Cracking, in petroleum refining, the process by which heavy hydrocarbon molecules are broken up into lighter molecules by means of heat and usually pressure and sometimes catalysts. Cracking is the most important process for the commercial production of gasoline and diesel fuel. 1  Cracking of petroleum yields light oils (corresponding to gasoline), middle-range oils used in diesel fuel, residual heavy oils, a solid carbonaceous product known as coke, and such gases as methane, ethane, ethylene, propane, propylene, and butylene.
Cholangiography is the imaging of the bile duct (also known as the biliary tree) by x-rays. percutaneous transhepatic cholangiography (PTC): Examination of liver and bile ducts by x-rays. This is accomplished by the insertion of a thin needle into the liver carrying a contrast medium to help to see blockage in liver and bile ducts.
A heart CT scan may also be called a coronary CT angiogram, if it is meant to view the arteries that bring blood to your heart.It may be called a coronary calcium scan if it meant to determine whether there is a build-up of calcium in your heart. computed tomography scanâcommonly called a CT scanâis a test that uses X-rays to view your heart and blood vessels. These scans use safe amounts of radiation to create detailed images of the body, which can help your doctor to detect any problems.