, Saudi Arabia, City Dammam, Saudi Arabia
| | - Y Musa
- Department of Physics, Faculty of Science, Universiti Teknologi Malaysia Johor Baru, Malaysia
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Khoramian D, Sistani S. Estimation and comparison of the radiation effective dose during coronary computed tomography angiography examinations on single-source 64-MDCT and dual-source 128-MDCT. J Radiol Prot 2017; 37:826-836. [PMID: 28910264 DOI: 10.1088/1361-6498/aa823f] [Citation(s) in RCA: 5] [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] [Indexed: 06/07/2023]
Abstract
GOAL To estimate and compare the radiation dose associated with coronary computed tomography angiography (CCTA) examinations on two multi-detector CT scanners (MDCT), 64-MDCT and 128-MDCT, in daily practice. METHODS Scan parameters of 90 patients undergoing retrospective electrocardiographic gating spiral CCTA exam were recorded during a period on a single-source 64-MDCT and a dual-source 128-MDCT, and average scan parameters were derived that were used for dosimetry. The computed tomography dose index (CTDI) with a pencil ionisation chamber and polymethyl methacrylate body phantom with diameter of 32 cm was measured on both scanners. The dose-length product (DLP) was calculated and the DLP to effective dose conversion factor (for chest scan at 120 kV of 0.014 mSv mGy-1 cm-1) was used to estimate effective dose (ED). RESULTS Patients' heart rate, scan length, pitch factor, CTDIv, DLP and ED for 128-MDCT were 64 (5) (beats min-1), 161 (10) (mm), 0.26, 47 (12) (mGy), 769 (212) (mGy cm) and 10.3 (3.1) (mSv), respectively [mean (one standard deviation)]. Patients' heart rate, scan length, pitch factor, CTDIv, DLP and ED for 64-MDCT were 60 (7) (beats min-1), 172 (14) (mm), 0.2, 60 (6) (mGy), 1068 (98) (mGy cm) and 14.9 (1.4) (mSv), respectively. CONCLUSION Our results indicated that the CTDIv, DLP and the effective dose with 128-MDCT is significantly lower than with 64-MDCT (p < 0.05). As differences between the exposure parameter mAs on two CT scanners was not significant (p > 0.05) and the kV was constant for both scanners (120 kV), the differences resulted from a shorter scan length on the 128-MDCT and use of a higher pitch factor (0.26 and 0.2 in the 128-MDCT and 64-MDCT, respectively). Comparison with other published studies confirms the findings and indicates methods for reducing patient dose.
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Yeh DM, Tsai HY, Tyan YS, Chang YC, Pan LK, Chen TR. The Population Effective Dose of Medical Computed Tomography Examinations in Taiwan for 2013. PLoS One 2016; 11:e0165526. [PMID: 27788231 PMCID: PMC5082950 DOI: 10.1371/journal.pone.0165526] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 10/13/2016] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To evaluate the annual effective dose per capita attributed to computed tomography (CT) examinations in 2013 and to predict the population effective dose from 2000 to 2013 in Taiwan. METHODS A CT examination database collected from 30 hospitals was divided into 22 procedures and classified into six regions: head, neck, chest, abdomen, pelvis, and other, respectively. The effective doses in different regions were evaluated by dose-length product (DLP) multiplied by conversion factors. RESULTS The CT scan dose parameters were collected from 4,407 patients. For the six scanned regions, the percentages of patients scanned were: head (39.8%), neck (3.9%), chest (23.3%), abdomen (26.7%), pelvis (4.8%), and other (1.6%), respectively. The DLPs per patient (mGy·cm/patient) were head (1,071±225), neck (1,103±615), chest (724±509), abdomen (1,315±550), pelvis (1,231±620) and other (1,407±937), respectively. The number of CT examinations increased rapidly, with an average annual growth rate of 7.6%. The number of CT examinations in 2013 was 2.6 times that in 2000. The population effective dose was 0.30 mSv per capita in 2000 and increased to 0.74 mSv per capita in 2013, with an annual growth rate of 7.2%. The growth trend indicates that the effective dose will continue to rise in Taiwan. CONCLUSION Some strategies should be applied to cope with this growth. Defining the CT dose reference level stipulated in official recommendations and encouraging the use of iterative reconstruction imaging instead of filtered back-projection imaging could be a useful method for optimizing the effective dose and image quality.
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Affiliation(s)
- Da-Ming Yeh
- Department of Medical Image, Chung Shan Medical University Hospital, Taichung, Taiwan
- Department of Medical Imaging and Radiological Sciences, Chung Shan Medical University, Taichung, Taiwan
- Department of Medical Imaging and Radiological Sciences, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Hui-Yu Tsai
- Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Medical Physics Research Center, Institute for Radiological Research, Chang Gung University / Chang Gung Memorial Hospital, Taoyuan, Taiwan
- Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital Linkou, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yen-Sheng Tyan
- Department of Medical Image, Chung Shan Medical University Hospital, Taichung, Taiwan
- School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Yu-Cheng Chang
- Department of Medical Image, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Lung-Kwang Pan
- Department of Medical Imaging and Radiological Sciences, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Tou-Rong Chen
- Department of Medical Image, Chung Shan Medical University Hospital, Taichung, Taiwan
- Department of Medical Imaging and Radiological Sciences, Chung Shan Medical University, Taichung, Taiwan
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