MR Guided Focused Ultrasound surgery: New Clinical Applications

Tissue destruction by thermal ablation occurs when the targeted delivery of heat or cold causes a rapid change in temperature (>55°C for heat or <−20–50°C for cold) in the local tissue environment. Imaging can be used to localize and target the thermal effects to the target/tumor for treatment, control the energy deposition, and assess treatment response. Therapeutic applications of ultrasound (US) have been tried and tested for many decades in clinical medical care. The primary mechanism applied to date has been the application of high intensity focused ultrasound (HIFU) to cause local tissue thermo-coagulation through local temperature elevation. This is caused by the mechanical motion of adjacent tissues due to the rapid passage of US waves. The majority of clinical cases have been performed using a combination of two US devices, one for therapeutic US delivery and one for diagnostic imaging.