For evaluating the potential of 18F-FDG uptake rate to monitor biological responses of irradiated tumor cells

18F-FDG uptake rates were detected for A549 and MCF-7 cells irradiated by 6 MV X-rays to

1

2

4

6

8 and 10 Gy single dose.Also

18F-FDG uptake rates of A549 and MCF-7 cells after 8 Gy single dose irradiation were detected at 1

2

3

4

5 and 6 d

and 1

2 and 3 w.The cell survival rate was detected by MTT.The cell cycles and apoptosis rate were detected by flow cytometry to evaluate tumor cell growth inhibition by ionizing radiation.Clonogenic assay was used to measure the survival fraction.The data were analyzed by the statistical software SAS8.0.The results showed that 18F-FDG uptake rate of A549 and MCF-7 cells decreased with increasing single doses.The 18F-FDG uptake rate after irradiation of different doses was negatively correlated with the apoptosis rate(r =– 0.96

P<0.005)

and positively correlated with G2/M%+S% and survival fraction(r =0.96;0.93

P <0.01.r =0.94;0.96

P <0.005).At different time after the single exposure of 8 Gy

the 18F-FDG uptake rate of A549 and MCF-7 cells gradually increased to reach the peak

then decreased.The cell viability was positively correlated with 18F-FDG uptake rate(r=0.78;0.86

P<0.05).It can be concluded that 18F-FDG uptake rate correlated with the changes of biology effect of tumor cells after irradiation

and it may be used to evaluate for irradiation effects of tumor cells.