Comparison of skin surface temperatures after ultrasounds with use of paraffin oil and ultrasounds with use of gel

Abstract

Ultrasound heat effects are relatively easily perceived, being manifested by a tissue temperature rise resulting from intratissular conversion of mechanical energy into thermal one. The goal of the study reported was an evaluation of skin surface temperature distribution changes as a result of ultrasound therapy applied, with reference to the coupling medium used. The study involved 40 healthy students, with the mean age of the subjects in the study group being 20 years. All of the subjects were submitted to sonographic procedures with the use of two different coupling media, whilst skin surface temperature at the site was recorded by a thermovision camera. Sonographic beams were applied to the region of the left quadriceps femoris muscle by a dynamic method, using a continuous ultrasound wave of 0.5 W/cm² intensity and 1 MHz frequency. The area treated amounted to 300 cm², the sonotherapy lasted 10 min. Paraffin oil enhanced the thermal effects of the ultrasound signals applied, inducing mean tissue temperature rises. The mean temperature recorded immediately after ultrasound application was higher than the mean base temperature by 0.33 °C, rising to 0.62 °C at the 15th minute following the procedure, with P < 0.05. In contrast, application of gel led to considerable reductions in the mean temperatures of tissues submitted to ultrasound treatment: immediately after the sonographic procedure, tissue temperature decreased by 3.96 °C. On the basis of the results of the study conducted, it was concluded that the type of coupling medium applied influenced temperature levels within the treated area.