Figure 1: Overview of the setup for in vivo experiments (plan view - not to scale). Tumours were aligned with the focus of a 500 kHz focused ultrasound (FUS) transducer with a rectangular cutout for a 4-11 MHz imaging array. B-mode imaging was interspersed with passive acoustic recording of the emissions from cavitation during FUS transducer pulses. Transverse and axial directions are defined relative to the centre of the front face of the imaging array. Exposures were performed in the presence of a magnet or non-magnetic bar.