The newly designed ligands have high potential with regard to PET and SPECT imaging with (68/67)Ga and targeted radionuclide therapy with (177)Lu.

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 10-20 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.

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DOTATOC uptake in NETs is mainly dependent on k (1) (receptor binding) and V(b) (fractional blood volume). Pharmacokinetic data analysis can help to separate blood background activity (V(b)) from the receptor binding (k (1)), which may help to optimise planning of (90)Y-DOTATOC therapy.