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Objective:To realize a fully automated synthesis of 11C-meta-hydroxyephedrine (mHED) and to perform imaging studies with it. Methods:11C-mHED was prepared by the 11CH 3-triflate method. The crude product was purified by semi-preparative high performance liquid chromatograph (HPLC) to obtain the final product. The radiochemical purity and specific activity were determined by radio-HPLC. The myocardial uptake and excretion process of the agent were monitored by microPET/CT imaging on 5 normal SD rats. The clinical imaging value was evaluated using PET/CT imaging in a patient (male, 42 years old) with myocardial infarction. Results:The automated synthesis of 11C-mHED was realized by a commercial synthesizer. The total synthesis time was about 30 min. The radiochemical yield was (15±2)% (non-decay corrected, n=10) and the radiochemical purity was greater than 98%. The specific activity was about 65 GBq/mmol. MicroPET/CT imaging in normal SD rats showed the myocardial uptake was highest at 10 min after the injection of imaging agent, and then the imaging agent was gradually excreted from the myocardium through the liver and gallbladder. PET/CT imaging of a patient with myocardial infarction showed an imaging agent defect near the apex in the inferior wall of the left ventricle, which was matched with results of ultrasound and electrocardiogram examination. Conclusions:11C-mHED can be successfully prepared automatically, with high radiochemical yield and specific activity. It can also highly concentrate in the myocardium, and the imaging effect with this agent is good in a patient with myocardial infarction.
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Objective:To compare the quantitative parameters of myocardial blood flow based on SPECT imaging and those determined by PET imaging in coronary microvascular disease (CMVD) animal models, in order to clarify the accuracy and feasibility of SPECT quantitative analysis in CMVD.Methods:Seven Saanen milk goats (either male or female; (20±5) kg), were selected for establishing CMVD animal models by microsphere embolization. Dynamic myocardial perfusion imaging (DMPI) with one-day method of resting + ATP stress 99Tc m-methoxyisobutylisonitrile (MIBI) SPECT was performed before and after the modeling, respectively. One-day method of resting + ATP stress 13N-ammonia PET DMPI was performed after the modeling. The quantitative parameters determined by SPECT and PET after the modeling, including stress myocardial blood flow (SMBF), resting myocardial blood flow (RMBF) and myocardial flow reserve (MFR), were compared by paired t test. Parameters based on SPECT after modeling were compared with those of baseline levels. Bland-Altman analysis was applied to access the agreement between SPECT and PET. Results:Four of the seven experimental goats were fully imaged. The RMBF(ml·g -1·min -1; 1.52±0.27 vs 1.29±0.20), SMBF(ml·g -1·min -1; 0.74±0.19 vs 0.99±0.26), and MFR (0.53±0.16 vs 0.76±0.10) of the left ventricle (global) obtained by SPECT and PET in CMVD models were not significantly different ( t values: 3.121, 1.195, 1.930, all P>0.05). Among left anterior descending branch (LAD), left circumflex (LCX) and right coronary artery (RCA), the RMBF, SMBF and MFR values quantified by SPECT and PET were neither statistically significant ( t values: 0.182-2.734, all P>0.05). Bland-Altman analysis showed the quantitative parameters measured by SPECT and PET DMPI in left ventricle, LAD, LCX, RCA had a good consistency. The difference between the two methods for determining RMBF was up to 0.63 ml·g -1·min -1, and that of SMBF was up to 0.66 ml·g -1·min -1. All points are within the 95% confidence limit; MFR differs at most by 0.56, and 14/16 points were within 95% confidence limit. The RMBF (ml·g -1·min -1) of left ventricle measured by SPECT after modeling was not significantly different from that before modeling (1.52±0.27 vs 1.57±0.36; t=0.166, P>0.05); the SMBF (ml·g -1·min -1) and MFR after modeling were significantly lower than those before modeling (0.74±0.19 vs 2.34±0.89, 0.53±0.16 vs 1.39±0.31, t values: 3.836, 6.309, both P<0.05). Similar results were found when comparing the parameters of LAD/LCX/RCA after modeling with those before modeling (RMBF t values: 0.191, 0.235, 0.195, all P>0.05; SMBF/MFR t values: 0.411-19.911, all P<0.05). Conclusion:The blood flow quantitative parameters measured by SPECT imaging have a good consistency with those based on PET imaging, and the myocardial blood flow quantitative analysis of SPECT can evaluate the blood flow perfusion of CMVD.
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Objective To evaluate 11C-MDA,a cardiac sympathetic nerve presynaptic molecular probe,in acute myocardial ischemia (AMI) and to compare with 13N-Ammonia myocardial perfusion imaging.Methods Twelve Bama miniature pigs were used to establish AMI models.11C-MDA and 13N-Ammonia PET/CT were performed before and after model establishment.The defect fraction,ratio of defect to normal region,defect volume of 11C-MDA and 13N-Ammonia PET/CT were calculated.Paired-t test and twosample t test were used.Results Eight models were established successfully and 4 pigs died.The defect fractions on 11C-MDA and 13N-Ammonia myocardial imaging were significantly different (13.4±3.3 vs 7.4±1.0,18.8±4.4 vs 4.8±1.0,10.5±4.2 vs 4.4±0.9;t values:4.901,8.864,4.030,all P＜0.001) at the first,third and sixth month post-model establishment.The ratios of defect to normal region on 11C-MDA and 13N-Ammonia PET/CT myocardial images were significantly different (0.47±0.14 vs 0.59±0.10,0.43±0.13 vs 0.61±0.09;t values:-2.166,-3.415,both P＜0.05) at the first and third month post-model establishment.The defect volumes on 11C-MDA and 13N-Ammonia PET/CT were significantly different ((4.20±0.34) vs (2.55±0.11) cm3,(10.66±0.71) vs (2.46±0.12) cm3,(5.95±0.50) vs (2.44±0.11) cm3;t values:12.925,32.149,19.440,all P＜0.001) at the first,third and sixth month post-model establishment.Conclusions Myocardial ischemia-reperfusion and cardiac sympathetic restoration might occur at different times.The recovery of myocardial ischemia-reperfusion is earlier than that of the cardiac sympathetic nerve.
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Objective To investigate the value of 18F-FDG PET/CT and serum CEA in patients with advanced gastric cancer after neoadjuvant chemotherapy combined with surgical treatment.Methods 96 cases of patients with advanced gastric cancer who underwent neoadjuvant chemotherapy combined with surgery as the research object,after more than 2 years of follow-up,PET/CT imaging and serum CEA levels were detected,and the diagnostic value of recurrence or metastasis of the two groups were evaluated and analyzed.Results Of the 96 patients enrolled in the study,there were 47 cases of recurrence and metastasis,PET/CT combined with CEA for recurrence or metastasis positive diagnosis rate and negative diagnosis rate was significantly higher than that of pure PET/CT and serum CEA,the difference was statistically significant(P<0.05).The sensitivity,specificity and accuracy of PET/CT combined with CEA in the diagnosis of recurrence or metastasis were higher than that of PET/CT and serum CEA,the difference was statistically significant(P<0.05).Conclusion The combined monitoring of 18F-FDG PET/CT imaging and serum CEA level in patients with advanced gastric cancer after neoadjuvant chemotherapy combined with surgical treatment is helpful to improve the diagnosis of metastasis or recurrence.
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Objective To synthesize 11 C-methyldopamine (MDA) and to explore its feasibility as an agent for cardiac sympathetic nerve imaging.Methods 11 C-MDA was synthesized by direct N-methylation method and purified by semi-preparation reverse HPLC.Thirty Kunming mice were divided into five groups by random number table.The mice were respectively sacrificed at 2,5,10,20 and 30 min after injection of 7.4 MBq 11C-MDA.The lung,liver,spleen,kidney,stomach,intestine,brain,muscle,bone tissues and blood of mice were removed and weighed before radioactive γ-counting.The ％ID/g was calculated.Six Chinese mini-swine were divided into normal group (n=3) and inhibition group (n =3) for myocardial imaging.Mini-swine of inhibition group were injected with 10 mg/kg imipramine hydrochloride at 30 min before 11C-MDA (370 MBq) injection.The data were analyzed with SPSS 15.0 software.Results The synthesis of 11 C-MDA took 45 min with radiochemical yields of (20±3)％.The solution of11 C-MDA was colorless and the pH value was 6.5.The radiochemical purity was more than 98％ and the specific activity was 50 GBq/mmol.The myocardial uptake reached the peak value of (8.78± 1.18) ％ID/g at 2 min after injection of 11 C-MDA in mice.11C-MDA was mainly metabolized through liver and kidney.PET/CT imaging showed that 11 C-MDA was highly uptaken in swine myocardium and could be blocked by imipramine hydrochloride.Conclusions 11C-MDA can be synthesized by a simple and economic method.The high uptake rate of 11 C-MDA in the heart suggests it may be a potential agent for cardiac nerve imaging.