Radiopharmaceutical tracking of particles injected into tumors: a model to study clearance kinetics.

Objectives: Success of selective drug therapies depends on the drug's depot time in the target to treat. Depot time is currently being prolonged, using drug-eluting beads or microspheres for selective internal radiation therapy. The purpose of this study was to establish a model for investigating the depot time of particles injected into tumors in relation to tumor vascularization and particle size.