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Poster — Wed Eve—23: Electron Energy Spectral Analyses on Electron Backscatter in Solid Water Using Low‐Energy Electron Beams
Author(s) -
Chow J,
Grigorov G
Publication year - 2009
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3244127
Subject(s) - electron , backscatter (email) , monte carlo method , range (aeronautics) , materials science , spectral line , imaging phantom , energy dispersive x ray spectroscopy , atomic physics , physics , optics , scanning electron microscope , nuclear physics , telecommunications , statistics , mathematics , composite material , astronomy , computer science , wireless
Electron energy spectral analyses were carried out to evaluate the dosimetric performance of electron backscatter, when Solid Water was used to substitute water as phantom in electron radiotherapy using low‐energy electron beams (≤ 6 MeV). Monte Carlo simulation (EGSnrc‐based code) was used to predict electron energy spectra of Solid Water and water slabs above 0.3 mm of lead (Pb) layers, using the 4 and 6 MeV electron beams produced by a Varian 21 EX linear accelerator. For the simulation geometry, slabs of Solid Water and water on top of a piece of Pb layer were irradiated by electron beams ( 10 × 10cm 2applicator and cutout) with the source‐to‐surface distance equal to 100 cm. The thickness of Solid Water or water above the Pb layer was equal to 0.5 and 1 cm. Electron energy spectra were determined at scoring planes at depths of 0, 0.5 and 1 cm of the phantoms. For comparison, Monte Carlo simulations were repeated with Pb layers taken out from the phantoms with the same experimental configuration. Analyses of the electron energy spectra at different depths showed that deviation of energy spectra between Solid Water and water was more significant in the high‐energy range ( i.e. close to the maximal electron energy) than lower range corresponding to the electron backscatter. The good agreement for the parts of the spectra representing the electron backscatter in Solid Water and water indicated that Solid Water performed well as a substitute of water for the electron backscatter when using low‐energy electron beams.