In-Vivo Radiation Dosimetry Using Portable L Band Epr: On-Site Measurement of Volunteers in Fukushima Prefecture, Japan

Abstract

The aim of this study was to make direct measurements of the possible radiation-induced EPR signals in the teeth of volunteers who were residents in Fukushima within 80 km distance from the Fukushima Nuclear Power plant at the time of the disaster, and continued to live there for at least 3 month after the disaster. Thirty four volunteers were enrolled in this study. These measurements were made using a portable L-band EPR spectrometer, which was originally developed in the EPR Center at Dartmouth. All measurements were performed using surface loop resonators that have been specifically designed for the upper incisor teeth. Potentially these signals include not only radiation-induced signals induced by the incident but also background signals including those from prior radiation exposure from the environment and medical exposure. We demonstrated that it is feasible to transport the dosimeter to the measurement site and make valid measurements. The intensity of the signals that were obtained was not significantly above those seen in volunteers who had not had potential radiation exposures at Fukushima.

Advances in in vivo EPR Tooth BIOdosimetry: Meeting the targets for initial triage following a large-scale radiation event

“…Electron Paramagnetic Resonance (EPR) tooth dosimetry has been well recognised for many years as an accurate method to assess whether people potentially exposed to ionising radiation received a clinically significant dose (1)(2)(3) . Although teeth (measured in vivo or in vitro) can be used to assess exposures many months or years after the fact (see Miyake et al's report (4) that assessed dose several years after a radiation event using EPR in vivo tooth dosimetry on people living nearby to the 2011 nuclear power plant accident in Fukushima), the focus of this paper is on individualised biodosimetry assessments needed within hours or days of the event. Especially apropos to the situation of a largescale terrorist event involving radiation, where hundreds to thousands of people have been potentially exposed, the current EPR in vivo tooth biodosimetry device can be transported to the areas where people are gathering and can provide rapid noninvasive assessments designed to facilitate appropriate and immediate triage to receive (or not) life-saving medical care to treat or mitigate the effects of acute radiation syndrome (ARS).…”

L-Band Electron Paramagnetic Resonance Tooth Dosimetry Applied to Affected Cattle Teeth in Fukushima

“…An EPR tooth dosimeter obtained from Clin-EPR, LLC was used for EPR tooth dosimetry. This instrument was based on instruments designed for in vivo dosimetry by the EPR Center for the Study of Viable Systems, Geisel School of Medicine at Dartmouth College in Hanover, NH, USA [15]. The spectrometer operates in continuous-wave (CW) mode and uses homodyne detection at an excitation frequency near 1.15 GHz (L-band) using a 41 mT dipole magnet weight 30 kg with 17 cm pole separation.…”

“…The spectra from each of the collected datasets were analyzed to estimate the peak-to-peak signal amplitudes of the RIS and 15 N-PDT. The RIS and signals of 15 N-PDT were then averaged to determine the mean amplitude for each tooth. For two cows (08411-03687, 08411-03274), the scan times were increased to 200, to increase signal/noise.…”

“…In order to carry out radiation dosimetry in live subjects such as for potential radiation emergencies, a lower-frequency L-band EPR apparatus that can be applied to teeth in situ has been developed for measurement under triage conditions [13]. This method is also applicable for retrospective dose assessment for a large-scale radiation exposure incident [14,15].…”

Developments in Biodosimetry Methods for Triage With a Focus on X-band Electron Paramagnetic Resonance In Vivo Fingernail Dosimetry

“…This dosimetry method has long been used in retrospective dosimetry to accurately estimate acute and chronic exposure doses of radiation to an individual because of the permanence of the radiation-induced signal in the tooth and the extremely low inter-individual variation in the dose-response of the signal (Fattibene and Callens 2010). Recent innovations in EPR instrumentation now provide a means to conduct minimally invasive, in vivo measurements of the radiation induced signal directly on the teeth in situ (Swartz et al 2014, Miyake et al 2016) in a portable instrumentation platform (Flood et al 2014, Williams et al 2014). It is these features which make this biodosimetry method an excellent choice as a point-of-care dosimetry method for the purposes of rapid, dose-based medical care screening during the triage of individuals in a mass radiation exposure event.…”