Bioimaging

Imaging by Light and Electromagnetics in Medicine and Biology

Shoogo Ueno

• Publisher: CRC Press
• Year: 2020
• ISBN:
  9780429536564
• Edition: 1
• Topic: Medicina
• Subtopic: Radiología, radioterapia y medicina nuclear

Choice Recommended Title, April 2021

Bioimaging: Imaging by Light and Electromagnetics in Medicine and Biology explores new horizons in biomedical imaging and sensing technologies, from the molecular level to the human brain. It explores the most up-to-date information on new medical imaging techniques, such as the detection and imaging of cancer and brain diseases.

This book also provides new tools for brain research and cognitive neurosciences based on new imaging techniques. Edited by Professor Shoogo Ueno, who has been leading the field of biomedical imaging for 40 years, it is an ideal reference book for graduate and undergraduate students and researchers in medicine and medical physics who are looking for an authoritative treatise on this expanding discipline of imaging and sensing in medicine and biology.

Features:

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• Provides step-by-step explanations of biochemical and physical principles in biomedical imaging

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• Covers state-of-the art equipment and cutting-edge methodologies used in biomedical imaging

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• Serves a broad spectrum of readers due to the interdisciplinary topic and approach

Shoogo Ueno, Ph.D, is a professor emeritus of the University of Tokyo, Tokyo, Japan. His research interests include biomedical imaging and bioelectromagnetics, particularly in brain mapping and neuroimaging, transcranial magnetic stimulation (TMS), and magnetic resonance imaging (MRI). He was the President of the Bioelectromagnetics Society, BEMS (2003-2004) and the Chairman of the Commission K on Electromagnetics in Biology and Medicine of the International Union of Radio Science, URSI (2000-2003). He was named the IEEE Magnetics Society Distinguished Lecturer during 2010 and received the d'Arsonval Medal from the Bioelectromagnetics Society in 2010.

1 Introduction

Shoogo Ueno

Contents

1.1 Introduction

1.2 Light and Electromagnetic Fields in Medicine and Biology

1.3 Advances in Biomedical Imaging and Stimulation

1.3.1 Computed Tomography

1.3.2 Magnetic Resonance Imaging

1.3.3 Magnetoencephalography

1.3.4 Transcranial Magnetic Stimulation

1.3.5 Magnetic Particle Imaging

1.3.6 Near-Infrared Spectroscopic Imaging

1.4 Advances in Molecular and Cellular Imaging

1.4.1 Green Fluorescent Protein

1.4.2 Optical Fluorescence and Cancer Therapy

1.4.3 Optogenetics and Studies of Neuronal Circuit Dynamics in the Brain

1.4.4 Raman Scattering and Coherent Raman Scattering Microscopy

1.4.5 Molecular Imaging Based on Magnetic Resonance Imaging

1.4.6 Magnetic Orientation of Living Systems and Biogenic Micromirrors

1.5 Summary

References

1.1 Introduction

Imaging techniques have been rapidly developing and expanding in a variety of fields in medicine and biology. This chapter gives an overview of a range of imaging techniques from molecular and cellular levels to the human brain, focusing on the imaging techniques using light and electromagnetics. We start with a brief history of the discovery of electromagnetic fields and review the imaging techniques using light, electromagnetic fields, or electromagnetic techniques in medicine and biology.

The overview includes green fluorescent protein (GFP) and its applications to bioimaging, molecular imaging of viable cancer cells, optogenetics and studies of neuronal circuit dynamics in the brain, molecular vibrational imaging by coherent Raman scattering, principles and applications of magnetic resonance imaging (MRI) such as functional MRI (fMRI), diffusion MRI of the human nervous system, and chemical exchange saturation transfer (CEST) and amide proton transfer (APT) imaging. Other important and new technologies include magnetic particle imaging (MPI) using magnetic nanoparticles and magnetic sensors, usage of the reporter gene for molecular MRI, magnetic control of the biogenic micromirror, and brain imaging by near-infrared spectroscopy (NIRS) and static magnetic fields. Transcranial magnetic stimulation (TMS) is also reviewed to discuss the functional mapping and imaging of the human brain associated with fMRI, magnetoencephalography (MEG), electroencephalography (EEG), and systems neuroscience based on optogenetics.

Historically, computed tomography (CT) and positron emission tomography (PET), as well as ultrasonic imaging systems, have been introduced in the medical world as biomedical imaging tools, and these imaging tools have changed the medical world dramatically in modern medicine. In this chapter, we do not describe ultrasonic imaging, but we focus our discussion on recent advances in electromagnetic-based and light-based biomedical imaging and stimulation techniques, which has brought a significant impact in medicine and biology in recent decades.

1.2 Light and Electromagnetic Fields in Medicine and Biology

Electromagnetic fields or electromagnetic waves were theoretically predicted by James Clerk Maxwell (1831–1879) in the UK in 1864, and the existence of electromagnetic waves was experimentally verified by Heinrich Rudolf Hertz (1857–1894) in Germany in 1888. Guglielmo Marches Marconi (1874–1937) in Italy applied electromagnetic waves for telecommunication over the English Channel between France and England in 1899. As Maxwell pointed out, light is one of the electromagnetic waves in a specific frequency band.

Maxwell derived the so-called four fundamental electromagnetic equations, and he obtained an equation to show the propagation velocity v of electromagnetic waves in free space or in vacuum space as follows.

v = 1 ( ε 0 μ 0 ) 1 / 2

(1.1)

where ε₀ is the dielectric constant or permittivity and μ₀ is the magnetic permeability in vacuum space.

Applying ε₀ = 8.8542 × 10⁻¹² F/m and μ₀ = 4π × 10⁻⁷ H/m,

we obtain

v = 2.998 × 10 8 m/s

(1.2)

If we use ε₀ = 1/(36π) × 10⁻⁹ F/m and μ₀ = 4π × 10⁻⁷ H/m,

we obtain

v = 3.00 × 10 8 m/s .

(1.3)

These values coincide with the light velocity c = 2.99792458 × 10⁸ m/s.

Here, the relationship between frequency and wavelength is described for further discussion.

Since the electromagnetic waves propagate at the light velocity in vacuum space, multiplication of wavelength λ and frequency f of electromagnetic waves are equal to the light velocity c as shown by

c = λ × f

(1.4)

Therefore, the wavelength λ is given by

λ = c / f

(1.5)

• The wavelength of 300 Hz electromagnetic fields is 1000 km.
• The wavelength of 300 kHz (300 × 10³ Hz) electromagnetic fields is 1 km
• The wavelength of 300 MHz (300 × 10⁶ Hz) electromagnetic fields is 1 m
• The wavelength of 300 GHz (300 × 10⁹ Hz) electromagnetic fields is 1 mm
• The wavelength of 300 THz (300 × 10¹² Hz) electromagnetic fields is 1 μm
• The wavelength of 300 PHz (300 × 10¹⁵ Hz) electromagnetic fields is 1 nm

Figure 1.1 shows the classification of electromagnetic fields used in telecommunication and medical applications. Medical devices and biomedical imaging systems used at different frequency bands are marked along the frequency axis.

FIGURE 1.1 Classification of electromagnetic fields. Medical devices and biomedical imaging systems used at different frequency bands are marked along the frequency axis. The electromagnetic fields or electromagnetic waves are legally handled up to 3 THz or 3000 GHz. Electromagnetic fields lower than a frequency at the vacuum ultraviolet ray of its wavelength around 200 nm are called non-ionizing radiation. The electromagnetic fields higher than a frequency at the vacuum ultraviolet ray are called ionizing radiation. The electromagnetic fields are classified from DC to higher frequencies by ELF (extremely low frequency), LF (low frequency), IF (intermediate frequency), HF (high frequency), and EHF (extremely high frequency) electromagnetic fields. Visible light is in the frequency range from red (780 nm) to violet (380 nm). X-ray and γ-ray are in the ionizing radiation range. In non-ionizing radiation or non-ionizing electromagnetic fields, SQUID (superconducting quantum interference device) and MEG (magnetoencephalography) are used at ELF; MPI (magnetic particle imaging) is used at LF and IF; TMS (transcranial magnetic stimulation) uses pulsed magnetic fields at IF; MRI (magnetic resonance imaging) uses its resonant frequencies at HF; and NIRS (near-infrared spectroscopy) uses a near-infrared (NIR) ray. Raman scattering and optical fluorescence are used at the visible light band. In contrast, CT (computed tomography) uses X-rays, and PET (positron emission tomography) and SPECT (single-photon emission computed tomography) use γ-rays.

The usage of electromagnetic fields is legally law-handled up to 3 THz or 3000 GHz. The electromagnetic fields below a point of the vacuum ultraviolet ray at around 200 nm in wavelength are called non-ionizing radiation or non-ionizing electromagnetic fields. In contrast, the electromagnetic fields higher than a point at the vacuum ultraviolet ray at around 200 nm in wavelength are called ionizing radiation or ionizing electromagnetic fields. Exposure to ionizing radiation causes ionization of molecules in cells and living tissues, which may result in undesirable effects on living systems when the intensity of irradiation exceeds a threshold level. Radiation therapy for cancer diseases use ionizing radiation.

In non-ionizing electromagnetic fields, frequency bands are classified as follows:

• Extremely low frequency (ELF) electromagnetic fields (DC ~ 3 kHz)
• Low frequency (LF) electromagnetic fields (3 kHz ~ 10 kHz)
• Intermediate frequency (IF) electromagnetic fields (10 kHz ~ 10 MHz)
• High frequency (HF) electromagnetic fields (10 MHz ~ 6 GHz)
• Extremely high frequency (EHF) electromagnetic fields (6 GHz ~ 3 THz)

In light bands, the near-infrared (NIR) band, the visible light band, and ultraviolet bands are classified in promotionally increasing frequency or in decreasing wavelength. In visible light band, from the wavelength of 780 nm (red) to the wavelength of 380 nm (violet), seven-color spectra exist like a rainbow; red, orange, yellow, green, blue, indigo, and violet.

In ionizing electromagnetic fields, the ionizing radiation is classified by X-ray, γ-ray, and the areas beyond X-ray and γ-ray where the waves act as heavy particles.

As shown in Figure 1.1, the MEG and superconducting quantum interference device (SQUID) systems are used at ELF; MPI is used at LF and IF; TMS for the stimulation of the human brain uses pulsed magnetic fields at IF; MRI uses its resonant frequencies at HF; and NIRS uses NIR rays. Raman scattering and optical fluorescence for molecular and cellular imaging are used at the visible light band. In contrast, CT uses X-rays, and PET and single-photon emission computed tomography (SPECT) use γ-rays.

MEG, MPI, TMS, and MRI are used in non-ionizing...

Table of contents

• Cover
• Half-Title
• Title
• Copyright
• Contents
• Preface
• Acknowledgments
• Editor
• List of Contributors
• Chapter 1 Introduction
• Chapter 2 Molecular Imaging of Viable Cancer Cells
• Chapter 3 Molecular Vibrational Imaging by Coherent Raman Scattering
• Chapter 4 Magnetic Resonance Imaging: Principles and Applications
• Chapter 5 Chemical Exchange Saturation Transfer and Amide Proton Transfer Imaging
• Chapter 6 Diffusion Magnetic Resonance Imaging in the Central Nervous System
• Chapter 7 Magnetic Particle Imaging
• Chapter 8 Sensing of Magnetic Nanoparticles for Sentinel Lymph Nodes Biopsy
• Chapter 9 Optimizing Reporter Gene Expression for Molecular Magnetic Resonance Imaging: Lessons from the Magnetosome
• Chapter 10 Magnetic Control of Biogenic Micro-Mirror
• Chapter 11 Non-Invasive Techniques in Brain Activity Measurement Using Light or Static Magnetic Fields Passing Through the Brain
• Index