Computed tomography (CT), more commonly known as a CAT scan, obtains multiple graphical images of body parts from many different angles using special x-ray equipment. These images are then joined together to form three-dimensional graphical cross-sections.
CAT Scans are so detailed that it can show, and distinguish between, bone tissue, soft tissue, internal organs, muscles and tumors, empowering physicians with a unique tool to diagnose medical conditions and aid their treatment. Using X-rays beams that pass through the body to measure how different tissues absorb different amounts of radiation, CT scans build an anatomical picture of an area of the body under investigation.
Computed Tomography is a diagnostic imaging tool that has huge potential due to its ability to provide painless, quick and detailed internal images of the body as well as being the only method that provides detailed images of bone, soft tissue, and blood vessels—allowing doctors to detect life-threatening conditions, such as cancer.
It was first developed in 1967 by Godfrey Hounsfield, a British electronics engineer. The first CT scans were performed in the 1970’s and took several hours per slice. At that time, CT images were 100 times clearer than normal x-ray images—and the speed, accuracy and overall quality of CT images has only improved since then.
How safe are CT scans?
While CAT scans are a powerful diagnostic imaging tool, it does carry some risks.
Radiation: CT scans require some exposure to radiation. Radiation dose from CT scans varies from patient to patient. A particular radiation dose will depend on the size of the body part examined, the type of procedure, and the type of CT equipment and its operation.
Radiation exposure is known to potentially increase the risk of cancer. However, patients should note that this risk is far outweighed by the benefits that can be achieved with a CT scan. This is especially true for patients who are suspected or known to already have cancer. A CT scan could mean the difference between stopping the disease in its tracks, or letting it spread throughout the body.
Allergic Reaction: The most common “side effect” of a CT scan is an allergic reaction to the contrast material. These reactions usually result from the iodine in the contrast material. Typically, the effects of iodine include a “flushed” feeling throughout the body, a metallic taste in the mouth, and possible itchiness on various parts of the body. In rare cases, more severe allergic reactions can occur, and range from bumps or hives on the skin to shortness of breath and swelling of the throat. Newer contrast materials pose less risk of an allergic reaction. If you know you have had adverse reactions to iodine in the past, tell you doctor. He or she may decide to use a newer material instead.
What can I expect to experience during a CT scan?
Computed Tomography is a painless procedure. However, a CT scan often requires the patient to lie still in one position for a long period of time. It also often requires the patient to hold his or her breath (though with fast spiral CT scanners, the scan is very quick). These aspects of the CT scan can be uncomfortable. Some patients may require a sedative.
What are the advantages of a CT scan?
CT is more powerful and more detailed than conventional x-rays. Conventional X-ray scans are rays of electromagnetic radiation used to diagnose and treat trauma and disease. When x-ray beams pass through the body, 2-dimensional images are created based on shadows made by body structures in the area being photographed. The image depends on the body structure’s absorption of the x-rays.
CT scans, meanwhile, produce a 3-dimensional cross-section of a particular body part. These images, too, are measures of x-ray absorption; however, many slices of the body join together to form an image. Typically, bone turns up white; air turns up black, and tissues and mucous turn up in shades of gray.
A total CT scan (also called a whole body CT scan or CT body scan) creates images of nearly the entire body. The images typically run from the chin to below the hips. Some patients believe this procedure to be beneficial in scanning the body for signs of disease, a sort of preventative form of health care.