MRI-controlled ultrasound thermal therapy.

Advances in medical imaging have enabled the development of new minimally and completely noninvasive therapies that produce a desired biological effect in a target, such as a tumor, with minimal damage to the surrounding tissue. One means of noninvasively achieving bioeffects in tissue is the use of ultrasound to generate heat. Specialized ultrasound transducers can be used to generate focal regions of heating non invasively, without inserting anything into the body or affecting the tissue outside the target region. Ultrasound thermal therapy can be used with magnetic resonance (MR) imaging (MRI) guidance and MRI temperature feedback to automatically control temperature distributions during heating, producing accurate thermal lesions, or maintaining optimal conditions to enhance drug delivery.