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Author Mitchell, T. ♦ Bush, K.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY ♦ APPLIED LIFE SCIENCES ♦ ALGORITHMS ♦ APERTURES ♦ CALIBRATION ♦ IMAGES ♦ IONIZATION CHAMBERS ♦ MONTE CARLO METHOD ♦ PARTICLE SOURCES ♦ PATTERN RECOGNITION ♦ PERTURBATION THEORY ♦ PHASE SPACE ♦ PHOTOGRAPHY ♦ RADIATION DOSES
Abstract Purpose: For electron cutouts of smaller sizes, it is necessary to verify electron cutout factors due to perturbations in electron scattering. Often, this requires a physical measurement using a small ion chamber, diode, or film. The purpose of this study is to develop a fast Monte Carlo based dose calculation framework that requires only a smart phone photograph of the cutout and specification of the SSD and energy to determine the electron cutout factor, with the ultimate goal of making this cloud-based calculation widely available to the medical physics community. Methods: The algorithm uses a pattern recognition technique to identify the corners of the cutout in the photograph as shown in Figure 1. It then corrects for variations in perspective, scaling, and translation of the photograph introduced by the user’s positioning of the camera. Blob detection is used to identify the portions of the cutout which comprise the aperture and the portions which are cutout material. This information is then used define physical densities of the voxels used in the Monte Carlo dose calculation algorithm as shown in Figure 2, and select a particle source from a pre-computed library of phase-spaces scored above the cutout. The electron cutout factor is obtained by taking a ratio of the maximum dose delivered with the cutout in place to the dose delivered under calibration/reference conditions. Results: The algorithm has been shown to successfully identify all necessary features of the electron cutout to perform the calculation. Subsequent testing will be performed to compare the Monte Carlo results with a physical measurement. Conclusion: A simple, cloud-based method of calculating electron cutout factors could eliminate the need for physical measurements and substantially reduce the time required to properly assure accurate dose delivery.
ISSN 00942405
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-06-15
Publisher Place United States
Journal Medical Physics
Volume Number 42
Issue Number 6


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