Fig. 4

Device cross-talk in array. A wide scan (40 × 40 mm, Δ = 0.7 mm) of one of the transducers at its treatment distance taken to examine the field intensity near surrounding transducers in the array. Denoted in white are the −6 (solid) and −18 dB (dashed) contours and in black are an approximation of the orthographic projection of the source transducer (dashed) and the approximate distance to the edge of a neighbouring transducer (dotted). The −18 dB contour shows that the intensity at the edge of neighbouring transducers is low (<−16 dB)