Medical Imaging Technology

Biomedical imaging is a relatively young discipline that started with Conrad Wilhelm Roentgen’s discovery of the x-ray in 1895. X-ray imaging was rapidly adopted in hospitals around the world. However, it was the advent of computerized data and image processing that made revolutionary new imaging modalities possible. Today, cross-sections and three-dimensional reconstructions of the organs inside the human body is possible with unprecedented speed, detail and quality. This book provides an introduction into the principles of image formation of key medical imaging modalities: X-ray projection imaging, x-ray computed tomography, magnetic resonance imaging, ultrasound imaging, and radionuclide imaging. Recent developments in optical imaging are also covered. For each imaging modality, the introduction into the physical principles and sources of contrast is provided, followed by the methods of image formation, engineering aspects of the imaging devices, and a discussion of strengths and limitations of the modality. With this book, the reader gains a broad foundation of understanding and knowledge how today’s medical imaging devices operate. In addition, the chapters in this book can serve as an entry point for the in-depth study of individual modalities by providing the essential basics of each modality in a comprehensive and easy-to-understand manner. As such, this book is equally attractive as a textbook for undergraduate or graduate biomedical imaging classes and as a reference and self-study guide for more specialized in-depth studies. Table of Contents Cover Medical Imaging Technology ISBN 9781461470724 ISBN 9781461470731 Preface Contents Chapter 1 Introduction 1.1 A Brief Historical Overview 1.2 Image Resolution and Contrast 1.3 Systems and Signals: A Short Introduction 1.4 The Fourier Transform Chapter 2 X-Ray Projection Imaging 2.1 X-Ray Generation 2.1.1 The X-Ray Tube 2.1.2 A Focus on Geometry 2.2 X-Ray Attenuation 2.2.1 Photon-Matter Interaction 2.2.2 Macroscopic Attenuation and Lambert-Beer's Law 2.2.3 Lambert-Beer's Law in Inhomogeneous Materials 2.2.4 Dual-Energy X-Ray Absorptiometry 2.3 X-Ray Detectors 2.3.1 Film-Based Imaging 2.3.2 Fluoroscopes 2.3.3 Semiconductor Detectors 2.3.4 Photomultiplier Tubes 2.4 Factors that Determine X-Ray Image Quality Chapter 3 Computed Tomography 3.1 CT Image Formation Principles 3.1.1 The Radon Transform and the Fourier Slice Theorem 3.1.2 Practical Image Reconstruction 3.2 Engineering Aspects of CT Scanners 3.3 Quantitative CT 3.4 Image Quality and Artifacts Chapter 4 Nuclear Imaging 4.1 Radiopharmaceuticals 4.2 Production of Short-Lived Radioactive Tracers 4.3 Detector Systems and the Anger Camera 4.4 Single Photon Emission Computed Tomography 4.5 Positron Emission Tomography 4.6 Multi-Modality Imaging Chapter 5 Magnetic Resonance Imaging 5.1 Proton Spins in an External Magnetic Field 5.2 The Spin-Echo Experiment 5.3 The Spin-Echo Pulse Sequence 5.3.1 Measurement of T2 5.3.2 Measurement of T1 Through Incomplete Recovery 5.3.3 Measurement of Proton Density 5.3.4 The Significanc of TE and TR 5.4 From NMR to MRI: The Gradient Fields 5.4.1 The Slice Encode Gradient 5.4.2 Fourier-Encoding with the Gradient 5.4.3 The Frequency Encode Gradient 5.4.4 The Phase Encode Gradient 5.5 Putting Everything Together: Spatially-Resolved Spin-Echo Acquisition 5.6 Other Imaging Sequences 5.6.1 Gradient-Recalled Echo Sequences 5.6.2 Inversion Recovery Sequence 5.6.3 Echo Planar Imaging 5.7 Technical Realization 5.7.1 B0 Magnet 5.7.2 Gradient Subsystem 5.7.3 RF Subsystem Chapter 6 Ultrasound Imaging 6.1 Sound Propagation in Biological Tissue 6.2 Ultrasound Image Formation 6.2.1 Ultrasound Generation and Echo Detection 6.2.2 A-Mode Scans 6.2.3 B-Mode Scans 6.2.4 M-Mode Scans 6.2.5 Volumetric Scans and 3D Ultrasound 6.3 Doppler Ultrasound Chapter 7 Trends in Medical Imaging Technology 7.1 Progress in Established Imaging Modalities 7.1.1 X-ray and CT 7.1.2 Magnetic Resonance Imaging 7.1.3 Ultrasound Imaging 7.1.4 PET and Multi-Modality Imaging 7.1.5 Molecular Imaging 7.2 Optical Tomography 7.3 Advanced Image Processing