While techniques exist to reduce such artifacts, they do not fully mitigate the artifacts and may even introduce new ones. These artifacts can obscure anatomical structures or affect calculations necessary for planning radiation therapy. Following evaluation in animal models, researchers plan to validate this CT imaging technique in human studies.Īccounting for metal implants in CT imaging: Metal objects, such as implants and prostheses, can introduce ‘artifacts’ that may appear as streaks or shadows on a CT scan. Such a technique could significantly shorten the time from the diagnosis of a stroke to the start of endovascular therapy, and could also guide the endovascular treatment.
This CT-based method can be used to rule out the presence of a hemorrhage to find the site of the blood clot and to identify the extent of damaged brain tissue.
NIBIB-funded researchers have developed an image reconstruction technique to more efficiently triage patients who present with symptoms of a stroke. Parents may want to ask the technologist or doctor if their machine settings have been adjusted for children. IV contrast agents should not be administered to patients with abnormal kidney function since they may induce a further reduction of kidney function, which may sometimes become permanent.īecause children are more sensitive to ionizing radiation and have a longer life expectancy, they have a higher relative risk for developing cancer from such radiation compared with adults. 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 magnetic resonance imaging (MRI) or ultrasound. Credit: iStockĪ 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. CT images of the heart and coronary artery. However, the risk of developing cancer from x-ray radiation exposure is generally small. This is a risk that increases with the number of exposures added up over the life of an individual. However, CT scans use x-rays, and all x-rays produce ionizing radiation. Ionizing radiation has the potential to cause biological effects in living tissue. An early diagnosis of these conditions could potentially be lifesaving. 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 two-dimensional 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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