Infinite Powers: How Calculus Reveals the Secrets of the Universe

by Steven H. Strogatz

CT scanning, is hundreds of times more sensitive than conventional x-ray films. Their precision has revolutionized medicine. The C stands for computerized and the T stands for tomography, meaning the process of visualizing something by cutting it into slices. A CT scan uses x-rays to image an organ or a tissue one slice at a time. When a patient is placed in a CT scanner, x-rays are sent through the person’s body at many different angles and recorded by a detector on the other side. From all that information—from all those views at different angles—it’s possible to reconstruct much more clearly what the x-rays passed through. In other words, CT is not just a matter of seeing; it’s a matter of inferring, deducing, and calculating. Indeed, the most brilliant and revolutionary part of CT is its use of sophisticated mathematics. With the help of calculus, Fourier analysis, signal processing, and computers, the CT software infers the properties of the tissue, organ, or bone through which the x-rays passed and then generates a detailed picture of that part of the body.