In a vascular implant for the prevention or elimination of vascular restrictions a tubular body to be inserted into a body vessel includes at least a first nuclide species which has a half life in the range of 7 hours to 7 days and a second nuclide species which has a half life of more than 100 days. Instead of providing a second nuclide species, the first nuclide species may also decay into the second nuclide species thereby providing a high initial radioactivity for a relatively short period and a relatively low radioactivity over a relatively long period.

A plastic catheter system for irradiation therapy by the afterloading method, made from: a flexible plastic matrix having one or more catheters or sheaths embedded therein, and having a synthetic fabric contained within the plastic matrix or on a side of the plastic matrix, wherein: a) when the plastic matrix has all flat surfaces, the synthetic fabric is located on a side opposite the location of the one or more catheters and covers the entire side in area, b) when the plastic matrix is cylindrical in shape, the synthetic fabric is located in a lower portion of the cylindrical plastic matrix and coaxially arranged, and c) when the plastic matrix is of a shape other than a) and b), the synthetic fabric is located on a side facing away from a side from which irradiation occurs.

A plastic catheter system for irradiation therapy by the afterloading method, made from: a flexible plastic matrix having one or more catheters or sheaths embedded therein, and having a synthetic fabric contained within the plastic matrix or on a side of the plastic matrix, wherein: a) when the plastic matrix has all flat surfaces, the synthetic fabric is located on a side opposite the location of the one or more catheters and covers the entire side in area, b) when the plastic matrix is cylindrical in shape, the synthetic fabric is located in a lower portion of the cylindrical plastic matrix and coaxially arranged, and c) when the plastic matrix is of a shape other than a) and b), the synthetic fabric is located on a side facing away from a side from which irradiation occurs.

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. Dose rate adjustment is controlled by selectively setting the distance between the source and the targeted tissue, or by appropriately selecting the length of the source according to the length of the site of targeted tissue along the vessel interior wall, and/or by appropriately attenuating the radiation emitted by the source to a desired reduced magnitude at the site of the targeted tissue, to positively assure that the dose rate delivered to the targeted tissue will not exceed 60 rads per second.

Methods and apparatuses for irradiating stent structures that are selectively collapsible or reducible along their longitudinal axis to reduce the total length thereof are described. Providing a collapsible stent structure reduces the effective surface area which must be exposed to the radiation beam, thereby reducing the time required for the irradiation process. Stent structures suitable for irradiation using the method and apparatus are also described.