X-ray beams are passed through the body and absorbed at different levels depending on the tissue density; this in turn produces an image of varying internal structures.
For instance x-ray beams penetrate easily through lungs whereas bone absorbs most of the beam.
No preparation required.
The amount of radiation used to produce an image is deemed very low therefore cause no adverse side effects. Hence; the amount of radiation from 38 chest X-rays is equivalent to a yearly radiation exposure from the environment