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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.
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Objective To assess the superiority of 99Tcm-3SPboroxime (99Tcm-3SP for short) as a fast-myocardial perfusion imaging (MPI) tracer in normal and acute myocardial infarction (AMI) mini-swine.Methods 99Tcm-3SP and 99Tcm-Teboroxime (99Tcm-TEBO for short) were prepared.Approximately 370 MBq 99Tcm-3SP or 99Tcm-TEBO was injected intravenously in 2 healthy mini-swine separately.Dynamic planar images were acquired immediately after injection and continued for 20 min using a standard SPECT camera.The radioactivity uptakes in the heart,liver,and lungs were measured,and heart/liver and heart/lung ratios over time were calculated.Dynamic SPECT studies were performed in 4 normal swine and 1 AMI-swine using cadmium zinc telluride-SPECT (CZT-SPECT).List mode acquisitions were immediately started and continued for 15 min after intravenous injection of approximately 370 MBq 99Tcm-TEBO and 99Tcm-3SP.The injection of two radiotracers in the same swine was completed within 2 d.The radioactivity uptakes in heart and liver were measured,and heart/liver ratio was calculated.Image quality was also evaluated.Paired t test was used to analyze the data.Results The radiochemical purity of 99Tcm-TEBO or 99Tcm-3SP were both above 95％.The initial heart uptake of 99Tcm-3SP was very close to that of 99Tcm-TEBO (planar image,2 min postinjection:309.32× 103 vs 314.13 × 103 counts/MBq;SPECT image,2 min postinjection (corrected):7.96±0.87 vs 8.24± 1.53,t =0.277,P＞0.05),but the myocardial retention time was much longer than that of 99Tcm-TEBO (planar image,20 min postinjection:218.67× 103 vs 143.19× 103 counts/MBq;SPECT image,15 min postinjection (corrected):6.76±0.45 vs 5.06±0.33,t =-12.412,P =0.001).The uptake of liver and heart/liver ratio between 99Tcm-TEBO and 99Tcm-3SP were similar (t values:-1.332-1.101,all P＞0.05 within 15 min).SPECT MPI images demonstrated uniform tracer distribution with clearly visualizable myocardial boundary in normal myocardium and intense perfusion defect in infarct myocardium.High quality SPECT images could be obtained in any of the 5 min imaging windows over the first 15 min after injection of 99Tcm-3SP in normal swine and AMI-swine.Conclusion 99Tcm-3SP is a promising 99 Tcm-labeled radiotracer for fast-MPI considering its high heart uptake,long myocardial retention time (20 min postinjection) and superior SPECT image quality.
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Objective@#To investigate the biodistribution of 4-chloro-2-tert-butyl-5-[2-[[1-[2-[2-18F-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 mini-swine.@*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 standardized 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 18F-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 mini-swine, 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.
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Objective@#To assess the superiority of 99Tcm-3SPboroxime (99Tcm-3SP for short) as a fast-myocardial perfusion imaging (MPI) tracer in normal and acute myocardial infarction (AMI) mini-swine.@*Methods@#99Tcm-3SP and 99Tcm-Teboroxime (99Tcm-TEBO for short) were prepared. Approximately 370 MBq 99Tcm-3SP or 99Tcm-TEBO was injected intravenously in 2 healthy mini-swine separately. Dynamic planar images were acquired immediately after injection and continued for 20 min using a standard SPECT camera. The radioactivity uptakes in the heart, liver, and lungs were measured, and heart/liver and heart/lung ratios over time were calculated. Dynamic SPECT studies were performed in 4 normal swine and 1 AMI-swine using cadmium zinc telluride-SPECT (CZT-SPECT). List mode acquisitions were immediately started and continued for 15 min after intravenous injection of approximately 370 MBq 99Tcm-TEBO and 99Tcm-3SP. The injection of two radiotracers in the same swine was completed within 2 d. The radioactivity uptakes in heart and liver were measured, and heart/liver ratio was calculated. Image quality was also evaluated. Paired t test was used to analyze the data.@*Results@#The radiochemical purity of 99Tcm-TEBO or 99Tcm-3SP were both above 95%. The initial heart uptake of 99Tcm-3SP was very close to that of 99Tcm-TEBO (planar image, 2 min postinjection: 309.32×103 vs 314.13×103 counts/MBq; SPECT image, 2 min postinjection (corrected): 7.96±0.87 vs 8.24±1.53, t=0.277, P>0.05), but the myocardial retention time was much longer than that of 99Tcm-TEBO (planar image, 20 min postinjection: 218.67×103 vs 143.19×103 counts/MBq; SPECT image, 15 min postinjection (corrected): 6.76±0.45 vs 5.06±0.33, t=-12.412, P=0.001). The uptake of liver and heart/liver ratio between 99Tcm-TEBO and 99Tcm-3SP were similar (t values: -1.332-1.101, all P>0.05 within 15 min). SPECT MPI images demonstrated uniform tracer distribution with clearly visualizable myocardial boundary in normal myocardium and intense perfusion defect in infarct myocardium. High quality SPECT images could be obtained in any of the 5 min imaging windows over the first 15 min after injection of 99Tcm-3SP in normal swine and AMI-swine.@*Conclusion@#99Tcm-3SP is a promising 99Tcm-labeled radiotracer for fast-MPI considering its high heart uptake, long myocardial retention time (20 min postinjection) and superior SPECT image quality.
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Objective To assess the imaging characteristics of 18F-Alfalide II in different tumorbearing mice and pharmacokinetics in Beagle dogs.Methods BALB/c nude mice(n-24)were used for subcutaneous tumor models(A549 and U87MG),orthotopic lung cancer models(A549)and orthotopic breast cancer models(MDA-MB-231)(n=6 in each group).18F-Alfatide II and 18F-fluorodeoxyglucose(FDG)microPET/CT images were compared in the 4 types of tumor-bearing nude mice models.18F-Alfatide II blocking experiment,biodistribution experiment and imaging studies in tumors of different growth cycles were performed in A549 subcutaneous tumor-bearing nude mice models.Pharmacokinetic experiments were carried out in Beagle dogs(n = 6)and CD-1 mice(n = 9).Two-sample t test was used to analyze the data.Results Compared with 18F-FDG,18F-Alfatide II microPET/CT images showed better imaging quality and contrast in subcutaneous A549,U87MG tumors and orthotopic A549(tumor/heart:4.50±1.17 vs 0.95±0.31;t = 4.125,P<0.01),orthotopic MDA-MB-231(tumor/muscle:6.60±1.53 vs 0.92±0.43;t = 3.984,P<0.01)transplantation nude mice models.18F-Alfatide II could specifically target A549 tumors,and the tumor uptake of 18F-Alfatide II was reduced by about 75% after pre-injection with cyclo(Arg-Gly-Asp-D-Tyr-Lys)(c(RGDyk)).18F-Alfatide II was rapidly cleared from the blood of Beagle dogs(T1/2 was(57.34±11.69)min).It was cleared in the form of prototype drug and(69.24±6.82)% of cumulative dose was excreted through the urine within 4 h after administration.Conclusions 18F-Alfatide II shows a higher target/non-target ratio than,18F-FDG in the imaging of A549,MDA-MB-231 and U87MG tumor-bearing nude mice models,which is more conducive to the diagnosis of tumor.18F-Alfatide II has excellent pharmacokinetic properties.
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Objective To study the factors affecting the synthesis of 18F-MyoZone,and to evaluate its potential as a myocardial perfusion imaging (MPI) agent in normal Chinese mini-swine.Methods 18F-MyoZone was prepared by substituting the leaving group toluenesulfonyloxy (OTs) from the precursor compound with 18F-fluoride (18F-F-).The conditions affecting the labeling yield were studied by varying the amount of K2CO3 and precursor compound,18F-fluorination reaction time and temperature.PET was performed at 5,30,60 and 120 min post-injection on normal Chinese mini-swine.Results The doses of K2CO3 and precursor,the reaction time and the reaction temperature could affect the labeling yield of 18F-MyoZone,especially K2CO3.The optimized synthetic condition was 1.0 mg K2CO3,2.0 mg mpp2-OTs,20 min reaction time at 90 ℃.The total radio-synthesis time in this condition was 60 min.The uncorrected radiochemical yield was (24.0±5.1) ％.The radiochemical purity was ＞98％.PET imaging showed that 18F-MyoZone had high initial uptake (SUV=8.17± 1.83 at 5 min post-injection) and good retention (SUV =5.78±0.99 at 120 min post-injection) in the heart.The clearance of 18F-MyoZone from liver was very fast.The heart/liver ratios were 3.32,5.31,6.09 and 5.76 at 5,30,60 and 120 min post-injection,respectively.From 5 to 120 min post-injection,the outline of heart was clear and intact.There was almost no interference from the adjacent organs.The quality of PET images was highly satisfactory.Conelusions 18 F-MyoZone has the potential to be a good myocardial perfusion agent.The amount of K2CO3 used could significantly affect the labeling yield of 18F-MyoZone.