Table 2. Acoustic parameters of imaging and ARF pulses.

Transducer type	L22-14v*
Pulse type	Imaging pulse	ARF pulse
Frequency (MHz)	20.8	4.5
Pulse length (cycle)	1	10
PRF† (Hz)	6	6×103
PNP‡ (MPa)	1.13	1.33
MI§	0.28	0.63

^*PNP and MI were measured at the depth of 8 mm.

^†Average pulse repetition frequency.

^‡Peak-negative pressure.

^§Mechanical index.