"Dysprosium aluminosilicate (DyAS) glass microspheres have a chemical durability which should be satisfactory for their in vivo use as a radiopharmaceutical. This recommendation is based upon the detection, by Inductively Coupled Plasma (ICP) analysis, of no cation leakage greater than 0.01 mg from DyAS glass microspheres in distilled water, 0.85wt% saline solution, and 0.1 wt% hyaluronic acid in 0.85wt% saline solution for 25 hours at 37 °C, the time period over which 99.9% of the activity of the radioisotope Dy165 decays. A weight loss of 0.01 mg of radioactive Dy165 after injection would result in a whole body dose of only 47 microrad which is less than the acceptable annual dosage limit of 0.5 rad. Cation leakage was detected in 0.1 wt% and 0.01 wt% ethylenediaminetetraacetic (EDTA) acid in 0.85 wt% saline solution after 7 hours or 5 Dy165 half lives. Bulk DyAS glasses have dissolution rates ranging from 3 to 10 x 10~9 g/cm2/min after 4 weeks in distilled water at 70 °C or after 2 weeks in saline at 37 °C. The dissolution rate for DyAS bulk glasses after 4 weeks in 0.1 N HC1 at 37 °C and 50 °C ranged from 2 to 30 xlO'7 g/cm2/min. DyAS glasses dissolved congruently at values of the Si02/Dy2C>3 molar ratio less than four in 0.1 N HC1 at 50 °C. DyAS glasses which had a molar ratio greater than about 4 formed a silica rich layer after preferential leaking of dysprosium and aluminum. The glass formation region was determined and properties (density, refractive index, thermal expansion and hardness) were measured for the DyAS glasses. The structure of the DyAS glasses was also discussed after examination using infra-red spectrum analysis"--Abstract, page iv.
Day, D. E.
Reidmeyer, Mary R.
Brown, Roger F.
Materials Science and Engineering
M.S. in Ceramic Engineering
University of Missouri--Rolla
xi, 70 pages
© 1993 Amy Louise McIntyre, All rights reserved.
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McIntyre, Amy Louise, "Chemical durability of Dy₂O₃-Al₂O₃-SiO₂ glasses for use as in vivo radiopharmaceuticals" (1993). Masters Theses. 1174.
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