Low-density magnesia-alumina-silica (MAS) microparticles for radiotherapy and/or radioimaging

Microparticles for radio-imaging or radiation therapy in a mammal, comprising biologically compatible magnesia-alumina-silica glass microparticles, said microparticles containing at least one beta or gamma radiation emitting isotope distributed substantially throughout the magnesia-alumina-silica glass which emits an amount of beta or gamma radiation, the microparticles having a chemical durability such that subsequent to administration of the microparticles to the mammal, the microparticles will not release a significant amount of the radioisotope into the mammal's system wherein the glass microparticles comprise approximately 8-14 wt % MgO, 32-35 wt % Al2O3, and 47-52 wt % SiO2.