Focused ultrasound

High-intensity focused ultrasound (HIFU) is a non-invasive therapeutic technique that uses non-ionizing ultrasonic waves to heat or ablate tissue. HIFU can be used to increase the flow of blood or lymph or to destroy tissue, such as tumors, via thermal and mechanical mechanisms. Given the prevalence and relatively low cost of ultrasound generation mechanisms, The premise of HIFU is that it is expect a non-invasive and low-cost therapy that can at minimum outperform of care. The technology is different from that used in ultrasonic imaging, though lower frequencies and continuous, rather than pulsed, waves are used to achieve the necessary thermal doses. However, pulsed waves may also be used if mechanical rather than thermal damage is desired. Acoustic lenses are often used to achieve the necessary intensity at the target tissue without damaging the surrounding tissue. The ideal pattern diagram is the beam-focusing of a magnifying glass of sunlight; only the focal point of the magnifying glass has high temperature. HIFU is combined with other imaging techniques such as medical ultrasound or MRI to enable guidance of the treatment and monitoring. Studies on localized prostate cancer showed that, after treatment, progression-free survival rates were high for low- and intermediate- risk patients with recurrent prostate cancer. The InsighTec ExAblate 2000 was the first MRgFUS system to obtain FDA market approval. There is no clear consensus on the boundaries between HIFU and other forms of therapeutic ultrasound. In particular literature, HIFU refers to the high levels of energy required to destroy tissue through ablation or cavitation, although it is also sometimes used to describe lower intensity applications such as occupational therapy and physical therapy. Either way, HIFU is used to non-invasively heat tissue deep in the body without the need for an incision. The main applications are the destruction of tissue caused by hypertharmia, increasing perfusion and physical therapy.