Developments and new trends for radiation accident dosimetry on biological samples and personal items

International Conference of Radiation Research / Varsovie, 27 août-2 septembre 2012

This presentation is an overview of recent developments and new trends in the field of physical and biophysical methods considered for radiation accident dosimetry and triage.

In all events of uncontrolled exposure of individuals to ionizing radiation, when data from conventional personal dosimetry do not exist (persons from the public exposed to orphan or lost radiation source, nuclear and radiological terrorism, absence of dosimeter, radiotherapy or interventional radiology accidents, etc.), it is desirable to have several complementary methods for accurately determining the dose distribution in victims’ organisms or for identifying people that need medical care and additional dose assessment during large scale events. A gold standard does not exist and the most appropriate choices are case dependent.

Over the last 30 years, bones and tooth enamel measured by Electron Paramagnetic Resonance (EPR) spectroscopy were frequently used as bio-indicators of external exposure. EPR remains very pertinent and complementary to biological dosimetry, especially when irradiations are localized or highly heterogeneous, because it can give the absorbed dose in one or several locations in the victim’s organism. Nevertheless, since it requires invasive sampling, its applicability has been limited. In order to overcome this difficulty in light of large scale events and implying new needs in terms of measurement capacity for triage, new approaches are investigated.

Since tooth enamel is one of the most sensitive materials for EPR, some new ways to measure it were investigated: (1) measuring teeth directly in the mouth with EPR at low microwave frequency; and (2) decreasing mass of biopsies (from 100 down to 2 mg) and using high frequency EPR.

Some alternative materials measured with conventional EPR are also foreseen and are illustrated in this presentation with specific focus on nails and LCD glass sheets from mobile phones. In addition, luminescence techniques are also considered with materials from mobile phones (LCD glass sheet, chips, and electronic components) or enamel (ex vivo and in vivo).

We give further insight into these new methodologies and discuss advantages and disadvantages, possible capacity, as well as complementarity with biological analysis methods.