Abstract: A method of imaging a subject, the method comprising the steps: administering a radiotracer to the subject such that the radiotracer enters the bloodstream of the subject; allowing the radiotracer to accumulate in a kidney of the subject; and imaging said kidney using positron emission tomography (PET); wherein the radiotracer comprises a protein labelled with a 6-[18F]fluoropyridin-3-ylcarboxy group. The disclosure also relates to radiotracers and compositions suitable for use in said method, as well as to processes, kits and cassettes for preparing said radiotracers.

Abstract: The present invention relates to complexes comprising one or more markers and one or more biomolecules for use as a contrast agent in positron emission tomography based imaging. The complexes according to the present invention preferably accumulate in a target compartment, such as the kidney. The present invention further relates to methods for generating the complexes and methods for using the complexes such as for evaluation of different aspects of kidney functionality e.g. for calculation of total and/or regional glomerular filtration rate in the kidney without the need for sampling blood or urine.

Abstract: The present invention relates to complexes comprising one or more marker(s) and one or more biomolecules. The complexes according to the present invention have a variety of utilities, such as utility as a contrast agent in imaging methods, for example magnetic resonance imaging.