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 < 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 < 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. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 42, 617–625, 1998.