X-ray (also called radiography) uses a very small dose of radiation to produce pictures of the inside of the body. X-rays are the most frequently used form of medical imaging and they are also the oldest. They are often used to help see bone fracture, injuries or infections; they are also used to locate foreign objects in soft tissue. In some cases, x-ray tests are used in conjunction with an iodine-based contrast material, which is swallowed, to help doctors see certain organs, blood vessels or tissue.