[MRI-guided surgery with high intensity focused ultrasound]

High-intensity focused ultrasound allows high-precision, non-invasive thermocoagulation of tissues within seconds, with sparing of surrounding areas. The resulting tissue necrosis is so sharply demarcated that the technique is also defined focused ultrasound surgery (FUS). The combination with magnetic resonance imaging (MRI) allows an exact definition of the target volume and a safe guidance of FUS. The present paper describes the physical equipment necessary to perform MRI-guided FUS, and reports an example of application of this technique for the therapy of breast cancer. Finally, the paper outlines further examples of FUS application and future perspectives.