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Dose calibrator response to brachytherapy sources: A Monte Carlo and analytic evaluation
Author(s) -
Williamson Jeffrey F.,
Morin Richard L.,
Khan Faiz M.
Publication year - 1983
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 - 10.1118/1.595234
Subject(s) - monte carlo method , brachytherapy , dose rate , point source , dosimetry , nuclear medicine , filtration (mathematics) , physics , computational physics , medical physics , mathematics , optics , statistics , medicine , radiology , radiation therapy
It is well known that the dose calibrator response/unit exposure rate depends significantly upon source energy. However, investigation of 1 3 7 Cs, 1 9 2 Ir, and 2 2 6 Ra brachytherapy sources by empirical, analytical, and Monte Carlo techniques shows that source filtration significantly affects the calibrator reading to exposure rate conversion factor. The results demonstrate that for each clinically used filtration thickness an exposure calibrated standard source is required to establish the response of the well chamber. An interesting consequence of this analysis is that the Sievert point dose algorithm for clinical sources overestimates the dose on the order of 3% at distances of approximately 3.5 cm from the source.