Zeman G H, Mohaupt T H, Taylor P L, MacVittie T J, Dubois A, Vigneulle R M
Armed Forces Radiobiology Research Institute, Bethesda, Maryland.
Radiat Res. 1990 Jan;121(1):54-62.
An experimental model has been developed for quantitative studies of radiobiological damage to the canine small intestine following partial-body nonuniform irradiation. Animals were irradiated with 60Co gamma rays to simulate the nonuniform irradiation which do occur in victims of radiation accidents. The model used a short source-to-surface distance for unilateral irradiations to produce a dose gradient of a factor of two laterally across the canine intestinal region. The remainder of the animal's body was shielded to prevent lethal damage to the bone marrow. In situ dosimetry measurements were made using thermoluminescent dosimeters to determine the radiation dose delivered as a function of position along a segment of the small intestine. This system made it possible to correlate the radiation dose delivered at a specific point along the small intestine with the macroscopic and microscopic appearance of the intestinal mucosa at that point, as determined by direct observation and biopsy using a fiberoptic endoscope. A key feature of this model is that dosimetry data for multiple sites, which receive a graded range of radiation doses, can be correlated with biological measurements to obtain a dose-response curve. This model is being used to evaluate the efficacy of new therapeutic procedures to improve survival following nonuniform irradiation.
已开发出一种实验模型，用于定量研究犬小肠在局部身体非均匀照射后的放射生物学损伤。用60Coγ射线照射动物，以模拟辐射事故受害者中确实会发生的非均匀照射。该模型在单侧照射时采用短源皮距，以在犬肠道区域横向产生两倍剂量梯度。动物身体的其余部分进行屏蔽，以防止对骨髓造成致命损伤。使用热释光剂量计进行原位剂量测定，以确定沿小肠一段的辐射剂量随位置的变化。该系统能够将小肠特定点处的辐射剂量与该点处肠黏膜的宏观和微观外观相关联，这是通过使用纤维内窥镜直接观察和活检确定的。该模型的一个关键特征是，接受分级辐射剂量范围的多个部位的剂量测定数据可以与生物学测量相关联，以获得剂量反应曲线。该模型正用于评估新治疗程序在改善非均匀照射后存活率方面的疗效。
