Radiology is a medical specialty in which a variety of radiologic methodologies are used to diagnose and treat diseases. Diagnostic radiology encompasses a variety of diagnostic and image guided therapeutic techniques, including all aspects of radiological diagnosis (nuclear radiology, diagnostic ultrasound, magnetic resonance, computed tomography, interventional procedures, and the use of other forms of radiant energy). Physicians studying diagnostic radiology are primarily hospital based and can specialize in a number of areas, including: vascular interventional; neuroimaging and intervention; abdominal imaging and intervention; nuclear medicine; chest and cardiac imaging; pediatric imaging; and mammography. The radiologist's role has grown not only through great improvements in diagnosis, but also through the technological developments that permit numerous interventional radiology procedures. A diagnostic radiologist is the eye of medicine, helping the primary care physician diagnose and treat diseases.