Zhou Pi-Xiao, Wang Rui-Hao, Yu Hui, Zhang Ying, Zhang Guo-Qian, Zhang Shu-Xu
Radiotherapy Center, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou, China.
Front Oncol. 2022 Aug 26;12:898141. doi: 10.3389/fonc.2022.898141. eCollection 2022.
Integration of 4D-CT ventilation function images into esophageal cancer radiation treatment planning aimed to assess dosimetric differences between different functional lung (FL) protection strategies and radiotherapy techniques.
A total of 15 patients with esophageal cancer who had 4D-CT scans were included. Lung ventilation function images based on Jacobian values were obtained by deformation image registration and ventilation imaging algorithm. Several different plans were designed for each patient: clinical treatment planning (non-sparing planning), the same beam distribution to FL-sparing planning, three fixed-beams FL-sparing intensity-modulated radiation therapy (IMRT) planning (5F-IMRT, 7F-IMRT, 9F-IMRT), and two FL-sparing volumetric modulated arc therapy (VMAT) planning [1F-VMAT (1-Arc), 2F-VMAT (2-Arc)]. The dosimetric parameters of the planning target volume (PTV) and organs at risk (OARs) were compared and focused on dosimetric differences in FL.
The FL-sparing planning compared with the non-sparing planning significantly decreased the FL-D, V and Lungs-D, V (V: volume of receiving ≥X Gy), although it slightly compromised PTV conformability and increased Heart-V (P< 0.05). The 5F-IMRT had the lowest PTV-conformability index (CI) but had a lower Lungs and Heart irradiation dose compared with those of the 7F-IMRT and 9F-IMRT (P< 0.05). The 2F-VMAT had higher PTV-homogeneity index (HI) and reduced irradiation dose to FL, Lungs, and Heart compared to those of the 1F-VMAT planning (P< 0.05). The 2F-VMAT had higher PTV conformability and homogeneity and decreased FL-D, V- and Lungs-D, V- but correspondingly increased spinal cord-D compared with those of the 5F-IMRT planning (P< 0.05).
In this study, 4D-CT ventilation function image-based FL-sparing planning for esophageal cancer can effectively reduce the dose of the FL. The 2F-VMAT planning is better than the 5F-IMRT planning in reducing the dose of FL.
将4D-CT通气功能图像整合到食管癌放射治疗计划中，旨在评估不同功能性肺（FL）保护策略与放射治疗技术之间的剂量差异。
纳入15例进行了4D-CT扫描的食管癌患者。通过变形图像配准和通气成像算法获得基于雅可比值的肺通气功能图像。为每位患者设计了几种不同的计划：临床治疗计划（非保留计划）、与FL保留计划相同的射束分布、三种固定射束FL保留调强放射治疗（IMRT）计划（5F-IMRT、7F-IMRT、9F-IMRT）以及两种FL保留容积调强弧形治疗（VMAT）计划[1F-VMAT（1弧）、2F-VMAT（2弧）]。比较计划靶区（PTV）和危及器官（OARs）的剂量学参数，并关注FL中的剂量差异。
与非保留计划相比，FL保留计划显著降低了FL-D、V以及肺-D、V（V：接受≥X Gy的体积），尽管它略微损害了PTV的适形性并增加了心脏-V（P<0.05）。5F-IMRT的PTV适形性指数（CI）最低，但与7F-IMRT和9F-IMRT相比，其肺和心脏的照射剂量较低（P<0.05）。与1F-VMAT计划相比，2F-VMAT具有更高的PTV均匀性指数（HI），并降低了对FL、肺和心脏的照射剂量（P<0.05）。与5F-IMRT计划相比，2F-VMAT具有更高的PTV适形性和均匀性，降低了FL-D、V以及肺-D、V，但相应增加了脊髓-D（P<0.05）。
在本研究中，基于4D-CT通气功能图像的食管癌FL保留计划可有效降低FL的剂量。在降低FL剂量方面，2F-VMAT计划优于5F-IMRT计划。
