Abstract: Apparatus and methods are provided for relieving a stenosed region of a blood vessel such as a coronary artery using a single catheter that relieves the angioplasty by conventional means and then delivers an easily controllable inherently uniform dosage of radiation to the walls of a blood vessel for preventing restenosis after angioplasty. An embodiment of the apparatus comprises a catheter having an angioplasty balloon that is inflatable with a liquid containing a suspended radioactive material such as .sup.125 I or .sup.32 P. The balloon is surrounded by a membrane to capture the radioactive liquid in the event the balloon ruptures. The catheter is advanced through the patient until the balloon is disposed in the stenosed region of the blood vessel.

Abstract: A method is disclosed for treating a blood vessel which has been subjected to interventional dilatation, to inhibit restenosis that would otherwise occur from cellular proliferation attributable to traumatic response at the site of the vessel interior wall where the dilatation was performed. The method includes introducing a radioactive source into the blood vessel so that the source is positioned adjacent to the site, and exposing targeted tissue of the vessel interior wall at the site to said radioactive source for a period of time sufficient to deliver a prescribed dose of radiation to the tissue. The rate at which the prescribed dose is delivered to the targeted tissue is adjusted to positively assure that the rate is held in a range with an upper limit of about 60 rads per second.

Abstract: Apparatus and methods are provided for relieving a stenosed region of a blood vessel such as a coronary using a single catheter that relieves the angioplasty by conventional means and then delivers an easily controllable inherently uniform dosage of radiation to the walls of a blood vessel for preventing restenosis after angioplasty. An embodiment of the apparatus comprises a catheter having an angioplasty balloon that is inflatable with a liquid containing a suspended radioactive material such as .sup.125 I or .sup.32 P. The balloon is surrounded by a membrane to capture the radioactive liquid in the event the balloon ruptures. The catheter is advanced through the patient until the balloon is disposed in the stenosed region of the blood vessel.

Abstract: A method and apparatus for intravascular radiotherapy for prevention of stenosis following angioplasty or other trauma to coronary arteries caused by smooth muscle cell hyperplasia in which a uniform dosage of radiation is delivered to the walls of the artery by positively positioning a radioactive source at the radial center of the artery being treated.

Abstract: 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 .sup.125 l or .sup.32 P. 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.