Table Of ContentModern Diagnostic
X-Ray Sources
Modern Diagnostic
X-Ray Sources
Technology, Manufacturing, Reliability
Second Edition
Rolf Behling
Second edition published 2021
by CRC Press
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and by CRC Press
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© 2021 Rolf Behling
First edition published by CRC Press 2016
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Library of Congress Cataloging‑in‑Publication Data
Names: Behling, Rolf, author.
Title: Modern diagnostic X-ray sources : technology, manufacturing,
reliability / Rolf Behling.
Description: Second edition. | Boca Raton : CRC Press, 2021. |
Includes bibliographical references and index.
Identifiers: LCCN 2020056865 (print) | LCCN 2020056866 (ebook) |
ISBN 9780367546922 (hardback) | ISBN 9781003095408 (ebook)
Subjects: LCSH: Radiography, Medical.
Classification: LCC RC78 .B392 2021 (print) | LCC RC78 (ebook) |
DDC 616.07/572—dc23
LC record available at https://lccn.loc.gov/2020056865
LC ebook record available at https://lccn.loc.gov/2020056866
ISBN: 9780367546922 (hbk)
ISBN: 9780367558451 (pbk)
ISBN: 9781003095408 (ebk)
Typeset in Sabon
by codeMantra
Contents
Preface xi
Preface to the Second Edition xiii
Acknowledgments xv
Author xvii
Symbols xix
1 Historical introduction and survey 1
1.1 The discovery—November 1895 1
1.2 The prehistory of X-rays 7
1.2.1 Cathode rays: first generation of X-rays—1857 7
1.2.2 Spooky rays 9
1.3 Early clinical use and industrialization from 1896 9
1.3.1 First sustained clinical installation 9
1.4 Beginning industrial production 11
1.4.1 Major pitfalls 12
1.4.2 Exploding span of ideas 14
1.4.3 Generator development 14
1.4.4 Clinical exploration 16
1.4.4.1 Three-dimensional imaging 16
1.4.4.2 Beam quality—low-energy X-rays 17
1.5 Victims and safety 19
1.6 High vacuum vs. semi-vacuum 20
1.7 Goetze’s line focus 24
1.8 Rotating targets 24
1.9 Stationary anode tubes 28
1.10 Metal center section and metal-ceramic tubes—1980 29
1.11 Philips liquid metal bearings—1989 32
1.12 Varian’s finned anode and electron trapping—1998 33
1.13 Electron beam computed tomography—mid-1980 34
1.14 Rotating frame tubes—2003 35
1.15 GE’s largest rotating anode—2005 36
1.16 CT requirements on the move 37
1.17 The highest power density CT tube platform—2007 37
1.18 Production 39
v
vi Contents
1.19 Epilog 40
1.20 Problems 41
References 41
2 Physics of generation of bremsstrahlung 45
2.1 Acceleration of electrons 46
2.2 Efficiency of energy conversion 47
2.3 The X-ray continuum spectrum 49
2.4 Characteristic radiation 55
2.5 Characteristic radiation and discontinuous attenuation 58
2.6 Theory of the angular distribution of the continuum radiation 62
2.7 Angular distribution of characteristic radiation 67
2.8 Polarization 67
2.9 Theory of electron scatter in the anode 68
2.10 Electron backscatter 71
2.11 The Thomson–Whiddington law in more detail 75
2.12 Measured and simulated isotropic X-ray intensity distribution 76
2.13 The heel effect 78
2.14 Problems 80
References 81
3 The interaction of X-ray with matter 85
3.1 Basics of the attenuation of X-rays 86
3.2 X-ray refraction and X-ray lenses 91
3.3 Thomson scattering 95
3.4 Rayleigh scattering 95
3.5 Compton scattering 97
3.6 Photoelectric absorption 100
3.7 Problems 104
References 105
4 More background on medical imaging 107
4.1 Non-X-ray methods 107
4.2 X-ray imaging 109
4.2.1 Attenuation imaging 109
4.2.2 Linear systems theory 113
4.2.3 Modulation transfer function 117
4.2.4 Stating the MTF 119
4.3 Spectral imaging 124
4.4 Phase-contrast imaging 126
4.5 Fluorescence imaging 128
4.6 Polarized X-rays 128
4.7 Problems 128
References 129
Contents vii
5 Imaging modalities and challenges 131
5.1 Computed tomography 132
5.1.1 History of CT 132
5.1.1.1 The beginning 132
5.1.1.2 Modern systems 134
5.1.2 Theoretical basis of CT 135
5.1.2.1 Image reconstruction 135
5.1.3 Multidetector CT 142
5.1.4 Cone-beam CT 143
5.1.5 Spiral CT 144
5.1.6 Spectral CT 146
5.1.6.1 Physical background 146
5.1.6.2 Spectral CT concepts in comparison 150
5.1.6.3 Spectral material decomposition 151
5.1.6.4 Source-based spectral CT 154
5.1.6.5 Detection-based spectral CT 156
5.1.7 Components of CT systems 157
5.1.7.1 The rotating gantry 157
5.1.7.2 Operating parameters for CT 159
5.1.7.3 Changing requirements for CT sources 160
5.1.7.4 X-ray source features for CT 164
5.1.7.5 CT collimators and beam shapers 170
5.1.7.6 Generators 171
5.1.7.7 X-ray detectors 172
5.1.8 Clinical outcome 179
5.1.9 Alternative concepts 182
5.1.9.1 Fourth-generation CT 182
5.1.9.2 Electron beam CT 182
5.1.9.3 Switching source stationary CT 182
5.1.9.4 Tomosynthesis versus computed tomography 183
5.1.9.5 Future development of CT 185
5.2 Cardiac and vascular imaging 185
5.3 Radiographic systems 191
5.4 Radiography/fluoroscopy (R/F) systems 192
5.5 Mammography systems 193
5.6 Surgical C-arm systems with monoblocks 194
5.7 Problems 195
References 197
6 Diagnostic X-ray sources from the inside 203
6.1 Working principle and types of medical X-ray tubes 203
6.1.1 Stationary anode tubes 206
6.1.2 Miniature tubes 209
6.1.3 Rotating anode tubes 210
6.1.4 Rotating frame tubes 211
viii Contents
6.2 Tube components in detail 213
6.2.1 The cathode 213
6.2.1.1 Energy required for electron
production—work function 213
6.2.1.2 Mechanisms of electron emission 215
6.2.1.3 Robustness of the tungsten emitter 220
6.2.1.4 Cathode characteristics—the emission chart 221
6.2.1.5 Filament heating 223
6.2.1.6 Electron beam focusing and metric for the focal spot size 226
6.2.1.7 Off-focal radiation 231
6.2.1.8 Special cathode features 232
6.2.1.9 Grid switching for fluoroscopy application 236
6.2.1.10 Advanced electron optics in medical X-ray tubes 238
6.2.1.11 Alternatives to tungsten emitters 241
6.2.1.12 Charge balance inside the X-ray tube 246
6.2.2 The anode 247
6.2.2.1 Stationary anode targets 248
6.2.2.2 Rotating anode targets 251
6.2.2.3 Thermal balance 251
6.2.2.4 Cooling channels 262
6.2.2.5 Temperatures in CT application 267
6.2.2.6 Temperatures in interventional and
general radiography application 269
6.2.2.7 Metric of anode heat storage capacity
abandoned—IEC standard 270
6.2.2.8 Stating thermal X-ray tube performance 270
6.2.3 Rotor systems, drives, and vacuum bearings 275
6.2.3.1 Rotor drive 275
6.2.3.2 Rotor dynamics, moment of inertia, and start-up time 277
6.2.3.3 Vibration and noise 278
6.2.3.4 Gyroscopic momentum 281
6.2.3.5 Ball bearing systems 281
6.2.3.6 Spiral groove or liquid metal bearings 282
6.2.3.7 Magnetic bearings 286
6.3 The tube frame 286
6.4 Maintaining vacuum 289
6.5 Vacuum discharges and high-voltage stability 294
6.6 Problems 302
References 307
7 Housings, system interfacing, and auxiliary equipment 311
7.1 X-ray source assembly 311
7.2 Radiation shield 312
7.3 Beam quality 315
7.4 Beam limitation 316
Contents ix
7.5 Protection against implosion and explosion 317
7.6 Cooling 318
7.6.1 Air convection and limits 319
7.6.2 Enforced cooling 320
7.7 Problems 322
References 322
8 The source of power 325
8.1 Basic functionality of the X-ray generator 325
8.2 High voltage chain 327
8.3 Sensing tube voltage and current 331
8.4 Energy quantization 332
8.5 Voltage ripple 333
8.6 Dual-energy (dual-X-ray color) imaging 334
8.7 Filament heating and emission control 334
8.8 Grid and electrostatic deflection supply 335
8.9 Multiple tubes 335
8.10 Other auxiliary supplies 336
8.11 Tube temperature supervision 337
8.12 Dose control 337
8.13 Matching generator and tube 338
8.14 Monoblocks 338
8.15 Problems 340
References 341
9 Manufacturing, service, and tube replacement 343
9.1 Introduction 343
9.2 Manufacturing of X-ray tubes 344
9.2.1 Cleanliness 344
9.2.2 Basic logistics 345
9.2.3 Production lines 345
9.2.4 Final testing 347
9.3 Process-oriented versus assembly-oriented
production 347
9.4 Production yield 347
9.5 Installation and service 349
9.5.1 Reconditioning 349
9.5.2 Warm-up 349
9.6 Tube replacement and recycling 350
9.6.1 Average tube lifetime 350
9.6.2 Warranty and costs of ownership 353
9.7 Recycling 354
9.8 Problems 355
Reference 355
