TUESDAY, APRIL 18, 2000 in 3269 Beckman

4:00 - 5:00 pm

Thresholds of Rat Lung Damage Due to 6.0 MHz Diagnostic Ultrasound

Christy K. Holland, Ph.D.

Department of Radiology

University of Cincinnati College of Medicine

Cincinnati, Ohio 45267-0761

Recent increases in the pressure output of diagnostic ultrasound scanners have led to an interest in establishing thresholds for bioeffects in many organs including the lungs of mammals. The thresholds of lung damage due to exposure to 6.0 MHz pulsed Doppler or color Doppler ultrasound have been determined in the Sprague-Dawley rat. In addition, the determination of the threshold of lung damage due to 6.75 MHz M-Mode pulses is in progress. Pathologic features of the damage include extravasation of erythrocytes into the alveolar spaces. In order to quantify the ultrasound exposure conditions under which damage occurs, the ultrasonic pressure field was measured near ex vivo, aerated rat lung in a water bath. The pressure output of the ATL L10-5 linear array was interrogated near the lung with a Sonic Technologies 0.4-mm bilaminar membrane-type PVDF hydrophone. In this seminar, the methods utilized to determine these damage thresholds as well as the histopathological features of the damage will be discussed. Establishing thresholds for damage in lung caused by diagnostic ultrasound will help clinicians evaluate and minimize the potential risks in the use of such instrumentation.