Optimization of a 90Sr/ 90Y radiation source train stepping for intravascular brachytherapy

Abstract

Purpose: Intravascular brachytherapy (IVB), using Beta radiation sources, has been shown to reduce the risk of subsequent restenosis in patients suffering from in-stent restenosis. The Beta-Cath™ device (Novoste Corporation, GA) that is currently used for such treatment has a 3 cm long 90Sr/90Y radiation source train (RST). While this device can deliver a relatively uniform radiation dose to a target coronary vessel of ≤ 2.5 cm in length, treatment of longer vessel lengths is challenging since abutting or overlapping fields must be used, and the RST must be stepped to achieve target coverage. However, such stepping of the RST may produce hot/cold spots in the target. We have developed and herein present a deterministic optimization algorithm that modulates the RST dwell time and dwell position to minimize dose heterogeneity in the target vessel. The dose distributions resulting from uniform stepping and the optimized dwell patterns are compared.