Ultrasonics

Part I - Basic physics and measurement
1. Ultrasound propagation
Pak-Kon Choi, Meiji Univ.
Abstract: Fundamentals of ultrasound propagation governed by wave equation are
shown. The sound velocity and the sound absorption were determined by the
elasticity of the propagating material, and by the viscosity and relaxation phenomena,
respectively. Theory of ultrasound fields is briefly described, and the measurement
methods were demonstrated.
2. Viscoelasticity and wave propagation
K. Sakai, Univ. of Tokyo
Abstract: Recent methodologies of viscoelasticity are introduced. First, the role of
viscoelasticity in ultrasonic relaxation is summarized. Then, two-dimensional
viscoelasticity studied through surface light scattering is discussed. Progress in
rheometry is also shown, in which the remote sensing by EMS method is described.
Finally, ultrafast measurement of liquid properties using micro liquid manipulation is
introduced.
3. Optical measurement of ultrasonic field in air/water and ultrasonic vibration of solid
K. Nakamura, Tokyo Inst. Tech.
Abstract: Optical methods to evaluate and visualize ultrasonic field in air/water are
introduced in this chapter. Sound pressure was detected as refractive index
modulation of media using optical interferometer or fiber optic probe. Principle of
laser Doppler vibrometer for out-of-plane and in-plane ultrasonic vibrations is also
explained.
4. Picosecond laser ultrasonics
O. Matsuda, O. B. Wright, Hokkaido Univ.
Absorption of picosecond optical pulses in a medium may generate GHz-THz acoustic
waves whose propagation can be monitored optically by the delayed light pulses. The
technique, picosecond laser ultrasonics, inspects the nano-scale structure and
physical properties of the sample. In this chapter, we see the basics of the technique
and its recent application to the submicron-scale structured samples.
Part II Industrial applications
5. Ball surface acoustic wave sensor and application to trace gas analysis
K. Yamanaka, T. Iwaya, S. Akao, Ball Wave Inc.
Ball surface acoustic wave SAW sensor where the SAW makes ultramultiple turns on a
spherical piezoelectric crystal due to a naturally collimated beam. It realizes rapid and
sensitive trace moisture analysis of industrial gases and portable gas chromatography
for on-site analysis of food flavor and hazardous gases. 6. Phase adjuster in a thermoacoustic system
S. Sakamoto, Y. Watanabe, Univ. Shiga Pref.
Focusing on the improvement of energy conversion efficiency in the thermoacoustic
system, we introduce a phase adjuster technique. A phase adjuster realizes energy
conversion at lower temperatures with good efficiency.
Part III Biological and medical applications
7. Ultrasonic characterization of bone
M. Matsukawa, Doshisha Univ.
Bone is anisotropic and heterogeneous, wherein ultrasonic wave propagation is very
complicated. Therefore, both morphological and material characteristics should be
considered for the evaluation of bone, which is a mixture of solid and liquid, and is an
ultrasonically very difficult material. This chapter gives a review on the characteristic
wave propagation in bone. It also discusses the effects of disease on the ultrasonic
wave properties in bone matrices, in addition to the bone piezoelectricity.
8. Acceleration and control of protein aggregation
H. Ogi, Osaka Univ.
Amyloidoses such as Alzheimer's disease are caused by aggregation of corresponding
causative proteins, and the high energy barrier for aggregation have prevented us
from studying the aggregation mechanism. It is, however, revealed that ultrasonic
irradiation can drastically accelerate protein aggregation reactions. This review
explains the acceleration mechanism related to ultrasonic cavitation and application
for diagnosis for amyloidoses.
9. High-frame-rate medical ultrasonic imaging
H. Hasegawa, Univ. Toyama
Conventional medical ultrasound imaging constructs an image by line-by-line
acquisition using a focused ultrasound beam. This acquisition scheme requires several
tens emissions to construct an image and, therefore, the imaging frame rate is limited
to several tens frames per second fps. On the other hand, a number of receiving
beams can be created simultaneously in every emission and, in an extreme case, a
frame rate of over 10,000 fps is realized by generating an image a single emission of
an unfocused transmit beam. Such an extremely high temporal resolution realizes
various functional imaging of biological tissues/organs, such as visualization of shear
wave propagating in tissues, blood flow imaging, etc. This article provides a review of
very high-frame-rate ultrasound and its application to functional medical imaging.
10. High-intensity focused ultrasound
S. Yoshizawa, S. Umemura, Tohoku Univ.
High-intensity focused ultrasound HIFU is a non-invasive treatment modality. A high
intensity ultrasound generated outside a body is focused to a target tissue. The tissue
in its focal region is thermally coagulated through ultrasound absorption. It has been
used for prostate, liver, and pancreatic cancer, and others.