TY - GEN
T1 - Viscoelastic imaging using acoustic impedance microscope and its application to biological tissue
AU - Hozumi, Naohiro
AU - Kajima, Shota
AU - Gunawan, Agus Indra
AU - Yoshida, Sachiko
AU - Kobayashi, Kazuto
AU - Saijo, Yoshifumi
AU - Yamamoto, Seiji
N1 - Publisher Copyright:
© 2015 IEEE.
PY - 2015/11/13
Y1 - 2015/11/13
N2 - A new method of viscoelastic micro-imaging for soft biological tissue has been proposed. A target is placed on a plastic substrate. Ultrasonic beam, which is focused on the target, is transmitted and the reflection is received by the same transducer. Shear wave can be produced as the result of oblique incidence to the substrate. By adjusting the distance between the transducer and target either pressure or shear wave can be focused onto the target. It is easy to identify and extract each mode of the reflection in time domain, because pulse wave is transmitted. The reflection is once interpreted into characteristic acoustic impedance of the target, making use of the acoustic parameters of the substrate and reference material. Precise sound field analysis is required to create the calibration curve, because the incidence is not totally perpendicular to the substrate. The acoustic impedance for pressure wave is directly converted into bulk modulus. The (apparent) acoustic impedance for shear wave is interpreted into shear modulus and viscosity, making use of its frequency dependency. A 2-D profile of bulk modulus, shear modulus and viscosity may be obtained by mechanically scanning the transducer. As for a preliminary experiment, cancerous liver of rat was observed using acoustic impedance microscope with a frequency range of roughly 30-100 MHz. Viscosity profile showed a good correlation with stained image by optical microscope.
AB - A new method of viscoelastic micro-imaging for soft biological tissue has been proposed. A target is placed on a plastic substrate. Ultrasonic beam, which is focused on the target, is transmitted and the reflection is received by the same transducer. Shear wave can be produced as the result of oblique incidence to the substrate. By adjusting the distance between the transducer and target either pressure or shear wave can be focused onto the target. It is easy to identify and extract each mode of the reflection in time domain, because pulse wave is transmitted. The reflection is once interpreted into characteristic acoustic impedance of the target, making use of the acoustic parameters of the substrate and reference material. Precise sound field analysis is required to create the calibration curve, because the incidence is not totally perpendicular to the substrate. The acoustic impedance for pressure wave is directly converted into bulk modulus. The (apparent) acoustic impedance for shear wave is interpreted into shear modulus and viscosity, making use of its frequency dependency. A 2-D profile of bulk modulus, shear modulus and viscosity may be obtained by mechanically scanning the transducer. As for a preliminary experiment, cancerous liver of rat was observed using acoustic impedance microscope with a frequency range of roughly 30-100 MHz. Viscosity profile showed a good correlation with stained image by optical microscope.
KW - acoustic impedance microscopy
KW - biological soft tissue
KW - viscoelastic micro-imaging
UR - http://www.scopus.com/inward/record.url?scp=84962019763&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84962019763&partnerID=8YFLogxK
U2 - 10.1109/ULTSYM.2015.0172
DO - 10.1109/ULTSYM.2015.0172
M3 - Conference contribution
AN - SCOPUS:84962019763
T3 - 2015 IEEE International Ultrasonics Symposium, IUS 2015
BT - 2015 IEEE International Ultrasonics Symposium, IUS 2015
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - IEEE International Ultrasonics Symposium, IUS 2015
Y2 - 21 October 2015 through 24 October 2015
ER -
