Methods and Applications of Statistics in Clinical Trials, Volume 2: Planning, Analysis, and Inferential Methods

Chapter 14

Imaging Science in Medicine, II: Basics of X-Ray Imaging

Anthony B. Wolbarst, Patrizio Capasso and Andrew R. Wyant

14.1 Introduction to Medical Imaging: Different Ways of Creating Visible Contrast Among Tissues

The principal job of a medical imaging modality is to provide clear maps of anatomy, or to make it possible to recognize irregularities in physiology, or both— ultimately, that is, to help find and identify pathologies. It does so by creating contrast among tissues, and the various modalities do this in biophysically diverse ways.

This chapter and Chapter 15 provide extremely brief sketches of the imaging technologies that involve X rays and are employed routinely in modern clinics to examine the structure and functioning of the body. This chapter covers the modalities that were slowly developed over the first three quarters of the twentieth century, like screen-film radiography and mammography, and image-intensifier tube fluoroscopy. Chapter 15 deals with X-ray technologies that have flourished only with the advent of high-speed but affordable computers—digital planar imaging like computed radiography (CR), digital radiography (DR), digital subtraction angiography (DSA), and computed tomography (CT), culminating in helical, multi-detector ring CT. A much expanded and more in-depth version of this material may be found in the book, Medical Imaging—Essentials for Physicians, by the authors, also published by Wiley (2013). The book also discusses modalities based ...