Figure 10 –
Comparison between free-field focus and transcranial focus along the sonication axis (left) and in the focal plane (right) from hydrophone beam maps. The focus is shifted in the direction of the skull and transducer due to the increased sound speed in the skull, and broadened from phase aberration. Transverse profiles shown on the right coincide with axial focal maxima in both cases. The transcranial pressure was 28% of free-field due to reflection and attenuation by the skull piece.