Dose-volunle characteristics of a 50-kV electronic brachytherapy source for intracavitary accelerated partial breast irradiation

PURPOSE: To describe dose-voluine data from a 50-kV electronic brachytherapy source in intracavitary accelerated partial breast irradiation. METHODS AND MATERIALS: Three spherical balloon applicators were imaged on a CT scanner in a water phantom and inflated throughout their suggested fill volume range. The planning target volume (PTV) was defined as a 1-cm margin around the balloon surface. Plans were created achieving 80%, 85%, and 90% coverage of the PTV, with a prescription dose of 34 Gy in 10 fractions. The PTV, V-90, V-100, V-150, V-200, and V-300 were recorded for each plan. RESULTS: For 80% target coverage, the V-200 varies from 11 to 14 cm(3) and the V-150 from 26 to 49 cm(3) over all the balloon applicators and fill volumes. For 85%, coverage, the V-200 varies from 14 to 18 cm(3) and the V-150 from 27 to 53 cm(3). For 90% coverage, the V-200 varies from 16 to 22 cm(3) and the V-150 cm(3) from 30 to 61 cm(3). CONCLUSIONS: Fifty-kilovolt electronic brachytherapy can provide PTV coverage similar to (192) Ir in the setting of intracavitary accelerated partial breast irradiation. (C) 2007 American Brachytherapy Society. All rights reserved.