A high-precision, high-resolution and fast dosimetry system for beta sources applied in cardiovascular brachytherapy

A fast dosimetry system based on plastic scintillator detectors has been de veloped which allows three-dimensional measurement of the radiation field i n water of beta-sources appropriate for application in cardiovascular brach ytherapy. This system fulfills the AAPM Task Group 60 recommendations for d osimetry of cardiovascular brachytherapy sources. To demonstrate the use of the system, measurements have been performed with an Y-90-wire source. The dose distribution was determined with a spatial resolution of better than 0.2 mm, with only a few minutes needed per scan. The scintillator dosemeter was absolutely calibrated in terms of absorbed dose to water with a precis ion of +/-7.5%. The relative precision achievable is +/-2.5%. The response of the system is linear within +/-2% for dose rates from 0.5 mGy s(-1) to 5 00 mGy s(-1). (C) 2000 American Association of Physicists in Medicine.