Age-dependent threshold and superthreshold behaviors of ultrasound-induced lung hemorrhage were investigated with one hundred ten 12.6 +/- 0.8-d-old rats, one hundred ten 22.9 +/- 0.8-d-old rats, and one hundred 57.7 +/- 3.9-d-old rats. Exposure conditions were: 2.8 MHz, 10-s exposure duration, 1-kHz pulse repetition frequency and 1.3-mus pulse duration. The in situ (at the pleural surface) pea...
