Suresh Rana1, E James Jebaseelan Samuel2. 1. Department of Radiation Oncology, Miami Cancer Institute, Baptist Health South Florida, Miami, FL, USA; Department of Radiation Oncology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA; Department of Physics, School of Advanced Sciences, Vellore Institute of Technology, Vellore, India. Electronic address: suresh.rana@gmail.com. 2. Department of Physics, School of Advanced Sciences, Vellore Institute of Technology, Vellore, India.
Abstract
PURPOSE: The purpose of the current study is to (i) investigate the feasibility of utilizing the XRV-124 - a cone-shaped scintillation detector - to measure the spot size and spot position in pencil beam scanning proton therapy, and (ii) compare the spot sizes acquired by the XRV-124 with that of the widely used Lynx detector. METHODS: Spot position was tested by delivering a map of 30 spots at different locations to the XRV-124. Spot position test included energies 70-210 MeV. Spot size measurements were performed at the isocenter using the XRV-124 and Lynx detectors for a total of 32 energies (70-225 MeV at an increment of 5 MeV) at four cardinal gantry angles. RESULTS: The position (X, Y, and Z) of the radiation isocenter was within ±0.3 mm. For spots placed on the horizontal (X) and longitudinal (Y) axes of the spot map, both the X and Y locations of the spots were within ±0.5 mm. The spots placed diagonally in the map showed a higher deviation (±0.9 mm). In evaluating spot sizes acquired using the XRV-124 vs. Lynx, the results from the XRV were found to be slightly higher but within 0.2 mm for energies ≥130 MeV and within 0.4 mm for energies <130 MeV. CONCLUSIONS: It is feasible to utilize the XRV-124 to perform the quality assurance of position and size of a pencil proton beam around the radiation isocenter but within the usable XRV-124 cone area.
PURPOSE: The purpose of the current study is to (i) investigate the feasibility of utilizing the XRV-124 - a cone-shaped scintillation detector - to measure the spot size and spot position in pencil beam scanning proton therapy, and (ii) compare the spot sizes acquired by the XRV-124 with that of the widely used Lynx detector. METHODS: Spot position was tested by delivering a map of 30 spots at different locations to the XRV-124. Spot position test included energies 70-210 MeV. Spot size measurements were performed at the isocenter using the XRV-124 and Lynx detectors for a total of 32 energies (70-225 MeV at an increment of 5 MeV) at four cardinal gantry angles. RESULTS: The position (X, Y, and Z) of the radiation isocenter was within ±0.3 mm. For spots placed on the horizontal (X) and longitudinal (Y) axes of the spot map, both the X and Y locations of the spots were within ±0.5 mm. The spots placed diagonally in the map showed a higher deviation (±0.9 mm). In evaluating spot sizes acquired using the XRV-124 vs. Lynx, the results from the XRV were found to be slightly higher but within 0.2 mm for energies ≥130 MeV and within 0.4 mm for energies <130 MeV. CONCLUSIONS: It is feasible to utilize the XRV-124 to perform the quality assurance of position and size of a pencil proton beam around the radiation isocenter but within the usable XRV-124 cone area.