Ultrasonic attenuation of dog tissues as a function of temperature

The effect of temperature and thermal dose referenced at 43°C on the attenuation and absorption was studied in dog muscle, liver and kidney in vitro. It was found that the attenuation and absorption increased for temperatures higher than 50°C, and eventually reached a maximum at 65°C. The change in attenuation or absorption when necrosis is produced was to about twice the value at 37°C. The change in attenuation or absorption occurred at thermal doses of 100-1000 min which corresponds to the range of threshold of necrosis. The maximum attenuation or absorption was reached at thermal dosages in the order of 10⁷ min