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Sakai Y, Monzen H, Takei Y, Kosaka H, Nakamura K, Yanagi Y, Wakabayashi K, Hosono M, Nishimura Y. Evaluation of In-room Volumetric Imaging Doses for Image-guided Radiotherapy: A Multi-institutional Study. J Med Phys 2023; 48:189-194. [PMID: 37576099 PMCID: PMC10419753 DOI: 10.4103/jmp.jmp_109_22] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 05/10/2023] [Accepted: 05/22/2023] [Indexed: 08/15/2023] Open
Abstract
Aims We investigated imaging dose and noise under clinical scan conditions at multiple institutions using a simple and unified method, and demonstrated the need for diagnostic reference levels in image-guided radiotherapy (IGRT). Materials and Methods Nine cone-beam and helical computed tomography (CT) scanners (Varian, Elekta, Accuray Inc., and BrainLAB) from seven institutions were investigated in this study. The weighted cone-beam dose index (CBDIw) was calculated for head and pelvic protocols using a 100 mm pencil chamber under the conditions used in actual clinical practice at each institution. Cone-beam CT image noise was evaluated using polymethylmethacrylate head and body phantoms with diameters of 16 and 32 cm, respectively. Results For head and pelvic protocols, CBDIw values ranged from 0.94-6.59 and 1.47-20.9 mGy, respectively. Similarly, standard deviation (SD) values ranged from 9.3-34.0 and 26.9-97.4 HU, respectively. The SD values tended to increase with decreasing imaging dose (r = -0.33 and -0.61 for the head and pelvic protocols, respectively). Conclusions Among the nine machines, the imaging dose for high imaging dose institutions was approximately 20 mGy to the pelvic phantom, and there was a 14-fold difference in dose compared with the other institutions. These results suggest the need to establish DRLs for IGRT to guide clinical decision-making.
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Affiliation(s)
- Yusuke Sakai
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Hyogo, Japan
- Department of Radiotherapy, Takarazuka City Hospital, Takarazuka, Hyogo, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Hyogo, Japan
| | - Yoshiki Takei
- Department of Radiology, Kindai University Nara Hospital, Ikoma, Nara, Japan
| | - Hiroyuki Kosaka
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Hyogo, Japan
| | - Kenji Nakamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Hyogo, Japan
| | - Yuya Yanagi
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Hyogo, Japan
| | - Kazuki Wakabayashi
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Hyogo, Japan
| | - Makoto Hosono
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, Japan
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Cumur C, Fujibuchi T, Hamada K. Dose estimation for cone-beam computed tomography in image-guided radiation therapy using mesh-type reference computational phantoms and assuming head and neck cancer. J Radiol Prot 2022; 42:021533. [PMID: 35705020 DOI: 10.1088/1361-6498/ac7914] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 06/15/2022] [Indexed: 06/15/2023]
Abstract
This study aimed to estimate the additional dose the cone-beam computed tomography (CBCT) system integrated into the Varian TrueBeam linear accelerator delivers to a patient with head and neck cancer using mesh-type International Commission on Radiological Protection reference computational phantoms. In the first part, for use as a benchmark for the accuracy of the Monte Carlo geometry of CBCT, Particle and Heavy Ion Transport code System (PHITS) calculations were confirmed against measured lateral and depth dose profiles using a computed tomography dose profiler. After obtaining good agreement, organ dose calculations were performed by PHITS using mesh-type reference computational phantom (MRCP) and irradiating the neck region; the effective dose was calculated utilising absorbed organ doses and tissue weighting factors for male and female MRCP. Substantially, it has been found that the effective doses for male and female MRCP are 0.81 and 1.06 mSv, respectively. As this study aimed to assess the imaging dose from the CBCT system used in image-guided radiation therapy, it is required to take into account this dose in terms of both the target organ and surrounding tissues. Although the absorbed organ dose values and effective dose values obtained for both MRCP males and females were small, attention should be paid to the additional dose resulting from CBCT. This study can create awareness on the importance of doses arising from imaging techniques, especially CBCT.
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Affiliation(s)
- Ceyda Cumur
- Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka City 812-8582, Japan
| | - Toshioh Fujibuchi
- Department of Health Sciences, Faculty of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka City 812-8582, Japan
| | - Keisuke Hamada
- Department of Radiological Technology, National Hospital Organisation Kyushu Cancer Center, 3-1-1, Notame Minami-ku, Fukuoka City 811-1395, Japan
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Sitathanee C, Tangboonduangjit P, Dhanachai M, Suntiwong S, Yongvithisatid P, Rutchantuk S, Changkaew P, Watjiranon R, Khachonkham S, Boonkitticharoen V. Secondary cancer risk from modern external-beam radiotherapy of prostate cancer patients: Impact of fractionation and dose distribution. J Radiat Res 2021; 62:707-717. [PMID: 33993271 PMCID: PMC8273793 DOI: 10.1093/jrr/rrab038] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/10/2021] [Indexed: 06/12/2023]
Abstract
Modern radiotherapy (RT) uses altered fractionation, long beam-on time and image-guided procedure. This study aimed to compare secondary cancer risk (SCR) associated with primary field, scatter/leakage radiations and image-guided procedure in prostate treatment using intensity-modulated RT (IMRT), CyberKnife stereotactic body RT (CK-SBRT) in relative to 3-dimensional conformal RT (3D-CRT). Prostate plans were generated for 3D-CRT, IMRT (39 fractions of 2 Gy), and CK-SBRT (five fractions of 7.25 Gy). Excess absolute risk (EAR) was calculated for organs in the primary field using Schneider's mechanistic model and concept of organ equivalent dose (OED) to account for dose inhomogeneity. Doses from image-guided procedure and scatter/leakage radiations were determined by phantom measurements. The results showed that hypofractionation relative to conventional fractionation yielded lower SCR for organs in primary field (p ≤ 0.0001). SCR was further modulated by dose-volume distribution. For organs near the field edge, like the rectum and pelvic bone, CK-SBRT plan rendered better risk profiles than IMRT and 3D-CRT because of the absence of volume peak in high dose region (relative risk [RR]: 0.65, 0.22, respectively, p ≤ 0.0004). CK-SBRT and IMRT generated more scatter/leakage and imaging doses than 3D-CRT (p ≤ 0.0002). But primary field was the major contributor to SCR. EAR estimates (risk contributions, primary field: scatter/leakage radiations: imaging procedure) were 7.1 excess cases per 104 person-year (PY; 3.64:2.25:1) for CK-SBRT, 9.93 (7.32:2.33:1) for IMRT and 8.24 (15.99:2.35:1) for 3D-CRT (p ≤ 0.0002). We conclude that modern RT added more but small SCR from scatter/leakage and imaging doses. The primary field is a major contributor of risk which can be mitigated by the use of hypofractionation.
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Affiliation(s)
- Chomporn Sitathanee
- Corresponding author. Department of Diagnostic and Therapeutic Radiology, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand, E-mail:
| | - Puangpen Tangboonduangjit
- Department of Diagnostic and Therapeutic Radiology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Mantana Dhanachai
- Department of Diagnostic and Therapeutic Radiology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Sawanee Suntiwong
- Department of Diagnostic and Therapeutic Radiology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Pornpan Yongvithisatid
- Department of Diagnostic and Therapeutic Radiology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Sukanya Rutchantuk
- Department of Diagnostic and Therapeutic Radiology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Pimolpun Changkaew
- Department of Diagnostic and Therapeutic Radiology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Rattana Watjiranon
- Department of Diagnostic and Therapeutic Radiology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Suphalak Khachonkham
- Department of Diagnostic and Therapeutic Radiology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Vipa Boonkitticharoen
- Department of Diagnostic and Therapeutic Radiology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
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Duan YH, Gu HL, Yang XH, Chen H, Wang H, Shao Y, Li XY, Feng AH, Ying YC, Fu XL, Ma K, Zhou T, Xu ZY. Evaluation of IGRT-Induced Imaging Doses and Secondary Cancer Risk for SBRT Early Lung Cancer Patients In Silico Study. Technol Cancer Res Treat 2021; 20:15330338211016472. [PMID: 34184567 PMCID: PMC8251513 DOI: 10.1177/15330338211016472] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Objectives: This study performed dosimetry studies and secondary cancer risk assessments on using electronic portal imaging device (EPID) and cone beam computed tomography (CBCT) as image guided tools for the early lung cancer patients treated with SBRT. Methods: The imaging doses from MV-EPID and kV-CBCT of the Edge accelerator were retrospectively added to sixty-one SBRT treatment plans of early lung cancer patients. The MV-EPID imaging dose (6MV Photon beam) was calculated in Pinnacle TPS, and the kV-CBCT imaging dose was simulated and calculated by modeling of the kV energy beam in TPS using Pinnacle automatic modeling program. Three types of plans, namely PlanEPID, PlanCBCT and Planorigin, were generated with incorporating doses of EPID, CBCT and no imaging, respectively, for analysis. The effects of imaging doses on dose-volume-histogram (DVH) and plan quality were analyzed, and the excess absolute risk (EAR) of secondary cancer for ipsilateral lung was evaluated. Results: The regions that received less than 50 cGy were significantly impacted by the imaging doses, while the isodose lines greater than 1000 cGy were barely changed. The DVH values of ipsilateral lung increased the most in PlanEPID, followed by PlanCBCT. Compared to Planorigin on the average, the estimated EAR of ipsilateral lung in PlanEPID increased by 3.43%, while the corresponding EAR increase in PlanCBCT was much smaller (about 0.4%). Considering only the contribution of the imaging dose, the EAR values for the ipsilateral lung due to the MV-EPID dose in 5 years,10 years and 15 years were 1.49 cases, 2.09 cases and 2.88 cases per 104PY respectively, and those due to the kV-CBCT dose were about 9 times lower, correspondingly. Conclusions: The imaging doses produced by MV-EPID and kV-CBCT had little effects on the target dose coverage. The secondary cancer risk caused by MV-EPID dose is more than 8.5 times that of kV-CBCT.
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Affiliation(s)
- Yan-Hua Duan
- Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Heng-Le Gu
- Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Xiao-Hui Yang
- Department of Engineering, Beijing Jingfang Technologies Co. Ltd, Beijing, China
| | - Hua Chen
- Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Hao Wang
- Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yan Shao
- Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Xiao-Yang Li
- Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Ai-Hui Feng
- Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yan-Chen Ying
- Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Xiao-Long Fu
- Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Kui Ma
- Clinical helpdesk, Varian Medical Systems, China
| | - Tao Zhou
- Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Shandong, China
| | - Zhi-Yong Xu
- Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
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Abstract
Purpose Cone beam computed tomography (CBCT) is often used for patient setup based solely on bony anatomy. The goal of this work was to evaluate whether CBCT dose can be lowered to the level of kV image pair doses when used for bony anatomy‐based IGRT without compromising positioning accuracy. Methods An anthropomorphic phantom was CT scanned in the head, head and neck, chest, and pelvis regions and setup on the linear accelerator couch with the isocenter near the planned location. Cone beam computed tomographies were performed with the standard “full dose” protocol supplied by the linac vendor. With sequentially lowering the dose, three‐dimensional (3D) matching was performed for each without shifting the couch. The standard kV image pair protocol for each site was also used to image the phantoms. For all studies, six degrees of freedom was included in the 2D or 3D matching to the extent they could be employed. Imaging doses were determined in air at isocenter following the TG‐61 formalism. Results Cone beam computed tomography dose was reduced by 81–98% of the standard CBCT protocol to nearly that of the standard kV image pair dose for each site. Relative to the standard CBCT shift values, translational shifts were within 0.3 and 1.6 mm for all sites, for the reduced dose CBCT and kV image pair, respectively. Rotational shifts were within 0.2 degree and 0.7 degrees for all sites, for the reduced dose CBCTs and kV image pair, respectively. Conclusion For bony anatomy‐based image guidance, CBCT dose can be reduced to a value similar to that of a kV image pair with similar or better patient positioning accuracy than kV image pair alignment. Where rotations are important to correct, CBCT will be superior to orthogonal kV imaging without significantly increased imaging dose. This is especially important for image guidance for pediatric patient treatments.
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Affiliation(s)
- Arthur J Olch
- Radiation Oncology Program, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - Parham Alaei
- Department of Radiation Oncology, University of Minnesota, Minneapolis, MN, USA
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6
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Okamoto H, Kito S, Tohyama N, Yonai S, Kawamorita R, Nakamura M, Fujimoto T, Tani S, Yomoda A, Isobe T, Furukawa H, Kotaka K, Itami J, Ikushima H, Dokiya T, Shioyama Y. Radiation protection in radiological imaging: a survey of imaging modalities used in Japanese institutions for verifying applicator placements in high-dose-rate brachytherapy. J Radiat Res 2021; 62:58-66. [PMID: 33074329 PMCID: PMC7779356 DOI: 10.1093/jrr/rraa088] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/02/2020] [Accepted: 06/23/2020] [Indexed: 06/11/2023]
Abstract
Institutional imaging protocols for the verification of brachytherapy applicator placements were investigated in a survey study of domestic radiotherapy institutions. The survey form designed by a free on-line survey system was distributed via the mailing-list system of the Japanese Society for Radiation Oncology. Survey data of 75 institutions between August 2019 and October 2019 were collected. The imaging modalities used were dependent on resources available to the institutions. The displacement of a brachytherapy applicator results in significant dosimetric impact. It is essential to verify applicator placements using imaging modalities before treatment. Various imaging modalities used in institutions included a computed tomography (CT) scanner, an angiography X-ray system, a multi-purpose X-ray system and a radiotherapy simulator. The median total exposure time in overall treatment sessions was $\le$75 s for gynecological and prostate cancers. Some institutions used fluoroscopy to monitor the brachytherapy source movement. Institutional countermeasures for reducing unwanted imaging dose included minimizing the image area, changing the imaging orientation, reducing the imaging frequency and optimizing the imaging conditions. It is worth noting that half of the institutions did not confirm imaging dose regularly. This study reported on the usage of imaging modalities for brachytherapy in Japan. More caution should be applied with interstitial brachytherapy with many catheters that can lead to potentially substantial increments in imaging doses for monitoring the actual brachytherapy source using fluoroscopy. It is necessary to share imaging techniques, standardize imaging protocols and quality assurance/quality control among institutions, and imaging dose guidelines for optimization of imaging doses delivered in radiotherapy should be developed.
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Affiliation(s)
- Hiroyuki Okamoto
- Department of Medical Physics, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku Tokyo, 104-0045, Japan
| | - Satoshi Kito
- Department of Radiotherapy, Tokyo Metropolitan Bokutoh Hospital, 4-23-15 Koutoubashi, Sumida-ku Tokyo, 130-8575, Japan
- Department of Radiotherapy, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 3-18 Honkomagome, Bunkyo-ku Tokyo, 113-8677, Japan
- Division of Medical Physics, Department of Information Technology and Medical Engineering, Human Health Sciences, Graduate School of Medicine, Kyoto University 53 Shogoin-Kawaharacho, Sakyo-ku Kyoto, Kyoto, 606-8507, Japan
| | - Naoki Tohyama
- Division ofMedical Physics,Tokyo Bay Advanced Imaging & Radiation Oncology Makuhari Clinic, 1-17 Toyosuna, Mihama-ku Chiba, Chiba, 261-0024, Japan
| | - Shunsuke Yonai
- Department of Accelerator and Medical Physics, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku Chiba, Chiba, 263-8555, Japan
| | - Ryu Kawamorita
- Department of Radiation Oncology, Tane General Hospital, 1-12-21 Kujyouminami, Nishi-ku Osaka, Osaka, 550-0025, Japan
| | - Masaru Nakamura
- Department of Radiology, Aichi Medical University Hospital, 1-1 Yazakokarimata, Nagakute, Aichi, 480-1195, Japan
| | - Takahiro Fujimoto
- Division of Clinical Radiology Service, Kyoto University Hospital, 54 Shogoin-Kawaharacho, Sakyo-ku Kyoto, Kyoto, 606-8507, Japan
| | - Syoji Tani
- Department of Medical Technology, Osaka General Medical Center, 3-1-56 Bandaihigashi, Sumiyoshi-ku Osaka, Osaka, 558-8558, Japan
| | - Akihiro Yomoda
- Technical Section, Medical Equipment Business, Chiyoda Technol Corporation, 1-7 Yushima, Bunkyo-ku Tokyo, 101-0021, Japan
| | - Toru Isobe
- Oncology Product Marketing Manager, Elekta K.K, 3-9-1 Shibaura, Minato-ku Tokyo, 108-0023, Japan
| | - Hiroshi Furukawa
- Japan Medical Imaging and Radiological Systems Industries Association, 2-2-23 Koraku, Bunkyo-ku, Tokyo, 112-0004, Japan
| | - Kikuo Kotaka
- Nuclear Safety Technology Center, 5-1-3-101 Hakusan, Bunkyo-ku, Tokyo, 112-8604, Japan
| | - Jun Itami
- Department of Radiation Oncology, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku Tokyo, 104-0045 Japan
| | - Hitoshi Ikushima
- Department of Therapeutic Radiology, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-cho, Tokushima, Tokushima, 770-8503, Japan
| | - Takushi Dokiya
- Department of Radiology, Kyoundo Hospital, 1-8 Kandasurugadai, Chiyoda-ku Tokyo, 101-0062, Japan
| | - Yoshiyuki Shioyama
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku Fukuoka, Fukuoka, 812-8582, Japan
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Tomita T, Isobe T, Furuyama Y, Takei H, Kobayashi D, Mori Y, Terunuma T, Sato E, Yokota H, Sakae T. Evaluation of Dose Distribution and Normal Tissue Complication Probability of a Combined Dose of Cone-Beam Computed Tomography Imaging with Treatment in Prostate Intensity-Modulated Radiation Therapy. J Med Phys 2020; 45:78-87. [PMID: 32831490 PMCID: PMC7416863 DOI: 10.4103/jmp.jmp_4_20] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/02/2020] [Accepted: 03/31/2020] [Indexed: 12/03/2022] Open
Abstract
Purpose: The purpose of this study is to evaluate the effects of cone-beam computed tomography (CBCT) on dose distribution and normal tissue complication probability (NTCP) by constructing a comprehensive dose evaluation system for prostate intensity-modulated radiation therapy (IMRT). Methods: A system that could combine CBCT and treatment doses with MATLAB was constructed. Twenty patients treated with prostate IMRT were studied. A mean dose of 78 Gy was prescribed to the prostate region, excluding the rectal volume from the target volume, with margins of 4 mm to the dorsal side of the prostate and 7 mm to the entire circumference. CBCT and treatment doses were combined, and the dose distribution and the NTCP of the rectum and bladder were evaluated. Results: The radiation dose delivered to 2% and 98% of the target volume increased by 0.90 and 0.74 Gy on average, respectively, in the half-fan mode and on average 0.76 and 0.72 Gy, respectively, in the full-fan mode. The homogeneity index remained constant. The percent volume of the rectum and bladder irradiated at each dose increased slightly, with a maximum increase of <1%. The rectal NTCP increased by approximately 0.07% from 0.46% to 0.53% with the addition of a CBCT dose, while the maximum NTCP in the bladder was approximately 0.02%. Conclusions: This study demonstrated a method to evaluate a combined dose of CBCT and a treatment dose using the constructed system. The combined dose distribution revealed increases of <1% volume in the rectal and bladder doses and approximately 0.07% in the rectal NTCP.
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Affiliation(s)
- Tetsuya Tomita
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan.,Department of Radiology, University of Tsukuba Hospital, Ibaraki, Japan
| | - Tomonori Isobe
- Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
| | | | - Hideyuki Takei
- Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
| | - Daisuke Kobayashi
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan.,Department of Radiology, University of Tsukuba Hospital, Ibaraki, Japan
| | - Yutaro Mori
- Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
| | | | - Eisuke Sato
- Faculty of Health Sciences, Juntendo University, Tokyo, Japan
| | - Hiroshi Yokota
- Department of Radiology, University of Tsukuba Hospital, Ibaraki, Japan
| | - Takeji Sakae
- Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
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Malajovich I, Teo BKK, Petroccia H, Metz JM, Dong L, Li T. Characterization of the Megavoltage Cone-Beam Computed Tomography (MV-CBCT) System on Halcyon TM for IGRT: Image Quality Benchmark, Clinical Performance, and Organ Doses. Front Oncol 2019; 9:496. [PMID: 31249808 PMCID: PMC6582256 DOI: 10.3389/fonc.2019.00496] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 05/24/2019] [Indexed: 11/24/2022] Open
Abstract
Purpose: The Varian Halcyon includes an ultrafast 6 MV flattening filter free (FFF) cone-beam computed tomography (MV-CBCT). Although a kV-CBCT add-on is available, in the basic configuration MV is used for image guided radiotherapy (IGRT). We characterized the MV-CBCT imager in terms of reproducibility, linearity, field of view (FOV) dependence, detectability of soft-tissue, and the effect of metal implants. The performance of the MV-CBCT in the clinic, including resulting dose to organs, is also discussed herein. Methods: A Gammex phantom was scanned using a Halcyon MV-CBCT and a 120 kVp Siemens Definition Edge CT. Mean and standard deviation of Hounsfield Units (HUs) for different electron density relative to water (ρeW) inserts were extracted. Doses to clinical patients due to MV-CBCT are calculated within Eclipse during treatment planning. Results: A stable and near-linear HU-to-ρeW curve was obtained using the MV-CBCT. As the scan length increased from 10 to 28cm, the linearity of curve improved while the mean HUs decreased by 30%. All soft tissue inserts in the Gammex phantom were distinguishable. A crescent artifact affected HU measurements by up to 40 HUs. Soft-tissue contrast was sufficient for clinical online image-guidance in the low dose (5 MU) mode. Mean doses per fraction to organs-at-risk (OARs) were as high as 6 cGy for head and neck, 5 cGy for breast, and 4 cGy for pelvis patients. Metal rods did not affect HU values or introduce noticeable artifacts. Conclusions: Halcyon's MV-CBCT has sufficient soft tissue contrast for IGRT and lacks metal-induced artifacts. Even though the absolute HU values vary with phantom size and scanning length, the HU-to-ρeW conversions are linear and stable day-to-day. In clinical cases, highest tissue doses from MV-CBCT ranged from 2-7cGy per fraction for various treatment sites, which could be significant for some organs at risk. Dose to out-of-treatment-field organs can be limited by reducing the scan length definition during planning and using the low dose mode. The high quality imaging mode did not provide material advantages over the low dose mode. Adequate IGRT was successfully delivered to multiple tumor sites using MV-CBCT.
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Affiliation(s)
- Irina Malajovich
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, United States
| | - Boon-Keng Kevin Teo
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, United States
| | - Heather Petroccia
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, United States
| | - James M Metz
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, United States
| | - Lei Dong
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, United States
| | - Taoran Li
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, United States
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9
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Ma X, Yan H, Nath R, Chen Z, Li H, Liu W. Adaptive Imaging Versus Periodic Surveillance for Intrafraction Motion Management During Prostate Cancer Radiotherapy. Technol Cancer Res Treat 2019; 18:1533033819844489. [PMID: 31177934 PMCID: PMC6558533 DOI: 10.1177/1533033819844489] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Objective: To evaluate the benefits of adaptive imaging with automatic correction compared to
periodic surveillance strategies with either manual or automatic correction. Methods: Using Calypso trajectories from 54 patients with prostate cancer at 2 institutions, we
simulated 5-field intensity-modulated radiation therapy and dual-arc
volumetric-modulated arc therapy with periodic imaging at various frequencies and with
continuous adaptive imaging, respectively. With manual/automatic correction, we assumed
there was a 30/1 second delay after imaging to determine and apply couch shift. For
adaptive imaging, real-time “dose-free” cine-MV images during beam delivery are used in
conjunction with online-updated motion pattern information to estimate 3D displacement.
Simultaneous MV-kV imaging is only used to confirm the estimated overthreshold motion
and calculate couch shift, hence very low additional patient dose from kV imaging. Results: Without intrafraction intervention, the prostates could on average have moved out of a
3-mm margin for ∼20% of the beam-on time after setup imaging in current clinical
situation. If the time interval from the setup imaging to beam-on can be reduced to only
30 seconds, the mean over-3 mm percentage can be reduced to ∼7%. For intensity-modulated
radiation therapy simulation, with manual correction, 110 and 70 seconds imaging periods
both reduced the mean over-3 mm time to ∼4%. Automatic correction could give another 1%
to 2% improvement. However, with either manual or automatic correction, the maximum
patient-specific over-3 mm time was still relatively high (from 6.4% to 12.6%) and those
patients are actually clinically most important. In contrast, adaptive imaging with
automatic intervention significantly reduced the mean percentage to 0.6% and the maximum
to 2.7% and averagely only ∼1 kV image and ∼1 couch shift were needed per fraction. The
results of volumetric-modulated arc therapy simulation show a similar trend to that of
intensity-modulated radiation therapy. Conclusions: Adaptive continuous monitoring with automatic motion compensation is more beneficial
than periodic imaging surveillance at similar or even less imaging dose.
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Affiliation(s)
- Xiangyu Ma
- 1 School of Biomedical Engineering, Capital Medical University, Beijing, China.,2 Department of Therapeutic Radiology, Yale University School of Medicine and Yale-New Haven Hospital, New Haven, CT, USA.,3 Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, China
| | - Huagang Yan
- 1 School of Biomedical Engineering, Capital Medical University, Beijing, China.,2 Department of Therapeutic Radiology, Yale University School of Medicine and Yale-New Haven Hospital, New Haven, CT, USA
| | - Ravinder Nath
- 2 Department of Therapeutic Radiology, Yale University School of Medicine and Yale-New Haven Hospital, New Haven, CT, USA
| | - Zhe Chen
- 2 Department of Therapeutic Radiology, Yale University School of Medicine and Yale-New Haven Hospital, New Haven, CT, USA
| | - Haiyun Li
- 1 School of Biomedical Engineering, Capital Medical University, Beijing, China.,3 Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, China
| | - Wu Liu
- 2 Department of Therapeutic Radiology, Yale University School of Medicine and Yale-New Haven Hospital, New Haven, CT, USA
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10
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Mao W, Gardner SJ, Snyder KC, Wen NW, Zhong H, Li H, Jackson P, Shah M, Chetty IJ. On the improvement of CBCT image quality for soft tissue-based SRS localization. J Appl Clin Med Phys 2018; 19:177-184. [PMID: 30294838 PMCID: PMC6236842 DOI: 10.1002/acm2.12470] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [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: 05/17/2018] [Revised: 08/10/2018] [Accepted: 09/11/2018] [Indexed: 12/02/2022] Open
Abstract
Purpose We explore the optimal cone‐beam CT (CBCT) acquisition parameters to improve CBCT image quality to enhance intracranial stereotactic radiosurgery (SRS) localization and also assess the imaging dose levels associated with each imaging protocol. Methods Twenty‐six CBCT acquisition protocols were generated on an Edge® linear accelerator (Varian Medical Systems, Palo Alto, CA) with different x‐ray tube current and potential settings, gantry rotation trajectories, and gantry rotation speeds. To assess image quality, images of the Catphan 504 phantom were analyzed to evaluate the following image quality metrics: uniformity, HU constancy, spatial resolution, low contrast detection, noise level, and contrast‐to‐noise ratio (CNR). To evaluate the imaging dose for each protocol, the cone‐beam dose index (CBDI) was measured. To validate the phantom results, further analysis was performed with an anthropomorphic head phantom as well as image data acquired for a clinical SRS patient. Results The Catphan data indicates that adjusting acquisition parameters had direct effects on the image noise level, low contrast detection, and CNR, but had minimal effects on uniformity, HU constancy, and spatial resolution. The noise level was reduced from 34.5 ± 0.3 to 18.5 ± 0.2 HU with a four‐fold reduction in gantry speed, and to 18.7 ± 0.2 HU with a four‐fold increase in tube current. Overall, the noise level was found to be proportional to inverse square root of imaging dose, and imaging dose was proportional to the product of total tube current‐time product and the cube of the x‐ray potential. Analysis of the anthropomorphic head phantom data and clinical SRS imaging data also indicates that noise is reduced with imaging dose increase. Conclusions Our results indicate that optimization of the imaging protocol, and thereby an increase in the imaging dose, is warranted for improved soft‐tissue visualization for intracranial SRS.
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Affiliation(s)
- Weihua Mao
- Henry Ford Health System, Detroit, MI, USA
| | | | | | | | | | - Haisen Li
- Henry Ford Health System, Detroit, MI, USA
| | | | - Mira Shah
- Henry Ford Health System, Detroit, MI, USA
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11
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Nakamura M, Ishihara Y, Matsuo Y, Iizuka Y, Ueki N, Iramina H, Hirashima H, Mizowaki T. Quantification of the kV X-ray imaging dose during real-time tumor tracking and from three- and four-dimensional cone-beam computed tomography in lung cancer patients using a Monte Carlo simulation. J Radiat Res 2018; 59:173-181. [PMID: 29385514 PMCID: PMC5950977 DOI: 10.1093/jrr/rrx098] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Indexed: 05/10/2023]
Abstract
Knowledge of the imaging doses delivered to patients and accurate dosimetry of the radiation to organs from various imaging procedures is becoming increasingly important for clinicians. The purposes of this study were to calculate imaging doses delivered to the organs of lung cancer patients during real-time tumor tracking (RTTT) with three-dimensional (3D), and four-dimensional (4D) cone-beam computed tomography (CBCT), using Monte Carlo techniques to simulate kV X-ray dose distributions delivered using the Vero4DRT. Imaging doses from RTTT, 3D-CBCT and 4D-CBCT were calculated with the planning CT images for nine lung cancer patients who underwent stereotactic body radiotherapy (SBRT) with RTTT. With RTTT, imaging doses from correlation modeling and from monitoring of imaging during beam delivery were calculated. With CBCT, doses from 3D-CBCT and 4D-CBCT were also simulated. The doses covering 2-cc volumes (D2cc) in correlation modeling were up to 9.3 cGy for soft tissues and 48.4 cGy for bone. The values from correlation modeling and monitoring were up to 11.0 cGy for soft tissues and 59.8 cGy for bone. Imaging doses in correlation modeling were larger with RTTT. On a single 4D-CBCT, the skin and bone D2cc values were in the ranges of 7.4-10.5 cGy and 33.5-58.1 cGy, respectively. The D2cc from 4D-CBCT was approximately double that from 3D-CBCT. Clinicians should Figure that the imaging dose increases the cumulative doses to organs.
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Affiliation(s)
- Mitsuhiro Nakamura
- Division of Medical Physics, Department of Information Technology and Medical Engineering, Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
- Corresponding author. Division of Medical Physics, Department of Information Technology and Medical Engineering, Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan. Tel: +81-75-751-4176; Fax: +81-75-771-9749;
| | - Yoshitomo Ishihara
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
- Division of Medical Physics, Department of Radiation Oncology, Japanese Red Cross Wakayama Medical Center, 4-20 Komatsubara-dori, Wakayama 640-8558, Japan
| | - Yukinori Matsuo
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | - Yusuke Iizuka
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | - Nami Ueki
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | - Hiraku Iramina
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
- Department of Nuclear Engineering, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku-Katsura, Nishikyo-ku, Kyoto 615-8520, Japan
| | - Hideaki Hirashima
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | - Takashi Mizowaki
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
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12
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Abstract
Purpose: To develop a projection quality-driven tube current modulation method in cone-beam computed tomography for image-guided radiotherapy based on the prior attenuation information obtained by the planning computed tomography and then evaluate its effect on a reduction in the imaging dose. Materials and Methods: The QCKV-1 phantom with different thicknesses (0-400 mm) of solid water upon it was used to simulate different attenuation (μ). Projections were acquired with a series of tube current–exposure time product (mAs) settings, and a 2-dimensional contrast to noise ratio was analyzed for each projection to create a lookup table of mAs versus 2-dimensional contrast to noise ratio, μ. Before a patient underwent computed tomography, the maximum attenuation μmaxθ within the 95% range of each projection angle (θ) was estimated according to the planning computed tomography images. Then, a desired 2-dimensional contrast to noise ratio value was selected, and the mAs setting at θ was calculated with the lookup table of mAs versus 2-dimensional contrast to noise ratio,μmaxθ. Three-dimensional cone-beam computed tomography images were reconstructed using the projections acquired with the selected mAs. The imaging dose was evaluated with a polymethyl methacrylate dosimetry phantom in terms of volume computed tomography dose index. Image quality was analyzed using a Catphan 503 phantom with an oval body annulus and a pelvis phantom. Results: For the Catphan 503 phantom, the cone-beam computed tomography image obtained by the projection quality-driven tube current modulation method had a similar quality to that of conventional cone-beam computed tomography . However, the proposed method could reduce the imaging dose by 16% to 33% to achieve an equivalent contrast to noise ratio value. For the pelvis phantom, the structural similarity index was 0.992 with a dose reduction of 39.7% for the projection quality-driven tube current modulation method. Conclusions: The proposed method could reduce the additional dose to the patient while not degrading the image quality for cone-beam computed tomography. The projection quality-driven tube current modulation method could be especially beneficial to patients who undergo cone-beam computed tomography frequently during a treatment course.
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Affiliation(s)
- Kuo Men
- 1 Department of Radiation Oncology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jianrong Dai
- 1 Department of Radiation Oncology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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13
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Miyamoto N, Ishikawa M, Sutherland K, Suzuki R, Matsuura T, Toramatsu C, Takao S, Nihongi H, Shimizu S, Umegaki K, Shirato H. A motion-compensated image filter for low-dose fluoroscopy in a real-time tumor-tracking radiotherapy system. J Radiat Res 2015; 56:186-196. [PMID: 25129556 PMCID: PMC4572582 DOI: 10.1093/jrr/rru069] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 07/14/2014] [Accepted: 07/14/2014] [Indexed: 06/03/2023]
Abstract
In the real-time tumor-tracking radiotherapy system, a surrogate fiducial marker inserted in or near the tumor is detected by fluoroscopy to realize respiratory-gated radiotherapy. The imaging dose caused by fluoroscopy should be minimized. In this work, an image processing technique is proposed for tracing a moving marker in low-dose imaging. The proposed tracking technique is a combination of a motion-compensated recursive filter and template pattern matching. The proposed image filter can reduce motion artifacts resulting from the recursive process based on the determination of the region of interest for the next frame according to the current marker position in the fluoroscopic images. The effectiveness of the proposed technique and the expected clinical benefit were examined by phantom experimental studies with actual tumor trajectories generated from clinical patient data. It was demonstrated that the marker motion could be traced in low-dose imaging by applying the proposed algorithm with acceptable registration error and high pattern recognition score in all trajectories, although some trajectories were not able to be tracked with the conventional spatial filters or without image filters. The positional accuracy is expected to be kept within ±2 mm. The total computation time required to determine the marker position is a few milliseconds. The proposed image processing technique is applicable for imaging dose reduction.
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Affiliation(s)
- Naoki Miyamoto
- Department of Medical Physics, Graduate School of Medicine, Hokkaido University, North-15 West-7, Kita-ku, Sapporo 060-8638, Japan
| | - Masayori Ishikawa
- Department of Medical Physics, Graduate School of Medicine, Hokkaido University, North-15 West-7, Kita-ku, Sapporo 060-8638, Japan
| | - Kenneth Sutherland
- Department of Medical Physics, Graduate School of Medicine, Hokkaido University, North-15 West-7, Kita-ku, Sapporo 060-8638, Japan
| | - Ryusuke Suzuki
- Department of Medical Physics, Hokkaido University Hospital, North-14 West-5, Kita-ku, Sapporo 060-8648, Japan
| | - Taeko Matsuura
- Department of Medical Physics, Graduate School of Medicine, Hokkaido University, North-15 West-7, Kita-ku, Sapporo 060-8638, Japan
| | - Chie Toramatsu
- Department of Medical Physics, Hokkaido University Hospital, North-14 West-5, Kita-ku, Sapporo 060-8648, Japan
| | - Seishin Takao
- Department of Medical Physics, Graduate School of Medicine, Hokkaido University, North-15 West-7, Kita-ku, Sapporo 060-8638, Japan
| | - Hideaki Nihongi
- Department of Medical Physics, Graduate School of Medicine, Hokkaido University, North-15 West-7, Kita-ku, Sapporo 060-8638, Japan
| | - Shinichi Shimizu
- Department of Radiology, Graduate School of Medicine, Hokkaido University, North-15 West-7, Kita-ku, Sapporo 060-8638, Japan
| | - Kikuo Umegaki
- Division of Quantum Science and Engineering, Graduate School of Engineering, Hokkaido University, North-15 West-7, Kita-ku, Sapporo 060-8638, Japan
| | - Hiroki Shirato
- Department of Radiology, Graduate School of Medicine, Hokkaido University, North-15 West-7, Kita-ku, Sapporo 060-8638, Japan
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