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Title: SU-F-T-507: Modeling Cerenkov Emissions From Medical Linear Accelerators: A Monte Carlo Study

Abstract

Purpose: Cerenkov emissions are a natural byproduct of MV radiotherapy but are typically ignored as inconsequential. However, Cerenkov photons may be useful for activation of drugs such as psoralen. Here, we investigate Cerenkov radiation from common radiotherapy beams using Monte Carlo simulations. Methods: GAMOS, a GEANT4-based framework for Monte Carlo simulations, was used to model 6 and 18MV photon beams from a Varian medical linac. Simulations were run to track Cerenkov production from these beams when irradiating a 50cm radius sphere of water. Electron contamination was neglected. 2 million primary photon histories were run for each energy, and values scored included integral dose and total track length of Cerenkov photons between 100 and 400 nm wavelength. By lowering process energy thresholds, simulations included low energy Bremsstrahlung photons to ensure comprehensive evaluation of UV production in the medium. Results: For the same number of primary photons, UV Cerenkov production for 18MV was greater than 6MV by a factor of 3.72 as determined by total track length. The total integral dose was a factor of 2.31 greater for the 18MV beam. Bremsstrahlung photons were a negligibly small component of photons in the wavelength range of interest, comprising 0.02% of such photons. Conclusion:more » Cerenkov emissions in water are 1.6x greater for 18MV than 6MV for the same integral dose. Future work will expand the analysis to include optical properties of tissues, and to investigate strategies to maximize Cerenkov emission per unit dose for MV radiotherapy.« less

Authors:
; ;  [1]
  1. Duke University Medical Center, Durham, NC (United States)
Publication Date:
OSTI Identifier:
22649094
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; 62 RADIOLOGY AND NUCLEAR MEDICINE; COMPUTERIZED SIMULATION; EMISSION; EMISSIVITY; INTEGRAL DOSES; LINEAR ACCELERATORS; MONTE CARLO METHOD; PARTICLE TRACKS; PHOTON BEAMS; PRODUCTIVITY; RADIOTHERAPY

Citation Formats

Shrock, Z, Oldham, M, and Adamson, J. SU-F-T-507: Modeling Cerenkov Emissions From Medical Linear Accelerators: A Monte Carlo Study. United States: N. p., 2016. Web. doi:10.1118/1.4956692.
Shrock, Z, Oldham, M, & Adamson, J. SU-F-T-507: Modeling Cerenkov Emissions From Medical Linear Accelerators: A Monte Carlo Study. United States. doi:10.1118/1.4956692.
Shrock, Z, Oldham, M, and Adamson, J. Wed . "SU-F-T-507: Modeling Cerenkov Emissions From Medical Linear Accelerators: A Monte Carlo Study". United States. doi:10.1118/1.4956692.
@article{osti_22649094,
title = {SU-F-T-507: Modeling Cerenkov Emissions From Medical Linear Accelerators: A Monte Carlo Study},
author = {Shrock, Z and Oldham, M and Adamson, J},
abstractNote = {Purpose: Cerenkov emissions are a natural byproduct of MV radiotherapy but are typically ignored as inconsequential. However, Cerenkov photons may be useful for activation of drugs such as psoralen. Here, we investigate Cerenkov radiation from common radiotherapy beams using Monte Carlo simulations. Methods: GAMOS, a GEANT4-based framework for Monte Carlo simulations, was used to model 6 and 18MV photon beams from a Varian medical linac. Simulations were run to track Cerenkov production from these beams when irradiating a 50cm radius sphere of water. Electron contamination was neglected. 2 million primary photon histories were run for each energy, and values scored included integral dose and total track length of Cerenkov photons between 100 and 400 nm wavelength. By lowering process energy thresholds, simulations included low energy Bremsstrahlung photons to ensure comprehensive evaluation of UV production in the medium. Results: For the same number of primary photons, UV Cerenkov production for 18MV was greater than 6MV by a factor of 3.72 as determined by total track length. The total integral dose was a factor of 2.31 greater for the 18MV beam. Bremsstrahlung photons were a negligibly small component of photons in the wavelength range of interest, comprising 0.02% of such photons. Conclusion: Cerenkov emissions in water are 1.6x greater for 18MV than 6MV for the same integral dose. Future work will expand the analysis to include optical properties of tissues, and to investigate strategies to maximize Cerenkov emission per unit dose for MV radiotherapy.},
doi = {10.1118/1.4956692},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = {Wed Jun 15 00:00:00 EDT 2016},
month = {Wed Jun 15 00:00:00 EDT 2016}
}