In some patients, contrast agents may cause allergic reactions, or in rare cases, temporary kidney failure. However, if neither of those can provide the answers needed, or there is an emergency or other time constraint, CT may be an acceptable alternative imaging option. In general, if imaging of the abdomen and pelvis is needed, doctors prefer to use exams that do not use radiation, such as MRI or ultrasound. However, the risk of developing cancer from radiation exposure is generally small.Ī CT scan in a pregnant woman poses no known risks to the baby if the area of the body being imaged isn’t the abdomen or pelvis. This is a risk that increases with the number of exposures added up over the life of an individual. Ionizing radiation has the potential to cause biological effects in living tissue. However, CT scans use x-rays, and all x-rays produce ionizing radiation. An early diagnosis of these conditions could potentially be life-saving. This method has many advantages including the ability to rotate the 3D image in space or to view slices in succession, making it easier to find the exact place where a problem may be located.ĬT scans can diagnose possibly life-threatening conditions such as hemorrhage, blood clots, or cancer. Image slices can either be displayed individually or stacked together by the computer to generate a 3D image of the patient that shows the skeleton, organs, and tissues as well as any abnormalities the physician is trying to identify. This process continues until the desired number of slices is collected. The x-ray scanning process is then repeated to produce another image slice.
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When a full slice is completed, the image is stored and the motorized bed is moved forward incrementally into the gantry. The thickness of the tissue represented in each image slice can vary depending on the CT machine used, but usually ranges from 1-10 millimeters. As the x-rays leave the patient, they are picked up by the detectors and transmitted to a computer.Įach time the x-ray source completes one full rotation, the CT computer uses sophisticated mathematical techniques to construct a 2D image slice of the patient. Instead of film, CT scanners use special digital x-ray detectors, which are located directly opposite the x-ray source. During a CT scan, the patient lies on a bed that slowly moves through the gantry while the x-ray tube rotates around the patient, shooting narrow beams of x-rays through the body. Unlike a conventional x-ray-which uses a fixed x-ray tube-a CT scanner uses a motorized x-ray source that rotates around the circular opening of a donut-shaped structure called a gantry.
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