A COMPARISON OF TEMPERATURE RISE IN HUMAN CALF MUSCLES FOLLOWING APPLICATIONS OF UNDERWATER AND TOPICAL GEL ULTRASOUND

For ultrasound to be effective, a conducting medium must be placed bet ween the soundhead and the skin. Little research has been performed to test whether or not these mediums actually work. The purpose of this study was to compare the effect of tap water immersion and ultrasound gel conducting mediums on tissue temperature rise in the human leg. A 23-gauge hypodermic needle microprobe was inserted 3 cm deep into the medial portion of the gastrocnemius muscle of 20 subjects. Each subjec t participated in two random order treatments using tap water immersio n and topical gel conducting mediums. Each treatment consisted of cont inuous ultrasound delivered topically at 1.5 W/cm2 for 10 minutes. Dur ing both treatments, the soundhead was moved at a speed of 4 cm per se cond, and the temperature was recorded every 30 seconds. A significant difference was found between the two treatment methods [t(19) = 9.18, p < .001]. The topical gel increased tissue temperature 4.8-degrees-C , whereas the underwater treatment increased tissue temperature only 2 .1-degrees-C. Therefore, at a tissue depth of 3 cm, ultrasound gel is a better conducting medium than water. Also, the authors discovered th at it took nearly 8 minutes for the temperature to reach therapeutic l evels during the gel technique. These findings should be of clinical s ignificance to clinicians who regularly use ultrasound.