1996 Fiscal Year Final Research Report Summary
Fundamental Investigation of Ultrasonic properties in Biological Tissues by Numerical Analysis.
| Project/Area Number |
06680869
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Biomedical engineering/Biological material science
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| Research Institution | AKITA National College of Technology |
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Principal Investigator |
SATO Masahiro AKITA National College of Technology, Department of Electrical Engineering, Assistant Professor, 電気工学科, 助教授 (90132563)
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| Project Period (FY) |
1994 – 1996
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| Keywords | Ultrasonic diagnosis / Numerical Analysis / Biological Tissues |
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| Research Abstract |
To analyze the ultrasonic waves in soft biologicasl tissues, I used the leap frog algorithm of finite difference method. It has advantage for transient analysis because of the possibility of explicit and simple formulation and easy setting of boundary conditions. In result, it's realized that shear and surface waves can be generated and propagate at lower frequencies (some decade kHz) than the frequencies (some MHz) at which longitudinal wave is commonly used by a conventional ultrasonic diagnosis equipment. If we can afford to employ the shear and surface elastic waves, the development of medical ultrasonic systems can be expected.
But the calculation was done with the approximation that the tissue is homogenous and not has nonlinearity. So the numerical result is confirmed by experimental one. So, the velocity and the attenuation coefficient of the surface wave on gelatin gel were measured by the laser Doppler vibromater. The measured velocity was 1-2 [m/s] from100 [Hz] to 800 [Hz] frequency range. The attenuation was about 0.1 [1/mm] at frequencies 100 [Hz] and 300 [Hz]. Because of the sensitivity of the measuring system and the distortion of waves by nonlinearity, I could not measure the values at high frequencies using by the numerical analysis. But the generation and propagation of surface waves, which shown the existence of shear waves, in vgiscoelastic soft materials were confirmed.
Next, I was going to make software by the same numerical method in time domain for analyzing ultrasonic diagnosis equipment to know the ultrasonic wave form emitted by the equipment, and ultrasonic microscope to measure the tissue's properties exactly. Now, it can analyze a ultrasonic transducer with a baking material and matching layrs in two dimension. And the reflection characteristics from measuring samples of a two dimensional line focus ultrasonic beam.
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Research Products
(12 results)
