SU‐FF‐T‐545: Feasibility Study for Treatment of Intracranial Multi‐Focal Stereotactic Radiosurgery with Multiple Intensity Modulated Arc Technique
Objectives: To investigate the feasibility of using an intensity modulated arc technique for multi‐focal intracranial stereotactic radiosurgery with a single isocenter setup to significantly decrease the treatment time. Methods: A Novalis Tx linear accelerator system with a high‐definition multi‐leaf collimator (HDMLC) was used for treatment. Multiple rotationally modulated beams with HDMLC (RapidArc, Varian Medical Systems) were used for treatment planning. Cone‐beam CT (CBCT) images were used for precise localization during treatment delivery. Patients with 2 to 5 lesions that were previously treated with conventional SRS plans using dynamic conformal arc and conformal beams were retrospectively planned with RapidArc™. Single‐arc RapidArc™, 5‐arc RapidArc™ and conventional SRS plans were compared for target coverage, conformality, dose distribution, and total monitor units. Results: Target coverage for single‐arc RapidArc™, 5‐arc RapidArc™ and conventional SRS plans are similar. The conformality and dose distributions of 5‐arc RapidArc™ plans are equivalent to or better than conventional SRS plans. However, the conformality and dose distributions of single‐arc RapidArc™ plans are slightly poorer than conventional SRS plans, though still reasonable. Overall treatment times with the single‐ and 5‐arc RapidArc™ plans were estimated to be 25% and 30%, respectively, of those of conventional SRS with 5‐isocenters. Conclusion: It is feasible to use intensity modulated arc for stereotactic radiosurgery of multiple intracranial lesions with a single setup. The treatment time can be significantly reduced with this approach. © 2009, American Association of Physicists in Medicine. All rights reserved.
Wang, Z; Kirkpatrick, J; Chang, Z; O'daniel, J; Willett, C; Yin, F
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