Evaluation of Tumor Position and PTV Margins Using Image Guidance and Respiratory Gating
- Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)
- Department of Pulmonary Medicine, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)
- Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)
- Department of Radiation Physics, The University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)
- Department of Bioinformatics and Computational Biology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)
Purpose: To evaluate the margins currently used to generate the planning target volume for lung tumors and to determine whether image-guided patient setup or respiratory gating is more effective in reducing uncertainties in tumor position. Methods and Materials: Lung tumors in 7 patients were contoured on serial four-dimensional computed tomography (4DCT) data sets (4-8 4DCTs/patient; 50 total) obtained throughout the course of treatment. Simulations were performed to determine the tumor position when the patient was aligned using skin marks, image-guided setup based on vertebral bodies, fiducials implanted near the tumor, and the actual tumor volume under various scenarios of respiratory gating. Results: Because of the presence of setup uncertainties, the reduction in overall margin needed to completely encompass the tumor was observed to be larger for imaged-guided patient setup than for a simple respiratory-gated treatment. Without respiratory gating and image-guided patient setup, margins ranged from 0.9 cm to 3.1 cm to completely encompass the tumor. These were reduced to 0.7-1.7 cm when image-guided patient setup was simulated and further reduced with respiratory gating. Conclusions: Our results indicate that if respiratory motion management is used, it should be used in conjunction with image-guided patient setup in order to reduce the overall treatment margin effectively.
- OSTI ID:
- 21372229
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 76, Issue 5; Other Information: DOI: 10.1016/j.ijrobp.2009.08.002; PII: S0360-3016(09)02915-0; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
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