Radiology is the specialty of directing medical imaging technologies to diagnose and sometimes treat diseases. Radiography involves the use of x-rays to produce radiographs. Today, following extensive training, radiologists also direct other imaging technologies such as ultrasound, computed tomography (CT), magnetic resonance imaging (MRI) and Nuclear Medicine to diagnose or treat disease.
Computed Tomography (CT) imaging uses X-rays in conjunction with computing algorithms to image the body. In CT, an X-ray generating tube opposite an X-ray detector (or detectors) in a ring shaped apparatus rotate around a patient producing a computer generated cross-sectional image (tomogram). Radiocontrast agents are often used with CT for enhanced delineation of anatomy and angiography. With computer manipulation, CT images can be reconstructed into 3D images. Faster scanning times in modern equipment has been associated with increased utilization.
Medical ultrasonography uses ultrasound (high-frequency sound waves) to visualize soft tissue structures in the body in real time. No ionizing radiation is involved, but the quality of the images obtained using ultrasound is highly dependent on the skill of the person (ultrasonographer) performing the exam. Ultrasound is also limited by its inability to image through air (lungs, bowel loops) or bone.