Radioactivity local delivery system

摘要

To determine a coefficient of diffusion of a radioisotope in a radioisotope-containing implant structure and to calculate a quantity of radioisotope to be introduced in an implant structure in view of administering to a vascular region of a patient's body a dose of radioactivity at a given dose rate, a relation is calculated between a coefficient of diffusion of the radioisotope in the implant structure and a coefficient of diffusion of the radioisotope in the vascular region of the patient's body for at least one given period of time during which the radioisotope has to be released. The diffusion coefficient of the vascular region is determined. The method also determines, from the diffusion coefficient of the vascular region and in connection with the above relation, the diffusion coefficient of the implant structure required to release the radioisotope within the given period of time. Finally, the quantity of radioisotope is calculated from the diffusion coefficient of the vascular region and the diffusion coefficient of the implant structure. The implant structure may comprise a helical stent with a polymer coating incorporating the radioisotope and with struts with varying spacing.