X-Ray Imaging (Radiography)

Radiography (X-ray imaging) uses X-rays - a form of electromagnetic radiation produced inside an X-ray tube - to visualise the internal structures of the body. The X-ray beam is passed through the patient and captured on the far side by a detector, which may be a film sensitive to X-rays or a digital detector plate. Different body tissues absorb X-rays to different degrees: dense structures such as bone absorb much more radiation, while soft tissue lets far more of the beam pass through. This difference in absorption produces a contrast image, giving a flat, two-dimensional representation of the structures the beam has passed through. X-ray imaging is an invasive technique in the sense that it exposes the patient to ionising radiation, though it is also available in a portable unit form and is markedly less costly than more advanced imaging methods such as MRI or CT. Clinically, X-rays are used to diagnose heart and lung disease and to detect fractures of bones and joints; to visualise hollow organs and blood vessels after they are filled with a radio-opaque contrast agent containing barium or iodine; in dental radiography, to diagnose problems inside the mouth and jaw; in mammography, a specialised form of X-ray imaging that produces detailed images of breast tissue; in fluoroscopy, which produces real-time moving X-ray images; and in radiation therapy, where focused X-rays are used to shrink cancerous tumour …