Fu Qi, Xu Yingjie, Yang Xi, An Jusheng, Li Zhaohan, Huang Manni, Dai Jianrong
Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medial Sciences and Peking Union Medical College, Beijing 100021, China.
RL Electronics, Tianjin 300399, China.
Clin Transl Radiat Oncol. 2025 Apr 17;53:100964. doi: 10.1016/j.ctro.2025.100964. eCollection 2025 Jul.
In current clinical practice, independent treatment plan optimization for each fraction of brachytherapy might not be able to fully leverage the dosimetric advantage of the cervical cancer radiotherapy combining external beam radiotherapy (EBRT) and brachytherapy (BT). This study proposed an offline adaptive planning method based on accumulated dose for BT, aiming to improve the total dose distribution of the combined radiotherapy.
This study retrospectively reviewed nine cervical cancer patients treated with EBRT followed by high-dose-rate BT. For each BT fraction, we used a multi-metric deformable image registration method to accumulate the dose distributions of previously delivered EBRT and BT. The accumulated dose distribution was then imported into a customized commercial BT treatment planning system as a background in the adaptive dose optimization. Main dosimetric parameters of the target and organs at risk (OARs) were compared between the adaptive BT (ABT) and conventional BT (CBT) planning methods.
For approximately 70 % of the BT fractions, the ABT plans have lower D2cc to the bladder or rectum compared with the CBT plans. In terms of total dose evaluation, the ABT planning method resulted in a decrease in mean values of D2cc, V60 and V50 for the bladder (-1.9 ± 2.0 Gy, -1.2 ± 1.2 %, and -0.9 ± 1.1 %) and rectum (-2.1 ± 1.8 Gy, -1.2 ± 1.2 %, and -1.4 ± 1.3 %).
The offline adaptive planning method could help decrease the doses to OARs and improve the total dose distribution of combined radiotherapy, showing promising prospects for clinical use.
在当前临床实践中，近距离放射治疗（BT）各分次的独立治疗计划优化可能无法充分发挥宫颈癌外照射放疗（EBRT）联合BT放疗的剂量学优势。本研究提出一种基于累积剂量的BT离线自适应计划方法，旨在改善联合放疗的总剂量分布。
本研究回顾性分析了9例接受EBRT序贯高剂量率BT治疗的宫颈癌患者。对于每个BT分次，我们使用多指标可变形图像配准方法累积先前给予的EBRT和BT的剂量分布。然后将累积剂量分布作为背景导入定制的商业BT治疗计划系统中进行自适应剂量优化。比较了自适应BT（ABT）和传统BT（CBT）计划方法中靶区和危及器官（OARs）的主要剂量学参数。
对于约70%的BT分次，与CBT计划相比，ABT计划使膀胱或直肠的D2cc更低。在总剂量评估方面，ABT计划方法使膀胱的D2cc、V60和V50的平均值降低（分别为-1.9±2.0 Gy、-1.2±1.2%和-0.9±1.1%），直肠的D2cc、V60和V50的平均值降低（分别为-2.1±1.8 Gy、-1.2±1.2%和-1.4±1.3%）。
离线自适应计划方法有助于降低OARs的剂量并改善联合放疗的总剂量分布，具有良好的临床应用前景。
