[en] Objective: To investigate the potential of ⁹⁹Tc^m-Duramycin and ⁹⁹Tc^m-RGD in detecting vulnerable plaque in rabbit models. Methods: Fifteen healthy New Zealand male rabbits were randomly divided into group A (control group, n = 5), group B (stable plaque group, n = 5) and group C (vulnerable plaque group, n = 5). Animals were injected with ⁹⁹Tc^m-Duramycin and ⁹⁹Tc^m-RGD at the end of 4, 8 and 12 weeks. SPECT/CT scanning was performed at 0.5 h post injection. One rabbit was sacrificed at the end of 4 weeks and one at the end of 8 weeks after imaging. The others were sacrificed at the end of 12 weeks after imaging studies. All aortas were collected. Intravascular ultrasound (IVUS) was performed at the end of B, 12 weeks before SPECT/CT scanning. The data was analyzed with paired t test. Results: In group A, the aortas had little uptake of the two probes. In group B, the aortas showed obvious radioactive uptake of ⁹⁹Tc^m-Duramycin and ⁹⁹Tc^m-RGD at the end of 8 weeks and 12 weeks, while ⁹⁹Tc^m-Duramycin gave better display than ⁹⁹Tc^m-RGD. In group C, ⁹⁹Tc^m-Duramycin uptake was higher than ⁹⁹Tc^m-RGD uptake in the aorta. The T/NT ratios of ⁹⁹Tc^m-Duramycin and ⁹⁹Tc^m-RGD in group C were 2.14 ± 0.34 and 1.46 ± 0.34 (t = 4.072, P < 0.05) at the end of 4 weeks, 2.93 ± 0.41 and 1.66 ± 0.22 (t = 5.578, at the end of 8 weeks, 3.25 ± 0.29 and 1.81 ± 0.28 (t = 19.692, P < 0.05) at the end of 12 weeks. In isolated specimen of group C, the yellow lipid plaque of the intima bulged on the lumen at the end of 12 weeks. IVUS indicated that, at the end of 8 weeks and 12 weeks, the endometrial thickness of group C was (450 ± 104) mm and (767 ± 52) mm (t = 44.024, P < 0.05) respectively, and the rates of luminal stenosis were (29.30 ± 2.81)% and (37.98 ± 6.41)% (t = 9.226, P < 0.05). Conclusions: Both ⁹⁹Tc^m-Duramycin and ⁹⁹Tc^m-RGD may be used to detect vulnerable plaque at early time. ⁹⁹Tc^m-Duramycin may detect vulnerable atherosclerotic plaque earlier than ⁹⁹Tc^m-RGD and provide better diagnostic image. (authors)