形变配准算法在肺癌自适应放疗中的应用研究

目的 探讨在肺癌自适应放疗中,图像形变配准方法对患者受量评估的影响。方法 在Raystation治疗计划系统平台上,用两种不同的形变配准算法(混合形变配准和生物动力学形变配准)、不同的形变次序(以放疗前图像作为参考图像和以放疗中期图像作为参考图像),共4种不同的形变配准方法为基础计算累积剂量。选择11例接受自适应放疗的肺癌患者,处方剂量在35.0~61.6 Gy之间,用4种形变配准方法分别计算肺、心脏和GTV的D_mean以及GTV的D₉₈和D₂,比较其剂量学差异。结果 用4种不同形变方式计算得到的11例患者肺D_mean的标准差在0.07~0.70 Gy;心脏D_mean的标准差在0.01~0.79 Gy;GTV的D_mean标准差在0.01~2.23 Gy,D₉₈的标准差在0.02~6.51 Gy,D₂的标准差在0.01~0.97 Gy。结论 图像形变配准方式的选择对肺癌自适应放疗的累积剂量计算造成了不可忽视的不确定性。

Application of deformable image registration in adaptive radiotherapy for lung cancer

Objective To evaluate the effect of different Methodsof deformable image registration on the dose evaluation in adaptive radiotherapy for lung cancer. Methods By using Raystation Ver4.5 treatment planning system platform,two algorithms (Hybrid-and Biomechanics-based deformable image registration) and two orders (CT images before and during radiotherapy as reference images) were adopted. Four deformable image registration methods were utilized to calculate the accumulative dose. Eleven patients of lung cancer received adaptive radiotherapy for 35.0-61.6 Gy were recruited. The mean doses of lung,heart and GTV and the D₉₈ and D₂ of GTV were statistically compared using four methods. Results With the four deformable image registration methods,the standard deviation of the mean lung dose of 11 lung cancer patients was ranged from 0.07 to 0.70 Gy,0.01 to 0.79 Gy for the mean heart dose,0.01 to 2.23 Gy for the mean GTV dose,0.02 to 6.51 Gy for the D₉₈ of GTV and 0.01 to 0.97 Gy for the D₂ of GTV,respectively. Conclusion The selection of deformable image registration method causes uncertainty to the calculation of accumulative dose during adaptive radiotherapy for lung cancer.