Epr Biodosimetry For Emergency Assessment Of Radiation Exposure

Purpose/Objective(s)In order to meet the potential need for emergency large-scale radiation biodosimetry following an accident or attack, we have developed in vivo EPR instrumentation and methodology for the quantification of radiation-induced radicals within intact teeth and fingernails. These techniques have several very desirable characteristics for triage, including: independence from confounding biologic factors; non-invasive measurement procedures; the capability to make measurements over wide periods in time after the event; immediate estimation of the absorbed dose; and the ability to perform measurements with non-expert operators at the site of an event. Throughout development there has been a particular focus on the need for a deployable system, including instrumental requirements for transport and field use, the need for high throughput, and use by minimally trained operators.Materials/MethodsWe have produced and tested an operational and deployable L-band (1200 MHz) EPR system for tooth dosimetry based on a 60 lb dipole permanent-magnet with a 17 cm gap which was designed to minimize weight, while maintaining adequate accessibility, and having a suitably sized region of magnetic field homogeneity. The electronics for EPR detection and sweeping of the magnetic field are contained in a single deployable instrument rack which can be powered using the public electric supply or a generator. The fully integrated software and hardware components of the instrument allow for complete automation of the data acquisition procedure and enable reliable use by operators without specialized training.ResultsMeasurements were performed on incisor teeth of unirradiated volunteers and patients who had received total body irradiation. The collection and analyses of sets of three serially-acquired spectra with independent placements of the resonator in a data collection process lasting approximately five minutes provides dose estimates with standard errors of prediction in the range of 0.5 - 1 Gy.ConclusionsThese studies have provided a direct and challenging test of our capability to identify subjects who would benefit from acute medical care following a catastrophic radiation event. Numerous measurements have been performed using this system in clinical and other non-laboratory settings. Together with biologically based radiation biodosimetry methods, as well as EPR measurements of intact nail tissue and isolated nail clippings, these approaches could help enable a rational response to a catastrophic radiation event. Purpose/Objective(s)In order to meet the potential need for emergency large-scale radiation biodosimetry following an accident or attack, we have developed in vivo EPR instrumentation and methodology for the quantification of radiation-induced radicals within intact teeth and fingernails. These techniques have several very desirable characteristics for triage, including: independence from confounding biologic factors; non-invasive measurement procedures; the capability to make measurements over wide periods in time after the event; immediate estimation of the absorbed dose; and the ability to perform measurements with non-expert operators at the site of an event. Throughout development there has been a particular focus on the need for a deployable system, including instrumental requirements for transport and field use, the need for high throughput, and use by minimally trained operators. In order to meet the potential need for emergency large-scale radiation biodosimetry following an accident or attack, we have developed in vivo EPR instrumentation and methodology for the quantification of radiation-induced radicals within intact teeth and fingernails. These techniques have several very desirable characteristics for triage, including: independence from confounding biologic factors; non-invasive measurement procedures; the capability to make measurements over wide periods in time after the event; immediate estimation of the absorbed dose; and the ability to perform measurements with non-expert operators at the site of an event. Throughout development there has been a particular focus on the need for a deployable system, including instrumental requirements for transport and field use, the need for high throughput, and use by minimally trained operators. Materials/MethodsWe have produced and tested an operational and deployable L-band (1200 MHz) EPR system for tooth dosimetry based on a 60 lb dipole permanent-magnet with a 17 cm gap which was designed to minimize weight, while maintaining adequate accessibility, and having a suitably sized region of magnetic field homogeneity. The electronics for EPR detection and sweeping of the magnetic field are contained in a single deployable instrument rack which can be powered using the public electric supply or a generator. The fully integrated software and hardware components of the instrument allow for complete automation of the data acquisition procedure and enable reliable use by operators without specialized training. We have produced and tested an operational and deployable L-band (1200 MHz) EPR system for tooth dosimetry based on a 60 lb dipole permanent-magnet with a 17 cm gap which was designed to minimize weight, while maintaining adequate accessibility, and having a suitably sized region of magnetic field homogeneity. The electronics for EPR detection and sweeping of the magnetic field are contained in a single deployable instrument rack which can be powered using the public electric supply or a generator. The fully integrated software and hardware components of the instrument allow for complete automation of the data acquisition procedure and enable reliable use by operators without specialized training. ResultsMeasurements were performed on incisor teeth of unirradiated volunteers and patients who had received total body irradiation. The collection and analyses of sets of three serially-acquired spectra with independent placements of the resonator in a data collection process lasting approximately five minutes provides dose estimates with standard errors of prediction in the range of 0.5 - 1 Gy. Measurements were performed on incisor teeth of unirradiated volunteers and patients who had received total body irradiation. The collection and analyses of sets of three serially-acquired spectra with independent placements of the resonator in a data collection process lasting approximately five minutes provides dose estimates with standard errors of prediction in the range of 0.5 - 1 Gy. ConclusionsThese studies have provided a direct and challenging test of our capability to identify subjects who would benefit from acute medical care following a catastrophic radiation event. Numerous measurements have been performed using this system in clinical and other non-laboratory settings. Together with biologically based radiation biodosimetry methods, as well as EPR measurements of intact nail tissue and isolated nail clippings, these approaches could help enable a rational response to a catastrophic radiation event. These studies have provided a direct and challenging test of our capability to identify subjects who would benefit from acute medical care following a catastrophic radiation event. Numerous measurements have been performed using this system in clinical and other non-laboratory settings. Together with biologically based radiation biodosimetry methods, as well as EPR measurements of intact nail tissue and isolated nail clippings, these approaches could help enable a rational response to a catastrophic radiation event.