Skip to content
Licensed Unlicensed Requires Authentication Published by De Gruyter (O) December 16, 2010

Comparison of different phosphorus-containing ligands complexing 68Ga for PET-imaging of bone metabolism

  • M. Fellner , P. Riss , N. S. Loktionova , K. P. Zhernosekov , O. Thews , Carlos F. G. C. Geraldes , Z. Kovacs , I. Lukes and Frank Rösch
From the journal Radiochimica Acta

Abstract

99mTc-phosphonate structures are well established tracers for bone tumour imaging. Our objective was to investigate different 68Ga-labelled phosphonate ligands concerning labelling kinetics, binding to hydroxyapatite and bone imaging using μ-PET. Seven macrocyclic phosphorus-containing ligands and EDTMP were labelled in nanomolar scale with n.c.a. 68Ga in Na-HEPES buffer at pH∼4. Except for DOTP, all ligands were labelled with >92% yield. Binding of the 68Ga-ligand complexes on hydroxyapatite was analysed to evaluate the effect of the number of the phosphorus acid groups on adsorption parameters. Adsorption of 68Ga-EDTMP and 68Ga-DOTP was >83%. For the 68Ga-NOTA-phosphonates an increasing binding with increasing number of phosphonate groups was observed but was still lower than 68Ga-DOTP and 68Ga-EDTMP. μ-PET studies in vivo were performed with 68Ga-EDTMP and 68Ga-DOTP with Wistar rats. While 68Ga-EDTMP-PET showed uptake on bone structures, an excess amount of the ligand (>1.5 mg EDTMP/kg body weight) had to be used, otherwise the 68Ga3+ is released from the complex and forms gallium hydroxide or it is transchelated to 68Ga-transferrin. As a result, the main focus of further phosphonate structures has to be on complex formation in high radiochemical yields with macrocyclic ligands with phosphonate groups that are not required for complexing 68Ga.


* Correspondence address: Johannes-Gutenberg-University of Mainz, Institute of Nuclear Chemistry, Fritz-Strassmann-Weg 2, 55128 Mainz, Deutschland,

Published Online: 2010-12-16
Published in Print: 2011-01

© by Oldenbourg Wissenschaftsverlag, Mainz, Germany

Downloaded on 28.3.2024 from https://www.degruyter.com/document/doi/10.1524/ract.2011.1791/html
Scroll to top button