Sparse random ultrasound array for focal surgery

The feasibility of using novel ultrasound phased arrays consisting of array elements larger than a wavelength and randomly located on a spherical shell have been investigated, both theoretically and experimentally, for surgical applications. Random placement of the sources minimizes grating lobes associated with the array. The size of the treatment volume, i.e., the region over which the focus of the array can be electronically scanned, is determined by the directive, overlapping beams from the circular sources that constitute the array elements. The treatment volume and the intensity at the focus have been determined for a range of frequencies and source dimensions. The source size and frequency determine the number of elements that are needed to generate the intensities required for tissue ablation. Gaussian sources were also evaluated for use in such an array. Results are presented for arrays consisting of 64 elements