Evaluation of the combined concentric-ring sector-vortex phased array for MR-guided ultrasound surgery

Using the combined concentric-ring sector-vortex phased array concept, the present work explores the viability of the design to treat regions of various sizes and depths. Several large-scale phased arrays were constructed to verify the array design for treatment of large deep-seated tumors. MRI guided in-vivo and ex-vivo experiments were performed to verify the extent to which the array´s power absorption pattern could be tailored for treatment of deep tissue. It is shown that the array design is able to target volumes of tissue at various distances from the transducer surface by electronically phasing the annular concentric ring elements. Furthermore, it is demonstrated that it is possible to increase the heated area in the radial plane by applying radial-sector phase rotation. Results are presented for a 12 cm diameter f/1.3 phased-array for ex-vivo and in-vivo experiments guided by MRI