Assessment of clinal target volume deformation in online adaptive radiotherapy for prostate cancer
10.3760/cma.j.cn112271-20250704-00223
- VernacularTitle:前列腺癌在线自适应放疗的靶区形变评估
- Author:
Wenyu WANG
1
;
Ran WEI
1
;
Siqi YUAN
1
;
Kuo MEN
1
Author Information
1. 国家癌症中心/国家肿瘤临床医学研究中心/中国医学科学院北京协和医学院肿瘤医院，北京 100021
- Publication Type:Journal Article
- Keywords:
Online adaptive radiotherapy (OART);
Intrafraction motion;
Target volume deformation;
Deformable point set registration;
Three-dimensional point cloud
- From:
Chinese Journal of Radiological Medicine and Protection
2025;45(10):973-978
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To assess intrafractional errors of the deformation of clinical target volumes (CTVs) during online adaptive radiotherapy (OART) for prostate cancer patients, aiming to provide a basis for online plan optimization.Methods:A retrospective analysis was conducted for 13 prostate cancer patients who received 1.5 T magnetic resonance imaging (MRI)-guided OART (8 Gy × 5 fractions, totaling 65 fractions) at the Department of Radiation Oncology, Cancer Hospital, Chinese Academy of Medical Sciences. The MRI images were collected at the beginning and end of various treatment fractions. Then, the CTVs and organs at risk (OARs) were delineated by the same radiation oncologist. After rigid registration and triangle mesh generation, the surface vertices were extracted. The deformable registration for the CTV surfaces was performed using the thin-plate spline robust point matching (TPS-RPM) algorithm, yielding vertex correspondences. Last, both systematic and random intrafractional errors of CTV deformation were calculated.Results:The average Hausdorff distance (HD) for deformable registration of treatment fractions was (1.68 ± 0.28) mm. The intrafractional systematic errors of CTV deformation were (0.25 ± 3.18) mm (anterior-posterior direction; A-P), (0.89 ± 3.85) mm (left-right direction, L-R), and (-1.98 ± 6.69) mm (superior-inferior direction, S-I). The intrafractional random errors of CTV deformation were determined at (-0.26 ± 1.89) mm (A-P), (-0.08 ± 0.88) mm (L-R), and (-0.04 ± 1.86) mm (S-I).Conclusions:During OART, CTV deformations primarily occur in the S-I direction. Therefore, it is necessary to consider the expanded size of margins in this direction during OART for prostate cancer.
