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英文誌(2004-)

Journal of Medical Ultrasonics

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1984 - Vol.11

Vol.11 No.01

Original Article(原著)

(0010 - 0016)

広帯域パルスによる生体組織の減衰特性の測定について —有限振幅音波の伝搬とその影響のシミュレーション—

On the Measurement of Frequency Dependent Attenuation in Biological Tissues Using Broadband Pulsed Ultrasound; *Simulation of Propagation and Behavior of Finite Amplitude Sound Wave*

秋山 いわき1, 西田 幸博1, 中島 真人1, 油田 信一2, 伊藤 貴司3

Iwaki AKIYAMA1, Yukihiro NISHIDA1, Masato NAKAJIMA1, Shinichi YUTA2, Takashi ITOH3

1慶応義塾大学理工学部電気工学科, 2筑波大学電子情報工学系, 3アロカ株式会社

1Department of Electrical Engineering, Keio Univ., 2Institute of Information Science and Electronics, Univ. of Tsukuba, 3Aloka Co., Ltd.

キーワード : frequency dependent attenuation, broadband pulse, continuous wave, nonlinear relation, finite amplitude sound wave

 It is expected that biological tissues can be characterized by the ultrasound transmission measurement of frequency dependent attenuation (F.D.A.) of the tissue specimen. This method could be performed by comparing the amplitude of the transmitting wave with the incident wave at every frequency. Continuous sinusoidal wave has been utilized in the early works as a transmitting wave. However, this technique is accompanied by the problem of the multiple reflection between the surface of transmitting and receiving transducer and the troublesomeness of changing the frequency over the wide range. Accordingly the method for determining F.D.A. at one shot by comparing the spectrum of a broadband RF pulse of the incident and transmitting wave has been recently become popular. We experimentally measured the attenuation vs. frequency curve by this technique and attained the nonlinear relation depending on the amplitude which is out of linear relation and never observed in the case of continuous wave experiment. As well as we found the similar characteristics in some data of the previous other works. We discussed this phenomenon by computer simulation and it is confirmed that this phenomenon results in the wave distortion according to a finite amplitude sound wave propagation.