The effects of continuous wave and pulsed ultrasound on rat thymocytes in vitro

Rat thymocytes in suspension were exposed to continuous wave and pulsed ultrasound at frequencies of 0.5 and 1 MHz. In qualitative confirmation of the observations of Chapman et al. (1979), cell lysis and cell survival were found to depend upon ultrasound intensity, frequency and time of exposure. Cell survival after 10 min, 2 W/cm², 0.5 MHz was approx. 40 percent of control. Pulsed exposures at 0.5 MHz with the same temporal average intensity but with a temporal peak intensity of 30 W/cm² showed no statistically significant decrease in survival in comparison with controls. The thymocyte observations provide no support for the belief that diagnostic ultrasound may cause biological effects in the fluids of the body.