Lung damage from exposure to pulsed ultrasound.
Motivated by a recent finding that threshold pressures for hemorrhage in mouse lung exposed to the fields of an electrohydraulic lithotripter were less than 2 MPa, we extended the exposures to pulsed ultrasound. Sharply defined thresholds of the order of 1 MPa were found with 10 microseconds length pulses and roughly twice that value for 1 microsecond pulses. The thresholds at 4 MHz are greater than at 1 MHz. The thresholds are comparable for focused and unfocused fields. As would be expected for a cavitation-like phenomenon, temporal average intensity is a very poor predictor of this effect. In the extreme case, lesions were found at temporal average intensities on the order of 1 mW/cm2.
Child
S Z
SZ
Department of Electrical Engineering, University of Rochester, NY 14627.
Hartman
C L
CL
Schery
L A
LA
Carstensen
E L
EL
D000818:Animals; D006470:Hemorrhage / Q000209:etiology*; D008171:Lung Diseases / Q000209:etiology*; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D014465:Ultrasonics / Q000009:adverse effects*