PREPARATION AND PROPERTIES OF RADIOACTIVE RHENIUM GLASS MICROSPHERES INTENDED FOR IN-VIVO RADIOEMBOLIZATION THERAPY

Rhenium glass microspheres composed of metallic rhenium particles disp ersed within a magnesium alumino berate glass matrix were produced by sintering ReO2 powder and glass frit at 1050 degrees C. The in vitro c hemical durability of radioactive and nonradioactive microspheres was determined from chemical corrosion tests on microspheres immersed in p hosphate-buffered saline (PBS) solution at 37 degrees C. The dosimetri c properties of these microspheres also were calculated. The rhenium g lass microspheres are chemically durable in body fluids and release < 1.2% of radioactive rhenium after being immersed in PBS solution for 3 2 days at 37 degrees C. Therapeutic radioactive rhenium activities can be obtained in < 10 h by neutron activation of these microspheres in a thermal neutron flux of 8 x 10(13) cm(-2)s(-1). A 50 mg injection of radioactive rhenium glass microspheres containing 3.7 GBq of Re-186 a nd 8.5 GBq of Re-188 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. (C) 1998 John Wiley & Sons, Inc.