ABSTRACT
Objective To study the correlation of ~(18)F-fluorodeoxyglucose (FDG) PET/CT with pathological changes of the VX2 rabbit tumors after treatment of Ar-He knife,and to explore the evolution of the Ar-He knife curative effect for VX2 rabbit tumors.Methods Thirty-six Japanese white rabbits had successfully been implanted with VX2 tumors in thighs.Four weeks later,the rabbits with VX2 tumors were imaged with FDG PET/CT before they were treated with Ar-He cryoablation.The rabbits were evenly and randomly divided into 6 groups (6 rabbits in each group) and imaged with FDG PET/CT respectively on the first day,third day,seventh day,fourteenth day,thirtieth day and sixtieth day after cryoablation.The rabbits in each group were sacriftced after post-treatment FDG PET/CT imaging for pathology and immunohistochemistry studies.The standardized uptake value (SUV) of tumor regions were calculated and compared with pathology and immunohistochemistry findings in the cryoablative area in each group.Paired-samples t-test and bivariate correlation analysis were evaluated by statistical software SPSS 16.0.Results After ArHe cryoablation,pathological changes of "necrosis-inflammatory response→organization" were found.On CT imaging,the tumors enlarged during 3-14 d after treatment and then shrank gradually.On FDG PET imaging,the maximum SUV (SUV_(max)) dropped dramatically on the first day after the operation(from 2.54±1.12 to 0.67±0.12),and increased slightly on the third day (1.71±0.82),and then continually dropped to 0.51±0.32 (60 d afterthe operation).The differences of SUV_(max) between pre-and after cryoablationin each stage were significant,respectively (t=5.471,8.716,11.388,5.713,7.144 and 7.213,all P＜0.05).The size and SUV_(max) of the targeting area did not correlate with each other(r=0.259,P=0.675).The change of the MVD closely correlated with SUV_(max)(r=0.865,P=0.032).Conclusion FDG PET/CT can reveal the pathological change of tumor tissue after Ar-He cryoablation therapy and therefore may be a potential tool for evaluating the curative effect of this treatment modality.