RADIATION REPAIR OF NORMAL MAMMALIAN TISSUE

本研究的目的是评估剂量因素 影响晚期并发症的分次和治疗量 放射治疗后。 增加了对发病机制的认识， 包括更好地定义剂量限制细胞的晚期效应将 更好地理解改变分馏的影响 方案和治疗量。 犬反应的等效应曲线 心脏和包括食道和气管的纵隔结构将 通过将这些组织暴露于给定的总剂量范围内产生 每部分的剂量范围。 将使用以下方法进行连续研究： 非侵入性内窥镜检查、放射学检查、心电图检查和 超声心动图技术。 组织学分析将进行两年 用于与功能研究进行比较，并提供 关于迟发效应发病机理的信息。 体积效应将是 通过照射狗的不同长度的脊髓进行评价。 将依次进行电生理测量，并进行组织学检查。 辐射后两年进行的分析。 如果体积效应 发现，将进行更多的研究，每个部分的剂量较小， 确定分馏对体积效应的影响。 这些研究 将定量显示组织对不同方法的反应， 辐射和组织学分析将有助于描述 迟发效应的发病机制。 生成的等效应曲线可以 提供用于调整分次大小和剂量输送的指导， 指出这些变化如何受到体积额外影响 辐射。

The objective of this research is to evaluate the factors of dose fractionation and treatment volume which influence late complications following radiation therapy. Increased knowledge of the pathogenesis of late effects including better definition of dose limiting cells will provide a better understanding of the effects of altered fractionation schemes and treatment volume. Isoeffect curves for response of canine heart and mediastinal structures including the esophagus and trachea will be generated by exposing those tissues to a range of total doses given a range of doses per fraction. Sequential studies will be done using noninvasive endoscopic, radiographic, electrocardiographic and echocardiographic techniques. Histologic analyses will be done two years after irradiation for comparison with functional studies and provide information on the pathogenesis of late effects. The volume effect will be evaluated by irradiating variable lengths of spinal cords of dogs. Electrophysiologic measurements will be made sequentially and histologic analyses done two years following irradiation. If a volume effect is found, additional studies will be done with smaller doses per fraction to determine the influence of fractionation on volume effect. These studies will show quantitatively how tissues respond to the different methods of irradiation and the histologic analyses will contribute to the description of pathogenesis of late effects. The isoeffect curves generated may provide directions for adjusting fraction size and dose delivery and indicate how those alterations may be additionally influenced by volume irradiated.