Skip to main content
. Author manuscript; available in PMC: 2018 Sep 1.
Published in final edited form as: Ultrasound Med Biol. 2017 Jun 20;43(9):1975–1985. doi: 10.1016/j.ultrasmedbio.2017.04.030

Table 2.

Range of peak negative focal pressures at which the corresponding effects were observed in transparent PA gel phantom upon delivering two 10-ms BH pulses (Figs. 4 and 5)

Frequency
Observed effects* 1 MHz 1.2 MHz 1.5 MHz 1.7 MHz 1.9 MHz
Boiling* —————— —————— 11.5–13 MPa       11–14.5 MPa 11–15.5 MPa
Cavitation/boiling† —————— ——————       13–14.5 MPa 14.5–15 MPa —————
Cavitation/boiling 2nd pulse‡ 13.5–14 MPa   —up to 13 MPa    14.5–15.5 MPa       15–15.5 MPa —————
*

Boiling bubble appeared in accordance with the time predicted by weak shock theory.

†

Boiling bubble appeared later than predicted because of the prefocal shielding by cavitation bubbles.

‡

Boiling did not occur within the first 10-ms pulse because of prefocal shielding, but did occur within the second 10-ms pulse. A dash indicates that the corresponding effect was not observed at any output level up to either the “high” level or the maximum attainable pressure level (for 1.2 frequency).