In the environment, artificial radionuclides exist in various mobile and non-mobile forms. One of the most kinetically stable radionuclides forms is so-called “hot” particles which could be found and extracted from soil samples using laser-scanned radiography with Imaging Plate. Method limitations are the signal fading over time and the lack of information about the quantitative capabilities of the method. In this work, the correlation between photostimulated luminescence (Cyclone Storage Phosphor System, PerkinElmer) and the radioactivity of various sources, their radiation energy, and exposure duration was determined. The fading of photostimulated luminescence over exposure time was studied for different radionuclides. As a result of the Imaging Plate Radiography calibration, the possibility of a semi-quantitative analysis of radioactively contaminated samples using Imaging Plate was confirmed. To carry out the comparative analysis of the samples from nuclear legacy sites a non-destructive tool has been developed for express definition of the fraction of radioactivity stored in “hot” particles. The application of this technique is demonstrated by examples of three different soil samples with "hot" particles.