Abstract:
It is important to constantly monitor developments in the preclinical imaging arena of infection.
Firstly, novel radiopharmaceuticals with the correct characteristics must be identified to funnel
into the clinic. Secondly, it must be evaluated if enough innovative research is being done and
adequate resources are geared towards the development of radiopharmaceuticals that could
feed into the Nuclear Medicine Clinic in the near future. It is proposed that the ideal infection
imaging agent will involve PET combined with CT but more ideally MRI. The radiopharmaceuticals
currently presented in preclinical literature have a wide selection of vectors and targets.
Ionic formulations of PET-radionuclides such 64CuCl2 and 68GaCl2 are evaluated for bacterial
infection imaging. Many small molecule based radiopharmaceuticals are being investigated
with the most prominent targets being cell wall synthesis, maltodextrin transport (such as [18F]
F-maltotriose), siderophores (bacterial and fungal infections), the folate synthesis pathway
(such as [18F]F-PABA) and protein synthesis (radiolabelled puromycin). Mycobacterial specific
antibiotics, antifungals and antiviral agents are also under investigation as infection imaging
agents. Peptide based radiopharmaceuticals are developed for bacterial, fungal and viral infections.
The radiopharmaceutical development could even react quickly enough on a pandemic to
develop a SARS-CoV-2 imaging agent in a timely fashion ([64Cu]Cu-NOTA-EK1). New immuno-
PET agents for the imaging of viruses have recently been published, specifically for HIV persistence
but also for SARS-CoV2. A very promising antifungal immuno-PET agent (hJ5F) is also
considered. Future technologies could include the application of aptamers and bacteriophages
and even going as far as the design of theranostic infection. Another possibility would be the
application of nanobodies for immuno-PET applications. Standardization and optimization of
the preclinical evaluation of radiopharmaceuticals could enhance clinical translation and
reduce time spent in pursuing less than optimal candidates.
