Electron Beam Response Corrections for an Ultra-High-Dose-Rate Capable Diode Dosimeter

Authors

Tianyuan Dai, Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA.
Austin M. Sloop, Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA.
Andreas Schönfeld, Sun Nuclear Corp, Melbourne, Florida, USA.
Veronika Flatten, Sun Nuclear Corp, Melbourne, Florida, USA.
Jakub Kozelka, Sun Nuclear Corp, Melbourne, Florida, USA.
Jeff Hildreth, Sun Nuclear Corp, Melbourne, Florida, USA.
Simon Bill, Sun Nuclear Corp, Melbourne, Florida, USA.
Jacob P. Sunnerberg, Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA.
Megan A. Clark, Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA.
Lesley Jarvis, Department of Medicine, Geisel School of Medicine, Dartmouth College Hanover, Lebanon, New Hampshire, USA.
Brian W. Pogue, Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA.
Petr Bruza, Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA.
David J. Gladstone, Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA.
Rongxiao Zhang, Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA.

Author Type(s)

Faculty

DOI

10.1002/mp.17121

Journal Title

Medical Physics

First Page

5738

Last Page

5745

Document Type

Article

Publication Date

8-1-2024

Department

Radiation Medicine

Abstract

BACKGROUND: Ultra-high-dose-rate (UHDR) electron beams have been commonly utilized in FLASH studies and the translation of FLASH Radiotherapy (RT) to the clinic. The EDGE diode detector has potential use for UHDR dosimetry albeit with a beam energy dependency observed. PURPOSE: The purpose is to present the electron beam response for an EDGE detector in dependence on beam energy, to characterize the EDGE detector's response under UHDR conditions, and to validate correction factors derived from the first detailed Monte Carlo model of the EDGE diode against measurements, particularly under UHDR conditions. METHODS: Percentage depth doses (PDDs) for the UHDR Mobetron were measured with both EDGE detectors and films. A detailed Monte Carlo (MC) model of the EDGE detector has been configured according to the blueprint provided by the manufacturer under an NDA agreement. Water/silicon dose ratios of EDGE detector for a series of mono-energetic electron beams have been calculated. The dependence of the water/silicon dose ratio on depth for a FLASH relevant electron beam was also studied. An analytical approach for the correction of PDD measured with EDGE detectors was established. RESULTS: Water/silicon dose ratio decreased with decreasing electron beam energy. For the Mobetron 9 MeV UHDR electron beam, the ratio decreased from 1.09 to 1.03 in the build-up region, maintained in range of 0.98-1.02 at the fall-off region and raised to a plateau in value of 1.08 at the tail. By applying the corrections, good agreement between the PDDs measured by the EDGE detector and those measured with film was achieved. CONCLUSIONS: Electron beam response of an UHDR capable EDGE detector was derived from first principles utilizing a sophisticated MC model. An analytical approach was validated for the PDDs of UHDR electron beams. The results demonstrated the capability of EDGE detector in measuring PDDs of UHDR electron beams.

Recommended Citation

Dai, T., Sloop, A. M., Schönfeld, A., Flatten, V., Kozelka, J., Hildreth, J., Bill, S., Sunnerberg, J. P., Clark, M. A., Jarvis, L., Pogue, B. W., Bruza, P., Gladstone, D. J., & Zhang, R. (2024). Electron Beam Response Corrections for an Ultra-High-Dose-Rate Capable Diode Dosimeter. Medical Physics, 51 (8), 5738-5745. https://doi.org/10.1002/mp.17121