Rare earth aluminosilicate glasses for in vivo radiation delivery

This chapter discusses rare earth aluminosilicate (REAS) glasses for use as in vivo radiation delivery vehicles. The glasses discussed herein contain >5 mol% Y2O3, Sm2O3, Ho2O3, or Dy2O3 as a primary component of the glass and are used in the form of microspheres (20 to 40 μm in diameter) or seeds (cylinders ∼0.8 mm in diameter x 5 mm long) to deliver large doses (>15,000 rads (cGy)) of beta radiation to sites inside the body. Relevant nuclear and physical properties of the rare earth aluminosilicate glasses are reviewed with emphasis on dose delivery and the chemical durability of REAS glasses in in vitro environments. Results of clinical trials where a yttrium aluminosilicate glass is used to irradiate malignant tumors in the liver of humans are described. (orig.)