Evaluation of a new brachytherapy iodine-125 source by AAPM TG43 formalism.
Dosimetric measurements were performed to characterize a new 125I source that is similar in design to existing sources and that has application in interstitial brachytherapy. Thermoluminescent dosimeters were placed in phantom to measure transverse-axis and angular dose profiles over a range of distances from 0.5 to 7 cm. The data were analyzed in terms of parameters recommended by AAPM Task Group #43. Tabular data evaluated in liquid water are provided for the dose-rate constant, lambda, radial dose function, g(r), the anisotropy function, F(r, theta), the anisotropy factor, phi an(r), the point-source approximation anisotropy constant, phi an, and the point-source average dose rate times the square of distance for unit air kerma strength, r2D(r). The new source is compared to the model 6702 125I source design, demonstrating similar dose-rate constant, lambda, and radial dose function, g(r). Differences in the anisotropy of the dose distributions are discussed. Finally, a comparison of the radial dose distribution is made between liquid water and tissue equivalent materials.
Wallace
R E
RE
Department of Radiation Oncology, University of California, Los Angeles 90095-6951, USA. rwallace@ucla.edu
Fan
J J
JJ
D016880:Anisotropy; D001918:Brachytherapy / Q000295:instrumentation* / Q000379:methods / Q000592:standards; D004867:Equipment Design; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008962:Models, Theoretical; D019047:Phantoms, Imaging; D017410:Practice Guidelines as Topic; D011786:Quality Control; D011879:Radiotherapy Dosage; D015203:Reproducibility of Results; D013819:Thermoluminescent Dosimetry / Q000295:instrumentation / Q000379:methods; D014867:Water
D007457:Iodine Radioisotopes; D014867:Water