Endovascular brachytherapy: physics and technology

Brachytherapy is the placement of radiation sources (usually radioactive materials) in or near a target tissue. This paper introduces the physics and technology needed to perform endovascular brachytherapy. Three main delivery systems under investigation are low activity radioactive stents; high activity solid-sources; and high activity gas or liquid filled balloons. A wide range of radionuclides is under consideration for each of these systems. There are fundamental differences in both the local and long-range distribution of radiation around beta or gamma emitting sources. Devices in the microCi range are permanently implanted. Devices in the mCi range are inserted for a few minutes. Both beta and gamma sources can be extremely dangerous if they are mishandled.