Ultrasound Arrays for Prostate Treatment

By Leon A. Frizzell, Joseph S. Tan, and Gary M. Warren

Most high intensity focused ultrasound systems for treating Benign Prostatic Hyperplasia (BPH) or cancer of the prostate currently use fixed focus transducers that are moved mechanically to treat the desired volume of tissue. Some groups are investigating the use of phased arrays to provide electronic steering of the focal region in at least one dimension to reduce the mechanical movement of the transducer and to allow rapid movement of the focus. Most of these systems use small element spacing to eliminate grating lobes and thus require a large number of elements. This study investigates the use of a smaller number of large elements to reduce the cost and complexity of manufacture, but makes use of random location and/or size of elements to reduce grating lobes to an acceptable level. Theoretical studies are being conducted to identify an appropriate design for fabrication and experimental testing.

References

S.A. Goss, L.A. Frizzell J.T. Kouzmanoff, J.M. Barich and J.M. Yang, "Sparse Random Phased Arrays for Focal Surgery," IEEE Trans. Ultrason. Ferroelectrics Freq. Control, UFFC-43: 1111-1121, 1996.

L.A. Frizzell, S.A. Goss, J.T. Kouzmanoff and J.M. Yang, "Sparse Random Ultrasound Array for Focal Surgery," Proc. 1996 IEEE Ultrasonics Sym., San Antonio, Texas, Nov. 4-6, 1996, pp. 1319-1323.

J.S. Tan, L.A. Frizzell, N.T. Sanghvi, R. Seip, J.S. Wu, and J.T. Kouzmanoff, "Design of Focused Ultrasound Phased Arrays for Prostate Treatment," 2000 IEEE Ultrasonics Symp. Proc., Oct. 22-25, 2000, pp 1247-1251.

J.S. Tan, L.A. Frizzell, N. Sanghvi, R. Seip, J. Wu, and J.T. Kouzmanoff, "Ultrasound Phased Arrays for Prostate Treatment, " J. Acoust. Soc. Am., 109, 3055-3064, 2001.

L.A. Frizzell, J. Tan, and G. Warren, "Theoretical Results for New Cylindrical Ultrasound Phased Array for Prostate Treatmnet," pp. 384-390 in Proc. 2nd Int'l Sym. Therapeutic Ultrasound, (Seattle, WA, July 29-Aug. 2,2002) Ed. by M.A. Andrew, L.A. Crum, and S. Vaezy, Center for Industrial & Medical Ultrasound, Applied Physics Laboratory, University of Washington, 2003.

R. Seip, W. Chen, J. Tavakkoli, L. Frizzell, and N.T. Sanghvi, "High-Intensity Focused Ultrasound (HIFU) Phased Arrays: Recent Developments in Transrectal Transducers and Driving Electronics Design," in Proc. 3rd Intl'l Sym. Therapeutic Ultrasound, (Lyon, France, June 22-25, 2003).