2005 Fiscal Year Final Research Report Summary
Development of Sound Speed Microscope for Nano-scale Imaging of Biological Tissue Using Pico-second Ultrasonic Pulse
| Project/Area Number |
15360217
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Measurement engineering
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| Research Institution | Toyohashi University of Technology |
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Principal Investigator |
HOZUMI Naohiro Toyohashi University of Technology, 工学部, 助教授 (30314090)
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| Co-Investigator(Kenkyū-buntansha) |
NAGAO Masayuki Toyohashi University of Technology, 工学部, 教授 (30115612)
SAIJO Yoshifumi Tohoku University, 加齢医学研究所, 助教授 (00292277)
KOBAYASHI Kazuto Honda Electronics Co.Ltd.
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| Project Period (FY) |
2003 – 2005
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| Keywords | ultrasonic imaging / sound speed / acoustic impedance / biological tissue |
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| Research Abstract |
Observation of biological tissue by ultrasonic micro-imaging has advantages of being non-destructive and non-contacting, making it possible to quantitatively obtain physical parameters like sound speed and attenuation. We have been developing an ultrasonic sound speed microscope for biological tissues. A thin sliced specimen is placed on a glass substrate, and the reflection of a focused ultrasound pulse with a wide band frequency is interpreted into sound speed and other parameters. A 2D image can be observed when the focal beam spot is mechanically scanned. Its clinical application to histopathological examination during surgery is being considered. The data are also important to assess the origin of clinical echographic imaging. However, the lateral resolution of conventional one used to be as poor as 15 micrometers, although one with a higher resolution was expected to bring important information in biological and medical point of view. In this research project, we aimed to develop an ultrasonic microscope with a resolution of sub-micron level. An ultrasonic microscope using a wide-band pulse spreading from 100-500 MHz was assembled. A piezo-electric stage was employed in order to obtain a resolution of sub-micron level. Cultured nerve cells taken from the hippocampus of a rat was clearly observed as both intensity and sound speed images.
In addition, it was clarified that the reflected wave at the interface between the substrate and tissue can be measured when the acoustic wave was transmitted from the rear side of the substrate. Therefore the reflection was visualized as two-dimensional profile of acoustic impedance, in order to observe the tissue without preparing a thin sliced specimen. The structure of the cerebella tissue of a rat was clearly observed as an acoustic impedance image.
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