Evaluation of [F-18]FHPG as PET tracer for HSVtk gene expression

In rats, the relationship between [F-18]FHPG accumulation and HSVtk expression was studied with PET and autoradiography. [F-18]FHPG distribution closely corresponded with HSVtk immunohistochemical staining. ROI analysis of tracer uptake 2 hours p.i. and Patlak graphical analysis were applied to quantify the PET data. For both analysis methods, the [F-18]FHPG PET signal correlated well with the fraction of HSVtk expressing cells implanted, but showed a plateau when plotted against HSVtk protein levels. This might be due to rate limiting [F-18]FHPG membrane transport. (C) 2003 Elsevier Inc. All rights reserved.