Patent ID: 6666811
Filing Date: 2003-12-23
Classification: A61K,A61N,A61P,C23C,G21G,H01J,Y10T

Abstract:
A method of producing multilayer coats of a microsphere for mass-production of multilayer one-piece seamless radioactive seeds, comprising the steps of:coating a central sphere having an outside diameter no greater than 1 millimeter with a plurality of layers in succession; one of which is a radioactive layer that contains a therapeutic amount of radioactivity, one of which is a diffusion barrier layer that provides a diffusion barrier coat, and one of which is a protective layer that provides an outer protective coat no more than 0.1 millimeters thick; the step of coating a central sphere having an outside diameter no greater than 1 millimeter with a plurality of layers in succession including the substeps of applying radioactive material to form said radioactive layer, applying said diffusion layer, applying said protective layer and applying a material that reacts chemically with said radioactive material in the radioactive layer.