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137 Cs dosimetry table for asymmetric source
Author(s) -
Waggener R.,
Lange J.,
Feldmeier J.,
Eagan P.,
Martin S.
Publication year - 1989
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 - 10.1118/1.596424
Subject(s) - dosimetry , table (database) , nuclear medicine , medical physics , physics , computer science , medicine , data mining
A common 1 3 7 Cs brachytherapy source has a 2‐cm physical length and 1.38‐cm active length. The active length is not symmetric with respect to the source center because one source end contains an eyelet. Current dose rate tables assume a symmetric source loading with respect to the source center. A computer program was written to calculate an asymmetric distribution using the manufacturers' source specifications. Corrections were made for attenuation and obliquity through the source materials. Dose rate values in cGy/h for a 1 3 7 Cs source equivalent to 1 mg of 226 Ra are shown as a function of the radius from the source center and angle from the source end containing the eyelet. Dose rate values in the table were confirmed by ferrous sulfate measurements using small volumes. The table values agree with published values at points more distant than a few cm and lying at an angle such that the asymmetry of the source loading has its minimum influence.