Stent for neutron capture therapy and method of manufacture therefor

Abstract

Improved method and apparatus for neutron capture therapy are disclosed, which may beneficially be used to counteract restenosis. An improved stent and a method for manufacturing the stent are also presented. The stent comprises a stable nuclide having a large neutron capture cross-section. When a clinical need exists for radiation therapy, the stent is irradiated with thermal neutrons, thereby giving rise to radiation in the proximity of the stent to a therapeutic benefit. Since radiation is applied by an external source, it can be delivered at any time after placement of the stent and easily can be repeated. The stent only contains stable nuclides and therefore can be handled without the precautions needed when handling radioactive matter.

Description

FIELD OF THE INVENTION [0001] The present invention relates to intravascular neutron capture therapy. More particularly, the present invention provides methods and apparatus for making and using an implantable stent comprising a material capable of reducing restenosis, thereby improving long-term patency of the implanted stent. BACKGROUND OF THE INVENTION [0002] Over the past 20 years, the number of percutaneous coronary revascularization procedures has increased to more than one million per year. About 50% of these procedures include stent implantation. A stent is often designed as a thin metal wire mesh, which keeps a fabric in a desired shape, for instance forming a very thin tube providing an open channel for a fluid. FIG. 1 illustrates an example of such a stent, which is commercially available from JOMED AB, Helsingborg, Sweden. A polyfluorotetraethylene (“PFTE”) graft material integrated into the stent is used to seal off a perforated or ruptured artery wall. [0003] One drawb...

AI Technical Summary

Benefits of technology

[0016] These and other objects are accomplished by providing a stent having a stable target nuclide with a large capture cross-section for thermal neutrons. This nuclide is preferably incorporated as an alloy in the stent. When there is a clinical need for neutron capture therapy, the stent is irradiated with thermal neutrons, thereby giving rise to ionization radiation around the stent device. Concentration of target nuclide and thermal neutron flux determines dose rate around the stent. Since radiation is applied by an external source, it can be delivered at any time after placement of the stent and easily may be repeated.

Problems solved by technology

One drawback associated with previously known stents is the restenosis effect, i.e., the epithelial cells of the vessel walls adjacent to the ends of the stent and surrounding the stent may experience excess growth of cells, thereby clogging the vessel.

Several problems are common to all devices for this type of intravascular brachytherapy.

Dimensions are small, and misplacement of the radiation source by as little as a few millimeters can give rise to a very inaccurate dose distribution.

Furthermore, working with radioactive sources in a catheterization laboratory is problematic, as a new catheterization has to be performed, thereby adding risk to the patient and costs to the treatment.

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