Assessment of dose accuracy for online MR-guided radiotherapy for cervical carcinoma

作者：Ding, Shouliang; Liu, Hongdong; Li, Yongbao; Wang, Bin; Li, Rui; Liu, Biaoshui; Ouyang, Yi; Wu, Dehua; Huang, Xiaoyan^*

来源：Journal of Radiation Research and Applied Sciences, 2021, 14(1): 159-170.

DOI：10.1080/16878507.2021.1888243

• MR-guided radiotherapy
• MR-Linac
• synthetic CT
• bulk ED assignment
• cervical carcinoma

This study aims to evaluate the dose accuracy of synthetic CT based bulk relative electron density (rED) assignment for application in 1.5 T MR-Linac for cervical carcinoma patients. Five cervix patients previously treated on 1.5 T MR-Linac were retrospectively investigated. Two sCTs were generated assigning bulk values to the different bone regions: the SCTFH was generated with delineation of femoral head, and the sCT(AB) was generated with the delineation of all the bone regions. The rest tissue of the patient data was set to mean rED values of the region of interests in CT. The same treatment plan based on original CT was recalculated or reoptimized on the SCTFH and sCT(AB). The result of gamma analysis showed that gamma passing rate of treatment plans based on sCT(AB) was higher than plans based on SCTFH. And the differences of dose volume parameters between plans on sCTs and original CT showed that the differences for plan based on sCT(AB) were much smaller than SCTFH. The sCT generated with bulk rED assignment approach guarantees an acceptable level of dose accuracy for cervix carcinoma patients with 1.5 T MR-Linac. The accuracy can be improved by using complete delineation of the pelvic bone regions.

• 单位
  南方医科大学; 中山大学