Digital Radiography in Practice [2 ed.] 0398094128, 9780398094126, 9780398094133

Table of contents :
DIGITAL RADIOGRAPHY IN PRACTICE
REVIEWERS
Consulting Physicists
PREFACE
Ancillary Resources
ACKNOWLEDGMENTS
CONTENTS
DIGITAL RADIOGRAPHY IN PRACTICE
Chapter 1 NATURE OF THE DIGITAL RADIOGRAPH
Objectives
Development of Digital Radiography
Nature of the Digital Image
Digitizing the Analog Image
Bit Depth, Dynamic Range, and Grayscale
What is a Pixel?
Voxels, Dels, and Pixels
Chapter Review Questions
Chapter 2 CREATING THE PROJECTED IMAGE
Objectives
Overview of Variables
Technical Variables
Geometric Variables
Patient Status
Creating Subject Contrast
X-Ray Interactions
X-Ray Beam Energy
Tissue Thickness
Tissue Density
Tissue Atomic Number
Contrast Agents
Summary of Variables Creating Subject Contrast
Why mAs and SID Do Not Control Subject Contrast in the Latent Image
Role of Radiographic Technique in the Digital Age
Subject Contrast and Spatial Resolution
“Controlling Factors” for the Projected Image
Variables Affecting the Quality of the Final Displayed Radiographic Image
Chapter Review Questions
Chapter 3 QUALITIES OF THE DIGITAL RADIOGRAPH
Objectives
Qualities of the Final Displayed Digital Image
Brightness
Contrast and Grayscale
Measuring Contrast
Noise and SNR
Spatial Resolution (Sharpness)
Shape Distortion
Geometric Magnification
Display Magnification
Qualities of the Projected Image Captured at the Image Receptor
Modulation Transfer Function
Chapter Review Questions
Chapter 4 RADIOGRAPHIC TECHNIQUE FOR DIGITAL IMAGING
Objectives
Understanding X-Ray Beam Penetration
Sensitivity of Digital Units to Subject Contrast
Subject Contrast and Exposure Latitude
Use of Grids
Sufficient Input Grayscale
Effect of mAs and kVp on the Displayed Digital Image
Minimizing Patient Exposure with the 15 Percent Rule
Benefits of High kVp Radiography
Chapter Review Questions
Chapter 5 PREPROCESSING AND HISTOGRAM ANALYSIS
Objectives
The Generic Steps of Digital Image Processing
Preprocessing
Correcting for Del Dropout
Correcting for Mottle
Field Uniformity
Constructing the Histogram
Histogram Analysis
Types of Histogram Analysis
Errors in Histogram Analysis
Chapter Review Questions
Chapter 6 RESCALING (PROCESSING) AND PROCESSING DOMAINS
Objectives
Rescaling the Image
Q Values and the “Permanent” LUT
Physicists’ Nomenclature
Digital Processing Domains
Spatial Domain Operations
Intensity Domain Operations
Frequency Domain Operations
Chapter Review Questions
Chapter 7 DEFAULT POSTPROCESSING I: GRADATION PROCESSING
Objectives
Gradation Processing
Data Clipping
Dynamic Range Compression and Equalization
Chapter Review Questions
Chapter 8 DEFAULT POSTPROCESSING II: DETAIL PROCESSING
Objectives
Understanding the Frequency Domain
Frequency Detail Processing
Transition Between Image Domains
Spatial Detail Processing (Kernels)
Preparation for Display
Chapter Review Questions
Chapter 9 MANIPULATING THE DIGITAL IMAGE: OPERATOR ADJUSTMENTS
Objectives
Procedural Algorithms
Windowing
Postprocessing Features
Equalization
Tissue Impression
Smoothing
Edge Enhancement
Summary Table of Operator Adjustments
Background Suppression
Brightness Correction by Region of Interest
Other Postprocessing Features
Chapter Review Questions
Chapter 10 MONITORING AND CONTROLLING EXPOSURE
Objectives
Speed Class and Exposure Indicators
The Deviation Index: Acceptable Parameters for Exposure
Limitations of the DI
Chapter Review Questions
Chapter 11 DIGITAL IMAGE ACQUISITION
Objectives
Direct-Conversion DR Detectors
Indirect-Conversion DR Detectors
Computed Radiography (CR)
The CR Reader (Processor)
Background and Scatter Radiation
Characteristics of the Image Acquisition System
Spatial Resolution (Sharpness) of Digital Systems
Hardware Matrices
The “Soft” Matrix of a Light Image
The Pixel Size Formula
Efficiency of Image Receptors
Detective Quantum Efficiency
Fill Factor
Digital Sampling and Aliasing
Aliasing from Grids
Other Digital Artifacts
Chapter Review Questions
Chapter 12 DISPLAYING THE DIGITAL IMAGE
Objectives
The Liquid Crystal Display (LCD) Monitor
LCD Image Quality
Spatial Resolution (Sharpness)
Luminance and Contrast
Nature of Display Pixels
Chapter Review Questions
Chapter 13 ARCHIVING PATIENT IMAGES AND INFORMATION
Objectives
Picture Archiving and Communication Systems (PACS)
Image Compression
Image Storage and Access
Medical Imaging Informatics
New Developments
Chapter Review Questions
Chapter 14 DIGITAL FLUOROSCOPY
Objectives
Image Recording from an Image Intensifier Tube
Dynamic Flat-Panel Detectors
Reducing Patient Dose
Temporal Averaging
Chapter Review Questions
Chapter 15 QUALITY CONTROL FOR DIGITAL EQUIPMENT
Objectives
Monitoring of Digital X-Ray Units
Field Uniformity
Intrinisic (Dark) Noise
Erasure Thoroughness and “Ghosting”
Spatial Resolution
Monitoring of Electronic Image Display Systems
Maximum Luminance
Luminance Response
Luminance Ratio
Luminance Uniformity
Reflectance and Ambient Lighting
Noise
Resolution
Dead and Stuck Pixels
Other QC Tests
Chapter Review Questions
GLOSSARY OF DIGITAL RADIOGRAPHIC TERMS
REFERENCES
INDEX