Investigation of interseed attenuation and tissue composition effects in 125I seed implant prostate brachytherapy

Advanced brachytherapy dose calculation methods that take account of ISA and tissue effects show that clinical 125I implant dose is different from TG-43U1 (AAPM Task Group No. 43 Report-Update 1) calculations, reducing DVH parameter values particularly for patients with calcifications. Peripheral dose and areas of the implant with relatively poorer coverage are particularly affected. However, dose reductions are small compared with other postimplant dose uncertainties.