Abstract: A method for making pulsed photothermal radiometric measurements to determine individual maximum safe radiant exposure (IMSRE) of biological subjects corresponding to radiant energy exposure (RE) without any use of a biological model includes a calibration procedure, including the steps of applying a statistical regression to an empirical data set of IMSRE and temporal REs applied to a sample population of the subjects to determine a IMSRE corresponding to each temporal RE. The IMSRE is set so that using the statistical regression separation of the data set into an acceptable injury grouping and an unacceptable injury grouping is obtained with a predetermined limitation of the proportion of subjects having unacceptable injury at a temporal RE below the corresponding IMSRE. The separation of the data set is thus used to predict an IMSRE for a corresponding temporal RE to a biological subject not included in the sample population.