Radiology is the science of high energy radiation and of the sources, including the study of the chemical, physical, and biological effects of radiation. Its a term usually refers to the diagnosis and treatment of disease using radiation. It is also a scientific discipline of medical imaging using ionizing radiation, radionuclides, nuclear magnetic resonance, and ultrasound.

One of the most useful technique in radiology is the computed tomography (CT) or computerized axial tomography (CAT). It gives anatomical information from a cross-sectional plane. Each image is generated by a computer synthesis of transmited X-ray obtained in many different directions in a given plane.

Because it provides detailed, cross-sectional views of all types of tissue, CT is one of the best tools for studying the chest and abdomen. It is often the preferred method for diagnosing many different cancers, including lung, liver, and pancreatic cancer, since the image allows a physician to confirm the presence of a tumor and to measure its size, precise location, and the extent of the tumor's involvement with other nearby tissue.

CT examinations are often used to plan and properly administer radiation treatments for tumors, and to guide biopsies and other minimally invasive procedures.

Currently, diagnoses have been carried out routinely with the following systems.