title: 99mTc bone scanning agents--II. Adsorption of 99mTc(Sn)pyrophosphate complexes on the mineral phase of bone.
abstract: The adsorption of pyrophosphate, tin-pyrophosphate and 99mTc(Sn)pyrophosphate on Ca3(PO4)2 was investigated at pH 4.0 and pH 7.4. All components were radioactively labeled. Tin and reduced technetium were in most cases almost completely bound. The adsorption of pyrophosphate, tin(II) and technetium-99m at pH 4.0 was higher than at pH 7.4. The presence of tin gave rise to an increase of the pyrophosphate adsorption that was much larger than can be accounted for by a stoichiometric adsorption of tin-pyrophosphate. It is concluded that tin and technetium are bound as negatively charged complexes with pyrophosphate. Finally it is argued that the fraction of the bone scanning agent that reaches the bone surface is adsorbed completely by the mineral phase.
mesh_terms: D000327:Adsorption; D001665:Binding Sites; D001842:Bone and Bones / Q000000981:diagnostic imaging* / Q000378:metabolism; D002130:Calcium Phosphates / Q000378:metabolism; D011756:Diphosphates / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D011122:Polyphosphates; D011877:Radionuclide Imaging; D013667:Technetium / Q000378:metabolism; D016698:Technetium Tc 99m Pyrophosphate; D014001:Tin / Q000378:metabolism; D014003:Tin Polyphosphates / Q000378:metabolism
chemical_list: D002130:Calcium Phosphates; D011756:Diphosphates; D011122:Polyphosphates; D014003:Tin Polyphosphates; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; C017742:technetium Tc 99m stannous pyrophosphate; D016698:Technetium Tc 99m Pyrophosphate; C485838:calcium phosphate, monobasic, anhydrous; D013667:Technetium; D014001:Tin; C020243:calcium phosphate; C485829:calcium phosphate, dibasic, anhydrous