A prototype sector-vortex phased-array applicator for ultrasound hyperthermia was constructed and acoustically evaluated. The array transducer consists of special lead-titanate ceramic elements of 16 sectors and two tracks attached on a disk-shaped aluminum shell with spherical curvature. Each array element is driven by a complimentary pair of power MOSFET's at 750 kHz. An annular focal field approximated by the Mth order Bessel function is theoretically predicted to be formed when the array elements are driven with a phase distribution that rotates M(≤8) times per rotation along a track. Annular fields with acoustic intensity distribution of several different diameters were produced and measured three-dimensionally using a multichannel PVDF membrane probe. The measured patterns compare remarkably well with the fields theoretically predicted by computer simulation. The output acoustic power into the focal region was also measured by plate deflection and it was demonstrated that the applicator is capable of producing focal acoustic power at the level required for hyperthermia.
|Number of pages||7|
|Journal||IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control|
|Publication status||Published - 1992 Jan|
ASJC Scopus subject areas
- Acoustics and Ultrasonics
- Electrical and Electronic Engineering