This book covers the contents of radiological physics decision by many universities to students and includes a simplified presentation of the prevention of radiation dangers. The book introduced some basic concepts of the atom and the disintegration of Radiology. The book contains twelve chapters devoted first and second for the presentation of the basic concepts of the atom and the nucleus, radioactive disintegration and laws, Chapter III to learn how to interact with different radiation article, Chapter IV deals with some types of ionizing radiation detectors.