Evaluation of the accuracy of CTVision image-guided stereotactic body radiation therapy for non-small cell lung cancer

Objective: To investigate the accuracy of CTVision image-guided stereotactic body radiation therapy (SBRT) for non-small cell lung cancer (NSCLC). Methods: 10 lung SBRT patients were imaged with CTVision before and after irradiation for acquiring and analyzing the three-dimensional set-up error data sets in our department from October 2010 to May 2012. Gross tumor volumes (GTVs) were contoured on pre-and post-SBRT CT sets and combined for generating internal gross tumor volumes (IGTVs). Planning target volume (PTV) margin was calculated, and IGTVs and PTVs were compared for off-line verification of accuracy of SBRT. A paired t-test statistical analysis was conducted with the datasets using SPSS 17. 0. Results: 80 CT image sets were totally obtained. Setup errors was significant difference before and after radiotherapy in the left-right, superior-inferior and anterior-posterior directions, that were (-0.10 ± 1.30) mm and (-0.15 ± 1.31) mm (P = 0.720), (0.18 ± 1.32) mm and (0.18 ± 1.43) mm (P = 1.000) and (-0.08 ± 1.19) mm and (-0.13 ± 1.18) mm (P = 0.750), respectively. IGTVs of ten patients were smaller than corresponding PTVs (13.53 cm³ and 37.84 cm³, P = 0.000). Conclusion: Accuracy and safety of SBRT could be verified by imaging with CTVision before and after delivery for non-small cell lung cancer. (authors)