Characterisation of nasal swab samples by alpha spectrometry

A positive nasal swab taken at a radiation emergency, when properly collected and analysed, is a good indication of a potential inhalation intake. It may be expected to be a useful method for early dose assessment in cases of accidental inhalation of an alpha emitter. To improve the first estimation of intake activity, the quality of a nasal swab measurement was experimentally investigated. Alpha spectrometry was used to examine the experimental nasal swab samples involved with a plutonium solution or particles. Also, a numerical simulation analysis on the alpha spectrum using advanced alpha-spectrometric simulation was made to characterise the experimental results. It was observed that the alpha energy spectrum had a quite different shape among samples, and it was characterised by the type of contaminant. This could be the second advantage of using alpha spectrometry in addition to nuclide identification. The absorption of alpha radiation within the experimental nasal swab sample was different between the types of contaminants. For a quantitative discussion, the absorption for a swab sample must be determined for each type of contaminant. This new finding could be very useful for first responders. A nasal swab sample measured using an alpha spectrometer will give more useful information during the first response of an emergency. (authors)