10 MV x-ray zero-area phantom scatter correction factors (Sp) obtained using three extrapolation methods.
Three sets of 10 MV x-ray zero-area phantom scatter correction factors (Sp) have been obtained using three methods. The three methods are all based on the Bjärngard-Petti extrapolation principle. The three sets of data assume lateral CPE (charged particle equilibrium) for the primary absorbed dose. Using the most reliable set of data, a set of 10 MV x-ray SMRs (scatter-maximum ratios) is produced and parameterized. With respect to the zero-area Sp correction factor at a depth of 2.5 cm, the parameterized expression gives Sp (0; 2.5) = 0.931 and a Rice-Chin Monte Carlo simulation gives Sp (0; 2.5) = 0.927. The former is only 0.4% larger than the latter.
Iwasaki
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School of Allied Medical Sciences, Hirosaki University, Aomori, Japan.
D006801:Humans; D009010:Monte Carlo Method; D019047:Phantoms, Imaging; D011878:Radiotherapy / Q000295:instrumentation / Q000379:methods*; D012542:Scattering, Radiation; D014965:X-Rays