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SU‐E‐T‐645: Treatment of Multiple Brain Metastases Using Stereotactic Radiosurgery with Single‐Isocenter Volumetric Modulated Arc Therapy: Comparison with Conventional Dynamic Conformal Arc and Static Beam Stereotactic Radiosurgery
Author(s) -
Huang C,
Ren L,
Kirkpatrick J,
Wang Z
Publication year - 2012
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4735734
Subject(s) - isocenter , radiosurgery , nuclear medicine , medicine , collimator , radiation treatment planning , stereotactic radiotherapy , radiation therapy , radiology , physics , optics , imaging phantom
Purpose: To investigate the treatment of multiple brain metastases using stereotactic radiosurgery with single‐isocenter volumetric modulated arc therapy (VMAT) compared with conventional multi‐isocenter dynamic conformal arc therapy (DCAT) and three‐dimensional conformal radiation therapy (3D‐CRT). Methods: Seventeen patients with 2 to 5 brain metastatic lesions were studied. The number of patients with 5, 4, 3, and 2 lesions were 4, 5, 4, and 4, respectively. For patients treated with DCAT/3D‐CRT plans, VMAT plans were retrospectively generated, and vice versa. Single‐isocenter set up was employed in VMAT plans while the number of isocenters was proportional to the number of lesions in DCAT/3D‐CRT plans. The DCAT/3D‐CRT and VMAT plans were generated using iPlan® RT Dose Version 4.1.1 (BrainLAB, Germany) and Eclipse™ Version 8.6 (Varian, USA) treatment planning system, respectively. All plans were designed to be delivered on Novalis Tx™ system (Varian, USA and BrainLAB, Germany), in which the accelerator equipped with a high definition multileaf collimator (HDMLC). Results: Conformity index for VMAT plans were equivalent to or better than that for DCAT/3D‐CRT plans. While VMAT and DCAT/3D‐CRT plans were similar in target coverage, quality of coverage for VMAT plans was better. However, the volume receiving 5Gy was 46% larger for VMAT plans. In addition, the distance from individual lesion to the VMAT isocenter has no impact on VMAT plans. Compared with DCAT/3D‐CRT plans, the mean monitor units (MU) decreased by 42% and the estimated treatment time decreased by 49% for VMAT plans. Conclusions: This work suggests that single‐isocenter VMAT is promising for stereotactic radiosurgery in the treatment of multiple brain metastases. Single‐isocenter VMAT is able to achieve comparable conformity, target coverage and quality of coverage with significantly superior delivery efficiency.