68Ga‐PET: a powerful generator‐based alternative to cyclotron‐based PET radiopharmaceuticals

Abstract

PET (positron emission tomography) is a powerful diagnostic and imaging technique which requires short‐lived positron emitting isotopes. The most commonly used are accelerator‐produced ¹¹C and ¹⁸F. An alternative is the use of metallic positron emitters. Among them ⁶⁸Ga deserves special attention because of its availability from long‐lived ⁶⁸Ge/⁶⁸Ga generator systems which render ⁶⁸Ga radiopharmacy independent of an onsite cyclotron. The coordination chemistry of Ga³⁺ is dominated by its hard acid character. A variety of mono‐ and bifunctional chelators have been developed which allow the formation of stable ⁶⁸Ga³⁺complexes and convenient coupling to biomolecules. ⁶⁸Ga coupling to small biomolecules is potentially an alternative to ¹⁸F‐ and ¹¹C‐based radiopharmacy. In particular, peptides targeting G‐protein coupled receptors overexpressed on human tumour cells have shown preclinically and clinically high and specific tumour uptake. Kit‐formulated precursors along with the generator may be provided, similar to the ⁹⁹Mo/^99mTc‐based radiopharmacy, still the mainstay of nuclear medicine. Copyright © 2008 John Wiley & Sons, Ltd.