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Kazuto Kobayashi – One of the best experts on this subject based on the ideXlab platform.

  • Three-dimensional Acoustic Impedance mapping of cultured biological cells.
    Ultrasonics, 2019
    Co-Authors: Naohiro Hozumi, Sachiko Yoshida, Kazuto Kobayashi

    Abstract:

    Abstract The Acoustic microscope is a powerful tool for the observation of biological matters. Non-invasive in-situ observation can be performed without any staining process. Acoustic microscopy is contrasted by elastic parameters like sound speed and Acoustic Impedance. We have proposed an Acoustic microscope that can acquire three-dimensional Acoustic Impedance profile. The technique was applied to cell-size observation. Glial cells were cultured on a 70 μm-thick polypropylene film substrate. A highly focused ultrasound beam was transmitted from the rear side of the substrate, and the reflection was received by the same transducer. An Acoustic pulse, its spectrum spreading briefly 100 through 450 MHz, was transmitted. By analyzing the internal reflections in the cell, the distribution of characteristic Acoustic Impedance along the beam direction was determined. Three-dimensional Acoustic Impedance mapping was realized by scanning the transducer, exhibiting the intra-cellular structure including nucleus and cytoskeleton.

  • Acoustic Impedance estimation using calibration curve for scanning Acoustic Impedance microscope
    2016 International Conference on Knowledge Creation and Intelligent Computing (KCIC), 2016
    Co-Authors: Agus Indra Gunawan, Yoshifumi Saijo, Naohiro Hozumi, Sachiko Yoshida, Kazuto Kobayashi, Seiji Yamamoto

    Abstract:

    Ultrasonic has been used since several decades ago. One of ultrasonic application is used in medical field to observe mechanical properties of target, such as speed of sound, density, Acoustic Impedance, attenuation, etc. Several methods are also available to estimate mechanical property of target. In the previous research, we developed Scanning Acoustic Microscope (SAM). On that research, we proposed a method to estimated Acoustic Impedance by utilizing calibration curve. A calibration curve is established based on echo intensity obtained from calculation of Acoustic propagation. The highest amplitude of a single frequency component is chosen and taken into calculation. The other frequency components are neglected. In this paper, authors propose a method to estimate Acoustic Impedance of target. The Acoustic Impedance is estimated based on calibration curve by considering all frequency components of Acoustic wave. This calculation is then compared to previous research. As a result, Acoustic Impedance of cerebellar tissue of rat are presented by utilizing two calibration curves.

  • numerical analysis of ultrasound propagation and reflection intensity for biological Acoustic Impedance microscope
    Ultrasonics, 2015
    Co-Authors: Agus Indra Gunawan, Yoshifumi Saijo, Naohiro Hozumi, Sachiko Yoshida, Kazuto Kobayashi, Seiji Yamamoto

    Abstract:

    Abstract This paper proposes a new method for microscopic Acoustic imaging that utilizes the cross sectional Acoustic Impedance of biological soft tissues. In the system, a focused Acoustic beam with a wide band frequency of 30–100 MHz is transmitted across a plastic substrate on the rear side of which a soft tissue object is placed. By scanning the focal point along the surface, a 2-D reflection intensity profile is obtained. In the paper, interpretation of the signal intensity into a characteristic Acoustic Impedance is discussed. Because the Acoustic beam is strongly focused, interpretation assuming vertical incidence may lead to significant error. To determine an accurate calibration curve, a numerical sound field analysis was performed. In these calculations, the reflection intensity from a target with an assumed Acoustic Impedance was compared with that from water, which was used as a reference material. The calibration curve was determined by changing the assumed Acoustic Impedance of the target material. The calibration curve was verified experimentally using saline solution, of which the Acoustic Impedance was known, as the target material. Finally, the cerebellar tissue of a rat was observed to create an Acoustic Impedance micro profile. In the paper, details of the numerical analysis and verification of the observation results will be described.

Naohiro Hozumi – One of the best experts on this subject based on the ideXlab platform.

  • Three-dimensional Acoustic Impedance mapping of cultured biological cells.
    Ultrasonics, 2019
    Co-Authors: Naohiro Hozumi, Sachiko Yoshida, Kazuto Kobayashi

    Abstract:

    Abstract The Acoustic microscope is a powerful tool for the observation of biological matters. Non-invasive in-situ observation can be performed without any staining process. Acoustic microscopy is contrasted by elastic parameters like sound speed and Acoustic Impedance. We have proposed an Acoustic microscope that can acquire three-dimensional Acoustic Impedance profile. The technique was applied to cell-size observation. Glial cells were cultured on a 70 μm-thick polypropylene film substrate. A highly focused ultrasound beam was transmitted from the rear side of the substrate, and the reflection was received by the same transducer. An Acoustic pulse, its spectrum spreading briefly 100 through 450 MHz, was transmitted. By analyzing the internal reflections in the cell, the distribution of characteristic Acoustic Impedance along the beam direction was determined. Three-dimensional Acoustic Impedance mapping was realized by scanning the transducer, exhibiting the intra-cellular structure including nucleus and cytoskeleton.

  • Acoustic Impedance estimation using calibration curve for scanning Acoustic Impedance microscope
    2016 International Conference on Knowledge Creation and Intelligent Computing (KCIC), 2016
    Co-Authors: Agus Indra Gunawan, Yoshifumi Saijo, Naohiro Hozumi, Sachiko Yoshida, Kazuto Kobayashi, Seiji Yamamoto

    Abstract:

    Ultrasonic has been used since several decades ago. One of ultrasonic application is used in medical field to observe mechanical properties of target, such as speed of sound, density, Acoustic Impedance, attenuation, etc. Several methods are also available to estimate mechanical property of target. In the previous research, we developed Scanning Acoustic Microscope (SAM). On that research, we proposed a method to estimated Acoustic Impedance by utilizing calibration curve. A calibration curve is established based on echo intensity obtained from calculation of Acoustic propagation. The highest amplitude of a single frequency component is chosen and taken into calculation. The other frequency components are neglected. In this paper, authors propose a method to estimate Acoustic Impedance of target. The Acoustic Impedance is estimated based on calibration curve by considering all frequency components of Acoustic wave. This calculation is then compared to previous research. As a result, Acoustic Impedance of cerebellar tissue of rat are presented by utilizing two calibration curves.

  • numerical analysis of ultrasound propagation and reflection intensity for biological Acoustic Impedance microscope
    Ultrasonics, 2015
    Co-Authors: Agus Indra Gunawan, Yoshifumi Saijo, Naohiro Hozumi, Sachiko Yoshida, Kazuto Kobayashi, Seiji Yamamoto

    Abstract:

    Abstract This paper proposes a new method for microscopic Acoustic imaging that utilizes the cross sectional Acoustic Impedance of biological soft tissues. In the system, a focused Acoustic beam with a wide band frequency of 30–100 MHz is transmitted across a plastic substrate on the rear side of which a soft tissue object is placed. By scanning the focal point along the surface, a 2-D reflection intensity profile is obtained. In the paper, interpretation of the signal intensity into a characteristic Acoustic Impedance is discussed. Because the Acoustic beam is strongly focused, interpretation assuming vertical incidence may lead to significant error. To determine an accurate calibration curve, a numerical sound field analysis was performed. In these calculations, the reflection intensity from a target with an assumed Acoustic Impedance was compared with that from water, which was used as a reference material. The calibration curve was determined by changing the assumed Acoustic Impedance of the target material. The calibration curve was verified experimentally using saline solution, of which the Acoustic Impedance was known, as the target material. Finally, the cerebellar tissue of a rat was observed to create an Acoustic Impedance micro profile. In the paper, details of the numerical analysis and verification of the observation results will be described.

Seiji Yamamoto – One of the best experts on this subject based on the ideXlab platform.

  • Acoustic Impedance estimation using calibration curve for scanning Acoustic Impedance microscope
    2016 International Conference on Knowledge Creation and Intelligent Computing (KCIC), 2016
    Co-Authors: Agus Indra Gunawan, Yoshifumi Saijo, Naohiro Hozumi, Sachiko Yoshida, Kazuto Kobayashi, Seiji Yamamoto

    Abstract:

    Ultrasonic has been used since several decades ago. One of ultrasonic application is used in medical field to observe mechanical properties of target, such as speed of sound, density, Acoustic Impedance, attenuation, etc. Several methods are also available to estimate mechanical property of target. In the previous research, we developed Scanning Acoustic Microscope (SAM). On that research, we proposed a method to estimated Acoustic Impedance by utilizing calibration curve. A calibration curve is established based on echo intensity obtained from calculation of Acoustic propagation. The highest amplitude of a single frequency component is chosen and taken into calculation. The other frequency components are neglected. In this paper, authors propose a method to estimate Acoustic Impedance of target. The Acoustic Impedance is estimated based on calibration curve by considering all frequency components of Acoustic wave. This calculation is then compared to previous research. As a result, Acoustic Impedance of cerebellar tissue of rat are presented by utilizing two calibration curves.

  • numerical analysis of ultrasound propagation and reflection intensity for biological Acoustic Impedance microscope
    Ultrasonics, 2015
    Co-Authors: Agus Indra Gunawan, Yoshifumi Saijo, Naohiro Hozumi, Sachiko Yoshida, Kazuto Kobayashi, Seiji Yamamoto

    Abstract:

    Abstract This paper proposes a new method for microscopic Acoustic imaging that utilizes the cross sectional Acoustic Impedance of biological soft tissues. In the system, a focused Acoustic beam with a wide band frequency of 30–100 MHz is transmitted across a plastic substrate on the rear side of which a soft tissue object is placed. By scanning the focal point along the surface, a 2-D reflection intensity profile is obtained. In the paper, interpretation of the signal intensity into a characteristic Acoustic Impedance is discussed. Because the Acoustic beam is strongly focused, interpretation assuming vertical incidence may lead to significant error. To determine an accurate calibration curve, a numerical sound field analysis was performed. In these calculations, the reflection intensity from a target with an assumed Acoustic Impedance was compared with that from water, which was used as a reference material. The calibration curve was determined by changing the assumed Acoustic Impedance of the target material. The calibration curve was verified experimentally using saline solution, of which the Acoustic Impedance was known, as the target material. Finally, the cerebellar tissue of a rat was observed to create an Acoustic Impedance micro profile. In the paper, details of the numerical analysis and verification of the observation results will be described.

  • Aberration correction for biological Acoustic Impedance microscope
    2009 IEEE International Ultrasonics Symposium, 2009
    Co-Authors: T. Uemura, Seiji Yamamoto, Naohiro Hozumi, Sachiko Yoshida, Kazuto Kobayashi, T. Suzuki, K. Hanai, Yoshifumi Saijo

    Abstract:

    This report deals with the scanning Acoustic microscope for imaging cross sectional characteristic Acoustic Impedance of biological soft tissues. A focused pulse wave is transmitted to the object placed on the “rear surface” of a plastic substrate. The reflected signals from the target and reference are interpreted into local Acoustic Impedance. Two-dimensional profile is obtained by scanning the transducer. This method, using a spherical transducer, produces a significant aberration, because the sound speed of the substrate is different from water that is used as a coupling medium. For this reason the spatial resolution is reduced. The spatial resolution was improved by using 3D deconvolution technique, considering the impulse response of the Acoustic system. In addition, as the incidence is not vertical, not only longitudinal wave but also transversal wave is generated in the substrate. Calibration for Acoustic Impedance was carried out after the deconvolution process, considering the above mentioned oblique incidence.