Herpes simplex virus thymidine kinase imaging in mice with (1-(2′-deoxy-2′-[18F]fluoro-1-β-D-arabinofuranosyl)-5-iodouracil) and metabolite (1-(2′-deoxy-2′-[18F]fluoro-1-β-D-arabinofuranosyl)-5-uracil)

Purpose FIAU, (1-(2′-deoxy-2′-fluoro-1-β-D-arabinofuranosyl)-5-iodouracil) has been used as a substrate for herpes simplex virus thymidine kinases (HSV-TK and HSV-tk, for protein and gene expression, respectively) and other bacterial and viral thymidine kinases for noninvasive imaging applications. Previous studies have reported the formation of a de-iodinated metabolite of 18F-FIAU. This study reports the dynamic tumor uptake, biodistribution, and metabolite contribution to the activity of 18F-FIAU seen in HSV-tk gene expressing tumors and compares the distribution properties with its de-iodinated metabolite 18F-FAU.