Qihong Xu
Xiaoyu Zheng
Robert Apfel
Ctr. for Ultrason. and Sonics, P.O. Box 208286, Yale Station, Yale Univ., New Haven, CT 06520
To study the potential for cavitation-related bio-effects, in vitro microcavitation events were generated using 2.46- and 4.3-MHz transducers and were detected in both distilled water seeded with polystyrene particles and in human blood under conditions similar to those found in the application of clinical diagnostic ultrasound. For the 2.46-MHz transducer, the measured cavitation thresholds range from 4 MPa in whole blood to 1 MPa in distilled water seeded with the polystyrene particles of 0.1 (mu)m diam. The mechanical index (MI) corresponding to the above cavitation thresholds was calculated and found to be in the upper range of the MIs achievable with some commercial diagnostic ultrasound equipment. [This work was supported by NIH through Grant. No. R01 CA39374.]