Evaluation of multi-fractional dose accumulation with deformable registration algorithm in brachytherapy for cervical cancer(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2021年第5期
- Page:
- 534-539
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Evaluation of multi-fractional dose accumulation with deformable registration algorithm in brachytherapy for cervical cancer
- Author(s):
- LI Jixuan1; SHAN Guoping2; WANG Binbing2; ZHOU Jianliang1
- 1. School of Nuclear Science and Technology, University of South China, Hengyang 421001, China 2. Department of Radiation Physics, Cancer Hospital, University of Chinese Academy of Sciences, Hangzhou 310022, China
- Keywords:
- Keywords: cervical cancer brachytherapy deformable registration cumulative dose
- PACS:
- R811.1
- DOI:
- DOI:10.3969/j.issn.1005-202X.2021.05.002
- Abstract:
- Abstract: Objective To quantitatively analyze the differences in total dose assessment caused by different methods for calculating cumulative dose in brachytherapy. Methods A total of 108 deformation registrations using hybrid deformation registration algorithm were performed on 32 patients with cervical cancer who had completed brachytherapy, and the total deformation dose of each patient was calculated. According to the volume controls of the bladder and the rectum, 32 patients were divided into volume control group (18 cases) and volume uncontrolled group (14 cases). The cumulative dose volume parameters (D0.1 cc, D1 cc, D2 cc) and Dice similarity coefficient were compared between two groups, and then compared with the results obtained by multi-fractional dose accumulation method recommended by GEC-ESTRO. Results The Dice similarity coefficient became worse as the relative volume ratio of the deformed image increased. In volume control group, the difference between the results obtained by the method recommended by GEC-ESTRO and deformable cumulative dose (DDIR/DGEC) was small. For the bladder, the maximum DDIR/DGEC of D2 cc in volume control group was 1.05, lower than 1.07 in volume uncontrolled group, and the minimum DDIR/DGEC was 0.91, higher than 0.80 in volume uncontrolled group. It suggested that in deformation dose evaluation, the deformation dose may be 5%-7% higher or 9%-20% lower than the results calculated by the recommended method of GEC-ESTRO. The main reason for the differences was dose grid scaling caused by volume difference in image deformation. The DDIR/DGEC of D0.1 cc and D1 cc was closer to 1. For the rectum, high DDIR/DGEC was not observed in volume control group. The maximum and minimum DDIR/DGEC of D2 cc were 0.99 and 0.80 in volume control group, lower than 1.06 and 0.85 in volume uncontrolled group, indicating that the DDIR/DGEC of uncontrolled group was 6% higher. The cumulative dose ratios of D0.1 cc, D1 cc, and D2 cc of the rectum were all close, and the difference was not as significant as that of the bladder. Conclusion In brachytherapy, the deformation volume can affect the calculation result of deformation cumulative dose. A reasonable control of the volume of the deformation contour is not only helpful to improve the accuracy of the deformation, but also makes the evaluation results of the total deformation dose more stable. It is recommended to pay attention to the volume control of the bladder and the rectum during brachytherapy.
Last Update: 2021-05-31