Department of Radiation Oncology, Kanagawa Cancer Center, Yokohama, Japan;
Section of Medical Physics and Engineering, Kanagawa Cancer Center, Yokohama, Japan.
Anticancer Res. 2021 Apr;41(4):1951-1958. doi: 10.21873/anticanres.14962.
BACKGROUND/AIM: This study focused on the hybrid-volumetric modulated arc therapy (hVMAT) for stage I esophageal cancer and compared the effects on dose distribution induced by changes in the ratio of three-dimensional conformal radiotherapy (3DCRT) to VMAT.
Fifteen patients who underwent 3DCRT for cT1bN0M0 esophageal cancer at Kanagawa Cancer Center from January 2014 to April 2019 were included in the study. The dose-volume histogram (DVH) parameters of the target volume and normal organs were evaluated in the 3DCRT, hVMAT, and VMAT treatment plans.
The homogeneity index of the target volume was significantly lower for hVMAT. In hVMAT, as the ratio of VMAT increased, the volume of low-dose region in the heart and lung increased, whereas the volume of the middle- to high-dose region decreased. As the ratio of VMAT increased, the mean dose in the heart decreased, whereas the mean dose in the lung increased.
Favorable dose concentration was obtained for the target volume in hVMAT for stage I esophageal cancer. Altering the ratio of VMAT significantly changed the DVH parameters in normal organs.
背景/目的：本研究聚焦于Ⅰ期食管癌的混合容积调强弧形治疗（hVMAT），并比较了三维适形放疗（3DCRT）与 VMAT 比值变化对剂量分布的影响。
本研究纳入了 2014 年 1 月至 2019 年 4 月在神奈川癌症中心接受 3DCRT 治疗的 15 例 cT1bN0M0 期食管癌患者。在 3DCRT、hVMAT 和 VMAT 治疗计划中，评估了靶区和正常器官的剂量体积直方图（DVH）参数。
hVMAT 的靶区均匀性指数显著降低。在 hVMAT 中，随着 VMAT 比例的增加，心脏和肺部低剂量区域的体积增加，而中高剂量区域的体积减少。随着 VMAT 比例的增加，心脏的平均剂量降低，而肺部的平均剂量增加。
hVMAT 为Ⅰ期食管癌获得了有利的靶区剂量集中。改变 VMAT 的比例会显著改变正常器官的 DVH 参数。
