Shandong Provincial Key Laboratory of Radiation Oncology, Department of Radiation Oncology, Shandong Academy of Medical Sciences, Shandong Tumor Hospital, No. 440 Jiyan Road, 250117 Jinan, China.
Technol Cancer Res Treat. 2014 Apr;13(2):95-100. doi: 10.7785/tcrt.2012.500365. Epub 2013 Aug 2.
The aim of this study is to evaluate anatomic lung tumor changes and dosimetric consequences utilizing the deformable daily kilovolt (KV) cone-beam computer tomography (CBCT) image registration. Five patients diagnosed with NSCLC were treated with three-dimensional conformal radiotherapy (3D CRT) and 10 daily KV CBCT image sets were acquired for each patient. Each CBCT image and plan CT were imported into the deformable image registration (DIR) system. The plan CT image was deformed by the DIR system and a new contour on CBCT was obtained by using the auto-contouring function of the DIR. These contours were individually marked as CBCT f1, CBCT f2,..., and CBCT f10, and imported into a treatment planning system (TPS). The daily CBCT plan was individually generated with the same planning criteria based on new contours. These plans were individually marked as CBCTp1, CBCTp2,..., and CBCTp10, followed by generating a dose accumulation plan (DA plan) in original pCT image contour sets by adding all CBCT plans using Varian Eclipse TPS. The maximum, minimum and mean doses to the plan target volume (PTV) in the 5 DA plans were the same with the CT plans. However, the volume of radiation 5, 10, 20, 30, and 50 Gy of the total lungs in DA plans were less than those of the CT plans. The maximum dose of the spinal cord in the DA plans were average 27.96% less than the CT plans. The mean dose for the left, right, and total lungs in the DA plans were reduced by 13.80%, 23.65%, and 12.96%, respectively. The adaptive 3D CRT based on the deformable registration can reduce the dose to the lung and the spinal cord with the same PTV dose coverage. Moreover, it provides a method for further adaptive radiotherapy exploration.
本研究旨在利用可变形千伏（kV）锥形束计算机断层扫描（CBCT）图像配准评估解剖性肺部肿瘤变化和剂量学后果。5 名被诊断为 NSCLC 的患者接受了三维适形放疗（3D CRT），每位患者采集了 10 套每日 kV CBCT 图像。将每个 CBCT 图像和计划 CT 导入到可变形图像配准（DIR）系统中。通过 DIR 系统对计划 CT 图像进行变形，并使用 DIR 的自动勾画功能在 CBCT 上获得新的轮廓。这些轮廓分别标记为 CBCT f1、CBCT f2、...、和 CBCT f10，并导入到治疗计划系统（TPS）中。根据新的轮廓，使用相同的计划标准分别为每个日常 CBCT 计划生成计划。这些计划分别标记为 CBCTp1、CBCTp2、...、和 CBCTp10，然后使用瓦里安 Eclipse TPS 通过添加所有 CBCT 计划在原始 pCT 图像轮廓集中生成剂量累加计划（DA 计划）。在 5 个 DA 计划中，PTV 的最大、最小和平均剂量与 CT 计划相同。然而，DA 计划中总肺的 5、10、20、30 和 50 Gy 剂量的体积小于 CT 计划。DA 计划中脊髓的最大剂量平均比 CT 计划低 27.96%。DA 计划中左、右和总肺的平均剂量分别降低了 13.80%、23.65%和 12.96%。基于可变形配准的自适应 3D CRT 可以在相同的 PTV 剂量覆盖下降低肺和脊髓的剂量。此外，它为进一步的自适应放疗探索提供了一种方法。
