The CT Handbook: Optimizing Protocols for Today's Feature-Rich Scanners

The CT Handbook: Optimizing Protocols for Today's Feature-Rich Scanners

Author:  Timothy P. Szczykutowicz
ISBN:  9780944838570
Published:  May 2020 | 580 pp | eBook

Price:   $ 165.00


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Table of Contents

Dedication v

Preface xvii

Acknowledgments xix

Chapter 1: Introduction to CT

1.1 How Does CT Work 1

1.2 Data Collection 5

1.2.1 Axial/Sequential Mode 10

1.2.2 Helical/Spiral Mode 10

1.2.3 Cine/Perfusion Mode 11

1.2.4 Shuttle Mode 11

1.2.5 CT Fluoroscopy 11

1.2.6 Gantry Tilting 12

1.2.7 Scan Angular Range 13

1.2.8 Detector Coverage 15

1.2.9 CBCT 16

1.3 Flavors of CT 17

1.3.1 Diagnostic Radiology 18

1.3.2 Interventional Radiology CT Fluoroscopy 20

1.3.3 Baggage Scanning CT 21

1.3.4 Interventional Radiology C-arm (CBCT) 21

1.3.5 Dedicated Head Scanner 22

1.3.6 Mobile CT 22

1.3.7 Dental CT 23

1.3.8 CT Simulation for Radiation Therapy 24

1.3.9 Image-Guided Radiation Therapy 25

1.3.10 TomoTherapy® and MVision® 26

1.3.11 Dedicated Breast CT 27

1.3.12 Synchrotron CT 28

1.3.13 Small Animal Imaging 29

1.3.14 Industrial CT 30

1.4 The Most Common Misconceptions in Medical CT Today 30

References 33

Chapter 2: Example CT Exam Workflows

2.1 Patient Preparation 35

2.1.1 Removable Artifact-Causing Objects 36

2.1.2 Pre-Scan Preparation and Questions 37

2.1.3 Inpatient Setting Prep and Transport 38

2.1.4 Outpatient Setting Prep and Transport 38

2.1.5 Emergency Department Setting Prep and Transport 39

2.2 Example MDCT Scan Workflow: Routine Non-Contrast Head 39

2.3 Scan Time Anatomical Landmark Guide 49

2.3.1 Example Anatomical Landmarks from CT Localizers 50

2.3.2 Example Scan Ranges 52

2.3.3 Bolus Tracking Locations 56

2.3.4 Basic Cross-Sectional CT Anatomy Tutorial 58

References 75

Chapter 3: Image Quality and System Performance

3.1 Image Noise 77

3.1.1 Factors that Influence Image Noise 81

3.1.2 Variability in ROI Measurements of CT Number 83

3.2 Image Contrast 85

3.3 CNR 87

3.4 Spatial Resolution 90

3.5 Temporal Resolution 94

3.6 Scatter 97

3.7 Slice Thickness 99

3.8 Other System Specifications Impacting Image Quality 101

3.8.1 DQE 101

3.8.2 Detector Dynamic Range and Bit Depth 101

3.8.3 Detector Element Size 102

3.8.4 Focal Spot Size 102

3.8.5 SID/SOD Magnification and Image Resolution 102

References 104

Chapter 4: Dose

4.1 Putting CT Ionizing Dose Risk in Perspective 111

4.2 Radiation Damage from CT and Guidance on Dose Thresholds 112

4.3 Overview of Patient Dose Surrogates 116

Understanding SSDE (Size-Specific Dose Estimate) 121

4.4 Diagnostic CT Dose 122

4.5 Shielding 134

4.5.1 Shielding in Diagnostic CT: Physical Shields 134

Guidance for PE Studies on Pregnant Patients 139

4.5.2 Shielding in Diagnostic CT: mA Modulation 140

4.5.3 Shielding in Diagnostic CT: Collimation 141

References 142

Chapter 5: Reconstruction Options

5.1 Slice Thickness and Interval 149

5.2 Reconstruction Kernels (Algorithms) 153

Vendor-Specific Options 155

5.3 Reconstruction Display Field of View/ Matrix Size 168

5.4 Display Window Width and Level 171

5.5 Nonlinear or Iterative Denoising Options 176

5.6 Beam Hardening Corrections 182

5.7 Clinical Recommendations: Master Protocol Concept for Reconstruction 185

References 188

Chapter 6: Acquisition Parameters and the Master Protocol Concept

6.1 Effective mAs 190

6.2 Pitch, Collimation, and Image Quality 194

6.3 Pitch, Collimation, and Dose 199

6.4 Why We Need Size-Based Protocols 203

6.5 Master Protocol Concept: Acquisition Parameters 206

References 224

Chapter 7: Automatic Exposure Control

7.1 Basic Principles of AEC 227

7.1.1 Tube Current Modulation 233

7.1.2 Beam Energy Modulation 235

7.2 Practical AEC Advice 237

7.3 MDCT Vendor Implementation Differences 241

7.3.1 GE 246

7.3.2 Canon (Toshiba) 248

7.3.3 Philips 252

7.3.4 Siemens 252

7.3.5 Rosetta Stone for CT AEC Systems? 253

References 255

Chapter 8: CT Contrast

8.1 Overview of CT Contrast and Injectors 257

8.2 Contrast Progression and Appearance in the Body 262

8.3 Contrast Injection Protocols and Protocol Parameters 263

8.4 Example Contrast-Enhanced Images 271

References 280

Chapter 9: Beam Energy, CT Number, and Dual-Energy CT

9.1 Beam Energy 282

Is It keV or kVp? 283

9.2 CT Number 286

9.3 Dual-Energy and Spectral Imaging 290

9.3.1 X-ray Attenuation Theory 290

9.3.2 Clinical Realization of Dual Energy 299

9.3.3 Types of Dual-Energy Images 302

9.3.4 Avoiding Confusion When Interpreting Basis Material Images 304

References 306

Chapter 10: Patient Positioning

10.1 Motivation for Patient Positioning 309

10.2 Position and Dose Modulation 315

10.3 Position and Spatial Resolution 318

10.4 Position and Temporal Resolution 320

10.5 Position and CT Number/Noise Uniformity 322

References 327

Chapter 11: Protocol Management

11.1 The Importance of Protocol Uniformity 329

11.1.1 How Scan Time May Affect Image Appearance 331

11.1.2 How Slice Thickness May Affect Image Appearance 332

11.1.3 How Slice/Reconstruction Interval May Affect Image Appearance 333

11.1.4 How Contrast Volume May Affect Image Appearance 333

11.1.5 How Contrast Strength May Affect Image Appearance 333

11.1.6 How Contrast-to-Scan Timing May Affect Image Appearance 334

11.1.7 How Contrast Injection Rate May Affect Image Appearance 334

11.1.8 How Reconstruction Kernel/Algorithm Sharpness May Affect Image Appearance 334

11.1.9 How Dose May Affect Image Appearance 335

11.1.10 How Beam Energy May Affect Image Appearance 335

11.1.11 How Scanner Platform May Affect Image Appearance 335

11.2 CT Protocol Optimization Team: Why We Need a Team 335

11.3 Components of a Protocol 342

11.4 Solutions for Protocol Management 348

11.5 Costs Associated with Protocol Management 352

References 353

Chapter 12: Protocol Review

12.1 Overview of Dose Tracking Software 355

12.1.1 Basic Functionality 355

12.1.2 IT Connections 357

12.1.3 Pitfalls of Dose Comparisons 358

12.2 How to Review Protocols Using Dose Information 360

12.3 Radiologist Image Review 365

12.4 Physicist and Technologist Protocol Review 369

References 372

Chapter 13: Clinical MDCT

13.1 Head/Neuro Imaging 375

13.2 Torso Imaging 384

13.3 Cardiac Gated Imaging 391

13.4 Musculoskeletal Imaging 396

13.5 Special Considerations for Pediatric Patients 399

References 401

Chapter 14: CBCT and Non-Diagnostic CT

14.1 CBCT 403

14.2 Industrial and Micro CT 410

14.3 CT Simulation (Radiation Therapy Treatment Planning) 416

References 421

Chapter 15: Informatics and CT

15.1 CT Dose Reporting 423

15.2 Networking 428

15.2.1 Master Protocol Concept in Networking 431

15.2.2 Digital Footprints in Radiology CT Workflows 431

15.3 Hanging Protocols 435

References 436

Chapter 16: Artifacts

16.1 Types of CT Artifacts 437

16.2 Workflow for Artifact Identification from the Reading Room 441

16.3 Workflow for Artifact Identification at the Scanner 443

16.3.1 Workflow for Being Sure You Have an Artifact that is Scanner-Based 443

16.3.2 Workflow for Figuring Out Which Scan Modes an Artifact Will Appear in or Which

Scanner Component/Process is Failing 444

16.4 Catalog of CT Artifact Examples 445

16.4.1 Isocentric Artifacts 445

16.4.2 Non-Isocentric Artifacts 447

References 508

Chapter 17: Buyer’s Guide of Optional Features in CT

17.1 MDCT Scanner Options 510

17.1.1 Software Ownership with Refurbished Scanners 511

17.1.2 Service Options 511

17.1.3 Apps Training 513

17.1.4 Slice Number 514

17.1.5 Option Bundling and Dependencies 516

17.1.6 Diagnostic CT-Specific Scanner Options 517

17.1.7 Radiation Therapy Scanner Options 521

17.1.8 PET/CT 523

17.1.9 Interventional CT Scanner Options 523

17.2 Scanner Options General to All Settings 524

17.2.1 Metal Artifact Reduction 524

17.2.2 RIS/PACS/EMR Workflow Options 525

17.2.3 3D Processing Workstations 525

17.3 Auxiliary Equipment Purchases 526

17.4 Indication-Specific MDCT Scanner Needs 528

17.5 Site Planning 528

References 531

Appendix A: Whitepaper—Using the Gammex Mercury 4.0 Phantom for Common Clinical Tasks in CT 533

Appendix B: “Homebrew” Dual Energy 559

Appendix C: Table of Figures Showing Common CT Artifacts 567