Alpha particle spectrometry in fluorescent nuclear track detectors with an automatic 3D track reanalysis algorithm

The main obstacle to applying aluminum oxide doped with carbon and magnesium (Al2O3:C,Mg)-based fluorescent nuclear track detectors (FNTDs) in radionuclide therapy with alpha emitters is that it has not been known how to achieve an accurate and in situ dose assessment for in vitro cellular experiments. In this study, we developed an automatic 3D track reanalysis algorithm (ATRA) to analyze the alpha energy spectra in FNTDs. The algorithm provides an excellent track identification rate and an excellent track linking rate (0.961) without significant variations in various track densities. The algorithm also achieves a reliable track detection rate exceeding 0.927 for track densities at the level of in situ measurement, and it successfully measures the alpha energy spectra for obtaining the absorbed dose. We also confirmed that the track overlap clearly interferes with accurate track reconstruction for track densities beyond 1.5 x 106 tracks cm-2. We provided a correction equation that can be used to obtain the actual alpha tracks for high track densities; the equation may also correct estimations of absorbed doses due to alpha particles.