The effect of therapeutic ultrasound on the formation of new blood vessels in full-thickness excised lesions in the flank skin of adult rats was assessed quantitatively using microfocal x-ray techniques. Wounds were either sham-treated (control group) or exposed to ultrasound for 5 min daily at an intensity of 0.1 W/cm2 SATA (frequency either 0.75 MHz or 3.0 MHz). By 5 days after injury there were more blood vessels in equivalent regions of the granulation tissue of the ultrasound-treated wounds than in the control wounds. This suggested that the ultrasound-treated wounds were at a more advanced stage in the repair process. By 7 days after injury there was no significant difference in blood vessel number between the three groups.

The effect of therapeutic ultrasound on angiogenesis.

The effect of therapeutic ultrasound on calcium uptake by embryonic chick 3T3 fibroblasts has been studied using calcium-45 radiotracer techniques. Cells were treated while suspended in culture medium at 36 degrees C at intensities from 0.25 W/cm2 SPPA to 1.5 W/cm2 SPPA (1 MHz, pulsed 2 ms on:8 ms off) and for exposure times from 1 min to 20 min. Ultrasound treatment was found to increase calcium uptake for SPPA intensities from 0.5 to 1.0 W/cm2 SPPA, with a maximum increase of 18% after a 5 min exposure. Calcium uptake also increased with increasing exposure time. Measurements performed up to 20 min after treatment showed that the cell was able to reduce this calcium influx, indicating that the membrane did not suffer irreparable damage as a result of the ultrasound exposure.

The effect of therapeutic ultrasound on calcium uptake in fibroblasts

Effect of therapeutic ultrasound on the healing of full-thickness excised skin lesions

1 – The Sound Field

During the last decade there has been great interest in the use of hyperthermia in cancer therapy. The reasons why elevated temperatures, either alone or together with radiotherapy or chemotherapy, may prove useful have been the subjects of several recent reviews (Connor et al., 1977; Field and Bleehen, 1979).* Clinical applications of hyperthermia fall into two broad categories—whole-body and localized hyperthermia. During whole-body hyperthermia, which has been used on patients with advanced and widespread malignancies, core temperature is maintained at 41.8–42°C for a few hours. This appears to be the range of maximum tolerated temperatures; the organs which limit such treatment are the liver, which may be relatively sensitive to thermal damage, and the heart. Methods of inducing whole-body hyperthermia include the use of wax baths (Pettigrew et al., 1974), hot air cabinets (Pomp, 1978), water blankets (Barlogie et al., 1979) and space suits (Bull et al., 1979). Common features of these methods are the...

Heating techniques in hyperthermia. II. Non-ionizing electromagnetic waves.

A simple instrument for determining the total power from ultrasonic therapy equipment is described. It employs a novel method of measuring the radiation force exerted by the ultrasonic beam radiated by the equipment into a water-filled test tank, and offers a number of advantages over established techniques with regard to simplicity, sensitivity and ease of use. Further development of the device now in progress could provide a simple means of measuring ultrasonic power at the much lower levels normally associated with diagnostic equipment.

K.C. Shotton

Papers

A tethered float radiometer for measuring the output power from ultrasonic therapy equipment