Radiography in the Digital Age: Physics Exposure Radiation Biology Third Edition

Book Preface

New to This Edition
This 3rd edition was peer-reviewed by four colleagues who brought many valuable corrections and improvements to the text. The entire textbook has been converted to metric units, and to Systeme International (SI) units for radiation biology and protection. This was done to make it more usable for an international community of educators, and to align with the American Registry of Radiologic Technologists’ adoption of SI units in 2016.
Medical imaging informatics was added to PACS in Chapter 36. Applying Radi-ographic Technique to Digital Imaging, Chapter 33, was substantially strengthened, including revised and updated material on the use of grids and new virtual grid software, all with an eye to reducing patient dose. The ability of digital processing not only to generally compensate for scatter radiation, but to correct specific fog patterns in the image is more fully explained.
Because we deal with several different kinds of “hard” and “soft” matrices, (the DR detector matrix, the light matrix of a CR reader, the “hardware pixel” matrix of a display monitor, and the “soft” matrix of the displayed light image), the relation-ship between field-of-view (FOV), matrix size, and spatial resolution is now com-pletely covered in all these contexts. A new Table 13-1 lists twenty types of digital image noise organized into eight broad categories. These important topics relating to noise are comprehensively explored as no other radiography textbook has done to date.
In radiation biology, the section on radiation units in Chapter 40 has been vastly expanded to include the concepts of air kerma, exposure area product, surface in-tegral exposure, absorbed dose, dose area product, integral dose, dose equivalent, effective dose, and collective effective dose. Optically stimulated luminescence (OSL) dosimeters were also added. Digital fluoroscopy was significantly strength-ened in Chapter 37. Conventional tomography has been eliminated because of its clinical obsolescence.
Many crisp illustrations have been added, along with helpful tables and refine-ments to the text designed to make the entire presentation more student-friendly. Remarkable clarity and concise descriptions help the student with more compli-cated topics, especially in the digital domain. The practical limitations of digital features such as smoothing and edge enhancement are covered with their direct implications for clinical application.
Several sections have been deleted, moved or reorganized to provide smoother transitions and development of the topics, with particular focus on the digital im-aging chapters. Material on rescaling the digital image has been greatly strength-ened, and new graphs have been added that make histogram analysis and errors much easier to grasp.

The math review chapter (Chapter 3) includes a section on basic graphs. Along with material on the x-ray beam spectrum, a new section titled Understanding the Digital Histogram has been added. which includes foundational support exercises directly related to the later chapters on digital image processing.
A glossary of technical radiographic and digital imaging terms has been ex-panded. In addition, a deliberate effort has been made to include the content areas identified in the Curriculum Guide published by the American Society of Radio-logic Technologists, and to address the Standard Definitions published by the American Registry of Radiologic Technologists.
Scope and Philosophical Approach
The advent of digital radiographic imaging has radically changed many paradigms in radiography education. In order to bring the material we present completely up-to-date, and in the final analysis to fully serve our students, much more is needed than simply adding two or three chapters on digital imaging to our textbooks:
First, the entire emphasis of the foundational physics our students learn must be adjusted in order to properly support the specific information on digital imaging that will follow. For example, a better basic understanding of waves, frequency, am-plitude and interference is needed so that students can later grasp the concepts of spatial frequency processing to enhance image sharpness. A more thorough cover-age of the basic construction and interpretation of graphs prepares the student for histograms and look-up tables. Lasers are also more thoroughly discussed here, since they have not only medical applications, but are such an integral part of com-puter technology and optical disc storage.
Second, there has been a paradigm shift in our use of image terminology. Perhaps the most disconcerting example is that we can no longer describe the direct effects of kVp upon image contrast; Rather, we can only describe the effects of kVp upon the subject contrast in the remnant beam signal reaching the image detector, a signal whose contrast will then be drastically manipulated by digital processing techniques. Considerable confusion continues to surround the subject of scatter radiation and its effects on the imaging chain. Great care is needed in choosing appropriate ter-minology, accurate descriptions and lucid illustrations for this material.
The elimination of much obsolete and extraneous material is long overdue. Our students need to know the electrical physics which directly bear upon the produc-tion of x-rays in the x-ray tube – they do not need to solve parallel and series circuit problems in their daily practice of radiography, nor do they need to be spending time solving problems on velocity. MRI is briefly overviewed when radio waves are discussed under basic physics, sonography is also discussed under the general head-ing of waves, and CT is described along with attenuation coefficients under digital imaging. But, none of these subspecialties has a whole chapter devoted to it.
It is time to bring our teaching of image display systems up to date by presenting the basics of LCD monitors and the basics of quality control for electronic images. These have been addressed in this work, as part of ten full chapters dealing specifi-cally with digital and electronic imaging concepts. If you agree with this educa-tional philosophy, you will find this textbook of great use.

Organization
The basic layout is as follows: In Part I, The Physics of Radiography, ten chapters are devoted to laying a firm foundation of math and basic physics skills. The descrip-tions of atomic structure and bonding go into a little more depth than previous textbooks have done. A focus is maintained on energy physics rather than mechan-ical physics. The nature of electromagnetic waves is more carefully and thoroughly discussed than most textbooks provide. Chapters on electricity are limited to only those concepts which bear directly upon the production of x-rays in the x-ray tube.
Part 2, Production of the Radiographic Image, presents a full discussion of the x-ray beam and its interactions within the patient, the production and characteristics of subject contrast within the remnant beam, and the proper use of radiographic technique. Image qualities are thoroughly covered. This is conventional informa-tion, but the terminology and descriptions used have been adapted with great care to the digital environment.
Part 3, Digital Radiography, includes nine chapters covering the physics of digital image capture, extensive information on digital processing techniques, and the practical application issues of both CR and DR. PACS and medical imaging infor-matics are included. There is a chapter on mobile radiography, fluoroscopy, and digital fluoroscopy, and an extensive chapter on quality control which includes dig-ital image QC.
Finally, Part 4 consists of five chapters on Radiation Biology and Protection, in-cluding an unflinching look at current issues and practical applications including an unflinching look at current issues and practical applications.
Feedback
For a textbook to retain enduring value and usefulness, professional feedback is always needed. Colleagues who have adopted the text are invited to provide con-tinuing input so that improvements might be made in the accuracy of the infor-mation as well as the presentation of the material. Personal contact information is available in the Instructor and Laboratory Manual on disc or download.
This is intended to be a textbook written “by technologists for technologists,” with proper focus and scope for the practice of radiography in this digital age. It is sincerely hoped that it will make a substantial contribution not only to the practice of radiography and to patient care, but to the satisfaction and fulfillment of radi-ographers in their career as well.