X-rays are very small and can interact with your body at the level of atoms and molecules. In your body, each atom and molecule has a distinct role to play in how well you function. If the interaction between the x-ray and one of the atoms or molecules inside your body results in a malfunction of that atom or molecule, your body may be compromised in some way. Fortunately, your body has evolved several ways to compensate for such changes because we live in a world where all kinds of radiation are present, even x-radiation that is naturally occurring. Science has spent a great deal of time and effort in finding ways to determine the effects of x-radiation on your body in measurable ways. We have concluded that the risk is never zero, but can be very small if we use x-rays wisely. As a result, we now have ways of measuring the risks associated with medical x-rays and relating these to the risks associated with not being able to diagnose certain diseases. This is known as the risk benefit ratio and is used by medical professionals when they decide whether or not to use x-rays to assist in diagnosis and treatment of various diseases. In addition, medical practices utilize the services of Engineers and Physicists to help them both measure x-rays and to develop ever better ways of reducing the energy needed to produce quality images from inside your body.