Professor Saltzman first reviews the electromagnetic spectrum, the different regimes of the spectrum, their respective wavelengths, energies, and ways of detecting them. He then talks about the use of high energy radio waves for imaging of the body. The history, components, advantages and limitations of X-ray imaging are presented in detail. Next, he introduces Computed Tomography, a related imaging technique which uses mathematical computation to compile line-scanned X-rays into a three dimensional image. Finally, Professor Saltzman touches on harmful effects of X-ray radiation, and ways to limit or avoid overexposure in these imaging techniques.