Radiology, which is the branch of medical science that deals with diagnosis and treatment through images of the human body. This is done by using various imagining technologies such as x-ray, ultrasound, computed tomography (CT), nuclear medicine, positron emission tomography (PET), and magnetic resonance imaging (MRI). It is a radiographer or radiologic technologist who carries out these procedures. Below are some of the prominent technologies which are used in radiography:
- Projection (plain) Radiography: Radiograph is the technique where x-rays are passed through a patient’s body and then are converted into an image for diagnosis of a particular body part. The most common images produced by x-rays are silver impregnated films; however, those are now being replaced by Digital Radiography (DR), in which x-rays strike over a plate of sensors which projects digital information and an image over a computer screen.
- Fluoroscopy: Fluoroscopy and angiography are the enhanced use of x-ray imaging, where under the radiography process a fluorescent screen and image intensifier tube is attached with a closed-circuit television system for real-time imaging. They take images of structures in motion for added radiocontrast. Radiocontrast agents are either injected into or administered through swallowing to examine the anatomy and working of blood vessels, the genitourinary system, or the gastrointestinal tract.
- Computed Tomography: CT imaging employ x-rays in coordination with computing algorithms to image the body in measured calculation. In a CT, an x-ray generating tube opposite an x-ray detector (or detectors) in a ring shaped apparatus revolves around a patient and generates computer produced cross-sectional images. CTs can pick up finer details of the patient’s body, but they also expose the patient to more ionizing radiation than a radiograph.
- Ultrasound: Medical ultrasonography uses ultrasound (high-frequency sound waves) to see soft tissue structures of the patient’s body. As the ultrasound process is devoid of ionization, its image quanlity depends upon the person who is taking ultrasound. It also has limitations due to incapacity image through air like lungs, bowel, loops, and bone.
- Magnetic Resonance Imaging: MRI is the technique where strong magnetic fields are used to determine atomic nuclei (usually hydrogen protons) within bodily tissues to produce a better imaging quality for diagnosing a patient. MRIs can produce images in axial, coronal, sagittal, and multiple oblique planes with equal ease. It produces the best soft tissue contrast among all the imaging techniques. With development in scanning speed, spatial resolution, computer 3D algorithms, and hardware, MRI has become quite handy in musculoskeletal radiology and neuroradiology.
- Nuclear Medicine: In nuclear medicine imaging, radiopharmaceuticals consisting of substances with affinity for certain body tissues labeled with radioactive tracer are administered to a patient. Tracers used most frequently are Technetium-99m, Iodine-123, Iodine-131, Gallium-67, and Thallium-201. The heart, lungs, thyroid, liver, gallbladder, and bones are the organs which are tested using these conditions and techniques.
- Positron Emission Tomography (PET): This sort of scanning falls under the category of nuclear medicine. Under this type of scanning there is a radioactive biologically active substance, usually Fluorine-18. Flurodeoxyglucose is injected into a patient, and the radiation left out by the patient is used for producing multi-planer images of the body.