Automatic treatment planning based on the degree of overlap between OAR and PTV(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2021年第10期
- Page:
- 1203-1208
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Automatic treatment planning based on the degree of overlap between OAR and PTV
- Author(s):
- PAN Xingchen1; 2; WANG Dong1; HU Liqin1
- 1. Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China 2. Science Island Branch, Graduate School of University of Science and Technology of China, Hefei 230026, China
- Keywords:
- Keywords: prostate cancer degree of overlap automatic planning organs-at-risk dose-volume histogram
- PACS:
- R811.1；R730.55
- DOI:
- DOI:10.3969/j.issn.1005-202X.2021.10.004
- Abstract:
- Abstract: Objective To establish a mathematical model of differential dose-volume histogram (DVH) according to the anatomical structure of prostate cancer patients for predicting the DVH of organs-at-risk (OAR) sub-blocks, and to improve the quality and efficiency of treatment plan by the accurate prediction of the DVH of OAR and automatic treatment planning. Methods Nine of 17 prostate cancer patients were randomly selected as training set and the rest as test set. Planning target volume (PTV) was expanded to cover OAR, and the OAR in the expanded area was successively separated into sub-blocks with a thickness of 3 mm. According to the skewed normal Gaussian function, a precise mathematical model of sub-block differential DVH was established for analyzing the relationship between the degree of overlap between OAR and PTV and sub-block differential DVH. The script program based on Pinnacle3 was used to obtain the OAR sub-blocks of 8 patients in test set, and each OAR differential DVH was predicted to guide the plan. Results The smaller the degree of overlap between OAR and PTV was, the more obvious the variation of differential DVH was. The homogeneity index and conformity index of automatic plan were superior to those of original plan (t=-1.871, 3.742 P<0.05). The V100% of PTV in automatic plan was decreased, while V95% was increased, but the differences were not statistically significant (P>0.05). Compared with those in original plan, the V70, V60, V50 (t=-2.471, -3.439, -2.376 P<0.05) and V40 (P>0.05) of the bladder in automatic plan were lower and the V70, V60, V50 and V40 (t=-2.540, -3.416, -2.666, -2.777 P<0.05) of the rectum were also decreased. The correlation analysis showed that the differences of the V70, V60, V50 and V40 of the bladder between automatic plan and original plan were negatively or positively correlated with the degree of overlap (correlation coefficient=-0.357, -0.976, -0.857, 0.381 P=0.385, 0.000, 0.007, 0.352), but there was no statistical significance between the differences of V70 and V40 and the degree of overlap. Conclusion The automatic treatment plan for prostate cancer designed using the precise DVH prediction model based on the degree of overlap between OAR and PTV increases target dose and decreases OAR irradiation dose.
Last Update: 2021-10-28