Figure 1: Top view inside the hemispheric transducer of the ExAblate™ 4000 HIFU headsystem. Each black tile contains 9 single ultrasound transmitting elements (total N=1,000). All elements transmit towards the center of the transducer (green star), creating a sharp focus beam of 4.0mm diameter in lateral and 6.0mm in elevational orientation. Parametric images of the focus, based on acoustic measurements, are given in XY (upper left) – and Z (upper right) – orientation.