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Title: SU-E-I-87: Calibrating Cherenkov Emission to Match Superficial Dose in Tissue

Abstract

Purpose: Through Monte Carlo simulations and phantom studies, the dominant factors affecting the calibration of superficial Cherenkov intensity to absolute surface dose was investigated, including tissue optical properties, curvatures, beam properties and imaging angle. Methods: The phasespace files for the TrueBeam system from Varian were used in GAMOS (a GEANT4 based Monte Carlo simulation toolkit) to simulate surface emission Cherenkov signals and the correlated deposited dose. The parameters examined were: i) different tissue optical properties (skin color from light to dark), ii) beam types (X-ray and electron beam), iii) beam energies, iv) thickness of tissues (2.5 cm to 20 cm), v) SSD (80 cm to 120 cm), vi) field sizes (0.5×0.5 cm2 to 20×20 cm2), vii) entrance/exit sides, viii) curvatures (cylinders with diameters from 2.5 cm to 20cm) and ix) imaging angles (0 to 90 degrees). In a specific case, for any Cherenkov photon emitted from the surface, the original position and direction, final position and direction and energy were recorded. Similar experimental measurements were taken in a range of the most pertinent parameters using tissue phantoms. Results: Combining the dose distribution and sampling sensitivity of Cherenkov emission, quantitatively accurate calibration factors (the amount of radiation dose represented by amore » single Cherenkov photon) were calculated. The data showed relatively large dependence upon different optical properties, curvature, entrance/exit and beam types. For a diffusive surface, the calibration factor was insensitive to imaging angles smaller than 60 degrees. Normalization with the reflectance image was experimentally validated as a simple and accurate method for calibrations of different optical properties. Conclusion: This study sheds light on how and to what extent different conditions affect the calibration from Cherenkov intensity to absolute superficial dose and provides practical solutions to allow quantitative Cherenkov imaging to be used as a dose surrogate for imaging.« less

Authors:
;  [1]; ;  [2]
  1. Dartmouth College, Hanover, NH (United States)
  2. Dartmouth Hitchcock-Medical Center, Hanover, NH (United States)
Publication Date:
OSTI Identifier:
22494029
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 42; Journal Issue: 6; Other Information: (c) 2015 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-2405
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; ANIMAL TISSUES; BIOMEDICAL RADIOGRAPHY; CALIBRATION; COMPUTERIZED SIMULATION; ELECTRON BEAMS; MONTE CARLO METHOD; PHANTOMS; PHOTONS; RADIATION DOSE DISTRIBUTIONS; RADIATION DOSES; THICKNESS

Citation Formats

Zhang, R, Pogue, B, Glaser, A, and Gladstone, D. SU-E-I-87: Calibrating Cherenkov Emission to Match Superficial Dose in Tissue. United States: N. p., 2015. Web. doi:10.1118/1.4924084.
Zhang, R, Pogue, B, Glaser, A, & Gladstone, D. SU-E-I-87: Calibrating Cherenkov Emission to Match Superficial Dose in Tissue. United States. https://doi.org/10.1118/1.4924084
Zhang, R, Pogue, B, Glaser, A, and Gladstone, D. 2015. "SU-E-I-87: Calibrating Cherenkov Emission to Match Superficial Dose in Tissue". United States. https://doi.org/10.1118/1.4924084.
@article{osti_22494029,
title = {SU-E-I-87: Calibrating Cherenkov Emission to Match Superficial Dose in Tissue},
author = {Zhang, R and Pogue, B and Glaser, A and Gladstone, D},
abstractNote = {Purpose: Through Monte Carlo simulations and phantom studies, the dominant factors affecting the calibration of superficial Cherenkov intensity to absolute surface dose was investigated, including tissue optical properties, curvatures, beam properties and imaging angle. Methods: The phasespace files for the TrueBeam system from Varian were used in GAMOS (a GEANT4 based Monte Carlo simulation toolkit) to simulate surface emission Cherenkov signals and the correlated deposited dose. The parameters examined were: i) different tissue optical properties (skin color from light to dark), ii) beam types (X-ray and electron beam), iii) beam energies, iv) thickness of tissues (2.5 cm to 20 cm), v) SSD (80 cm to 120 cm), vi) field sizes (0.5×0.5 cm2 to 20×20 cm2), vii) entrance/exit sides, viii) curvatures (cylinders with diameters from 2.5 cm to 20cm) and ix) imaging angles (0 to 90 degrees). In a specific case, for any Cherenkov photon emitted from the surface, the original position and direction, final position and direction and energy were recorded. Similar experimental measurements were taken in a range of the most pertinent parameters using tissue phantoms. Results: Combining the dose distribution and sampling sensitivity of Cherenkov emission, quantitatively accurate calibration factors (the amount of radiation dose represented by a single Cherenkov photon) were calculated. The data showed relatively large dependence upon different optical properties, curvature, entrance/exit and beam types. For a diffusive surface, the calibration factor was insensitive to imaging angles smaller than 60 degrees. Normalization with the reflectance image was experimentally validated as a simple and accurate method for calibrations of different optical properties. Conclusion: This study sheds light on how and to what extent different conditions affect the calibration from Cherenkov intensity to absolute superficial dose and provides practical solutions to allow quantitative Cherenkov imaging to be used as a dose surrogate for imaging.},
doi = {10.1118/1.4924084},
url = {https://www.osti.gov/biblio/22494029}, journal = {Medical Physics},
issn = {0094-2405},
number = 6,
volume = 42,
place = {United States},
year = {Mon Jun 15 00:00:00 EDT 2015},
month = {Mon Jun 15 00:00:00 EDT 2015}
}