INTRODUCTION: The therapeutic ultrasound act in biological tissues by means of vibration can produce physiological effects of thermal and non-thermal. OBJECTIVE: To discuss the parameters that affect the heating of biological tissues by ultrasound. MATERIALS AND METHODS: We conducted a literature research based on ISI Web and SCOPUS database. We selected the articles in the English language that have studied the temperature variation after the application of ultrasound in humans. RESULTS: There are significant variations related to tissue-temperature rise. For the 3MHz ultrasound, there is an average increase of 2.6 ºC in superficial tissues, and to the 1MHz US, there is an average increase of 1.7 ºC in deep tissues. There is a higher heating of the treated tissue when an area twice the ERA (effective radiating area) size, the shorter the higher the heating, there is an increase in temperature relative intensities. Intensities ranging from 0.5 to 3 W/cm² have a significant increase in temperature. Regarding the mode of application, the gel provides an improved coupling, generating more heat with an application time of five minutes - the application time depends on the treatment area and power density. However, the speed of application appears to modify the heating up to 7-8 cm/s. Also, different commercial devices produce heat differently. CONCLUSION: Parameters for ultrasound application must be controlled and adjusted to generate deep heating of tissues considering that it may vary among devices.
Therapeutic ultrasound; Temperature; Thermal effects
