Abstract： Objective To investigate the feasibility of 99Tcm-tetrofosmin G-MPI with a one-day stress/rest protocol in subjects suspected with coronary heart disease (CHD).Methods Fifty-two subjects who had undertaken 99Tcm-tetrofosmin myocardial SPECT and CAG because of suspected CHD were retrospectively analyzed.The patients were divided into a coronary artery stenosis group and a normal group according to CAG results.Exercise and rest G-MPI was performed using a one-day protocol with the interval of exercise and rest imaging at (129 ±4) min.SPECT acquisition started at about 30 min after tracer administration.In addition,during stress imaging,dynamic anterior planar imaging (from 1-30 min after tracer injection) and a planar image at 2 h were acquired.Radioactivity in the left ventricle myocardium,liver and chest was analyzed using ROI technology.Left ventricle myocardial segment perfusion and left ventricle function were evaluated with Cedars myocardial quantitative assessment software.The parameters of left ventricle function (LVEF,EDV and ESV) obtained from G-MPI were compared with that from ultrasonic cardiogram using a paired t test.CAG was used as the gold standard to evaluate the diagnostic efficacy of G-MPI for coronary diseases.Results Radiochemical purity of 99Tcm-tetrofosmin was (97.5 ±0.4)％.The image quality of myocardial SPECT was satisfactory.Radioactivity ratio of the left ventricular myocardium to the liver increased from 12 min after tracer injection and reached a peak (0.710) at 30 min.Left ventricular myocardium was not visualized at the 2 h planar image.The diagnostic sensitivity and specificity of G-MPI for detecting coronary lesions was 84.6％ (22/26) and 92.3％ (24/26),respectively.LVEF,EDV and ESV parameters from G-MPI were comparable with those of ultrasonic cardiogram (LVEF:(60.27 ± 7.49) ％vs (60.84±5.98)％,t=1.254; EDV:(97.82±18.98) ml vs (98.70±17.89) ml,t=0.835; ESV:(47.67±10.32) mlvs (45.49±10.15) ml,t=0.981,allP＞0.05).Conclusions 99Tcm-tetrofosmin is easy to prepare with a stable radiochemical quality.A one-day protocol of stress/rest G-MPI with 99Tcm-tetrofosmin may be feasible and effective in detecting myocardial ischemia and evaluating left ventricular function.