TABLE 3.

Comparison of shockwave and HIFU induced BBB opening.

	HIFU	Shockwave
Frequency range	0.5–1.0 MHz Narrow band width	Broad band with audible low frequency components
Pulse length	Short	Long
Number of waves/second	106 times level	1–10 times
Energy level	10–15 J	0.43 mJ
Thermal effects	High	Low
Focus space	10 mm3	25 mm3
Free radical generation	More	Less