Focused ultrasound - A review

Focused ultrasound (FUS) is a term used to describe a range of techniques using high intensity ultrasound in medical treatment. It is not new - the first patient treatment was recorded in 1957 but for many years, the technology was considered unwieldy and of limited usefulness since it was difficult to track progress during treatment. However, FUS has enjoyed a resurgence of interest recently - partly due to new imaging techniques that allow FUS treatment to be accurately targeted and monitored in real time. In addition, FUS is non-ionising and non-invasive, two attractive attributes as modern healthcare continues to move towards minimally invasive treatments and shorter hospital stays. FUS can interact with tissue in many ways. High intensity thermal interactions and disruptive mechanical interactions, (such as cavitation), are well understood and widely used in surgical treatments. However, several other non-thermal interactions are possible and have interesting therapeutic applications such as sonoporation, localised vasodilation, opening of the blood-brain-barrier, and neuromodulation. Further development is still needed to improve the effectiveness, safety and applicability of FUS but a significant number of clinical trials are ongoing. Many of the early trials have recently come to a conclusion and have demonstrated promising results, clearing the way for the use of FUS treatments in the wider population. If this happens, FUS could significantly reduce the need for radiation and surgery in healthcare and change patient management in a wide variety of illnesses.