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. Author manuscript; available in PMC: 2012 Nov 1.
Published in final edited form as: Curr Med Imaging Rev. 2011 Nov 1;7(4):328–339. doi: 10.2174/157340511798038657

Table 1.

Typical parameters used for an ARFI push pulse in different clinical scenarios.

Frequency 2–7 MHz
F-number F-2
Intensity(Isppa.5)* 1400 W/cm 2
Intensity(Ispta.3) 0.7 W/cm2
Mechanical Index 1.5–3.0
Pulse Duration 0.1–0.5 ms
Temperature Rise 0.02–0.2°C
Displacement (peak) 10–20 µm
*

Acoustic parameters are quantified using a 0.6 mm active spot size PVDF membrane hydrophone (Sonic Technologies) submerged in attenuating fluid (evaporated milk and water) in the appropriate concentration to achieve the desired attenuation (α) in order to accurately quantify the in situ intensity for radiation force and thermal calculations. The peak negative pressure measurement used to determine the Mechanical Index is performed in fluid with α=0.3 dB/cm/MHz as prescribed by its definition. The temporal average intensity is computed using the appropriate duty cycle, which can be modulated to reduce average heating.