In contrast, the current study in a porcine MI model demonstrated that retrovirally transduced sr39HSV1-tk-MSCs suspended in PBS and injected transendomyocardially into the periinfarct area using NOGA guidance, were clearly detectable in the injection site 4–6 hours later by [18F]FEAU PET/CT in all animals. The gene discussed is TKT; the disease is myocardial infarction.