Effects of different methods of dosimetry parameter computation on treatment plan evaluation results(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2018年第5期
- Page:
- 519-525
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Effects of different methods of dosimetry parameter computation on treatment plan evaluation results
- Author(s):
- JI Weixing; ZHANG Jianying; XIAO Han; LI Tingting; ZHANG Yujie
- Department of Radiation Oncology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
- Keywords:
- ; nasopharyngeal carcinoma; treatment planning system; dosimetry; dose-volume histogram
- PACS:
- R730.55
- DOI:
- DOI:10.3969/j.issn.1005-202X.2018.05.005
- Abstract:
- Objective To analyze the changes of plan evaluation results when calculating the dosimetry parameters with different algorithms. Methods The treatment plans designed by two different planning systems for 66 cases of nasopharyngeal carcinoma were selected as the research objects. A self-developed evaluation software was adopted to read the dosimetry parameters of the plans, and these results were compared with those obtained with treatment planning system. Then the differences between D2 and Dmax were analyzed, and the feasibility of replacing Dmax with D0.01 cc was discussed. Results Differences between the dosimetry parameters read from Pinnacle and XiO system and the evaluation software were similar. With the reduced volume of the organs, the differences in Dmax and Dmean became larger, and the differences in Dmax were much greater. In all the plans, 5% of Dmax difference was higher than 292 cGy, and 5% of Dmean difference was higher than 55 cGy. Except for PTVnx, the mean value of the differences in D2 was less than Dmax. The dose difference was (45.5±30.4) cGy for D0.01 cc in related organs, and (107.6±56.8) cGy for Dmax. The dose differences of D0.01 cc were less than 100 cGy except for BRAINSTEM_PRV2. Conclusion When calculating the same treatment plan with different methods of dosimetry parameter computation, the differences in Dmax is greater than Dmean. The smaller the volume is, the larger the difference is. The use of D2 instead of Dmax can significantly reduce the difference in the calculation of dosimetry parameters, and replacing Dmax with D0.01 cc can significantly reduce the calculation errors.
Last Update: 2018-05-22