| Objective To investigate the binding characteristics of 18F-FDG or 18F-FLT before and after chemotherapeutic in human lymphoma cell Raji as well as the preliminary linical applications of 18F-FDG and 18F-FLT,in order to observe the value of the two kinds of PET imaging agent in the diagnosis and follow up of lymphoma.Methods (1) The binding rates of 18F-FDG or 18F-FLT was measured under different conditions: 1×105～1×107cells, 1.85～29.6KBq18F-FDG or 18F-FLT , 0～11.1mmol/L glucose levels, and 20～120min to measure;(2) MTT was ultilized to measure the inhibitory rate on raji cell with different dose of rituximab or vincristine at 48h and calculate the IC50.the binding efficiency of 18F-FDG were detected at 12,24 and 48h after administration of rituximab or vincristine at their dose of IC50;(3) The expression of GLUT1 was detected immunohistochemically in Raji cell before and after chemotherapeu- tics;(4) 18F-FDG and 18F-FLT PET/CT imaging was performed in 6 patients with lymphoma who were certified by histopathology. The positive focus of infection and its SUVmax was analyzed.Results (1) The binding rate of 18F-FDG was(50.42±1.07)% at the condition of 1×107cells, 3.7 KBq18F-FDG, 0～2.78mmol/L glucose levels,100 min. while 18F-FLT was (59.48±0.77)% at the same conditions.The difference of binding rates between 18F-FDG and 18F-FLT was significan(tp<0.01);(2) The inhibitory rate of raji cell was (13.54±0.03)%,(13.53±0.01)%,(16.48±0.01)%,(15.05±0.01)% and (15.41±0.008)% after administration of rituximab at the dose of 100,200,400,800 and 1600μg/ml respectively,while it was (76.80±0.01)%,(79.58±0.01)%,(84.98±0.01)%,(96.53±0.01)%,(97.38±0.003)%after administration of vincristine at the dose of 30,60,120,240 and 480μg/ml.The IC50 of vincristine was 29.17μg/ml. The binding inhibitory rate of 18F-FDG were (10.05±0.010)%,(16.55±0.006)% and (12.44±0.010)% respectively at 12,24 and 48h after administration of 400μg/ml rituximab while it was (25.43±0.020)%,(51.85±0.002)% and(61.32±0.006)% after administration of vincristine in the dose of 29μg/ml; (3) The positive rate of GLUT1 was (80.47±0.69)%,(81.03±1.96)% and (82.17±2.15)% at 12,24 and 48h respectively after administration of rituximab while it was (42.9±3.15)%,(37.91±1.69)% and(36.09±2.03)% after administration of vincristine.The controlled group was(91.17±2.03)%. The positive rate of experimental group was lower than controlled(p<0.05), the positive rate of GLUT1 was not correlate with the time after administration of rituximab .The difference of the positive rate was not significant in the group(p>0.05). The positive rate of vincristine group was lower obviously than controlled .The difference of the positive rate was not significant between 24 and 48h(p=0.359),while the difference was significant between the others (P<0.05). The positive rate of GLUT1 was negative correlated with the binding inhibitory rate of 18F-FDG(r=0.832,p=0.003)after administration of vincristine,but it had no correlativity between them after administration of rituximab(p>0.05);(4) 6 patients with lymphoma was all both positive in 18F-FDG and 18F-FLT PET/CT imaging. 18 lesions of lymphoma were found out by either 18F-FDG or 18F-FLT. The SUVmax of 18F-FDG was from 3.12 to 12.17 and mean SUVmax was 7.04.while 18F-FLT was from 2.14 to 6.56 and mean SUVmax was 4.0.The Conformance of 18F-FDG and 8F-FLT was 100%.Conclusion (1) The uptake of 18F-FDG and 18F-FLT in human lymphoma cell Raji is high,and at the same condition, the uptake rate of 18F-FLT is higher than 18F-FDG.; (2) Raji cell was inhibited slightly by rituximab,which was significant by vincristine .the inhibition by vincristine increased with time and concerned with the expression of GLUT1; (3) The Conformance of 18F-FDG and 18F-FLT was high in lymphoma PET/CT imaging, but the imaging quality of 18F-FLT was poorer than 18F-FDG generally.and the SUV of 18F-FLT was lower than 18F-FDG.
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