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Experimental determination of dosimetric characteristics of Best ® 125 I brachytherapy source
Author(s) -
Meigooni Ali S.,
Gearheart Darren M.,
Sowards Keith
Publication year - 2000
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 - 10.1118/1.1289256
Subject(s) - brachytherapy , dosimeter , dosimetry , imaging phantom , nuclear medicine , thermoluminescent dosimetry , calibration , thermoluminescent dosimeter , materials science , physics , radiation therapy , medicine , radiology , quantum mechanics
125 I brachytherapy sources are being used for interstitial implants in tumor sites such as the prostate. Recently, the Best ®125 I source became commercially available for interstitial brachytherapy treatment. Dosimetric characteristics (dose rate constant, radial dose function, and anisotropy function) of this source were experimentally determined, following the AAPM Task Group 43 recommendations, and were related to the NIST 1999 calibration assigned to this source. Measurements were performed in Solid Water™ phantom using LiF thermoluminescent dosimeters. The results indicated a dose rate constant, Λ, of 1.01 ± 0.08 cGy h− 1 U− 1for the new source. The radial dose function, g ( r ) , of the new source was measured at distances ranging from 0.5 to 10.0 cm. The anisotropy function, F ( r , θ ) , of the new source was measured at distances of 2, 5, and 7 cm from the source center. These data compare favorably with those from the Nycomed/Amersham Models 6711 and 6702 sources. The anisotropy constant, φ an , of the Best ®125 I source was found to be 0.982. Complete dosimetric parameters of the new source are presented in this paper.