The Establishment Of Molecular Neuroimaging Technology Platform And Its Application In Evaluation Of Acupuncture Analgesia Effect On 5-HT_1A Receptor And Dopamine Transporter In Human Brain

Molecular imaging was defined as technology to imaging and analyse functional molecular events in living organisms at the cellular and molecular levels. Based on the traditional cross-sectional imaging and molecular biology, molecular imaging provides potential for early detection of molecular abnormity in diseases, as well as understanding the biology pathway. Depending on its specific probes with high affinity, sensitive imaging technology with high resolution and effective imaging analyse method, molecular neuroimaging by positron emission tomography has been applied for decades as a reliable technique. At present, with the development of promising PET radioligand, serotonin (5-HT), dopamine (DA) and its related receptors in brain were widely studied by molecular imaging. The superior performance of PET radioligands for dopamine transporter and 5-HT1A receptor make it possible for detection of these two important neuromolecular with PET. Establishment of normalized methodology was demanded for its application in human. The aim of the present study was to set up a suitable method of dopamine transporter and 5-HT1A receptor PET imaging in vivo. The imaging method was verified by initial exploration of acupuncture analgesia effect on 5-HT1A receptor and dopamine transporter in human brain.Part I Synthesis and quality control of 5-HT1A receptor and DAT PET radioligandi) Synthesis and quality control of 18F-MPPFObjective The aim of the present study was to set up a fast and effective synthesis method of 18F-MPPF based on the experience of previous study, and to implement its identification and quality control.Methods Nucleophilic substitution of fluoro replacement reaction was proceeding in dimethyl sulfoxide solution by oil bath heating. Radiochemical purity (RCP) was determined by high pressure liquid chromatography (HPLC). Quality control of the radio ligand was carried out according to the criterion.Results The production was identified as the same material as MPPF standard substance, RCP determined by HPLC was over 95%. The quality of the production met the criterion.Conclusion 18F-MPPF labeled by fluoro with the reaction of nucleophilic substitution of replacement was qualified. Rapid and efficient synthesis method was a great advantage of 18F-MPPF.ii) Synthesis and quality control of 11C-CFTObjective The aim of the present study was to develop an automatic synthesis method for the on-line preparation of dopamine transporter (DAT) radioligand 11C-CFT according to the previous experices, and to implement its identification and quality control.Methods A mid-product, 11C-methyl triflate made from 11C-methyl iodide, was bubbled into 0.1 mg precursor, nor-β-CFT, to get 11C-CFT. The final product 11C-CFT, was then purified through C-18 column, the column was eluted by 10 ml water twice and then by ethanol. Quality control of the radioligand was carried out according to the criterion.Results The production was identified as the same material as CFT standard substance, RCP determined by HPLC was over 95%. The quality of the production met the criterion.Conclusion The automated on-line preparation method was verified in producing nC-CFT of high radiochemical purity. The production was qualified and possible for research as a radioligand.Part II Establishment of technical methods to study 5-HT1A receptor and DAT in vivo using PET radioligand 18F-MPPF and "C-CFTi) Establishment of technical methods to study 5-HT1A receptors in vivo with 18F-MPPFObjective The aim of the present study was to establish a suitable technical method to detect 5-HT1A receptor in human brain using 18F-MPPF as a PET radioligand.Methods Nine volunteers, including three women, underwent an 18F-MPPF PET scan. One of them underwent 90min dynamic scan while the other eight volunteers underwent static scan. Region of Interest (ROI) method was employed to analysis the time-activity curves (TACs) and binding potential (BP) value from dynamic data with Inveon research workplace (IRW). Semiquantitative ratio index (ROIs/cerebellum-1), SUV value and SUV ratio (SUVR) were also calculated based on the static data. The statistical assessment of gender effect and difference between right and left side was performed.Results After i.v. injection of 18F-MPPF, time-activity curves revealed a rapid inflow and washout in cerebellum. On the contrary, in target regions including amygdaloid body, hippocampus, cingulum, temporal pole, insula and raphe nuclei, the TACs were delayed by the apparent binding of 18F-MPPF, reaching pseudo-equilibrium 20 min after injection. The BP value, average Semiquantitative ratio, SUV and SUVR value of amygdaloid body and hippocampal regions were highest of all. There was no difference between left and right side of the 18F-MPPF uptake. The uptake of female in bilateral temporal pole and insula was higher than male (P<0.05).Conclusion 18F-MPPF reached pseudo-equilibrium 20 min after injection. The uptake of 18F-MPPF was in accordance with known 5-HT1A receptor distribution.18F-MPPF would be an excellent PET tracer for in vivo detection of 5-HT1A receptor following proper image acquisition and data analysis method.ii) Establishment of technical methods to study DAT in vivo with 11C-CFT.Objective The aim of the present study was to establish a suitable technical method to detect dopamine transporter (DAT) in human brain using 11C-CFT as a PET radioligand.Methods One health volunteer underwent 90min dynamic UC-CFT PET scan. TACs and BP values of 10 regions in brain were estimated. The other 31 health volunteers (20 male,11 female, average age was 55+2.4 years) were divided into three age and sex-matched groups. Each group went through static PET scan after 11C-CFT injection in different time windows (40-60min,60-80min and 80-100min). Semiquantitative ratio of bilateral caudate and putamen were analyzed using automatic region of interest(ROI) method (ROI/ratio of Parieto-occipital cotex-1) and compared by one way analysis of variance (one-way ANVOA) to determine the best scan time window. Age and gender effect were also analyzed.Results The 11C-CFT uptake of the caudate and putamen slowly got equilibrium at 60min after injection. While the other region of brain washed out rapidly. The BP values of bilateral caudate and putamen is higher than that of other region. Semiquantitative ratio of left caudate, right anterior putamen and bilateral posterior putamen were significant different (F=3.588、4.479、3.557; P<0.05) in these three groups. There were significant difference of ratio of bilateral caudate and putamen between 40-60min scan time window group and the other two groups (P<0.05), while no valid difference of ratio of that area was shown between the groups of 60-80min and 80-100min scan time window(P<0.05). Compared with volunteer under 60yr, the 11C-CFT uptake of volunteer over 60yr was significant decreasedin all region (all P value<0.05). There was no difference between 11C-CFT uptake of female and male (all P value>0.05).Conclusions 11C-CFT reached pseudo-equilibrium 60 min after injection. The uptake of 11C-CFT was in accordance with known DAT distribution. The best static scan time window of 11C-CFT PET scan was 60-80min after injection. Age effect on 11C-CFT uptake should be considered. Automatic ROI method by SPM provided an effective way for quantitative analysis of 11C-CFT imagine. All of above would promote its application in Parkinson’s disease and other research field.Part Ⅲ Acute effect of acupuncture analgesia on 5-HT1A receptors and DAT in human brain.Objective 5-HT1A receptor and DAT in vivo imaging mothed using PET radioligand 18F-MPPF and 11C-CFT have been set up preliminarily. In order to verify and improve these mothed, we estimate the acute acupuncture analgesia effect on 5-HT1A receptors and DAT in human brain.Methods Nine health volunteers underwent 18F-MPPF and 11C-CFT PET scan respectively before and after electroacupuncture (EA).2-100Hz EA was applied to acupoints bilateral Hegu (LI 4), Taichong (LV3) and Jinmen (GB25) for 20-40min before PET scan.18F-MPPF and 11C-CFT semiquantitative ratio and SUVR values of both states were analyzed with ROI method, and compared by paired t test. Gender effect was also estimated by splitting male and female volunteers to different group for analysis respectively.Results No significant difference of either 18F-MPPF or11C-CFT uptake were shown after EA, the same as male and female group. However, slightly increased uptake of 18F-MPPF and decreased uptake of 11C-CFT were observed after EA in most volunteers.Conclusion EA had no significant effect on 5-HT1A receptors and DAT in human brain. However, EA might slightly regulate both of 5-HT1A receptors and DAT in order to modulate acupuncture analgesia effect. The ability to meet the needs of various researches, as well as to take advantage of the method, would promote the molecular neuroimaging technology platform widely applicated.Summary1. The processe of 18F-MPPF labeled by fluoro with the reaction of nucleophilic substitution of replacement was rapid and efficient. This radioligand reached pseudo-equilibrium 20 min after injection. The uptake of 18F-MPPF was in accordance with known 5-HT1A receptor distribution. Proper image acquisition and data analysis method were necessary for accurate image analysis.2. The automated on-line preparation method was verified in producing 11C-CFT of high radiochemical purity. 11C-CFT reached pseudo-equilibrium 60 min after injection. The uptake of 11C-CFT was in accordance with known DAT distribution. The best static scan time window was 60-80min after injection. Age effect on 11C-CFT uptake should be considered. Automatic ROI method by SPM provided an effective way for quantitative analysis of 11C-CFT imagine. All of above would promote its application in Parkinson’s disease and other research field.3. EA had no significant effect on 5-HT1A receptors and DAT in human brain. However, EA might slightly regulate both of 5-HT1A receptors and DAT in order to modulate acupuncture analgesia effect.4. The success of molecular neuroimaging technology platform relied on the progress of probe, imaging technology and effective image analysis method. The ability to meet the needs of various researches, as well as to take advantage of the method, would promote the molecular neuroimaging technology platform widely applicated.