Article

In vivo EPR dosimetry to quantify exposures to clinically significant doses of ionising radiation

EPR Center for Viable Systems, Dartmouth Medical School, 703 Vail, Hanover, NH 03755, USA.
Radiation Protection Dosimetry (Impact Factor: 0.91). 02/2006; 120(1-4):163-70. DOI: 10.1093/rpd/nci554
Source: PubMed

ABSTRACT

As a result of terrorism, accident or war, populations potentially can be exposed to doses of ionising radiation that could cause direct clinical effects within days or weeks. There is a critical need to determine the magnitude of the exposure to individuals so that those with significant risk can have appropriate procedures initiated immediately, while those without a significant probability of acute effects can be reassured and removed from the need for further consideration in the medical/emergency system. It is extremely unlikely that adequate dosemeters will be worn by the potential victims, and it also will be unlikely that prompt and accurate dose reconstruction at the level of individuals will be possible. Therefore, there is a critical need for a method to measure the dose from radiation-induced effects that occur within the individual. In vivo EPR measurements of radiation-induced changes in the enamel of teeth is a method, perhaps the only such method, which can differentiate among doses sufficiently to classify individuals into categories for treatment with sufficient accuracy to facilitate decisions on medical treatment. In its current state, the in vivo EPR dosemeter can provide estimates of absorbed dose of +/- 0.5 Gy in the range from 1 to >10 Gy. The lower limit and the precision are expected to improve, with improvements in the resonator and the algorithm for acquiring and calculating the dose. In its current state of development, the method is already sufficient for decision-making action for individuals with regard to acute effects from exposure to ionising radiation for most applications related to terrorism, accidents or nuclear warfare.

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    • "Radiation dose assessment based on lymphocyte counts continues (Hu, Blakely and Cucinotta, 2015b). Dosimeters will also be needed for effective medical management (Swartz, et al., 2006). Finally, the development of MCMs has been painfully slow (Brenner, et al., 2015). "
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    ABSTRACT: Children require specialized treatment that differs from adults in nearly every field of medicine, particularly as it relates to emergency response to a large-scale radiation event. Infancy, childhood, and adolescence are distinct stages of growth and development that pose unique vulnerabilities, biological variations, physiological differences, and developmental needs. Screening, decontamination, treatment strategies, and the use of medical countermeasures must occur with respect for these differences. Responding to radiation disasters that impact children requires rapid evaluation and response by health care providers who are equipped with the knowledge, skills, and abilities to appropriately address the physical, emotional, and mental health needs of children.
    No preview · Article · Dec 2015 · Journal of Radiology Nursing
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    • "EPR spectroscopy in other mw bands (both lower and higher than X-band) offers two significant opportunities to overcome these obstacles. The lower frequency of L-band EPR systems (1.2 GHz) makes EPR measurements less perturbed by high water content in a sample and allows in vivo measurements of whole teeth (see, for example, Swartz et al. 2006). The higher frequency Q-band (34 GHz) spectrometers require much smaller samples for the dose measurements because of their increased "
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    ABSTRACT: Electron paramagnetic resonance (EPR) dosimetry of tooth enamel in X-band has been established as a suitable method for individual reconstruction of doses 0.1 Gy and higher. The objective was to demonstrate the feasibility of using Q-band EPR in small biopsy tooth enamel samples to provide accurate measurements of radiation doses. Q-band spectra of small (<10 mg) irradiated samples of dentine and bone were studied to investigate the possibility of using Q-band EPR for dose measurements in those materials if there are limited amounts of enamel available, and there is no time for the chemical sample preparation required for accurate X-band measurements in dental enamel. Our results have shown that Q-band provides accurate measurements of radiation doses higher than 0.5 Gy in tooth enamel biopsy samples as small as 2 mg. Q-band EPR spectra in powdered dentine and bone demonstrated significantly higher resolution and sensitivity than in conventional X-band measurements.
    Full-text · Article · Mar 2012 · Applied Magnetic Resonance
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    • "The most promising are the methods based on the measurements of the long lived radiation induced stable radicals in the hydroxyapatite component of teeth and bones which can be measured by electron paramagnetic resonance (EPR).3 With the recent development of low-frequency EPR (1 GHz) the measurements in vivo on teeth seems to become plausible.4 "
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    ABSTRACT: The aim of this study was to examine whether (31)P NMR can efficiently detect X-ray radiation induced changes of energy metabolism in mice. Exposure to ionizing radiation causes changes in energy supply that are associated with the tissue damage because of oxidative stress and uncoupled oxidative phosphorylation. This has as a consequence decreased phosphocreatine to adenosine triphosphate ratio (Pcr/ATP) as well as increased creatine kinase (CK) and liver enzymes (transaminases AST and ALT) levels in serum. In this study, experimental mice that received 7 Gy of X-ray radiation and a control group were studied by (31)P NMR spectroscopy and biochemically by measuring CK and liver enzyme levels in plasma. Mice (irradiated and control) were measured at regular time intervals for the next three weeks after the exposure to radiation. A significant change in the Pcr/ATP ratio, determined from corresponding peaks of (31)P NMR spectra, was observed in the 7 Gy group 2 days or more after the irradiation, while no significant change in the Pcr/ATP ratio, was observed in the control group. This result was supported by parallel measurements of CK levels that were highly increased immediately after the irradiation which correlates with the observed decrease of the Pcr/ATP ratio and with it associated drop of muscle energy supply. The (31)P NMR measurements of the Pcr/ATP ratio can in principle serve as an instantaneous and noninvasive index for assessment of the received dose of irradiation.
    Full-text · Article · Sep 2010 · Radiology and Oncology
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