ADAPTATION OF EPR INSTRUMENTATION FOR USE IN HUMAN SUBJECTS

由于辐射的严重和不可治愈的后果 脊髓病，许多椎旁区的肿瘤接受的 最佳辐射剂量。即使是略微降低了 给定治疗剂量的辐射损伤将允许使用 增加剂量可能会增加局部感染的可能性 解药。准确评估空气中氧浓度的能力 辐射脊髓是研究其潜在机制的关键。 放射性脊髓病，并在帮助确定更有效 使用和传递放射治疗脊柱旁区域癌症的方法。 我们的结果显示，受照射的大鼠脊髓组织中的PO2 在中级(最高水平为18Q3 mm Hg)显著增加 在辐射后55天)和辐射后的长时间段 (照射后90至180天内平均水平为15Q 3毫米汞柱)， 与未照射对照组比较(平均水平为9Q2 在整个实验过程中均为毫米汞柱)。发现氧分压是 在受辐射的脊髓中升高是意想不到的，并表明 目前人们对脑部疾病病理生理学的普遍预期 应重新考虑辐射对脊髓的损伤。 其发病机制可能与氧化损伤有关。 与血氧分压升高有关。尽管用于 在这项研究中，PO2的增加目前还不清楚，但减少了 耗氧量和/或辐射引起的血管张力丧失和 受照区域的微血管重构和扩张 看似合理的因素。这些结果也表明EPR血氧测定仪是一种 重复测定中枢神经系统血氧饱和度的实用无创性方法 组织在较长的时间内无侵入性。

Due to the severe and untreatable consequences of radiation myelopathy, many tumors in the paraspinal region receive a less than optimal radiation dose. Even a modest reduction in the risk of radiation injury from a given therapeutic dose would allow for the use of an increased dose which could enhance the probability of a local cure. The ability to accurately assess oxygen concentration in the radiated spinal cord is critical to studying the underlying mechanisms of radiation myelopathy, and in helping to determine more effective ways to use and deliver radiation to cancers in the paraspinal region. Our results show that spinal cord tissue pO2 in the irradiated rats increased significantly at intermediate (maximum level of 18 q 3 mm Hg at 55 days post irradiation) and long time periods after the radiation (average level 15 q 3 mm Hg between 90 and 180 days post irradiation), compared with the non-irradiated control group (average level of 9 q 2 mm Hg throughout the experiment). The finding that the pO2 was elevated in the irradiated spinal cord was unexpected and suggests that the prevailing expectations on the pathophysiology of radiation-induced damage to the spinal cord should be reconsidered. It seems possible that the pathogenesis is related to oxidative damage associated with the increased pO2. Although the mechanisms for the increase in pO2 in this study are not currently known, decreased oxygen consumption and/or radiation induced loss of vascular tone and microvascular remodeling and dilatation in the irradiated region are plausible factors. These results also indicate that EPR oximetry is a useful and noninvasive method for repeatedly assessing the pO2 of CNS tissue non-invasively over an extended period of time.