Abstract
The objective of this study was to determine the area and method of localization of samarium-153-ethylenediaminetetramethylene phosphonic acid (153Sm-EDTMP) in normal bone so that this information might.be used to refine the current dosage regimen and aid in the design of new bone tumor therapeutic radiopharmaceuticals. No binding occurred between 153Sm-EDTMP and any of the non-collagenous proteins of bone in an extract of canine cortical bone using both a gel overlay and solution binding assay. Using electron microscopy and electron probe x-ray analysis, Sm-EDTMP was found to localize in growing areas of rat bone matrix, specifically the layer of osteoid undergoing mineralization during administration of EDTMP. In order to determine the mechanism of localization, thin sections were analyzed for samarium and for hydroxyapatite using selected area electron diffraction analysis after demineralization. In all animals receiving Sm-EDTMP, samarium was detected and narrow bands of hydroxyapatite were preserved on the surface of bone trabecula in regions where samarium was found prior to demineralization. A control rat treated with Sm[^+3] showed complete demineralization and no samarium was detected. These results suggest that there is a strong interaction between EDTMP and hydroxyapatite in vivo. The mineral binding is intimate enough to prevent the dissolution of hydroxyapatite crystals in a solution which will normally remove all mineral from the tissue section.
Chambers, Mark Douglas (1991). Localization of samarium-153 EDTMP in normal bone. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -1207712.