Program Information
Dosimetric Verification and Commissioning for A Small Animal Radiation Research Platform
Y Wang1*, S Lin2 , Y Na3 , P Black4 , C Wu5 , S Cheng6 , E Connolly7 , C Wuu8 , (1) Columbia University, New York, NY, (2) Columbia University, New York, NY, (3) Columbia University Medical Center, New York, NY, (4) Columbia University Medical Center, New York, NY, (5) Columbia University Medical Center, New York, NY, (6) Columbia University Medical Center, New York, NY, (7) Columbia University Medical Center, New York, NY, (8) Columbia University, New York, NY
Presentations
SU-I-GPD-T-642 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose: As advanced small animal models are playing an increasing role in cancer research, there is a corresponding increased need for image-guided, targeted mouse irradiation. In this study, the beam data for small field sizes used in a CBCT image-guided small animal irradiator, Small Animal Radiation Research Platform (SARRP), was acquired using radiochromic films (EBT3) with submillimeter resolution to verify the dosimetric parameters. 2-D dose distributions from EBT3 measurements were also compared with the results from treatment planning system.
Methods: First, dosimetric data including depth dose curves from surface, beam profiles, penumbra, and cone factors were measured with radiochromic films (EBT3) for 220 kV photon beam with 5 different field sizes (0.5 mm, 1 mm, 3x3mm2, 5x5mm2, 10x10mm2) and 33cm SSD. In this study, to acquire accurate and reliable beam data, PDD for larger-size cones was measured by irradiating films along central axis, and PDD for smaller-size cones was measured by irradiating films perpendicular to central axis at different depths. In addition, protocol for film scanning and analysis was optimized. Secondly, Cone factors of all collimators measured with films were compared to those measured with an edge detector. Finally, 2-D dosimetric accuracy of CBCT image-guided target dose calculation in the treatment planning system, Muriplan, was verified with EBT3 film dosimetry.
Results: The flatness and symmetry of all collimators are within ± 3% and 2% at the surface. The difference of planning and measured depth dose at all depths for all collimators was within 5%. The difference of planning and measured penumbra for all collimators was within 0.1 mm.
Conclusion: In this study, comprehensive dosimetric commissioning for an image-guided small animal irradiator with small field sizes was presented. It has been demonstrated that the CBCT-based treatment planning system can provide precise targeting and accurate dosimetry with proper commissioning.
Funding Support, Disclosures, and Conflict of Interest: Grant Number: 1S10RR031622-01A1
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