Heavy metals such as cadmium, lead and mercury are common air pollutants. and are emitted (predominantly into the air) as a result of various industrial ac-. tivities. This report reviews the available information on the sources, chemical. properties and spatial distribution of pollution by cadmium, lead and mercury.
Assuming that you are already inside the CT scanner ready to get scanned. CT scan without contrast (head, sinus, orbits, abdomen, pelvis, cervical, thoracic, lumbar and dental scans) take approximately 15 minutes. CT studies with contrast of the chest, pelvis, head or neck take approximately 30 minutes. Whereas, aortic contrast studies may take up to 45 minutes.
From this information a computer creates many images called slices. Slices can be studied individually, or placed together to form a three-dimensional model of the area of the body being studied. A CT scan usually takes just a few minutes, and is painless. A dye, often referred to as contrast, is sometimes given to highlight a desired area, which helps to produce a more distinct image. The ingestion of this dye can cause slight nausea or an allergic reaction in some people, but such symptoms are closely monitored and in many cases no dye is needed.