The Basic Research Of¹¹C-acetate And¹⁸F-FDG On Therapeutic Effect Evaluation In Cryosurgical Ablation For Hepatocellular Carcinoma

Objective:To investigate the method of rapid, high-performance radiosynthesis and qulity control of11C-acetate. Simulating the argon-helium cryosurgical ablation (CSA) refrigeration system, analyse the uptake regularity of18F-FDG and11C-acetate for thr-ee different differentiation humanized hepatocellular carcinoma (HCC) cell lines,and compare with cell survival rate,growth inhibition rate and apoptosis after freeze thawing,to set up mathematic model of each other.Explore the feasibility of18F-FDG and11C-acetate combined imaging in diagnosing HCC and evaluating early the therapeutic effect of CSA. Observe the biodistribution of healthy mice in vivo, estab-lish subcutaneous xenografts models of living nude mice. To lay the foundations of researching in vivo and in clinic.Methods:(1)Improve the synthesis method of11C-acetate, to raise up the yield to the ideal level.Detect the activity concentration,radiochemical purity,radionuclide purity,physico-chemical property,sterility test,bacterial endotoxin of11C-acetate.(2) Inoculate the three different differentiation humanized hepatocellular carcinoma cells to3.5cm diameter flat plates with proper density.When the cells grew to exponential growth phase, simulate the CSA refrigeration system. At lh,6h and24h after different freeze thawing cycle,collect cells to do relation test.(3)Observe the shape change of cells before and after freeze thawing,dye the cells with trypan blue,count the number of death cells and survival cells,and compute the total cellular score and survival rate.(4)Assay cell growth inhibition rate using MTT, detect quantitative cell aoptosis changes using flow cytometry.(5)Every group of cells was incubated with18F-FDG for60min and11C-acetate for15min apart,then detect the radio uptake with radio-immunity counter.At the same time, detect the radio uptake of standard tube which only had radiopharmaceutic without cells.Computer the relative intensity of radioactivity every1×104cells.(6) Compare the different results of the same cell line and the results of different cell lines above-mentionger,using excel and SPSS statistic-cal software packages17.0for data analysis.(7)All the mice were injected with approximately50μci11C-acetate each via tail vein.Imaging were performed using PET scanner at5min after injection.The mice were sacrificed,and the main organs were excised,weighed and measured with activity.For each mouse,radioactivity uptake was expressed as the%ID/g of tissue.(8) Establish the hepatocellular carcinoma xenograft nude model,observe the growth situation of them.Results:(1)Synthesis11C-acetate with activity concentration15mCi/ml,radiochemical purity60%,radionuclide purity>99%,physico-chemical property.In our study,the11C-acetate solution is achromatic and transparent with pH6.0,and it is sterile and free from pyrogens.(2) The freeze thawing has apparente lethal effect on the three kinds of liver cell lines.(3)The poorly differentiated HCC SMMC-7721uptake more18F-FDG than11C-acetate,the well differentiated HCC HepG2uptake more11C-acetate than18F-FDG,and the moderate differentiated HCC BEL-7402have the similar uptake.(4)The combination of18F-FDG and11C-acetate imaging can imply the real condi-tion of cells,and can evaluate early CSA therapeutic effect at the cellular level.(5)The mice after injected11C-acetate had the highest radioactive uptake in the upper abdomen,in which the pancreas and liver excretion were slow,the kidney and spleen excretion were fast.The heart,head, blood,muscle and stomach uptake were little.(6)Establish the hepatocellular carcinoma xenograft nude mice model successfully.Conclusions:(1) Synthesis rapid, high-performance radiosynthesis and qulity control of11C-acetate successfully.(2) The freeze thawing have apparente lethal effect on the three kinds of liver cell lines.(3)18F-FDG has well imaging to moderate-poorly differentiated HCC,11C-acetate has well imaging to well-moderate differentiated HCC,and the combination of18F-FDG and11C-acetate imaging can evaluation early CSA therapeutic effect at the cellular level.(4)The body distribution and the imaging research of the mice in our study conform to other research.(5)Establish the hepatocellular carcinoma xenograft nude model successfully.(6)The results of this study apply the dependable theory and experiments with next in vivo study and the combination imaging of11C-acetate and18F-FDG on therapeutic effect evaluation in CSA for hepatocellular carcinoma.