The energy of a histotripsy device is often targeted using an imaging probe that is fixed with respect to the therapy transducer. While this desirably maintains registration with the therapy transducer focal spot, it precludes repositioning the imaging probe for better coupling to patient tissue or to avoid obstructions such as bone or air cavities, or the use of intra-cavity probes whose position is not readily fixed.
A UW-Madison researcher has developed a technique for real-time localization of an ultrasound probe for a histotripsy system whose image is registered to the therapy transducer using acoustic signals transmitted through the patient. These acoustic signals are produced and detected using the existing therapy transducer and transducer elements of the ultrasound probe and thus may be implemented with minimal hardware modifications to existing histotripsy machines. It can use an ultrasound probe independently positionable with respect to the ultrasound therapy transducer array to receive acoustic signals transmitted through the patient.