基于kV-CBCT图像验证非小细胞肺癌立体定向放疗的照射剂量

Delivered dose verification for stereotactic body radiotherapy in non-small cell lung cancer using kilovoltage cone-beam computed tomography image

目的:基于千伏级锥形束CT(kV-CBCT)图像验证非小细胞肺癌(NSCLC)立体定向放疗(SBRT)的照射剂量。方法:收集20例行SBRT的NSCLC患者的100张CBCT图像。采用形变配准和非形变配准两种方法在CBCT图像上对单次照射剂量分布进行重新计算。使用剂量体积直方图对计划剂量和重新计算的照射剂量进行比较。结果:患者内靶区的平均覆盖率(V100%)相对差异较小;计划之间的适形度指数和梯度指数表现出很好的一致性。对于危及器官,在计划剂量和照射剂量之间仅在一名患者中发现有明显差异(P<0.05)。结论:CBCT图像能用来验证NSCLC的SBRT剂量,并提供相关的3D执行剂量的信息。

Objective To verify the delivered dose of stereotactic body radiotherapy(SBRT) in non-small cell lung cancer(NSCLC) using kilovoltage cone-beam computed tomography(kV-CBCT) image. Methods A total of 100 CBCT images were collected from 20 patients receiving SBRT for NSCLC. Delivered fractionated dose distributions were recalculated on CBCT images using deformable registration and non-deformable registration, separately. The planned and delivered dose distributions were compared using dose-volume histograms. Results The relative differences in the average target coverage(V100%) of internal target volume were small. The conformity index and gradient index showed a good agreement among the plans. For the organs-at-risk, significant differences between the planned dose and delivered dose were found in only one patient(P<0.05). Conclusion CBCT images can be used to verify the delivered dose of SBRT in NSCLC and provide relevant 3D executive dose information.