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Original article68Ga-labelled DOTA-derivatised peptide ligandsG.-J. Meyer1, H. Mcke2, J. Schuhmacher3, W. H. Knapp1, M. Hofmann11 Klinik fr Nuklearmedizin, Medizinische Hochschule Hannover, Hannover, Germany2 Universittsspital Basel, Switzerland3 Deutsches Krebsforschungszentrum, Heidelberg, GermanyReceived: 15 November 2003 / Accepted: 28 January 2004 / Published online: 17 March 2004
Springer-Verlag 2004Abstract. 68Ge/68Ga generators provide cyclotron-independent access to positron emission tomography (PET)
radiopharmaceuticals. We describe a system which allows the safe and efficient handling of 68Ge/68Ga generator eluates for labelling of DOTA-derivatised peptide ligands. The system comprises concentration and purification of the 68Ga eluate as well as labelling and purification steps for peptides, and can be used with different
68Ge/68Ga generator types. The suitability and efficiency
were tested with two different DOTA-derivatised somatostatin derivatives and a DOTA-derivatised bombesin derivative. Amounts of 1020 nmol of the peptides
were sufficient and resulted in labelling yields of 50%
for all peptides. The built-in safety precautions have
proven to be appropriate in allowing use of the method
for routine clinical applications. The system was set up
and operated in a hot lab by personnel with no previous experience in the preparation of PET radiopharmaceuticals.Keywords: Radiopeptides PET Gallium-68
68Ge/68Ga generator DOTAEur J Nucl Med Mol Imaging (2004) 31:10971104DOI 10.1007/s00259-004-1486-0Introduction68Ga is a short-lived positron emitter (half-life 67.6 min),
the production of which requires no cyclotron since it is
available as a generator nuclide. 68Ge/68Ga generators
(half-life of the parent radionuclide 68Ge=270.8 days) are
commercially available as systems which yield a radiochemical. The 68Ga solutions which can be obtained
from the generators are usually too acidic and too diluted
for use in direct labelling procedures. The aim of this
work was the development of a method to concentrate
the 68Ga solution and to reduce the acidity in order to
obtain a 68Ga solution suitable for the labelling of
nanomolar amounts of peptides.Whereas earlier described 68Ge/68Ga generator types,
based on alumina support, were eluted with a solution of
a strong complexing agent like EDTA [1, 2], more recent
generator systems are eluted with solutions of weaker
complexing agents like aqueous citrate, sodium hydroxide solution or hydrochloric acid at various strengths(5.5 M to 0.1 M), depending on the generator matrix. As
a matrix for such generators, a pyrogallol-formaldehyde
copolymer has been used successfully for elution with5.5 M HCl [3], alpha...