of physical principles and technology with the major goal of improving the care and management of the patient. Furthermore, a significant benefit of these innovations is focused on reducing the radiation dose to the patient without compromising image quality. Radiographic sciences deal with the physics of various diagnostic imaging modalities (radiography, fluoroscopy, mammography, and computed tomography [CT]) and include x‐ray generation, x‐ray production, x‐ray emission, and x‐ray interaction with tissues. Furthermore, radiographic sciences also address radiation risks and radiation protection. Radiographic technology, on the other hand, addresses the equipment components and how they function to produce diagnostic images, image quality characteristics, and quality control (QC) aspects of these imaging modalities.
The workhorse of radiology has been film‐screen radiography which is now obsolete and has been replaced globally with digital imaging. The scope of digital imaging is extremely wide and now involves a basic understanding of computer sciences, to explain how the new digital imaging modalities work. These modalities include computed radiography (CR), flat‐panel digital radiography (FPDR), digital fluoroscopy (DF), digital mammography (DM), digital tomosynthesis, and CT. In addition, the digital imaging environment now demands that operators understand what has been referred to as “imaging informatics,” an area of study that involves picture archiving and communication systems (PACS), enterprise imaging, Big Data, machine learning (ML), deep learning (DL), and artificial intelligence (AI).
With the above in mind, various professional organizations such as the American Society of Radiologic Technologists (ASRT), the Canadian Association of Medical Radiation Technologists (CAMRT), and other professional medical imaging organizations throughout the world have prescribed curricula for diagnostic imaging programs which provide guiding, principles that assist academic program leaders in designing foundational learning outcomes that are intended to meet the professional standards, and more importantly meet the entry requirements for clinical practice. Institutions offering educational programs in diagnostic imaging should be then able to raise the level of these foundational learning outcomes and content to meet the requirements of degree programs, including graduate degree programs in diagnostic imaging.
A good example of the above is offered by the ASRT curriculum content which is organized around the following subject matter [1]: Introduction to Radiologic Science and Health Care; Ethics and Law in the Radiologic Sciences; Human Anatomy and Physiology; Pharmacology and Venipuncture; Imaging Equipment; Radiation Production and Characteristics; Principles of Exposure and Image Production; Digital Image Acquisition and Display; Image Analysis; Radiation Biology; Radiation Protection; Clinical Practice; Patient Care in Radiologic Sciences; Radiographic Procedures; Radiographic Pathology; Additional Modalities and Radiation Therapy; Basic Principles of Computed Tomography and Sectional Anatomy. Similar content is characteristic of other curricula offered by other medical imaging professional organizations around the world.
Keeping the above ideas in mind, this book will address content that are considered radiographic sciences and technology. Specifically, the chapters included present a summary of the critical knowledge base needed for effective and efficient imaging of the patient, and wise use of the technical factors that play a significant role in optimization of the dose to the patient without compromising the image quality necessary for diagnostic interpretation. Furthermore, the summaries of the technical elements of radiographic sciences and technology will assist the student in preparing to write certification examinations. As such, the major and significant principles and concepts will be reviewed in three sections as follows:
Section 1: Radiographic imaging systems: major modalities and components
Section 2: Radiographic physics and technology
Section 3: Radiation protection and dose optimization
RADIOGRAPHIC IMAGING SYSTEMS: MAJOR MODALITIES AND COMPONENTS
In this book, the following radiographic imaging systems will be reviewed. These include x‐ray imaging modalities such as digital radiography (DR) which includes CR and FPDR, DF, DM, digital radiographic and breast tomosynthesis, and CT. Furthermore, these systems include imaging informatics which has become commonplace since radiology and more importantly hospitals are now all operating in the digital environment; that is, all data acquired from the patient are now in digital form and are stored and communicated using digital technologies. Informatics topics of importance include that nature and scope of PACS, enterprise imaging, cloud computing, Big Data, and the more recent of computer applications in medical imaging: AI. More details of these major technologies and how they work will be presented in Chapter 6 on Digital Imaging Modalities and Chapter 10 on Imaging Informatics.
RADIOGRAPHIC PHYSICS AND TECHNOLOGY
Radiographic physics and technology subject matter include basic physics concepts, and more specifically the physics of diagnostic imaging; technical aspects of the modalities; radiographic exposure technique; image quality, quality assurance (QA), and QC; CT physical principles; imaging informatics; radiobiology and radiation protection.
Essential physics of diagnostic imaging
The physics of diagnostic imaging is an important and vital topic that explains the nature of how these imaging modalities work to produce diagnostic images of the patient. Understanding the fundamental physics will provide the user with the tools not only needed to produce optimum image quality but more importantly to protect the patient from unnecessary radiation. As such, it is now a common characteristic of imaging departments to optimize radiation dose and work within the International Commission on Radiological Protection (ICRP) philosophy of as low as reasonably achievable (ALARA) to reduce the dose to the patient but not compromise the diagnostic quality of the images used to make a diagnosis of the patient's medical condition.
In this book, the topics in physics that will emphasize the imaging modalities are the nature of radiation, x‐ray generation, x‐ray production, x‐ray emission, x‐ray attenuation, and x‐ray interaction with matter. Furthermore, other physics topics of significance are radiation quantities and their associated units and measurement concepts. These topics and more fall in the domain of Health Physics. Three radiation quantities that are important to radiation protection of the patient are exposure, absorbed dose, and effective dose (ED). The units associated with each of these include coulombs per kilogram (C/kg), Grays (Gy), and Sieverts (Sv), respectively. In order to measure radiation, it must first be detected.
Digital radiographic imaging modalities
As listed earlier in this chapter, these modalities include CR, FPDR or DR as it is sometimes referred to, DF, DM, digital radiographic tomosynthesis (DRT), digital breast tomosynthesis (DBT), and last but not least CT. Additionally, since all of the above‐mentioned modalities include image processing using computers, the concepts of Digital Image Processing will be reviewed since it has become an essential tool for technologists, radiologists, and medical physicists working in a digital radiology department.
These imaging modalities include specific physics concepts that must be understood for optimum results. For example, CR is based on the use of photostimulable phosphors (PSP) which are based on the physical principle of photostimulable luminescence (PSL). An example of one such phosphor is barium fluoro halide (BaFX) where the halide (X) can be chlorine (Cl), bromine (Br), iodine (I), or a mixture
