A spherical-section ultrasound phased array applicator for deep localized hyperthermia

Computer data are presented for a nonplanar phased-array proposed as an applicator for deep, localized hyperthermia. The array provides precise control over the heating pattern in three dimensions. The array elements form a rectangular lattice on a section of a sphere so that the array has a natural focus at its geometric center when all its elements are driven in phase. When compared to a planar array with similar dimensions, the spherical-section array provides higher focal intensity gain. The relative grating-lobe level (with respect to the focus) is lower for scanned foci synthesized with this array (compared to a planar array with equal center-to-center spacing and number of elements). The spherical-section array has been simulated for use as a spot-scanning applicator as well as an applicator producing directly synthesized heating patterns.