Size and positioning reproducibility of an Ir-192 brachytherapy stepping source

In this paper we describe techniques for measuring the dimensions and posit ion reproducibility of an Ir-192 brachytherapy stepping source. Measurement s were carried out using a 0.25 X 10 X 152 mm(3) collimator placed in front of a detector of our own design. The brachytherapy source was translated p ast the collimator in 0.025 mm increments using a stepper motor. The source was found to be 3.58 mm long and 0.69 mm wide, which is in good agreement with the manufacturer's values of 3.5x0.6 mm(2). The source position was re producible to within 0.12 mm. (C) 2000 American Association of Physicists i n Medicine.