Radionuclide excited phosphorescent material for administering pdt

Abstract

Constructs including bars, capsules, beads, and sheets are configured with a radionuclide core that emits energetic particles activating a phosphorescent shell material surrounding the radionuclide core so that it emits light to administer light therapy or PDT. A biocompatible coating that is generally optically transparent encloses the radionuclide core and phosphorescent material to prevent a patient's body in which the constructs are disposed from being affected by any toxicity of the phosphorescent shell material. In a typical application of the constructs, a photoreactive agent is infused into the treatment site and selectively absorbed by abnormal tissue, for example, in a cancerous tumor. Light emitted by the phosphorescent material when activated by the energetic particles emitted from the radionuclide core administers photodynamic therapy, which destroys the abnormal tissue. Particularly, the beads, which are relatively small in size, can be targeted to abnormal tissue by providing a linking mechanism on the biocompatible coating so that the beads are coupled to antibodies found on the abnormal cells, but not on normal tissue. If a glass phosphor material that includes fused quartz or silica glass doped with metal ions is used for the phosphorescent shell material, the beads or other construct must be exposed to IR or other light, causing electrons that have been trapped inside the glass materials to combine with holes, emitting light of a shorter wavelength. The glass phosphor material is preferable, since it is substantially less toxic than other types of scintillators or phosphor materials.