Efficacy of radiotherapy in MDA-MB-231 breast cancer bearing nude mice evaluated by 18F-FDG total-body PET/CT dynamic imaging / 中华核医学与分子影像杂志

ABSTRACT

Objective:To investigate the value of 18F-FDG total-body PET/CT dynamic imaging in evaluating the efficacy of early radiotherapy for MDA-MB-231 breast cancer bearing nude mice. Methods:MDA-MB-231 breast cancer bearing nude mice were established and divided into control group and radiotherapy group based on the random number table method ( n=10 for each group). 18F-FDG total-body PET/CT dynamic imaging was performed before and after the radiotherapy. The SUV max and the maximum tracer uptake net influx constant ( Kimax) of tumors, and the target-to-background ratio (TBR) were calculated. The change of tumor volume was recorded. The value of 18F-FDG total-body PET/CT dynamic imaging in evaluating the efficacy of radiotherapy was accessed using pathological findings as the reference. Paired t test, independent-sample t test and Pearson correlation analysis were used for data analysis. Results:After radiotherapy, SUV max and Kimax(4.66±0.46 and 0.14±0.03) were reduced in the radiotherapy group compared with those before radiotherapy (5.30±0.52 and 0.19±0.03; t values 4.61, 8.31, P values 0.001, <0.001), while the SUV max (5.94±0.74 vs 5.24±0.50) and Kimax (0.23±0.03 vs 0.19±0.02) were increased compared with baseline in the control group ( t values 4.77, 6.87, P values 0.001, <0.001). TBR Ki was significantly higher than TBR suv based on all images of the 2 groups (14.11±5.58 vs 5.91±1.60; t=8.92, P<0.001). The tumor volume in the radiotherapy group decreased compared with that before radiotherapy, but the difference was not statistically significant ((0.74±0.12) vs (0.81±0.08) cm 3; t=2.24, P=0.052). The results of immunohistochemistry showed that glucose transport protein (Glut)1 was highly expressed in tumors, and the Glut1 positive cell percentage of the radiotherapy group was significantly lower than that of the control group ((38.30±6.18)% vs (69.78±5.37)%; t=12.17, P<0.001). The expression of Glut1 was significantly positively correlated with SUV max and Kimax(the control group rsuv=0.75, P=0.012; rKi=0.77, P=0.010; the radiotherapy group rsuv=0.67, P=0.035; rKi=0.77, P=0.010). The apoptosis index (AI) of tumor cells in the radiotherapy group was higher than that in the control group ((24.15±4.00)% vs (10.15±3.05)%; t=8.85, P<0.001). Conclusion:18F-FDG total-body PET/CT dynamic imaging can sensitively monitor the effect of early radiotherapy in MDA-MB-231 breast cancer bearing nude mice.