TY - JOUR
T1 - The Sector-Vortex Phased Array
T2 - Acoustic Field Synthesis for Hyperthermia
AU - Umemura, Shin Ichiro
AU - Cain, Charles A.
N1 - Funding Information:
!&nuscript received January 8, 1988; revised August 6 1988: accepted August 15. 1988. This work was supported in part by an award from HI-tachi Central Research Laboratory (HCRL). Hitachi Ltd., Tokyo. Japan. NIH Grant CA 44124. and in part by Grant ECS 870001 from the National Center of Supercomputer Applications (NCSA) at the University of Illi- nois. Champaign-Urbana. S. Umemura is with the Central Research Laboratory, Hitachi Ltd., Ko- kubunji, Tokyo 185, Japan, and temporarily wlth the Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering. University of Illinois, Urbana, IL 61801, during 1986-1987. when this work was performed. C. A. Cain IS with the Bioacoustics Research Laboratory. Department of Electrical and Computer Eng~neering, Universlty of Illlnoih, Urbana. IL 61801. IEEE Log Number 8824754.
PY - 1989/3
Y1 - 1989/3
N2 - A disk-shaped phased array with a geometric focus di vided into N sectors (“sector-vortex” array) can directly synthesize an acoustic field suitable for heating nonsuperficial small tumors. By driving the N sectors with a phase that rotates M(≤ N/2) times per revolution around the disk, an annular vortex shaped acoustic field pattern is produced that is approximated by an Mth-order Bessel function on the geometric focal plane. The diameter of the annulus can be adjusted to the tumor size by controlling the mode number M. Moreover, unwanted acoustic “hot spots” are not formed between the array and the focal plane or beyond the focal plane. The sector-vortex array partitioned into multiple tracks can synthesize more complicated and useful patterns by controlling the acoustic interference between the fields produced by each track. Multitrack arrays also allow a larger diameter foci to be formed, and the heating field can be split into more than one annulus along the depth axis. Acoustic field patterns that can be synthesized by the sector-vortex array are studied using appropriate numerical simulations. The steady state temperature distribution around a tumor model, produced by time-sharing irradiation (scanning) between two different field patterns, is computed by solving a bioheat equation numerically.
AB - A disk-shaped phased array with a geometric focus di vided into N sectors (“sector-vortex” array) can directly synthesize an acoustic field suitable for heating nonsuperficial small tumors. By driving the N sectors with a phase that rotates M(≤ N/2) times per revolution around the disk, an annular vortex shaped acoustic field pattern is produced that is approximated by an Mth-order Bessel function on the geometric focal plane. The diameter of the annulus can be adjusted to the tumor size by controlling the mode number M. Moreover, unwanted acoustic “hot spots” are not formed between the array and the focal plane or beyond the focal plane. The sector-vortex array partitioned into multiple tracks can synthesize more complicated and useful patterns by controlling the acoustic interference between the fields produced by each track. Multitrack arrays also allow a larger diameter foci to be formed, and the heating field can be split into more than one annulus along the depth axis. Acoustic field patterns that can be synthesized by the sector-vortex array are studied using appropriate numerical simulations. The steady state temperature distribution around a tumor model, produced by time-sharing irradiation (scanning) between two different field patterns, is computed by solving a bioheat equation numerically.
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U2 - 10.1109/58.19158
DO - 10.1109/58.19158
M3 - Article
AN - SCOPUS:0024626879
SN - 0885-3010
VL - 36
SP - 249
EP - 257
JO - Transactions of the IRE Professional Group on Ultrasonic Engineering
JF - Transactions of the IRE Professional Group on Ultrasonic Engineering
IS - 2
ER -