title: The influence of EDTMP-concentration on the biodistribution of radio-lanthanides and 225-Ac in tumor-bearing mice. The ISOLDE Collaboration.
abstract: High-resolution gamma spectroscopy was applied to measure simultaneously the biodistribution of carrier-free radionuclides of several lanthanides (141Ce, 145Sm, 149Gd, 167Tm) and 225Ac in tumor-bearing nude mice. Mixtures of the radiotracers were injected in solutions containing different concentrations of EDTMP (ethylenediaminetetramethylenephosphonic acid). The strong dependence of liver uptake on the ionic radius of the radio-lanthanides was confirmed for all tracers used. The ratios of radioactivity concentrated in tumour that concentrated in liver are strongly influenced by the EDTMP concentration, reaching values close to 10 for Tm, 3 for Sm, and 1 for Ac. The optimal EDTMP concentrations, giving highest tumor-to-liver ratios of enrichment, were between 1 and 10 mM for 100 microL injected volume for the animal model used in this experiment. In radionuclide therapy using EDTMP as ligands, close control of ligand concentration will be necessary.
authors.affiliation: Cantonal Hospital, University of Geneva, Div. Nuclear Medicine, Switzerland.
authors.forename: G J
authors.initials: GJ
authors.lastname: Beyer
authors.forename: R
authors.initials: R
authors.lastname: Offord
authors.forename: G
authors.initials: G
authors.lastname: Künzi
authors.forename: Y
authors.initials: Y
authors.lastname: Aleksandrova
authors.forename: U
authors.initials: U
authors.lastname: Ravn
authors.forename: S
authors.initials: S
authors.lastname: Jahn
authors.forename: J
authors.initials: J
authors.lastname: Barker
authors.forename: O
authors.initials: O
authors.lastname: Tengblad
authors.forename: M
authors.initials: M
authors.lastname: Lindroos
mesh_terms: D000186:Actinium / Q000493:pharmacokinetics*; D000818:Animals; D002614:Chelating Agents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D008024:Ligands; D008099:Liver / Q000378:metabolism; D008674:Metals, Rare Earth / Q000493:pharmacokinetics*; D051379:Mice; D008819:Mice, Nude; D009374:Neoplasms, Experimental / Q000378:metabolism*; D009943:Organophosphorus Compounds / Q000494:pharmacology*; D014018:Tissue Distribution
chemical_list: D002614:Chelating Agents; D008024:Ligands; D008674:Metals, Rare Earth; D009943:Organophosphorus Compounds; C018940:(ethylenedinitrilo)-tetramethylenephosphonic acid; D000186:Actinium