Study on radiation effect to malignant tumors and its influence on metastasis

1)从评价剂量率效应的研究结果看，JCL：ICR雄性小鼠的低剂量率照射(LDR)为7Gy100/30。在致死效应上，高剂量率照射(HDR)4Gy值接近5.5GyLDR，HDR5.5Gy值接近LD_(50)/30Gt；6GyHDR照射约等于7GyLDR照射。通过评价辐射对成纤维细胞和软骨细胞DNA含量的影响，进一步研究辐射剂量率效应。5GyHDR对培养细胞DNA含量的抑制作用强于LDR。实验结果证实，辐射效应受剂量率的影响，即使差别只有1~20。2)对原发灶照射对转移发生率的影响进行了实验研究。结果表明，兔股骨VX2移植瘤单次照射3、5、10Gy后，与未照射对照组相比，肿瘤转移发生率明显增加。

1) From the results of study performed for evaluation of dose rate effect 7 Gy with low dose rate irradiation (LDR) corresponded nearly to LD_<100/30> for Jcl:ICR male mouse. Four Gy with high dose rate irradiation (HDR) was almost equivalent to 5.5 Gy with LDR on lethal effect, and 5.5 Gy with HDR nearly to LD_<50/30>. Six Gy with HDR was estimated at nearly 7 Gy with LDR. Further study on dose rate effect was made by evaluating the irradiation effects on DNA contents of cultured fibroblasts and chondrocytes. Five Gy with HDR was more inhibitive to DNA contents in cultured cells than with LDR. As the results it was confirmed that the radiation effects were influenced by dose rate even though the difference was only 1 to 20.2) An experimental study was performed on the effect of irradiation for primary lesion to the incidence of metastasis. The results of the study suggested that a single exposure of 3,5 and 10 Gy each to the transplanted VX2 carcinomas of rabbit femur increased the incidence of metastasis as compared with the non-irradiated control group.