Monte Carlo dosimetry of the Buchler high dose rate Ir-192 source

In this study a complete set of dosimetric data is presented for the high d ose rate (HDR) source from Amersham used in the Buchler remote afterloading HDR unit. These data have been calculated by means of the Monte Carlo simu lation code GEANT taking into account the detailed geometry of the source. Absolute dose rate distributions in water were calculated around this sourc e and are presented as conventional 2D Cartesian look-up tables. All dosime tric quantities recommended by the AAPM Task Group 43 report have been calc ulated. Quantities determined are: dose rate constant, radial dose function , anisotropy Function, anisotropy factor and anisotropy constant. The dose rate distributions of the Buchler HDR source are compared with those of oth er HDR sources used in brachytherapy, showing that the differences are larg e in zones near the long source axis due to oblique filtration. These Monte Carlo simulated data in water can be used for clinical applications.