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Yamazawa Y, Osaka A, Fujii Y, Nakayama T, Nishioka K, Tanabe Y. Evaluation of the effect of sagging correction calibration errors in radiotherapy software on image matching. Phys Eng Sci Med 2024; 47:589-596. [PMID: 38372942 PMCID: PMC11166816 DOI: 10.1007/s13246-024-01388-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 01/08/2024] [Indexed: 02/20/2024]
Abstract
To investigate the impact of sagging correction calibration errors in radiotherapy software on image matching. Three software applications were used, with and without a polymethyl methacrylate rod supporting the ball bearings (BB). The calibration error for sagging correction across nine flex maps (FMs) was determined by shifting the BB positions along the Left-Right (LR), Gun-Target (GT), and Up-Down (UD) directions from the reference point. Lucy and pelvic phantom cone-beam computed tomography (CBCT) images underwent auto-matching after modifying each FM. Image deformation was assessed in orthogonal CBCT planes, and the correlations among BB shift magnitude, deformation vector value, and differences in auto-matching were analyzed. The average difference in analysis results among the three softwares for the Winston-Lutz test was within 0.1 mm. The determination coefficients (R2) between the BB shift amount and Lucy phantom matching error in each FM were 0.99, 0.99, and 1.00 in the LR-, GT-, and UD-directions, respectively. The pelvis phantom demonstrated no cross-correlation in the GT direction during auto-matching error evaluation using each FM. The correlation coefficient (r) between the BB shift and the deformation vector value was 0.95 on average for all image planes. Slight differences were observed among software in the evaluation of the Winston-Lutz test. The sagging correction calibration error in the radiotherapy imaging system was caused by an auto-matching error of the phantom and deformation of CBCT images.
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Affiliation(s)
- Yumi Yamazawa
- Department of Radiology, Niigata Prefectural Central Hospital, 205, Shin-minamimachi, Niigata, 205943-0192, Japan
| | - Akitane Osaka
- Department of Radiology, Niigata Prefectural Central Hospital, 205, Shin-minamimachi, Niigata, 205943-0192, Japan
| | - Yasushi Fujii
- Department of Radiology, Chugoku Central Hospital of the Mutual Aid Association of Public School Teachers, 148-13, Miyuki, Fukuyama, Hiroshima, 720-2121, Japan
| | - Takahiro Nakayama
- Department of Radiology, Chugoku Central Hospital of the Mutual Aid Association of Public School Teachers, 148-13, Miyuki, Fukuyama, Hiroshima, 720-2121, Japan
| | - Kunio Nishioka
- Department of Radiology, Tokuyama Central Hospital, 1-1 Kodacho, Shunan, Yamaguchi, 745-8522, Japan
| | - Yoshinori Tanabe
- Faculty of Medicine, Graduate School of Health Sciences, Okayama University, 2-5-1, Shikata, Kita, Okayama, 700-8525, Japan.
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Tanabe Y. [9. Safer and Ideal Radiation Treatment Planning]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2023; 79:193-195. [PMID: 36804810 DOI: 10.6009/jjrt.2023-2152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Affiliation(s)
- Yoshinori Tanabe
- Faculty of Medicine, Graduate School of Health Sciences, Okayama University
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Evaluation of patient-specific motion management for radiotherapy planning computed tomography using a statistical method. Med Dosim 2022; 47:e13-e18. [PMID: 34991966 DOI: 10.1016/j.meddos.2021.12.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/11/2021] [Accepted: 12/02/2021] [Indexed: 12/25/2022]
Abstract
We evaluated the probabilistic randomness of predictions by using individual numerical data based on general data for treatment planning computed tomography (CT) and evaluated the importance of patient-specific management through statistical analysis of our facility's data in lung stereotactic body radiotherapy (SBRT) and prostate volumetric modulated arc therapy (VMAT). The subjects were 30 patients who underwent lung SBRT with fiducial markers and 24 patients who underwent prostate VMAT. The average 3-dimensional (3D) displacement error between the fiducial marker and lung mass in 4DCT of lung SBRT was calculated and then compared with the 3D displacement error between the upper-lobe group (UG) and middle- or lower-lobe group (LG). The duty cycles between the lung tumor and fiducial marker at the <2-mm3 ambush area were compared between the UG and LG. In the prostate VMAT, the Shewhart control chart was analyzed by comparing multiple acquisition planning CT (MPCT) and cone-beam CT (CBCT) during the treatment period. The average 3D displacement errors in 4DCT for the lung tumor and fiducial marker were significantly different between the UG and middle- or lower-lobe group, but there was no correlation with the duty cycle. The Shewhart control chart for 3D displacement errors of the prostate for MPCT and CBCT showed that errors of >8 mm exceeded the control limit. In lung SBRT and prostate VMAT, overall statistical data from planning CT showed probabilistic randomness in predictions during the treatment period, and patient-specific motion management was needed to increase accuracy. A radiotherapy planning CT report showing a statistical analysis graph would be useful to objective share with staff.
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