Evaluation of Tumor Position and PTV Margins Using Image Guidance and Respiratory Gating

摘要: Purpose To evaluate the margins currently used to generate planning target volume for lung tumors and determine whether image-guided patient setup or respiratory gating is more effective in reducing uncertainties tumor position. Methods Materials Lung 7 patients were contoured on serial four-dimensional computed tomography (4DCT) data sets (4–8 4DCTs/patient; 50 total) obtained throughout course of treatment. Simulations performed position when was aligned using skin marks, based vertebral bodies, fiducials implanted near tumor, actual under various scenarios gating. Results Because presence uncertainties, reduction overall margin needed completely encompass observed be larger imaged-guided than a simple respiratory-gated Without setup, ranged from 0.9 cm 3.1 tumor. These reduced 0.7–1.7 simulated further with Conclusions Our results indicate that if motion management used, it should conjunction order reduce treatment effectively.