Fig. 3
From: Multi-focal HIFU reduces cavitation in mild-hyperthermia
Example PAM images for a set of 60 W sonications in phantoms, time-integrated over all 30 s of HIFU + PAM acquisition. The columns are as follows--Left: single-focus. Middle: 4-mm multi-focus. Right: 8-mm multi-focus. Rows (a) and (b) show Probe 1 and Probe 2 reconstructed according to Eq. (1). In row (c) Probe 2 was registered to Probe 1 and both probes reconstructed in the co-registered pixel domain. In PAM images tail artifacts can be easily recognized. The ratio of apparent tail strength to magnitude of the foci is larger with multi-focus. It can also be seen that, in each multi-focus case, the focal point furthest from the probe has a larger tail effect. This is perhaps due to reverberation and backscattering of waves from cavitation at the closer foci