RESUMEN
Objective To quantitatively compare the diagnostic capability of 68Ga-NGR and 18F-FDG in well-differentiated hepatocellular carcinoma (HCC) bearing mice by microPET/CT imaging.Methods The in vitro cellular uptake,in vivo microPET/CT imaging and biodistribution studies of 68Ga-NGR and 18F-FDG were quantitatively compared in SMMC-7721-based well-differentiated HCC.The human fibrosarcoma (HT-1080) and human colorectal adenocarcinoma (HT-29) cells/xenografts were respectively used as positive and negative reference groups for CD13.The expression of CD13 was qualitatively verified by immunohistostaining.The levels of CD13 and glucose-6-phosphatase (G6Pase) were semi-quantitatively analyzed by Western blot test for all 3 types of tumors.Two-sample t test was used for data analysis.Results The in vitro cellular uptake showed that the 68Ga-NGR uptake in SMMC-7721 and HT-1080 cells was higher than that in HT-29 cells,and the 68Ga-NGR uptake was higher than 18F-FDG uptake in SMMC-7721 cells.The in vivo micro-PET/CT imaging results revealed that the uptake of 68Ga-NGR in SMMC-7721 tumor was (2.17±0.21) ％ID/g,remarkably higher compared to (0.73±0.26) ％ID/g of 18F-FDG uptake (t =8.826,P＜0.01).The tumor/liver ratio of 68Ga-NGR was 2.05±0.16,which was 2.03-fold higher than that of 18F-FDG.In the HT-1080 tumors,the uptakes of 68 Ga-NGR and 18F-FDG were both high,and the values were (2.46±0.23) ％ID/g,(3.47±0.31) ％ID/g.The uptake of 68Ga-NGR was significantly lower than that of 18F-FDG in HT-29 tumors:(0.67±0.20) ％ID/g vs (3.17±0.29) ％ID/g;t=4.221,P＜0.01.Western blot and immunohistostaining results were as follows:HT-1080(CD13+,G6Pase-),SMMC-7721(CD13+,G6Pase+),HT-29 (CD13-,G6Pase-).Conclusions The uptake of 68Ga-NGR is higher than 18F-FDG uptake in SMMC-7721 tumor bearing mice,therefore it is worthwhile to consider the feasibility of clinical translation for PET/CT in diagnosis of HCC.Furthermore,because of the difference in 68Ga-NGR and 18F-FDG avidities in tumors with different molecular phenotypes of CD13 and G6Pase,there is an underlying potential for molecular imaging in the determination of molecular phenotypes.
RESUMEN
Objective To quantitatively compare the diagnostic capability of 68Ga-NGR and 18F-FDG in well-differentiated hepatocellular carcinoma (HCC) bearing mice by microPET/CT imaging.Methods The in vitro cellular uptake, in vivo microPET/CT imaging and biodistribution studies of 68Ga-NGR and 18F-FDG were quantitatively compared in SMMC-7721-based well-differentiated HCC.The human fibrosarcoma (HT-1080) and human colorectal adenocarcinoma (HT-29) cells/xenografts were respectively used as positive and negative reference groups for CD13.The expression of CD13 was qualitatively verified by immunohistostaining.The levels of CD13 and glucose-6-phosphatase (G6Pase) were semi-quantitatively analyzed by Western blot test for all 3 types of tumors.Two-sample t test was used for data analysis.Results The in vitro cellular uptake showed that the 68Ga-NGR uptake in SMMC-7721 and HT-1080 cells was higher than that in HT-29 cells, and the 68Ga-NGR uptake was higher than 18F-FDG uptake in SMMC-7721 cells.The in vivo microPET/CT imaging results revealed that the uptake of 68Ga-NGR in SMMC-7721 tumor was (2.17±0.21) %ID/g, remarkably higher compared to (0.73±0.26) %ID/g of 18F-FDG uptake (t=8.826, P<0.01).The tumor/liver ratio of 68Ga-NGR was 2.05±0.16, which was 2.03-fold higher than that of 18F-FDG.In the HT-1080 tumors, the uptakes of 68Ga-NGR and 18F-FDG were both high, and the values were (2.46±0.23) %ID/g, (3.47±0.31) %ID/g.The uptake of 68Ga-NGR was significantly lower than that of 18F-FDG in HT-29 tumors: (0.67±0.20) %ID/g vs (3.17±0.29) %ID/g;t=4.221, P<0.01.Western blot and immunohistostaining results were as follows: HT-1080(CD13+, G6Pase-), SMMC-7721(CD13+, G6Pase+), HT-29(CD13-, G6Pase-).Conclusions The uptake of 68Ga-NGR is higher than 18F-FDG uptake in SMMC-7721 tumor bearing mice, therefore it is worthwhile to consider the feasibility of clinical translation for PET/CT in diagnosis of HCC.Furthermore, because of the difference in 68Ga-NGR and 18F-FDG avidities in tumors with different molecular phenotypes of CD13 and G6Pase, there is an underlying potential for molecular imaging in the determination of molecular phenotypes.