An algorithm of cone-beam CT registration based on dosimetry parameters of plans
10.3760/cma.j.cn113030-20230110-00005
- VernacularTitle:基于计划目标剂量的锥形线束CT图像配准方法研究
- Author:
Yewei WANG
1
;
Xin LI
;
Helong WANG
;
Lina FENG
;
Yanling BAI
Author Information
1. 哈尔滨医科大学附属肿瘤医院放疗科，哈尔滨 150081
- Keywords:
Radiotherapy, online adaptive;
Dose-guided image registration;
Multi-objective optimization
- From:
Chinese Journal of Radiation Oncology
2023;32(12):1064-1069
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To improve the accuracy of cone-beam CT (CBCT) image registration by using a dose-guided registration algorithm based on multi-objective optimization.Methods:A total of 28 sets of CBCT images of 6 patients with lung cancer and 5 patients with cervical cancer admitted to Harbin Medical University Cancer Hospital in 2022 were retrospectively analyzed. Using the results of bone-based registration as the starting points for dose registration algorithm, the dose fluence weighted mean square errors of each displacement point in surrounding three-dimensional space were calculated, and the candidate displacement points were selected by unsupervised k-means clustering method. The three-dimensional dose distribution of each candidate displacement point was calculated by using the limited size pencil beam algorithm, and the dose histogram indexes were extracted as the optimization variables of the multi-objective optimization algorithm. After the Pareto optimal solution set obtained using multi-objective genetic algorithm, the optimal unique solution was then determined based on the predetermined objective weight scheme.Results:After dose optimization registration, the values of D 90%, D 95%, D 98%, D mean and conformity index (CI) of planning target volume (PTV) of lung cancer patients were increased by 0.23 Gy, 0.49 Gy, 1.05 Gy, 0.15 Gy, 0.03 compared with conventional registration, respectively, and no significant difference was found for the organs at risk (OAR). For cervical cancer cases, the values of D 90%, D 95%, D 98%, D mean and CI of PTV were increased by 0.72 Gy, 1.15 Gy, 2.53 Gy, 0.24 Gy, 0.05 compared with conventional registration, respectively, whereas the evaluation indexes of partial OAR were decreased by 1.06-1.81 Gy. Conclusion:The proposed dose-guided registration algorithm can improve the dose coverage for the target area, decrease the dose for OAR and reduce residual error of rigid registration algorithm, which can be implemented as part of online adaptive radiotherapy.
