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10‐MV x‐ray primary and scatter dose calculation using convolutions
Author(s) -
Iwasaki Akira
Publication year - 1990
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 - 10.1118/1.596499
Subject(s) - kerma , convolution (computer science) , dosimetry , percentage depth dose curve , backscatter (email) , physics , computational physics , optics , mathematics , nuclear medicine , ionization , ionization chamber , computer science , medicine , ion , telecommunications , wireless , quantum mechanics , machine learning , artificial neural network
Three‐dimensional (3‐D) forward and backward primary dose spread functions in water were developed for 10‐MV x rays. Three‐dimensional forward and backward primary dose spread functions in a heterogeneous medium were constructed from the ones in water using the density scaling theorem. Each of the forward and backward primary dose components were calculated using a method of convolving the primary water collision kerma distribution with the forward or backward primary dose spread function. Scatter dose was separated into forward and backward components. Each scatter dose component was calculated using a differential scatter method, a kind of convolution method, where the primary water collision kerma distribution was convolved with a differential scatter‐maximum ratio or differential backscatter factor equation. From the dose calculation and measurement results obtained for water phantoms containing a cork or aluminum slab, it was found that the 3‐D forward and backward primary dose functions were effective especially in regions where there was a loss of longitudinal and/or lateral electronic equilibrium.