1992 Fiscal Year Final Research Report Summary
New Development of Tissue Characterization using Acoustic Microscopy with High Frequency Ultrasound
| Project/Area Number |
03557109
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
医学一般
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| Research Institution | Kagawa Medical School |
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Principal Investigator |
SENDA Shoichi Kagawa Medical School, Second Department of Internal Medicine, Assistant Professor, 医学部・附属病院, 助教授 (30145049)
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| Co-Investigator(Kenkyū-buntansha) |
KATAKURA Kageyoshi Central Research Laboratory, Hitachi, Ltd., Senior Researcher, 主管研究員
NISHIMURA Toshihiro Oita University, The Department of Electronic and Electrical Engineering, Resear, 工学部, 助手 (70117406)
MORITA Hisaki Kagawa Medical School, Second Department of Internal Medicine, Assistant Profess, 医学部・附属病院, 講師 (70145051)
UDA Hirotsugu Kagawa Medical School, 副学長 (80107044)
MATSUO Hirohide Kagawa Medical School, Second Department of Internal Medicine, Professor, 医学部, 教授 (90028514)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Acoustic microscopy / Ultrasonic tissue characterization / Acoustic parameter / Propagation velocity / Acoustic impedance / Acoustic cover membrane / Bulk modulus / Density |
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| Research Abstract |
In this study, we have newly developed an acoustic tissue characterization system using an acoustic microscopy with high frequency ultrasound. In this system, we can measure the propagation velocity and ultrasonic attenuation of human tissue specimen in order to evaluate the hardness of the specimen in arteriosclerosis. Furthermore, in order to evaluate the hardness of the tissue more precisely, we developed a new method to evaluate the bulk modulus and density of tissue specimen.
1. We used a reflecting and scanning acoustic microscopy utilizing a highly frequency (more than 450 MHz) microscope (HSAM-500S) coupled with a computer controller and analyzer. Specimen which were obtained from human coronary arteries and other tissue by autopsy, were cut in 4 micron thickness, and prepared without paraffin on slide glass. In C mode image, we obtained clear images similar to those from optical microscopy. Furthermore we measure the ultrasonic attenuation in C mode image. In X-Z mode image, we were able to obtain propagation velocities through specimen (Vs) by inserting values for the propagation velocity through the coupling medium (Vw), the specimen thickness (ds) and the shift in the interference fringe (DELTAz) into the following equation : Vs=Vw/(1-DELTAz/ds).
2. We developed an acoustic cover membrane covering specimen in order to measure bulk modulus (Ks) and density (rhos) of specimen. This cover membrane is made of polycarbonate and is interposed between the specimen and the propagating medium. The cover membrane has a known acoustic impedance (3.5MKS) higher than either of the two. The intensity of the signal reflected from the cover membrane represents the acoustic impedance (Zs) of the specimen. So, if we measure Zs and Vs of specimen using the acoustic microscopy with this cover membrane, we can estimate Ks and rhos of specimen as follows ; Ks=ZsVs, rhos=Zs/Vs. In this way, we can evaluate the hardness of specimen more precisely.
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