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Extrapolation of linear attenuation coefficients of biological materials from diagnostic‐energy x‐ray levels to the megavoltage range
Author(s) -
Payne William H.,
McDavid William D.,
Waggener Robert G.,
Dennis Michael J.,
Sank Victor J.
Publication year - 1977
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 - 10.1118/1.594351
Subject(s) - extrapolation , attenuation , range (aeronautics) , effective atomic number , atomic number , computational physics , physics , nuclear medicine , mathematics , materials science , atomic physics , statistics , optics , medicine , composite material
A dual‐energy algorithm is used in determining the effective atomic number, atomic density, and electron density of biological substances. These quantities are then used to calculate linear attenuation coefficients at the megavoltage level. The validity of the method is checked several ways, including a comparison of extrapolated values with experimental data reported by Rao and Gregg where linear attenuation coefficients at 60 and 122 keV are used to extrapolate to coefficients at 662 keV. Except for a few instances, the extrapolated values agree quite well with the reported experimental values. This method is also used to calculate coefficients at the 60 Co range, and these are compared with experimental values measured in water and various types of tissue‐equivalent materials. An additional algorithm is developed to extrapolate coefficients in water and bone up to 10 MeV. These quantities are compared with accepted values previously reported in the literature.