This chapter aims to present a brief discussion on radiology. Radiology is the medical specialty concerned with the study of parts and functions of body by means of X-rays. Nuclear medicine (NM) is a specialty that deals with the characteristics and uses of radioactive substances in the diagnosis and treatment of diseases. Imaging is the latest form of visualizing the part of the body by means of ultrasonography (USG), computerized tomography (CT) and magnetic resonance imaging (MRI). X-rays are a special type of rays which can be absorbed by the body substance (e.g. calcium in bones), they do not reach the photographic plate held behind the patient, and white areas are left in the X-ray film. In the process of clinical diagnosis, X-rays are used to assess the nature of bone fractures, dislocations, vertebral disk prolapse, cardiomegaly, pathological cavities in lungs. X-radiation (composed of X-rays) is a form of electromagnetic radiation. The measure of X-rays ionizing ability is called the exposure. In modern hospitals a photostimulable phosphor plate (PSP plate) is used in place of the photographic plate. After the plate is X-rayed, excited electrons in the phosphor material remain ‘trapped’ in ‘color centers’ in the crystal lattice until stimulated by a laser beam passed over the plate surface.