ESTIMATION OF THE TEMPERATURE INCREASE IN THE FOCUS OF A LITHOTRIPTER FOR THE CASE OF HIGH-RATE ADMINISTRATION

In a recent study Delius et al. demonstrated an increased amount of kidney damage when applying shock waves with a high pulse repetition frequency equal to 100 Hz. The authors interpreted this effect by means in terms of a cavitational mechanism although they could not exclude thermal effects. The present paper estimates the temperature increase for the conditions of the pre-cited study. Taking into account spectral properties of the pressure in the form of cosine, triangle pulses, including their overshoot, as well as an experimental shock wave pulse shape it was possible to compute the temperature increase within the focus of the lithotripter. The maximum estimated temperature increase was equal to 1.8°C for 3000 shock wave pulses of 80 MPa peak pressure. The results of those computations exclude the possibility of significant thermal effects in the damage of kidney tissues even if the administration rate equals 100 shock wave pulses per second. © 1990.