RENAL DAMAGE IN THE MOUSE - THE RESPONSE TO VERY SMALL DOSES PER FRACTION
RENAL DAMAGE IN THE MOUSE - THE RESPONSE TO VERY SMALL DOSES PER FRACTION
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DOI：
10.2307/3577233
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发表时间：
1988-05-01
影响因子：
3.4
通讯作者：
JOHNS, H
中科院分区：
文献类型：
--
作者：
JOINER, MC;JOHNS, H
进行实验以研究每部分 0.2 至 1.6 Gy 范围内的重复 X 射线剂量和每部分 0.05 至 0.25 Gy 范围内的中子剂量对小鼠肾脏的影响。使用了实验的顶上设计，以便给予额外的分级剂量的 d(4)-Be 中子 (.hivin.EN = 2.3 MeV)，以使这些处理产生的阈下损伤进入可测量的范围。这种方法避免了使用大量分数来研究每个分数的低剂量的必要性。使用三种方法评估肾损伤：51Cr-EDTA 清除率、尿量和放射后 16-50 周的血细胞比容。获得的剂量反应曲线在第 29 周时得到最好的解决。然而，还通过将二阶多项式拟合到辐射后反应时间的数据并使用这些函数在 29 周时的插值来构建剂量反应曲线来检查结果。该方法稍微减少了剂量反应数据的变化，但剂量反应曲线之间的相互关系保持不变。这些数据用于测试潜在 X 射线剂量分割关系的线性二次 (LQ) 描述。该模型很好地拟合了每分数 .apprx 的 X 射线剂量。 1 Gy，但每灰度较低的 X 射线剂量比 LQ 预测的更有效，正如之前在皮肤中看到的那样 [M. C.Joiner 等人，Int。 J.辐射。生物。 49, 565-580 (1986)]。这种 X 射线有效性的增加和 LQ 的偏差直接反映在 d(4)-Be 中子相对于低剂量 X 射线的 RBE 降低上，因为在这个低剂量区域对这些中子的潜在响应是线性的。随着每次分次的 X 射线剂量从 0.8 Gy 降至 0.2 Gy 以下，RBE 从 9.9 降至 4.7，反映出 X 射线有效性提高了 2.1 倍。讨论了一个模型，试图解释每次分次低剂量时的这种行为。
Experiments were undertaken to study the effect on the mouse kidney of repeated X-ray doses in the range 0.2 to 1.6 Gy per fraction and neutron doses in the range 0.05 to 0.25 Gy per fraction. A top-up design of experiment was used, so that additional graded doses of d(4)-Be neutrons (.hivin.EN = 2.3 MeV) were given to bring the subthreshold damage produced by these treatments into the measurable range. This approach avoided the necessity to use a large number of fractions to study low doses per fraction. Renal damage was assessed using three methods: 51Cr-EDTA clearance, urine output, and hematocrit at 16-50 weeks postirradiation. The dose-response curves obtained were resolved best at 29 weeks. However, the results were also examined by fitting second-order polynomials to the data for response versus time postirradiation and using interpolated values from these functions at 29 weeks to construct dose-response curves. This method reduced slightly the variation in the dose-response data, but the interrelationship between the dose-response curves remained the same. The data were used to test the linear-quadratic (LQ) description of the underlying X-ray dose-fractionation relationship. The model fits well down to X-ray doses per fraction of .apprx. 1 Gy, but lower X-ray doses were more effective per gray than predicted by LQ, as seen previously in skin [M. C. Joiner et al., Int. J. Radiat. Biol. 49, 565-580 (1986)]. This increased X-ray effectiveness and deviation from LQ are reflected directly in a decrease in the RBE of d(4)-Be neutrons relative to X-rays at low doses, since the underlying response to these neutrons is linear in this low-dose region. The RBE decreases from 9.9 to 4.7 as the X-ray dose per fraction is reduced below 0.8 Gy to 0.2 Gy, reflecting an increase in X-ray effectiveness by a factor of 2.1 A model is discussed with attempts to explain this behavior at low doses per fraction.