BACKGROUND Dosimetry: individual measurements and methods of evaluating the received dose Internal contamination Numerical dosimetric reconstruction The dose due to the external exposure received by the victim of a radiological accident can be evaluated by calculation. This dosimetric reconstruction is carried out using the physical parameters of the accident, seeking the expertise of IRSN if necessary: • based on the information on the irradiation source: radionuclide and activity in the case of sealed sources, characteristics of the irradiator (collimator, etc.), parameters of the X-ray tube or accelerator, etc. • based on the circumstances of the accident. The questioning must be carried out within the shortest possible timeframe. A questionnaire sheet and an examination sheet must be filled out for each victim, giving a precise description of the circumstances of the accident. The following shall be indicated as a minimum: • the type of radiation, the activity of the sealed source or the dose rate, the parameters of the X-ray tube, etc.; • the distance between the victim and the source; • the position of the victim with respect to the source and any shielding; • the nature (material) and dimensions of the shielding, if any; • the different exposure sequences; • the exposure durations for each sequence. SEE SHEETS 5 14 Retrospective dosimetry MATERIALS To confirm the exposure scenario and allow an estimation of the exposure of the different organs or tissues, numerous materials present in the victim’s personal effects or clothing can be used: • materials that might have been collected from the victims (fingernails, dental enamel, etc.); • objects carried by the victims or present in their near environment during the accident (sugars, plastics, etc.). TECHNIQUES The techniques are based on Electron Paramagnetic Resonance (EPR) spectroscopy and Thermally or Optically Stimulated Luminescence (TSL and OSL respectively). The doses are associated with the information on the location of the samples taken. IN PRACTICE IRSN, the advisor point of contact IRSN has a dosimetry department, specialised in the reconstruction of doses in irradiation accidents and in retrospective dosimetry. It also has a radiobiology laboratory for accidental exposures which carries out the quantification of chromosomal aberrations and provides its expertise concerning the other examinations to schedule. In the event of a radiological emergency, contact the IRSN on-call engineer, 24h/24, 7d/7: +33 6 07 31 56 63 The dose can be estimated from the individual internal contamination measurements. SEE SHEET 37 These individual measurements (radiotoxicological and whole-body radiation measurement analyses) allow the identification and quantification of the radionuclides that caused the contamination. The dose received by the contaminated person can be calculated from the measured activities, the time elapsed between contamination and measurement (or sampling) and the circumstances of the accident. The choice of the measurement(s) to take depends on the contaminating element, the contamination route (inhalation, ingestion or wound) and the time elapsed since the contamination. The dosimetric references give an indication on the radiotoxicity of the radionuclide according to its chemical form and the exposure route. SEE radionuclides handbook 12 SHEET 44 MEDICAL RESPONSE IN NUCLEAR OR RADIOLOGICAL EMERGENCY
RkJQdWJsaXNoZXIy NjQ0NzU=