| 1 Introduction | p. 1 |
| 1.1 Image Reconstruction from Projections | p. 1 |
| 1.2 Probability and Random Variables | p. 18 |
| 2 An Overview of the Process of CT | p. 27 |
| 2.1 What Are We Trying to Do? | p. 27 |
| 2.2 Traditional Tomography | p. 27 |
| 2.3 Data Collection for CT | p. 30 |
| 2.4 Voxels, Pixels, and CT Numbers | p. 31 |
| 2.5 The Problem of Polychromaticity | p. 32 |
| 2.6 Reconstruction Algorithms | p. 34 |
| 3 Physical Problems Associated with Data Collection in CT | p. 37 |
| 3.1 Photon Statistics | p. 37 |
| 3.2 Beam Hardening | p. 42 |
| 3.3 Other Sources of Error | p. 44 |
| 3.4 Scanning Modes | p. 47 |
| 4 Computer Simulation of Data Collection in CT | p. 53 |
| 4.1 Pictures and Digitization | p. 53 |
| 4.2 Creation of a Phantom | p. 54 |
| 4.3 A Piecewise-Homogeneous Head Phantom | p. 56 |
| 4.4 Head Phantom with a Large Tumor and Local Inhomogeneities | p. 59 |
| 4.5 Creation of the Ray Sums | p. 60 |
| 4.6 Fast Calculation of a Ray Sum for a Digitized Picture | p. 63 |
| 5 Data Collection and Reconstruction of the Head Phantom | p. 67 |
| 5.1 Methods of Picture Comparison | p. 67 |
| 5.2 Task-Oriented Comparison of Algorithm Performance | p. 69 |
| 5.3 An Illustration Using Selective Smoothing | p. 73 |
| 5.4 Reconstruction from Perfect Data | p. 78 |
| 5.5 Effects of Photons Statistics | p. 83 |
| 5.6 Effect of Beam Hardening | p. 86 |
| 5.7 The Effects of Detector Width and Scatter | p. 91 |
| 5.8 Simulation of Different Scanning Modes | p. 95 |
| 6 Basic Concepts of Reconstruction Algorithms | p. 101 |
| 6.1 Problem Statement | p. 101 |
| 6.2 Transform Methods | p. 106 |
| 6.3 Series Expansion Methods | p. 108 |
| 6.4 Optimization Criteria | p. 111 |
| 6.5 Blob Basis Functions | p. 119 |
| 6.6 Computational Efficiency | p. 122 |
| 7 Backprojection | p. 125 |
| 7.1 Continuous Backprojection | p. 125 |
| 7.2 Implementation of the Backprojection Operator | p. 127 |
| 7.3 Discrete Backprojection | p. 131 |
| 8 Filtered Backprojection for Parallel Beams | p. 135 |
| 8.1 Convolutions, Hilbert Transforms, Regularization | p. 135 |
| 8.2 Derivation of the FBP Method | p. 139 |
| 8.3 Implementation of the FBP Method | p. 140 |
| 8.4 Fourier Transforms | p. 143 |
| 5.5 Sampling and Interpolation | p. 146 |
| 8.6 The Choice of Convolving and Interpolating Functions | p. 147 |
| 8.7 Why So Popular? | p. 157 |
| 9 Other Transform Methods for Parallel Beams | p. 159 |
| 9.1 Two-Dimensional Fourier Transforms | p. 159 |
| 9.2 The Fourier Method of Reconstruction | p. 161 |
| 9.3 Linograms | p. 166 |
| 9.4 Rho-Filtered Layergram | p. I73 |
| 10 Filtered Backprojection for Divergent Beams | p. 177 |
| 10.1 The Divergent Beam FBP Algorithm | p. 177 |
| 10.2 Choice of the Window Function | p. 181 |
| 10.3 Point Response Function | p. 182 |
| 10.4 Noise Reconstruction | p. 186 |
| 10.5 Comparison of Algorithms Based on Reconstructions | p. 188 |
| 11 Algebraic Reconstruction Techniques | p. 193 |
| 11.1 What is Art? | p. 193 |
| 11.2 Relaxation Methods for Solving Systems of Inequalities and Equalities | p. 196 |
| 11.3 Additive Art | p. 201 |
| 11.4 Tricks | p. 205 |
| 11.5 Efficacy of Art | p. 210 |
| 12 Quadratic Optimization Methods | p. 217 |
| 12.1 Mathematical Background to Quadratic Optimization | p. 217 |
| 12.2 Richardson's Method for Solving Systems of Equations | p. 221 |
| 12.3 Smoothing Matrices | p. 224 |
| 12.4 Implementation of Richardson's Methods for Image Reconstruction | p. 226 |
| 12.5 A Demonstration of Quadratic Optimization | p. 227 |
| 13 Truly Three-Dimensional Reconstruction | p. 235 |
| 13.1 Three-Dimensional Series Expansion | p. 236 |
| 13.2 Dynamically Changing 3D Phantoms and Their Projections | p. 237 |
| 13.3 Three-Dimensional Reconstructions of the Dynamic Phantom | p. 240 |
| 14 Three-Dimensional Display of Organs | p. 243 |
| 14.1 The Basic Approach | p. 243 |
| 14.2 Boundary Detection | p. 246 |
| 14.3 Hidden Surface Removal | p. 251 |
| 14.4 Shading | p. 253 |
| 15 Mathematical Background | p. 259 |
| 15.1 The Dimensionality of the Linear Attenuation Coefficient | p. 259 |
| 15.2 The Line Integral of the Relative Linear Attenuation | p. 260 |
| 15.3 The Radon Inversion Formula | p. 261 |
| 15.4 A Picture is Not Uniquely Determined by a Finite Number of Its Views | p. 265 |
| 15.5 Analysis of the Photon Statistics | p. 267 |
| 15.6 The Integral Expression for Polychromatic Ray Sums | p. 269 |
| 15.7 Proof of the Regularization Theorem | p. 270 |
| 15.8 Convergence of the Relaxation Method for Inequalities | p. 273 |
| References | p. 277 |
| Index | p. 293 |