The use of radiology (see X-RAYS) to enable doctors to carry out diagnostic or treatment procedures under direct radiological vision. This X-ray procedure is used in MINIMALLY INVASIVE SURGERY (MIS) – for example, ANGIOPLASTY, the removal of stones from the kidney (see KIDNEYS, DISEASES OF), and the observation of obstructions in the bile ducts (percutaneous CHOLANGIOGRAPHY). (See also MRI.)