^(18)F-FDG PET-CT显像评估大鼠C6胶质瘤放疗早期疗效实验研究

The role of ^(18)F-FDG PET-CT in evaluation of early radiotherapeutic efficacy in C6 rat glioma

目的了解大鼠C6胶质瘤放疗前后18F-脱氧葡萄糖正电子发射体层显像-X线计算机断层成像(18F-FDG PETCT)显像特点,探讨18F-FDG PET-CT评估大鼠C6胶质瘤早期放疗疗效价值。方法建立荷C6胶质瘤SD大鼠模型,按随机数字表法分成对照组及放疗组,两组分别于放疗前及放疗后24 h、7 d行18F-FDG PET-CT显像,采集不同时期大鼠肿瘤最大标准摄取值(SUVmax-T)、对侧脊柱旁肌肉最大标准摄取值(SUVmax-M),计算两者比值(T/M)并观察肿瘤体积变化。放疗结束,取两组肿瘤,常规HE染色,免疫组织化学法测定肿瘤细胞增殖指数Ki-67及微血管密度(MVD)表达情况。结果 1放疗24 h T/M值较放疗前降低(t=5.991,P<0.01)。对照组24 h T/M值较首次显像增高(t=5.196,P<0.01)。2放疗7 d T/M值较放疗后24 h(t=3.082,P<0.05)、放疗前(t=4.822,P<0.01)显著降低(F=5.902,P<0.01)。对照组7 d T/M值较24 h明显增高(t=3.621,P<0.05)。3 HE染色示放疗组较对照组坏死明显,放疗组Ki-67与MVD表达水平较对照组明显减低(t=7.201、2.986,P<0.01)。4 T/M值与Ki-67表达呈明显正相关(r=0.824,r2=0.679,P<0.05);T/M值与MVD表达呈正相关(r=0.779,r2=0.606,P<0.05)。结论18FFDG PET-CT可评估大鼠C6胶质瘤放疗早期疗效,并可反映胶质瘤的增殖活性和血管生成情况。

Objective To study the characteristics of 18 F-flurodeoxygluse positron emission tomography with compu- ted tomography （lSF-FDG PET-CT） imaging in C6 rat glioma models before and after radiotherapy, and to investi- gate the therapeutic effect of radiotherapy in C6 rat glioma model using 18F-FDG PET-CT. Methods Sixteen C6 rat glioma models were randomly dived into two groups （8 rats in each group）, one radiotherapy group, and the other control group. 18 F-FDG PET-CT imaging was performed before radiotherapy and 24 h, one week after radiotherapy. Tumor＇ s SUV the lateral spinal muscles＇ SUV the ratio of SUVmax of tumor to muscles and the volume of the tumor were calculated. All of the rats were sacrificed after radiotherapy, pathological changes were observed by HE staining, and the expression of proliferation index Ki-67 and microvesset density MVD were measured by immuno- histochemical staining. Results ① At 24 h post-radiotherapy, the ratio of tumor to muscles （T/M） value of radio- therapy group was significantly lower than that before radiotherapy （ t = 5.991, P 〈 0.01 ）. While the T/M value of the control group of first and 24 h imaging were 10. 408 ±1. 958,10. 086 ± 1. 983, respectively（ t = 5. 196, P 〈 0. 01 ）. ② One week after radiotherapy, the T/M value of radiotherapy group was significantly lower than that of 24 h imaging（t = 3.082, P 〈 0.05 ） and before radiotherapy （ t = 4. 822, P 〈 0.01 ） （ F = 5. 902, P 〈 0.01 ）. While the T/M value of the control group was higher than that of 24 h imaging （t = 3.621, P 〈 0. 05 ）. ③ More obvious necrosis was observed in the radiotherapy group than the control group by HE staining. The expressions of Ki-67 and MVD staining in the radiotherapy group were significantly decreased compared with the control group. All of the results above were statistically significant （t = 7. 201, 2. 986 ,P 〈 0. 01 ）. ④ T/M value was positively correla- ted with Ki-67 expression （r = 0. 824, r2 = 0. 679, P 〈 0. 05 ）, and had positive correlation with MVD expression（ r = 0. 779, r2 = 0. 606, P 〈 0. 05）. Conclusion 18F-FDG PET-CT not only can be used to assess the early radio- therapeutic effect of C6 rat glioma, but also can measure the proliferation activity and angiogenesis of gliomas.