Spherical phased array design optimized for ultrasound surgery

A simple model is presented to illustrate the focal limitations of a spherically sectioned array designed for the treatment of deep seated liver tumors. The design is optimized using the acoustic dose as a function of the focal depth and available acoustic aperture. A quantitative measure of the possible region of focal necrosis is presented as a function of array parameters with the limiting criteria being near field heating. The maximum distance to produce continuous necrosis between foci in a multiple focus pattern and in a temporally multiplexed pattern is approximately 50% larger than the distance needed between sequential foci