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Extrapolated surface dose measurements with radiochromic film
Author(s) -
Butson Martin J.,
Yu Peter K. N.,
Metcalfe Peter E.
Publication year - 1999
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 - 10.1118/1.598539
Subject(s) - ionization chamber , dosimetry , materials science , extrapolation , percentage depth dose curve , optics , beam (structure) , ionization , dose profile , surface (topology) , photon , atomic physics , physics , nuclear medicine , ion , medicine , mathematical analysis , geometry , mathematics , quantum mechanics
A radiochromic film extrapolation method is described for the measurement of surface dose from high energy photon beams. Extrapolated central axis entrance surface dose using Gafchromic film for a 10 × 10 cm 2field size is 15 % ± 2 % and 13 % ± 2 % of D maxfor 6 and 10 MV x rays, respectively. Extrapolated surface dose for a 30 × 30 cm 2field with a 10 mm perspex block tray is 49 % ± 2 % and 48 % ± 2 % of D maxfor 6 and 10 MV beams, respectively. All results agree with uncorrected Attix parallel plate ionization chamber surface ionization within 4% for the same beam energies and configurations.