Introduction to the Special Issue on Histotripsy: Approaches, Mechanisms, Hardware, and Applications

Histotripsy is a therapeutic ultrasound technology to liquefy tissue into acellular debris using sequences of high-power focused ultrasound pulses. Research on histotripsy has been rapidly growing in the past decade; newer applications are being proposed and evaluated for clinical use. In contrast to conventional high-intensity focused ultrasound (HIFU) thermal therapy, the major mechanism of histotripsy is mechanical, which enables localized tissue disintegration at the target sites without thermal damage to overlying and surrounding tissues. Two major approaches, cavitational histotripsy and boiling histotripsy, with two different mechanisms, have been extensively explored lately. Histotripsy therapy is being evaluated for treating cancer, thrombosis, hematomas, abscess, neurological diseases, for inducing an enhanced immune response and performing noninvasive biopsy in preclinical studies with small and large animal models. The first clinical trials using histotripsy for benign prostatic hyperplasia, liver cancer, and calcified aortic stenosis have been undertaken.