FIAU: From reporter gene imaging to imaging of bacterial proliferation.

The radioiodinated thymidine analogue, FIAU, is a tracer that has been developed for reporter gene, for cells that were transfected with herpes simplex virus thymidine kinase, HSV-TK. FIAU is also a specific substrate of bacterial TK due to the homology between viral and bacterial TK. In this issue of AJNMMI (http://www.ajnmmi.us), Pullamb-hatla et al. reported that the accumulation of (125)I-FIAU in pulmonary infectious foci correlated with the bacterial burden in the lungs. (125)I-FIAU could be used to monitor the efficacy of anti-microbial therapy in mice. Potentially (124)I-FIAU PET could be used to discriminate microbial from sterile inflammation in patients with prosthetic implants.