In MRI-guided High Intensity Focused Ultrasound (HIFU), the ultrasound generated by the transducer is focused into a small focal tissue volume at specific target locations. During treatment, the beam of focused ultrasound energy penetrates through soft tissue and causes localized temperatures elevation up 55-70°C for a few seconds within the target producing well defined regions of irreversible protein denaturation, cell damage, and coagulative necrosis. A single exposure of focused ultrasound energy is called a "sonication." Multiple sonications are necessary to ablate the targeted tissue. Tight focusing is designed to limit the ablation to the targeted location.