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High Resolution Ultrasonic Imaging Using a Large Aperture Annular Array Transducer of P(VDF-TrFE) Copolymer

  • N. Hashimoto
  • T. MIya
  • K. Yoneya
  • A. Ando
  • H. Ohigashi
Part of the Acoustical Imaging book series (ACIM, volume 17)

Abstract

A 7.5 MHz concave annular array ultrasonic transducer comprising a piezoelectric film of vinylidene fluoride and trifluoroethylene copolymer, and its driving system has been developed for high resolution medical imaging. The transducer is composed of eight annular elements of equal areas and has a large aperture (70 mm) and a long radius of curvature (180 mm). With phase controlled electric driving pulses, the focal length can be varied dynamically from 150 to 200 mm. The transducer is scanned mechanically in a sector mode in a water bag container to which the objects to be examined are contacted. The acoustic field distribution, pulse waveform, and frequency response characteristics are analysed experimentally and theoretically. The consistency is quite satisfactory. The lateral resolution obtained is 0.5-1.0 mm over the focal zone, and the depth resolution is 0.3 mm. Clear and fine echotomographic images of the breasts and thyroid glands can be obtained with this imaging system.

Keywords

Vinylidene Fluoride Acoustical Image Conversion Loss Piezoelectric Film Piezoelectric Polymer 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    N. Chubachi and T. Sannomiya, Composite Resonators Using PVDF Film and its Application to Concave Transducers for Focusing Radiation of VHF Ultrasonic Waves, 1977 IEEE Ultrasonic Symposium, p. 119.Google Scholar
  2. 2.
    H. Ohigashi, Ultrasonic Transducer in the MHz Range, in “Applications of Ferroelectric Polymers“, T. T. Wang, J. M. Herbert, and A. M. Glass, eds., Blackies, Glasgow (1987).Google Scholar
  3. 3.
    K. Koga and H. Ohigashi, Piezoelectricity and Related Properties of Vinylidene Fluoride and Trifluoroethylene Copolymers, J. Appl. Phys. 59:2142 (1986).ADSCrossRefGoogle Scholar
  4. 4.
    R. Omoto, M. Maruyama, M. Kobayashi, H. Ohigashi, T. Nakanishi, and M. Suzuki, Piezoelectric Polymer Trasnsducers for High Resolution Ultrasound Imaging, Proceedings of the 26th Annual Meeting of the American Institute of Ultrasound in Medicine (1981, San Francisco) p.135Google Scholar
  5. 5.
    H. Ohigashi, K. Koga, M. Suzuki, T. Nakanishi, K. Kimura, N. Hashimoto, Piezoelectric and Ferroelectric Properties of P(VDF-TrFE) Copolymers and Their Applications to Ultrasonic Transucers, Ferroelectrics, 60:263 (1984).CrossRefGoogle Scholar
  6. 6.
    K. Kimura, N. Hashimoto, and H. Ohigashi, Performance of of a Linear ArrayTransducer of Vinylidene Fluoride and Trifluoroethylene Copolymer, IEEE Trans. Sonics & Ultrason. SU-32:566 (1985).Google Scholar
  7. 7.
    K. Kimura and H. Ohigashi, Generation of Very High Frequency Ultrasonic Waves Using Thin Film of Vinylidene Fluoride and Trifluoroethylene Copolymer, Appl. Phys. 61:4749 (1987).Google Scholar
  8. 8.
    H. Ohigashi and K. Koyama, S. Takahashi, Y. Wada, Y. Maida, R. Suganuma, and T. Jindo, Ferroelectic Polymer Transducer for Hiqh Resolution Scanning Acoustic Microscopy, Acoustical Imaging, 16 (1977), in press.Google Scholar
  9. 9.
    Y. Miyake, K. Fujieda, M. Hirose, and H. Hirose, High Resolutional Ultrasonic Diagnastic Equipment Using Annular Array Transducer, Jpn. Soc. Ultrasound in Medicine, Proceedings, 43:449 (1983).Google Scholar
  10. 10.
    W. P. Mason, “Electromechanical Transducers and Wavefilters”, D. Van Nostrand, New Jersey (1948).Google Scholar
  11. 11.
    K. Kimura, K. Yoneya, and H. Ohigashi, A Wide-Band Polymer Ultrasonic Transducer Using Acoustic Impedance Matching Technique, Jpn. J. Appl. Phys. 27:547 (1988).ADSCrossRefGoogle Scholar

Copyright information

© Plenum press, New York 1989

Authors and Affiliations

  • N. Hashimoto
    • 1
  • T. MIya
    • 1
  • K. Yoneya
    • 1
  • A. Ando
    • 1
  • H. Ohigashi
    • 2
  1. 1.Engineering Research LaboratoriesToray Industries, Inc.Sonoyama, OtsuJapan
  2. 2.Department of Polymer Materials Engineering, Faculty of EngineeringYamagata UniversityJonan, YonezawaJapan

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