Steiss J E, Adams C C
Scott-Ritchey Research Center, College of Veterinary Medicine, Auburn University, AL 36849, USA.
Am J Vet Res. 1999 Jan;60(1):76-80.
To determine effect of coat during ultrasound treatment and to establish a protocol to achieve adequate thermal effects.
9 healthy adult dogs.
A standardized area was treated on the semitendinosus muscle of sedated dogs. Needle thermistors were inserted in the biceps femoris muscle to depths of 5 and 10 cm and in the ultrasound gel in the treatment area. Each dog was given 4 randomized 10-minute treatments (intensities of 0.5, 1.0, 1.5, and 2.0 W/cm2). Temperatures were measured at 30-second intervals during treatment and at 1- to 2-minute intervals after treatment.
Baseline temperatures (mean+/-SD) were 30.6+/-1.8 C for coat, 38.2+/-1.2 C at a depth of 5 cm, and 39.0+/-0.7 C at a depth of 10 cm. At the 5-cm depth, an increase of > 1.6 C was obtained only with the maximum intensity when coat was clipped. Treatment with maximum intensity through short and long coats yielded mean increases at a depth of 5 cm of 0.7 and 0.4 C, respectively. Temperature at the 10-cm depth increased < 0.6 C for all treatments. Temperatures within the coat increased approximately 8.3 C and 22.2 C for short and long coats, respectively, with intensities of 1.5 and 2.0 W/cm2.
Ultrasound treatment applied through an intact coat considerably warmed the coat with loss of thermal effects in underlying tissues. Inappropriate heating was apparently affected by selection of intensity, duration, and size of treatment area.
Coat can impede successful use of ultrasound treatment of dogs.
