Huang Peng, Shang Jiawen, Xie Xin, Hu Zhihui, Liu Zhiqiang, Yan Hui
Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Department of Radiation Oncology, Clinical Oncology School of Fujian Medical University, Fujian Cancer Hospital, Fuzhou, China.
Quant Imaging Med Surg. 2024 Aug 1;14(8):5789-5802. doi: 10.21037/qims-24-296. Epub 2024 Jul 16.
Currently, intensity-modulated radiation therapy (IMRT) is commonly used in radiotherapy clinics. However, designing a treatment plan with multiple beam angles depends on the experience of human planners, and is mostly achieved using a trial-and-error approach. It is preferrable but challenging to solve this issue automatically and mathematically using an optimization approach. The goal of this study is to develop a mixed-integer linear programming (MILP) approach for the beam angle optimization (BAO) of non-coplanar IMRT for liver cancer.
MILP models for the BAO of both coplanar and non-coplanar IMRT treatment plans were developed. The beam angles of the IMRT plans were first selected by the MILP model built using mathematical optimization software. Next, the IMRT plans with the selected beam angles was created in a commercial treatment planning system. Finally, the fluence map and dose distribution of the IMRT plans were generated under pre-defined dose-volume constraints. The IMRT plans of 10 liver cancer patients previously treated at our institute were used to assessed the proposed MILP models. For each patient, both coplanar and non-coplanar IMRT plans with beam angles optimized by the MILP models were compared with the IMRT plan clinically approved by physicians.
The MILP model-guided IMRT plans showed reduced doses for most of the organs at risk (OARs). Compared with the IMRT plans clinically approved by physicians, the doses for the spinal cord (28.5 . 36.1, P=0.001<0.05) and liver (27.6 . 29.1, P=0.005<0.05) decreased significantly in the IMRT plans with non-coplanar beams selected by the MILP models.
The MILP model is an effective tool for the BAO in coplanar and non-coplanar IMRT treatment planning. It facilitates the automation of IMRT treatment planning for current high-precision radiotherapy.
目前，调强放射治疗（IMRT）在放射治疗临床中普遍使用。然而，设计具有多个射束角度的治疗计划依赖于人类计划者的经验，并且大多通过试错法来实现。使用优化方法自动且数学地解决此问题是可取的，但具有挑战性。本研究的目的是开发一种混合整数线性规划（MILP）方法，用于肝癌非共面IMRT的射束角度优化（BAO）。
开发了共面和非共面IMRT治疗计划的BAO的MILP模型。IMRT计划的射束角度首先由使用数学优化软件构建的MILP模型选择。接下来，在商业治疗计划系统中创建具有所选射束角度的IMRT计划。最后，在预定义的剂量体积约束下生成IMRT计划的通量图和剂量分布。使用我们研究所先前治疗的10例肝癌患者的IMRT计划来评估所提出的MILP模型。对于每位患者，将由MILP模型优化射束角度的共面和非共面IMRT计划与医生临床批准的IMRT计划进行比较。
MILP模型引导的IMRT计划显示大多数危及器官（OARs）的剂量降低。与医生临床批准的IMRT计划相比，在由MILP模型选择非共面射束的IMRT计划中，脊髓（28.5. 36.1，P = 0.001<0.05）和肝脏（27.6. 29.1，P = 0.005<0.05）的剂量显著降低。
MILP模型是共面和非共面IMRT治疗计划中BAO的有效工具。它有助于当前高精度放射治疗中IMRT治疗计划的自动化。
