Swarts Steven G, Sidabras Jason W, Grinberg Oleg, Tipikin Dmitriy S, Kmiec Maciej M, Petryakov Sergey V, Schreiber Wilson, Wood Victoria A, Williams Benjamin B, Flood Ann Barry, Swartz Harold M
Department of Radiation Oncology, University of Florida, P.O. Box 100385, Gainesville, FL 32610 USA.
Max Planck Institute for Chemical Energy Conversion, Biophysical Chemistry, Stiftstr. 34-36, 45470 Mülheim, Germany.
Health Phys. 2018 Jul;115(1):140-150. doi: 10.1097/HP.0000000000000874.
Instrumentation and application methodologies for rapidly and accurately estimating individual ionizing radiation dose are needed for on-site triage in a radiological/nuclear event. One such methodology is an in vivo X-band, electron paramagnetic resonance, physically based dosimetry method to directly measure the radiation-induced signal in fingernails. The primary components under development are key instrument features, such as resonators with unique geometries that allow for large sampling volumes but limit radiation-induced signal measurements to the nail plate, and methodological approaches for addressing interfering signals in the nail and for calibrating dose from radiation-induced signal measurements. One resonator development highlighted here is a surface resonator array designed to reduce signal detection losses due to the soft tissues underlying the nail plate. Several surface resonator array geometries, along with ergonomic features to stabilize fingernail placement, have been tested in tissue-equivalent nail models and in vivo nail measurements of healthy volunteers using simulated radiation-induced signals in their fingernails. These studies demonstrated radiation-induced signal detection sensitivities and quantitation limits approaching the clinically relevant range of ≤ 10 Gy. Studies of the capabilities of the current instrument suggest that a reduction in the variability in radiation-induced signal measurements can be obtained with refinements to the surface resonator array and ergonomic features of the human interface to the instrument. Additional studies are required before the quantitative limits of the assay can be determined for triage decisions in a field application of dosimetry. These include expanded in vivo nail studies and associated ex vivo nail studies to provide informed approaches to accommodate for a potential interfering native signal in the nails when calculating the radiation-induced signal from the nail plate spectral measurements and to provide a method for calibrating dose estimates from the radiation-induced signal measurements based on quantifying experiments in patients undergoing total-body irradiation or total-skin electron therapy.
在放射/核事件中进行现场分诊时，需要能够快速准确估算个体电离辐射剂量的仪器和应用方法。其中一种方法是基于体内X波段电子顺磁共振的物理剂量测定法，可直接测量指甲中的辐射诱导信号。目前正在开发的主要组件包括关键仪器特性，例如具有独特几何形状的谐振器，其允许大的采样体积，但将辐射诱导信号测量限制在指甲板上，以及用于处理指甲中干扰信号和根据辐射诱导信号测量校准剂量的方法。这里重点介绍的一种谐振器开发是一种表面谐振器阵列，旨在减少由于指甲板下方软组织导致的信号检测损失。几种表面谐振器阵列几何形状以及用于稳定指甲放置的人体工程学特征，已在组织等效指甲模型中以及在健康志愿者的体内指甲测量中进行了测试，这些测量使用了指甲中模拟的辐射诱导信号。这些研究表明，辐射诱导信号检测灵敏度和定量限接近≤10 Gy的临床相关范围。对当前仪器功能的研究表明，通过改进表面谐振器阵列和仪器人机界面的人体工程学特征，可以降低辐射诱导信号测量的变异性。在确定该测定法在剂量测定现场应用中的分诊决策定量限之前，还需要进行更多研究。这些研究包括扩大体内指甲研究以及相关的体外指甲研究，以便在根据指甲板光谱测量计算辐射诱导信号时，提供明智的方法来处理指甲中潜在的干扰天然信号，并提供一种基于对接受全身照射或全身电子治疗的患者进行定量实验来校准辐射诱导信号测量剂量估计的方法。
