[en] Six radiopharmaceuticals were screened in a small-animal model as potential infarct-localizing agents. The model used was subcutaneous inyection of isoproterenol (30 mg/kg of body weight) - induced myocardial lesions in rats, similar to an infarct and ischemia in human beings, corroborated by histological findings. The uptake of each radiopharmaceuticals is measured at various times after lesion initiation. The results are expressed as % I.D./g and through the contrast relations between the activity of whole heart of treated rats and the others tissues. The relation damaged heart/normal heart (DH/NH) of the phosphorated radiopharmaceuticals (sup(99m) Tc-PPi, sup(99m) Tc-MDP, sup(113m) In-EDTMP), and ¹⁹⁷Hg-MPG are significatively greater in rats with heart damaged than in the controls animals (undamaged); these were followed by sup(99m) Tc-GH and sup(99m) Tc-DMSA. Sup(99m) Tc-PPi, was the tracer that showed the mot favorable concentration in the lesion and the best target-non target ratios in most of the time intervals. At early time intervals ¹⁹⁷Hg-MPG showed the best DH/NH relation. (Author)