Preparation and Properties of Radioactive Rhenium Glass Microspheres Intended for in Vivo Radioembolization Therapy

Rhenium glass microspheres composed of metallic rhenium particles dispersed within a magnesium alumino borate glass matrix were produced by sintering ReO2 powder and glass frit at 1050°C. The in vitro chemical durability of radioactive and nonradioactive microspheres was determined from chemical corrosion tests on microspheres immersed in phosphate-buffered saline (PBS) solution at 37°C. The dosimetric properties of these microspheres also were calculated. The rhenium glass microspheres are chemically durable in body fluids and release \u3c 1.2% of radioactive rhenium after being immersed in PBS solution for 32 days at 37°C. Therapeutic radioactive rhenium activities can be obtained in \u3c 10 h by neutron activation of these microspheres in a thermal neutron flux of 8 × 1013 cm-2s-1. A 50 mg injection of radioactive rhenium glass microspheres containing 3.7 GBq of 186Re and 8.5 GBq of 188Re could deliver a 100 Gy dose to a cancerous liver while limiting the total body dose from rhenium dissolution in vivo to approximately 1 mGy