Sparse Random Ultrasound Phased Arrays for Focal Surgery

A number of studies have suggested that noninvasive surgery using high intensity ultrasound ablatiofeasible, and offers significant advantages over conventional surgical techniques for many applicatiultrasound transducer is used to insonate a small tissue target or targets deep within the body caustargeted tissue. In the past, ultrasound delivery systems for high intensity focal surgical applicatelement geometrically focused devices, employing bowl-shaped transducers or lenses to provide the deHowever, ultrasound phased array technology may also be useful for surgical applications, enabling eprogrammable synthesis of focal size and shape, as well as position, thus eliminating the necessitymechanical scanning apparatus. While phased arrays have been employed for medical diagnostic and theapplications (hyperthermia), there remain fundamental problems associated with their use for surgerylargely from the small size of each array element dictated by the wavelength employed at surgical ap(approximately 4 MHz), the array aperture size required for the desired focal characteristics, and telements and electronic drive channels required to provide RF energy to the entire array. This Phasetheoretical and experimental examination of novel ultrasound phased arrays consisting of array elemewavelength, minimizing the number of elements in an aperture through a combination of geometric focubeams, and sparse random placement of array elements for direct application to tissue ablation appliaims of the proposed work are to 1) examine theoretically the feasibility of sparse random array consurgery, 2) build a prototype test array to be driven with an existing maximum 64 channel digitallysystem for examining the feasibility of such systems for surgical ablation applications, and 3) testprototype array to verify the energy deposition pattern and overall performance of the new array conapply the results obtained in Phase I to the design of a prototype ultrasound ablation system suitabdemonstrate the potential of this technology.