Delivered Dose Verification for Lung Cancer Stereotactic Body Radiotherapy Using Cone-Beam CT

Purpose: Verified the delivered dose distribution of lung cancer Stereotactic Body Radiotherapy (SBRT) using the cone-beam CT images. Methods: Twenty lung cancer patients who underwent SBRT with 100 CBCT images were enrolled in this study. Delivered dose distributions were recalculated on CBCT images with the deformed and non-deformed methods, respectively. The planned and delivered dose distributions were compared using the dose-volume histograms. Results: The delivered target coverage (V100) per patient inside target volume deviated on average were 0.83% ± 0.86% and 1.38% ± 1.40% for Pct vs. Pcbct and Pct vs. Pdcbct, respectively. The Conformity Index (CI) and Gradient Index (GI) showed a good agreement among the plans. For the critical organs, only minor differences were observed between the planned dose and the delivered dose. Conclusions: CBCT images were a useful tool for setup and dose delivery verification for lung cancer patients who underwent SBRT.