Breiter N, Sassy T, Trott K R
Institute of Radiobiology, GSF, Neuherberg, Germany.
Radiother Oncol. 1993 Jun;27(3):223-8. doi: 10.1016/0167-8140(93)90078-m.
Localized 300 kV X-irradiation of the rat stomach with single and fractionated (two and five fractions given daily and in 4 weeks) doses was performed. In the second and third week after irradiation acute radiation gastritis developed which resulted in a dose-dependent drop in body weight. The alpha/beta value for a 10% drop in body weight was calculated to be 9.6 Gy (95% confidence interval 2.1-25.9 Gy). Between 4 and 40 weeks after irradiation subchronic radiation damage was observed which presented itself as atonic dilatation of the stomach. For this effect, the alpha/beta value is 4.8 Gy (graphical estimation) and 5.3 Gy (95% confidence interval 0.4-13.1 Gy; direct Poisson model). In the five-fraction (5F) experiment a significant increase in tolerance amounting to 0.8 Gy/day for the acute effect and 0.4 Gy/day for the subchronic effect was observed when intervals were increased from 1 day to 1 week. In a separate experiment animals were pre-irradiated with subtoxic and toxic radiation doses. One hundred days later acute tolerance to a second irradiation was completely restored. However, no recovery of subchronic damage was observed.
对大鼠胃部进行局部300 kV X射线照射，采用单次和分次（每天给予两次和五次，共4周）剂量。照射后第二周和第三周出现急性放射性胃炎，导致体重呈剂量依赖性下降。计算得出体重下降10%时的α/β值为9.6 Gy（95%置信区间2.1 - 25.9 Gy）。照射后4至40周观察到亚慢性放射性损伤，表现为胃弛缓性扩张。对于这种效应，α/β值为4.8 Gy（图形估计）和5.3 Gy（95%置信区间0.4 - 13.1 Gy；直接泊松模型）。在五分次（5F）实验中，当间隔从1天增加到1周时，观察到急性效应的耐受量显著增加，达到0.8 Gy/天，亚慢性效应的耐受量增加到0.4 Gy/天。在另一个实验中，动物预先接受亚毒性和毒性辐射剂量照射。100天后，对第二次照射的急性耐受性完全恢复。然而，未观察到亚慢性损伤的恢复。
