Combined Use of Passive Acoustic and Infrared Thermometry for Monitoring Uhf Heating

Controlling deep temperature in parts of the human body is necessary for hyperthermia and thermal ablation used in oncology. UHF heating of single hands of patients was chosen as the model for this procedure. For the control, a plastisol cylinder was heated in the same manner: a substance with acoustic and thermophysical properties close to those of soft tissues of the human body. Passive acoustic thermometry was used to measure the deep temperature of the hand, and infrared thermometry was used to measure the surface temperature. After 5 min of UHF heating, the deep temperature of the hand increased by an average of 0.7 ± 0.6°C, and the surface temperature, by 0.8 ± 0.6°C. The same methods, as well as independent measurements, were used to determine the plastisol temperature. After the same procedure, the deep temperature of the plastisol increased by 4.3 ± 0.4°C; the surface temperature, by 3.2 ± 0.2°C; the temperature measured with a thermometer at the center of the object, by 3.3 ± 0.5°C. The smaller heating of the hand compared to the model object is related to effect of blood flow, which should be adequately taken into account in further studies. The noninvasive methods indicated in the study can be used to control temperature in oncology during hyperthermia and thermal ablation under the effect of a high-frequency electromagnetic field.