Experimental research of PET imaging with novel 18F-labeled myocardial perfusion imaging tracer: 18F-MyoZone / 中华核医学与分子影像杂志

ABSTRACT

Objective To investigate the biodistribution of 4-chloro-2-tert-butyl-5-[2-[[1-[2-[2-18 F-fluroethoxy] ethoxymethyl]-1H-1,2,3-triazol-4-yl] methyl] phenylmethoxy]-3(2H)-pyridazinone (18F-MyoZone) and evaluate its clinical potential as a PET myocardial perfusion imaging (MPI) tracer in miniswine.Methods 18F-MyoZone was prepared.Twelve Bama mini-swine were intravenously injected with approximately 111 MBq of 18F-MyoZone to evaluate PET imaging characteristics.Whole-body PET scans were performed at the timing of 5,20,40,60 and 120 min postinjection to measure time-dependent mean stand-ardized uptake value (SUVmean) in multiple organs of health animals (n =6).SUVmean ratios of myocardium/liver and myocardium/lung over time were then calculated.Mini-swine with induced acute myocardial infarction (n =3) and chronic myocardial ischemia (n =3) accompanying with health mini-swine (n =3) were utilized to evaluate the diagnostic capability of 18F-MyoZone PET MPI.Results The typical decay-corrected radiochemical yield of 18 F-MyoZone reached (52.0±4.3)％ (n =3) with a high radiochemical purity (＞98％).In the biodistribution study,high initial myocardial uptake (SUVmean =10.40±2.40 at 5 min postinjection) and remarkable myocardial retention (SUVmean =9.30±2.00 at 120 min postinjection) were observed.The adjacent organs (like the liver and lungs) indicated low tracer uptake and rapid clearance.The heart/liver and heart/lung SUVmean ratios were 4.77±0.91 and 17.14±5.84 respectively at 5 min postinjection,with an increase to 11.16± 1.38 and 21.69±7.09 at 120 min postinjection.In the MPI study of miniswine,normal myocardium demonstrated uniform tracer distribution with clearly visualizable myocardial boundary,infarct myocardium and severe ischemia myocardium performed intense resting perfusion defect,and ischemia myocardium revealed reversible perfusion defect by stress/rest MPI.The myocardial image quality remained stable within 120 min postinjection.Conclusions MPI with 18F-MyoZone exhibits high initial myocardial uptake and low extracardiac activities in adjacent organs.Advantages in early imaging and wide diagnostic time window make it a promising PET MPI tracer.