Biodosimetry based on EPR measurements of teeth in vivo Dartmouth Medical School

项目总结(见说明)： 我们最近证明了在活体受试者中进行指甲测量的可行性，使得不需要夹指甲来进行指甲剂量测量，而是使用一种新型的谐振器来进行测量，该谐振器可以在体内直接在指甲上进行高频(9.5 GHz或“X波段”)的灵敏测量。我们将在需要在现场应用的条件下，充分确定在感兴趣的剂量范围内以足够的精度和灵敏度进行测量的可行性和能力，然后确定哪些参数可能影响剂量-响应关系，开发应对这些因素的方法，开发基于体内测量的快速和准确的剂量测量方案，然后制定全功能EPR剂量测量仪的可克隆原型的标准。我们建议使该仪器能够由非专家用户操作。这些研究将利用我们在活体测量人类受试者牙齿剂量的经验，以及我们在体外用修剪的指甲进行EPR测量的经验。 由于测量是基于电离辐射的物理效应，预计可以在暴露后的任何时间在几周的窗口内进行。这些变化在暴露后立即出现，并持续几周，以便在事件发生时立即进行测量和分析。这些变化也不受事件发生后人群中可能存在的因素的影响，因此将与基于生物的生物剂量测定相辅相成和协同作用。本项目的测量结果将为项目2的推进提供关键因素，促进对机械诱导的EPR信号在钉子中的来源和分布的了解。仪器核心将提供谐振器开发的关键部分，并最终用于构建用于现场测量的灵敏X波段EPR光谱仪。TBI核心将为在活体内照射指甲的患者组提供必要的通道。仪器的开发和原型仪器的建造将与A、C和E岩心合作进行。

PROJECT SUMMARY (See Instructions): We recenfiy have demonstrated the feasibility of making measurements of nails in living subjects in situ and in vivo, making it feasible to avoid the need for clipping nails to carry out nail dosimetry, instead making the measurements with a new type of resonator that can make sensifive measurements at a high frequency (9.5 GHz or "X-Band") directly on the nail in vivo. We will determine fully the feasibility and capability of measurements with sufficient accuracy and sensifivity within the dose range of interest under the conditions that would be needed to apply in the field and then determine what parameters may affect the doseresponse relationships, develop methods to cope with these factors, develop a protocol for fast and accurate dosimetry based on measurements in vivo, and then develop criteria for a clonable prototype of a fully functional EPR dosimetry instrument. We propose to make this instrument capable of being operated by non-expert users. The studies will ufilize our experience in making measurements in vivo with human subjects for tooth dosimetry and our experience in making EPR measurements in vitro in clipped nails. Because the measurements are based on a physical effect of ionizing radiafion, it is expected that they can be made at any time after the exposure within a window of several weeks. These changes are present immediately after exposure and persist for a period of a few weeks allowing measurements to be immediately taken and analyzed If an event did occur. The changes are also unaffected by factors that are likely to be present in the population after such an event and therefore will be complementary and synergistic to biologically based biodosimetry. The results of the measurements in this project will provide a crifical element for the advancement of project 2, advancing understanding of the origins and distribufions of the mechanically-induced EPR signals in nails. The instrumental core will provide critical parts of the developments of the resonators and ultimately in the construction of a sensitive X-Band EPR spectrometer for making the measurements in the field. The TBI core will provide essential access to the patient group with nails irradiated in vivo. The instrumental developments and the construction of the prototype instrument will be carried out in collaboration with Cores A,C , and E.