Fingernail dosimetry: current status and perspectives.

A summary of recent developments in fingernail EPR dosimetry is presented in this paper. Until 2007, there had been a very limited number of studies of radiation-induced signals in fingernails. Although these studies showed some promising results, they were not complete with regard to the nature of non-radiation signals and the variability of dose dependence in fingernails. Recent study has shown that the two non-radiation components of the EPR spectrum of fingernails are originated from mechanical stress induced in the samples at their cut. The mechanical properties of fingernails were found to be very similar to those of a sponge; therefore, an effective way to eliminate their mechanical deformation is by soaking them in water. Stress caused by deformation can also significantly modify the dose response and radiation sensitivity. Consequently, it is critically important to take into account the mechanical stress in fingernail samples under EPR dose measurements. Obtained results have allowed formulating a prototype of a protocol for dose measurements in human fingernails.