Biodosimetry based on EPR measurements of nails in vivo: Dartmouth Medical School

我们最近证明了在活体和原位测量指甲的可行性，使之可以避免需要夹钉子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”)的测量。我们将充分确定在现场应用所需条件下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准确剂量测量方案，然后制定全功能EPR剂量测量仪的可克隆原型的标准。我们建议使这台仪器能够由 非专业用户。这些研究将利用我们在活体测量人类受试者牙齿剂量学方面的经验，以及我们在体外用剪下的指甲进行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。该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。仪器的发展和原型仪器的构建 将与核心A、C和E合作执行

We recentiy 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 condifions 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 utilize 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 critical 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 crifical 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 pafient group with nails irradiated in vivo. The instrumental developments and the construction of the prototype instrument will be carried out in collaborafion with Cores A,C , and E