Intravascular radiotherapy employing a liquid-suspended source

摘要

Apparatus and methods are provided for delivering an easily controllable inherently uniform dosage of radiation to the walls of a blood vessel for preventing restenosis after angioplasty. The apparatus comprises a catheter having a balloon tip which is inflatable with a liquid containing a suspended radioactive material such as 125l or 32P. The catheter is advanced through the patient until this treatment balloon is disposed in the stenosed region of the blood vessel. The balloon is filled with the radioactive fluid which simultaneously expands and relieves the stenosis while irradiating the tissue, or if the stenosis has previously been relieved, the target tissue is irradiated by filling the treatment balloon with the radioactive fluid until the outer wall of the balloon engages, without substantially expanding, the inner wall of the blood vessel. An outer containment balloon is also provided to prevent loss of radioactive fluid in the event the treatment balloon ruptures and which may be used to perform the angioplasty prior to filling the treatment balloon with the radioactive fluid. The treatment balloon may be configured to minimize the volume of radioactive fluid necessary by providing an inner balloon filled with an inert material or by configuring the treatment balloon itself as a hollow cylinder with an annular chamber for receiving the radioactive fluid.