MODIFICATION OF INTENSITY DISTRIBUTIONS FROM LARGE-APERTURE ULTRASOUND SOURCES

The Fresnel-Kirchhoff diffraction theory has been used to model the acoustic fields produced by a variety of apodizations of large aperture, axially symmetric ultrasound sources. The forms of resulting intensity maxima and their resulting suitability for surgical Lesioning of tissues are compared, through a "lesioning capability" and a "focal efficiency." Although only modest changes in intensity distribution are possible, some may have applications in making arrays of lesions for control of focal cancer and other pathologies.