Carbon ion dosimetry on a fluorescent nuclear track detector using widefield microscopy

Fluorescent nuclear track detectors (FNTDs) are solid-state dosimeters used in a wide range of dosimetric and biomedical applications in research worldwide. FNTDs are a core but currently underutilized dosimetry tool in the field of radiation biology which are inherently capable of visualizing the tracks of ions used in hadron therapy. The ions that traverse the FNTD deposit their energy according to their linear energy transfer and transform colour centres to form trackspots around their trajectory. These trackspots have fluorescent properties which can be visualized by fluorescence microscopy enabling a well-defined dosimetric readout with a spatial component indicating the trajectory of individual ions. The current method used to analyse the FNTDs is laser scanning confocal microscopy (LSM). LSM enables a precise localization of track spots in x, y and z however due to the scanning of the laser spot across the sample, requires a long time for large samples. This body of work conclusively shows for the first time that the readout of the trackspots present after 0.5 Gy carbon ion irradiation in the FNTD can be captured with a widefield microscope (WF). The WF readout of the FNTD is a factor ∼10 faster, for an area 2.97 times the size making the method nearly a factor 19 faster in track acquisition than LSM. The dramatic decrease in image acquisition time in WF presents an alternative to LSM in FNTD workflows which are limited by time, such as biomedical sensors which combine FNTDs with live cell imaging.