Evaluation of the dose distribution for prostate implants using various 125I and 103Pd sources

Recently, several different models of I-125 and Pd-103 brachytherapy sources have been introduced in order to meet the increasing demand for prostate seed implants. These sources have different internal structures; hence, their TG-43 dosimetric parameters are not the same. In this study, the effects of the dosimetric differences among the sources on their clinical applications were evaluated. The quantitative and qualitative evaluations were performed by comparisons of dose distributions and dose volume histograms of prostate implants calculated for various designs of I-125 and Pd-103 sources. These comparisons were made for an identical implant scheme with the same number of seeds for each source. The results were compared with the Amersham model 6711 seed for I-125 and the Theragenics model 200 seed for Pd-103 using the same implant scheme.