Feasibility study of histotripsy with the clinical device FocalOne®

This study investigates the feasibility of generating histotripsy lesions in biological tissues ex vivo with the HIFU clinical device FocalOne® (EDAP-TMS). The Focal One® probe, composed of a 192-element imaging array and a 16-element therapy transducer operating at 3 MHz, was used with an upgraded amplifier (ADECE, 500W, 200 kHz-6MHz ) and a Verasonics Vantage system for passive cavitation and elastography monitoring. To ensure reproducibility, efficiency, and safety, efforts were directed into the electrical hardware stability and power optimization. Pressure fields, non-linear simulations, radiation force balance, and electrical instant power measurements were performed to validate that this setup can produce boiling histotripsy which is characterized in literature by a 10–18 MPa negative pressure and a shock amplitude >70 MPa. Typical treatment exposure was 10 ms repeated 60 times at 1 Hz pulse repetition frequency. Experiments in gel phantoms and fresh degassed bovine liver were performed. The ablations were detected with ultrasound B-mode at the focal spot. The millimetric lesions were confirmed by hyposignals on 3-D MRI scans and visual observation of cavities at the targeted spot after dissection. Further studies will be required to optimize treatment parameters and improve reproducibility of histotripsy using the Focal One® probe.