Intracoronary brachytherapy in the Cath Lab. Physics dosimetry, technology and safety considerations.

Vascular brachytherapy for prevention of restenosis is an evolving field. In recent years numerous animal experiments and feasibility clinical pilot trials have demonstrated that low doses of radiation when applied following intracoronary intervention reduce neointimal proliferation, prevent vessel contraction and alter the restenosis rate. This novelty introduced new aspects of vascular radiation biology, radiation physics, radiation safety and new devices to deliver the radiation intraluminally. A variety of beta or gamma isotopes for use in vascular brachytherapy has been suggested. These isotopes are delivered intracoronary to provide the therapeutic dose to the target cell. Two basic platforms of delivery are available: catheter-based systems and radioactive stents. Many practical issues and considerations are related to the implementation of this technology in the cardiac catheterization laboratory. Among these are questions about dosimetry, shielding, handling and disposal of radioisotopes, certification for potential users, expense, which patients should receive the treatment? And who should be the users? and above all the safety and the efficacy of this procedure. These and other issues related to this new exciting field are discussed.