(a) MRI-based temperature image during a sonication (130 W for 30 seconds) into rabbit thigh muscle during a test of an MRI-compatible transrectal phased array applicator for MRgFUS of prostate (b) The thermal lesion (arrow) seen in T2-weighted imaging. The bright region to the right of the lesion is a tissue fascia layer. Figure reproduced from Sokka SD, Hynynen K. The feasibility of MRI-guided whole prostate ablation with a linear aperiodic intracavitary ultrasound phased array. Phys Med Biol 2000; 45:3373–3383), with permission from the authors and from the publisher (Institute of Physics Publishing, Bristol, UK, Editor: S. Webb).