A Dual Plane Co-RASOR Technique for Accurate and Rapid Tracking and Position Verification of an Ir-192 Source for Single Fraction HDR Brachytherapy

Hendrik de Leeuw¹, Marinus A. Moerland², Marco van Vulpen², Peter R. Seevinck¹, Chris J.G. Bakker¹

Treatment of prostate cancer by single fraction High-Dose-Rate (HDR) brachytherapy potentially provides an improvement in prostate cancer treatment, but safe dose delivery is mandatory. Accurate localization of a HDR source requires adequate temporal and spatial resolution, which are not easily achieved by conventional MRI. In this in vitro study, we present a dual plane version of the 3D co-RASOR technique. Two orthogonal 2D center-out encoded slices allow 3D tracking of an HDR brachytherapy source in inhomogeneous tissue. The method was shown to provide a spatial accuracy comparable to CT, with an appropriate temporal resolution, 3.2 seconds, for the intended application.