The aim of this primer is to provide a concentrated and focused information package as a quick reference guide for students, pertaining to diagnostic radiation usage and safety, with a focus on modalities that involve the use of x-rays. Medical schools throughout the world emphasize radiological examination interpretation, but through our combined experience, we have concluded that little is taught on the science behind these examinations and the potential harm of exposure to radiation of certain energy. This primer gives a brief overview of ionizing radiation, the dosage associated with various radiological examinations, the precautions that need to be taken with a pregnant patient and the techniques of basic protection from radiation exposure as a physician, student or resident.