In vivo EPR for after-the-fact measurement of dose

总体目标是满足一个关键需求：在事故发生后立即确定个人是否接受了可能导致急性临床症状的辐射剂量。如果暴露条件表明急性影响是可能的，我们需要能够迅速和准确地将个人归入适当的剂量类别，以指导治疗方法和咨询。随着可能制定减轻电离辐射损害的程序，确定谁处于危险之中的必要性更加迫切，因为这种干预措施很可能在尽早使用时最有效。当曝光时 被发现在不太可能导致急性影响的范围内，测量的可用性将提供保证，并减少进入医疗保健系统的人数。有大量数据表明，基于牙齿辐射诱导效应的在体EPR剂量学具有灵敏度和准确性，可以满足这种事后定量剂量评估的主要需求，在不到五分钟的时间内提供有效的筛查信息和即时读数。在这个项目中，我们提出了一套相关的具体目标，以(A)解决当前的需求和(B)寻求更长期的发展，以加强能力。最迫切的需要是一种可现场部署的仪器，用于 快速的“事后”剂量测定。这将是我们的首要任务。我们最初将使达特茅斯的现有设施全面投入使用，用于紧急剂量测定，并将利用这些设施和进一步的改进作为快速开发适合现场使用的便携式剂量计的基础。这将在罗切斯特进行测试，在那里它还将用于扩展校准/验证，利用那里的专业知识和患者群体。还有一些可行的办法来提高该方法的敏感性和实地可部署性；将在不影响首要优先事项的情况下尽可能有效地采取这些办法。这些措施包括 手持式剂量计的潜在发展，以及几种有希望提高灵敏度的方法。这种灵敏度的提高将进一步减少进行测量所需的时间，并使我们能够将该方法扩展到较低的阈值，可能会远远低于可能导致急性临床影响的剂量。也有一些看似合理的方法来补充体内EPR剂量学，通过在体外进行测量，使用头发、手指/脚趾甲或非常小的牙齿碎片。这些测量可以扩大筛查能力，也有助于解决不对称暴露。

The overall objective is to meet a critical need: determining immediately after an incident whether individuals have received a radiation dose that could result in acute clinical symptoms. If the exposure conditions indicate that acute effects are possible, we need to be able to place individuals into appropriate dose categories rapidly and accurately, to guide therapeutic approaches and counseling. With the potential development of procedures to mitigate damage from ionizing radiation, the need to determine who is at risk is even more urgent, since such interventions are likely to most effective when used as early as possible. When exposures are found to be in a range that is unlikely to lead to acute effects, the availability of the measurement will provide reassurance and reduce the number of people entering the medical care system. There are substantial data available that indicate that in vivo EPR dosimetry, based on radiation-induced effects in teeth, has the sensitivity and accuracy to meet a major part of the needs for such after-the-fact quantitative dose assessment, providing effective screening information and immediate readouts in less than five minutes. In this project, we propose a set of related specific aims to (a) address the immediate needs and (b) pursue longer-term developments to enhance capabilities. The most urgent need is a field deployable instrument for rapid "after-the-fact" dosimetry. This will be our first priority. We initially will make the existing facility at Dartmouth fully operational for emergency dosimetry, and will use these and further improvements as the basis for the rapid development of a transportable dosimeter suitable for field use. This will be tested at Rochester, where it also will be used for extending calibrations/validations, using the expertise and patient populations there. There also are a number of feasible ways to improve the sensitivity and field deployability of the method; these will be pursued as efficiently as possible without affecting the first priorities. These include the potential development of a hand-held version of the dosimeter, and several promising methods to enhance sensitivity. Such increases in sensitivity will further reduce the time needed to make the measurements and enable us to extend the method to a lower threshold, potentially to doses well below those that can cause acute clinical effects. There also are some plausible means to complement in vivo EPR dosimetry by making measurements in vitro, using hair, finger/toenails, or very small chips of teeth. These measurements could broaden the capacity for screening, and also aid in resolution of asymmetric exposures.