Mechanical destruction of canine prostate using a novel low-intensity histotripsy based on a perfluoropentane-filled...

Low-intensity, pulsed, focused ultrasound (FUS) combined with the local injection of phase-change perfluorocarbon droplets can mechanically disrupt the canine prostate; however, long-term observation of prostate shrinkage is lacking. This study aimed to develop an acoustic-responsive scaffold (ARS) to limit the washing out of droplets and achieve long-term observation of treated prostates.

A spherical single-element FUS transducer provided therapeutic ultrasound (US). The ARS consisted of sodium alginate and perfluoropentane emulsion. Subsequently, 18 male beagles were treated with FUS and local prostate injection of the ARS at different levels of peak negative pressure (PNP) (1.5-4.1 MPa). The long-term observation was a 1-month follow-up. US imaging and pathological examination were used to assess treatment.

US imaging showed that the bubble cloud produced in the P4.1 (PNP = 4.1 MPa) group exhibited stronger echoes and a larger range compared with the other groups, and it persisted for > 72 h. Gross and hematoxylin and eosin (H&E) staining showed that the total area of prostate damage was significantly larger and the damage ratio was significantly higher in the P4.1 group than in the other groups. Prostate volumes significantly decreased 1 month after FUS treatment, from 6.57 ± 0.92 cm³ to 4.84 ± 0.15 cm³. H&E staining revealed atrophy of the prostate tissue in the target area, reduced glandular cavities, and decreased glandular cells.

In conclusion, at a PNP of 4.1 MPa, FUS and ARS not only cause mechanical damage to prostate tissues but also lead to a significant 20.8% reduction in prostate volume at the 1-month follow-up.