Photoacoustic Imaging and Spectroscopy

Lihong Wang, Lihong V. Wang

• Publisher: CRC Press
• Year: 2017
• ISBN:
  9781351834988
• Edition: 1
• Topic: Physical Sciences
• Subtopic: Optics & Light

Photoacoustics promises to revolutionize medical imaging and may well make as dramatic a contribution to modern medicine as the discovery of the x-ray itself once did. Combining electromagnetic and ultrasonic waves synergistically, photoacoustics can provide deep speckle-free imaging with high electromagnetic contrast at high ultrasonic resolution and without any health risk. While photoacoustic imaging is probably the fastest growing biomedical imaging technology, this book is the first comprehensive volume in this emerging field covering both the physics and the remarkable noninvasive applications that are changing diagnostic medicine.

Bringing together the leading pioneers in this field to write about their own work, Photoacoustic Imaging and Spectroscopy is the first to provide a full account of the latest research and developing applications in the area of biomedical photoacoustics.

Photoacoustics can provide functional sensing of physiological parameters such as the oxygen saturation of hemoglobin. It can also provide high-contrast functional imaging of angiogenesis and hypermetabolism in tumors in vivo. Discussing these remarkable noninvasive applications and so much more, this reference is essential reading for all researchers in medical imaging and those clinicians working at the cutting-edge of modern biotechnology to develop diagnostic techniques that can save many lives and just as importantly do no harm.

Part I

Fundamentals of Photoacoustics

1 Photoacoustic Monopole Radiation: Waves from Objects with Symmetry in One, Two, and Three Dimensions

Gerald J. Diebold

Brown University

CONTENTS

1.1 Introduction

1.2 Coupled Equations for Temperature and Pressure

1.3 Integral Solutions for Short Optical Pulses

1.3.1 The Layer

1.3.2 The Cylinder

1.3.3 The Sphere

1.4 Frequency Domain Solution to the Wave Equation

1.4.1 The Layer

1.4.2 The Cylinder

1.4.3 The Sphere

1.4.4 Eigenfunctions for Symmetric Motion

1.5 Photoacoustic Waves from Mappings

1.5.1 Short Pulse Excitation

1.5.1.1 One Dimension

1.5.1.2 Three Dimensions

1.5.1.3 Two Dimensions

1.5.2 Long Pulse Excitation

1.5.2.1 One Dimension

1.5.2.2 Two Dimensions

1.5.2.3 Three Dimensions

1.6 Experimental Procedure

1.7 Discussion

Acknowledgment

References

1.1 Introduction

The most common and successful laboratory applications of the photoacoustic effect have been as analytical methods for trace gas analysis and spectroscopic investigation of solid surfaces. The subject of this chapter is to describe the temporal and spatial characteristics of photoacoustic waves that gives the effect a different analytical capability, namely, determination of the geometrical and acoustic properties of bodies through measurement of the temporal and spatial characteristics of the acoustic radiation excited by short optical pulses.

There are a number of excellent reviews on the subject of photoacoustic waveforms generated by absorption of laser radiation that include the monographs of Gusev and Karabutov [1]; Bunkin, Kolomensky, and Mikhalevich [2]; and Lyamshev [3]; as well as the review articles that cover sound generation by light absorption [4–9] in general. In addition to the author’s work, which is concerned specifically with optically thin objects surrounded by transparent fluids, a number of excellent papers have been published that describe the physics of photoacoustic wave generation [10–24]. This review describes determination of the acoustic waveforms generated by optical irradiation of fluid bodies with simple geometries, in particular, the infinite layer, the infinite cylinder, and the sphere, with the aim of determining the information content of the photoacoustic wave that is emitted as a result of thermal expansion. The conclusion of the research presented here is that the temporal features of photoacoustic waves emitted from optically thin bodies irrad...