Characterization of Newly Designed EDGE Detector for UHDR FLASH Radiotherapy
A Sloop1*, M Rahman1, J Kozelka2, M Ashraf1,3, P Bruza1, D Gladstone1,4,5, B Pogue1,5,6, J Kapatoes2, W Simon2, R Zhang1,4,5, (1) Dartmouth College, Lebanon, NH, (2) Sun Nuclear Corporation, Melbourne, FL, (3) Stanford University, Stanford, CA, (4) Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College, Hanover, NH, (5) Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, (6) Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover NH
Presentations
(Saturday, 3/26/2022) 10:30 AM - 12:30 PM [Central Time (GMT-5)]
Room: Celestin D-E
Purpose: To characterize the Sun Nuclear EDGE Detector paired with a custom electrometer under electron UHDR-FLASH conditions.
Methods: Dose-rate dependencies, absolute dose measurements, long-term stability, dose-per-pulse, and beam characteristic measurements made with a Sun Nuclear EDGE Detector at Dmax were compared to film, an Exradin W1 Scintillator Detector at Dmax, and an ion chamber placed in the Bremsstrahlung tail for electron FLASH conditions up to 190 Gy/s. The ion chamber was placed in the lower dose Bremsstrahlung region to prevent saturation.
Results: The EDGE detector saw linear responses within 0.2% after repeated deliveries for mean dose rates spanning 30 to 190 Gy/s when compared to the Ion chamber readings. The EDGE detector agreed with IC measured absolute dose to within 0.4%. The EDGE detector agreed with film measured output with varying dose, dose rate, and average dose-per-pulse to within 2%, 5%, and 1%, respectively. Dose-per-pulse agreed with the film within 4% and PDD measurements agreed to within 3%. Under long term exposure, a 2% reduction in response was seen after 5 kGy of radiation was delivered to the detector.
Conclusion: The Sun Nuclear EDGE Detector appears to be a viable detector for measurement of electron FLASH beams and may have potential as a future QA device or as a part of the dose controller for a linear accelerator under conditions where Ion chambers or scintillators normally saturate. Its small size and energy independence could allow for measurements in-vivo during FLASH experimentation. The high temporal resolution was able to maintain a linear response of per-pulse dose up to 0.63 Gy/pulse, and the response was linear for a wide range of doses and mean dose rates.
Keywords
Film, Diodes, Ionization Chamber
Taxonomy
TH- Radiation Dose Measurement Devices: diodes/solid state
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