Abstract: The purpose of this study was to evaluate the necrosis target and imaging potential of necrotic myocardium of ¹³¹I-emodin and ¹³¹I-emodic acid. The iodogen coating method was used to radioiodinate emodin and emodic acid with iodine-131. Mice model of muscular necrosis and rat model of myocardial infarction(MI)were established to evaluate the necrosis affinity and imaging potential of ¹³¹I-emodin and ¹³¹I-emodic acid. Mice were sacrificed at 2, 12 and 24 h after injection respectively. The radioactive uptake in major organs and necrotic muscle were calculated by a γ-counter. At 6 h after administration, SPECT/CT imaging of necrotic myocardium in rats, biodistribution detection, histopathological analysis were applied to evaluate their necrosis affinity and imaging potential. The results of biodistribution from mice demonstrated that ¹³¹I-emodin and ¹³¹I-emodic acid showed peculiar necrosis target and exhibited an obvious clearance of radioactivity from normal organs. On SPECT/CT images, relatively high uptake as a hot spot was shown in the heart of the model rat, while no obvious uptake was observed in the heart of the control rat. The radioactivity ratios of necrotic to normal myocardium of ¹³¹I-emodin and ¹³¹I-emodic acid amounted up to 9. 72 and 13. 14 by quantitative autoradiography analysis, respectively. These results suggested that ¹³¹I-emodin and ¹³¹I-emodic acid possess the necrosis target and imaging potential of necrotic myocardium.