Modeling infrared temperature measurements: Comparison of experimental results with simulations

Infrared cameras have been used to monitor the thermal response of tissue to pulsed and continuous wave laser irradiation. A computer model has been developed previously to predict radiometric temperature estimations and demonstrate potential discrepancies between surface and radiometric temperatures. To quantitatively verify the modeling, experiments were performed in which gelatin phantoms (similar to 98% water) were irradiated with low-radiant-exposure (e.g. subablative) CO2 laser pulses. Radiometric temperatures were estimated using a 3-5 mu m band-limited thermal camera and compared to computer model predictions of the measured temperatures. By fitting model calculations to measured data, theoretical surface temperatures were determined as a function of time and the onset of nonlinear changes in the: thermal response of tissue identified.