Abstract
Purpose
The aim of this study was realization of a broadband measurement system that is capable of effectively carrying out a frequency compound method. In the present method, the secondary wave components of difference and sum frequencies are generated along with the higher harmonic components through the nonlinear interaction of two-frequency ultrasound. A multiple-frequency beam is generated together with the initially radiated frequency components.
Methods
For the structure of a transducer capable of simultaneously radiating two sound waves with different frequencies, a coaxial arrangement of a circular-disc piezoelectric transducer and a ring piezoelectric transducer was designed. The radiating frequencies chosen were 2 and 8 MHz. In addition to the 4-MHz second harmonic sound of the 2-MHz primary sound, sounds of the 6-MHz difference frequency and the 10-MHz sum frequency can be generated.
Results
By measuring the acoustic pressure distribution, the formation of a multiple-frequency beam was confirmed. The signal-to-noise ratio in an agar-gel phantom image was increased by 5–6 dB with application of the frequency compound method. The validity of the proposed method was demonstrated through the generation of a human finger image. Further, it was found that the influence of the Doppler effect was small enough that almost all the secondary waves were attributable to the nonlinear propagation of sounds.
Conclusions
A multiple-frequency sound beam was realized by radiating a two-frequency sound. The effectiveness of the presented method was demonstrated through actual imaging.
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References
Averkiou MA, Roundhill DN, Powers JE. A new imaging technique based on the nonlinear properties of tissues. IEEE Ultrason Symp 1997;2:1561–1566.
Hasegawa H, Kanai H. Measurement of nonlinear properties of artery wall using remote cyclic actuation. J Med Ultrason 2006;33:143–151.
Andre MP, Barker CH, Sekhon N, et al. Pre-clinical experience with full-wave inverse scattering for breast imaging. Acoust Imaging 2008;29:73–80.
Filho EDS, Yoshizawa M, Tanaka A, et al. Moment-based texture segmentation of luminal contour in intravascular ultrasound images. J Med Ultrason 2005;32:91–99.
Magnin PA, Vonramm OT, Thurston FL. Frequency computing for speckle contrast reduction in phased-array images. Ultrason Imaging 1982;4:267–281.
Trahey GE, Allison JW, Smith SW, et al. A quantitative approach to speckle reduction via frequency compounding. Ultrason Imaging 1986;8:151–164.
Bamber JC, Phelps JC. Real-time implementation of coherent speckle suppression in B-scan images. Ultrasonics 1991;29:218–224.
Akiyama I, Yamamoto H, Ohashi G, et al. Speckle reduction by summation of higher order harmonic images. Acoust Imaging 2004;27:651–657.
Akiyama I, Saito S, Ohya A. Speckle noise reduction by superposing many higher harmonic images. Jpn J Appl Phys 2005;44:4631–4636.
Akiyama I, Saito S, Ohya A. Development of an ultra-broadband ultrasonic imaging system: prototype mechanical sector device. J Med Ultrason 2006;33:71–76.
Akiyama I, Ohya A, Saito S. Ultra-broadband ultrasonic imaging using bi-layer structure probe. Acoust Imaging 2007;28:101–109.
Hamilton MF. Sound beams, In: Hamilton MF, Blackstock DT, editors. Nonlinear acoustics. San Diego: Academic; 1998.p. 233–261.
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Yoshizumi, N., Saito, S., Koyama, D. et al. Multiple-frequency ultrasonic imaging by transmitting pulsed waves of two frequencies. J Med Ultrasonics 36, 53–60 (2009). https://doi.org/10.1007/s10396-009-0213-7
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DOI: https://doi.org/10.1007/s10396-009-0213-7