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Radial dose distribution of 1 9 2 Ir and 1 3 7 Cs seed sources
Author(s) -
Thomason C.,
Higgins P.
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 - 10.1118/1.596420
Subject(s) - dosimetry , dosimeter , thermoluminescence , thermoluminescent dosimeter , isotropy , materials science , atomic physics , physics , analytical chemistry (journal) , nuclear medicine , optics , nuclear physics , irradiation , chemistry , medicine , chromatography
The radial dose distributions in water around 192 Ir seed sources with both platinum and stainless steel encapsulation have been measured using LiF thermoluminescent dosimeters (TLD) for distances of 1 to 12 cm along the perpendicular bisector of the source to determine the effect of source encapsulation. Similar measurements also have been made around a 137 Cs seed source of comparable dimensions. The data were fit to a third order polynomial to obtain an empirical equation for the radial dose factor which then can be used in dosimetry. The coefficients of this equation for each of the three sources are given. The radial dose factor of the stainless steel encapsulated 192 Ir and that of the platinum encapsulated 192 Ir agree to within 2%. The radial dose distributions measured here for 192 Ir with either type of encapsulation and for 137 Cs are indistinguishable from those of other authors when considering uncertainties involved. For clinical dosimetry based on isotropic point or line source models, any of these equations may be used without significantly affecting accuracy.