Multiple-frequency phased array patterns for therapeutic ultrasound

John R. Ballard, Dalong Liu, Andrew J. Casper, Yayun Wan, Mohamed Khaled Almekkawy, Emad S. Ebbini

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Modern transducer technology allows for the design and implementation of therapeutic arrays with relatively wide bandwidths (>50%) and low cross coupling between elements. We present results from a 3.5 MHz, 64-element prototype designed for small-animal and superficial therapeutic HIFU applications (Imasonic, Inc.) This transducer has a 58% 6-dB fractional BW average on its elements allowing for therapeutic output in the frequency range of 2.7 - 4.6 MHz. We present a simulation/experimental study to evaluate and optimize the focusing capabilities of the phased array prototype when excited by multiple-frequency components. Preliminary results have shown that multiple-frequency excitation may be beneficial in enhancing the therapeutic effects of HIFU beams. A multiple-focus pattern synthesis algorithm for arrays excited by multiple-frequency signals has been developed and tested using linear pressure field simulations. The algorithm maintains the precise phase relationship between the frequency components at each focal spot to achieve a desirable outcome. Hydrophone measurements to validate the approach show that nonlinear effects at the focal location are more prominent with the frequency mixing compared to conventional single frequency excitation. An in vitro study of lesion formation in freshly excised porcine liver was investigated.

Original languageEnglish (US)
Title of host publication11th International Symposium on Therapeutic Ultrasound
Pages9-13
Number of pages5
Volume1481
DOIs
StatePublished - 2012
Event11th International Symposium on Therapeutic Ultrasound, ISTU 2011 - New York, NY, United States
Duration: Apr 11 2011Apr 13 2011

Other

Other11th International Symposium on Therapeutic Ultrasound, ISTU 2011
CountryUnited States
CityNew York, NY
Period4/11/114/13/11

Fingerprint

phased arrays
transducers
prototypes
hydrophones
cross coupling
pressure distribution
liver
lesions
excitation
animals
simulation
frequency ranges
bandwidth
output
synthesis

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Cite this

Ballard, J. R., Liu, D., Casper, A. J., Wan, Y., Almekkawy, M. K., & Ebbini, E. S. (2012). Multiple-frequency phased array patterns for therapeutic ultrasound. In 11th International Symposium on Therapeutic Ultrasound (Vol. 1481, pp. 9-13) https://doi.org/10.1063/1.4757302
Ballard, John R. ; Liu, Dalong ; Casper, Andrew J. ; Wan, Yayun ; Almekkawy, Mohamed Khaled ; Ebbini, Emad S. / Multiple-frequency phased array patterns for therapeutic ultrasound. 11th International Symposium on Therapeutic Ultrasound. Vol. 1481 2012. pp. 9-13
@inproceedings{449dfcea2ea240059826c87199fcced3,
title = "Multiple-frequency phased array patterns for therapeutic ultrasound",
abstract = "Modern transducer technology allows for the design and implementation of therapeutic arrays with relatively wide bandwidths (>50{\%}) and low cross coupling between elements. We present results from a 3.5 MHz, 64-element prototype designed for small-animal and superficial therapeutic HIFU applications (Imasonic, Inc.) This transducer has a 58{\%} 6-dB fractional BW average on its elements allowing for therapeutic output in the frequency range of 2.7 - 4.6 MHz. We present a simulation/experimental study to evaluate and optimize the focusing capabilities of the phased array prototype when excited by multiple-frequency components. Preliminary results have shown that multiple-frequency excitation may be beneficial in enhancing the therapeutic effects of HIFU beams. A multiple-focus pattern synthesis algorithm for arrays excited by multiple-frequency signals has been developed and tested using linear pressure field simulations. The algorithm maintains the precise phase relationship between the frequency components at each focal spot to achieve a desirable outcome. Hydrophone measurements to validate the approach show that nonlinear effects at the focal location are more prominent with the frequency mixing compared to conventional single frequency excitation. An in vitro study of lesion formation in freshly excised porcine liver was investigated.",
author = "Ballard, {John R.} and Dalong Liu and Casper, {Andrew J.} and Yayun Wan and Almekkawy, {Mohamed Khaled} and Ebbini, {Emad S.}",
year = "2012",
doi = "10.1063/1.4757302",
language = "English (US)",
isbn = "9780735410930",
volume = "1481",
pages = "9--13",
booktitle = "11th International Symposium on Therapeutic Ultrasound",

}

Ballard, JR, Liu, D, Casper, AJ, Wan, Y, Almekkawy, MK & Ebbini, ES 2012, Multiple-frequency phased array patterns for therapeutic ultrasound. in 11th International Symposium on Therapeutic Ultrasound. vol. 1481, pp. 9-13, 11th International Symposium on Therapeutic Ultrasound, ISTU 2011, New York, NY, United States, 4/11/11. https://doi.org/10.1063/1.4757302

Multiple-frequency phased array patterns for therapeutic ultrasound. / Ballard, John R.; Liu, Dalong; Casper, Andrew J.; Wan, Yayun; Almekkawy, Mohamed Khaled; Ebbini, Emad S.

11th International Symposium on Therapeutic Ultrasound. Vol. 1481 2012. p. 9-13.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

TY - GEN

T1 - Multiple-frequency phased array patterns for therapeutic ultrasound

AU - Ballard, John R.

AU - Liu, Dalong

AU - Casper, Andrew J.

AU - Wan, Yayun

AU - Almekkawy, Mohamed Khaled

AU - Ebbini, Emad S.

PY - 2012

Y1 - 2012

N2 - Modern transducer technology allows for the design and implementation of therapeutic arrays with relatively wide bandwidths (>50%) and low cross coupling between elements. We present results from a 3.5 MHz, 64-element prototype designed for small-animal and superficial therapeutic HIFU applications (Imasonic, Inc.) This transducer has a 58% 6-dB fractional BW average on its elements allowing for therapeutic output in the frequency range of 2.7 - 4.6 MHz. We present a simulation/experimental study to evaluate and optimize the focusing capabilities of the phased array prototype when excited by multiple-frequency components. Preliminary results have shown that multiple-frequency excitation may be beneficial in enhancing the therapeutic effects of HIFU beams. A multiple-focus pattern synthesis algorithm for arrays excited by multiple-frequency signals has been developed and tested using linear pressure field simulations. The algorithm maintains the precise phase relationship between the frequency components at each focal spot to achieve a desirable outcome. Hydrophone measurements to validate the approach show that nonlinear effects at the focal location are more prominent with the frequency mixing compared to conventional single frequency excitation. An in vitro study of lesion formation in freshly excised porcine liver was investigated.

AB - Modern transducer technology allows for the design and implementation of therapeutic arrays with relatively wide bandwidths (>50%) and low cross coupling between elements. We present results from a 3.5 MHz, 64-element prototype designed for small-animal and superficial therapeutic HIFU applications (Imasonic, Inc.) This transducer has a 58% 6-dB fractional BW average on its elements allowing for therapeutic output in the frequency range of 2.7 - 4.6 MHz. We present a simulation/experimental study to evaluate and optimize the focusing capabilities of the phased array prototype when excited by multiple-frequency components. Preliminary results have shown that multiple-frequency excitation may be beneficial in enhancing the therapeutic effects of HIFU beams. A multiple-focus pattern synthesis algorithm for arrays excited by multiple-frequency signals has been developed and tested using linear pressure field simulations. The algorithm maintains the precise phase relationship between the frequency components at each focal spot to achieve a desirable outcome. Hydrophone measurements to validate the approach show that nonlinear effects at the focal location are more prominent with the frequency mixing compared to conventional single frequency excitation. An in vitro study of lesion formation in freshly excised porcine liver was investigated.

UR - http://www.scopus.com/inward/record.url?scp=84873174597&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84873174597&partnerID=8YFLogxK

U2 - 10.1063/1.4757302

DO - 10.1063/1.4757302

M3 - Conference contribution

AN - SCOPUS:84873174597

SN - 9780735410930

VL - 1481

SP - 9

EP - 13

BT - 11th International Symposium on Therapeutic Ultrasound

ER -

Ballard JR, Liu D, Casper AJ, Wan Y, Almekkawy MK, Ebbini ES. Multiple-frequency phased array patterns for therapeutic ultrasound. In 11th International Symposium on Therapeutic Ultrasound. Vol. 1481. 2012. p. 9-13 https://doi.org/10.1063/1.4757302