The CT scan, also known as a CAT scan, is a diagnostic tool that uses radioactive waves, similar to the x-ray. The major difference between the CT scan and the traditional x-ray is that the CT scan takes pictures from multiple angles and produces a three-dimensional image. The traditional x-ray only takes pictures from one angle, and produces a two-dimensional image. CT scans also allow the technician to take images in narrow slices to pinpoint a much smaller area than a traditional x-ray.
CT Scan Uses
Due to the detailed images they create, CT scans have a variety of diagnostic uses. Because CT scans can “see” soft tissue, they are often used to diagnose diseases and disorders of the organs, such as:
- emphysema in the lungs
- tumors or bleeding in the brain
- blocked arteries in the heart
CT scans can also take images of bone and are often used to view and diagnose fractures and dislocations that might not show up on a traditional x-Ray. In addition to detecting cancers, CT scans are also used to gauge the effectiveness of cancer treatments, by:
- detecting if cancer cells are growing, or shrinking
- detecting if cancer has spread to other areas
How the CT Scan Works
When the CT rays hit the body, the structures inside the body absorb them, which causes those structures to “light up.” Denser tissue, like bone, tends to shine bright white, while softer tissue tends to be dimmer. Abnormalities could appear as dark areas, as in the case of fractures; or as very bright areas, as in the case of cancers in soft tissue.
Sometimes a full body scan is conducted. If the target tissue is very small, like blood vessels; or very soft, like the intestines, the radiology physician might inject a high-contrast dye into the patient via IV, or have him drink a high contrast medium to make the tissues appear brighter.
CT Scan Concerns
One of the major issues or perceived "minuses" with CT scans is the risk of overexposure to radiation, which could make you more vulnerable to certain cancers. Another issue is that the dyes used to augment the procedure could cause kidney damage in some individuals. The people at greatest risk for complications are:
- Children, due to their smaller size, and because their cells are in a hyper-growth phase, which could make them vulnerable to cancerous mutations
- Individuals who have had several x-rays or CT scans in the past, and are concerned about cumulative exposure
- Individuals with kidney disease
How to Protect Yourself
The best way to protect yourself is to limit your number of CT scans. The average person might only have one CT scan in his lifetime, if at all. However, if you are in treatment for cancer or lung disease, or if you are under treatment from several different physicians, you could end up having many more. You will have to be proactive in limiting your CT scans in the following ways:
- If you have multiple physicians, make sure your records in each office are up-to-date with your history of CT scans
- If you need to have frequent monitoring to track your disease, discuss the possibility of using alternative scanning and tracking methods, such as:
- Ultrasounds that use sound waves, instead of radiation, and can detect and track some anomalies in soft tissue (though ultrasound is not effective for detecting issues in or around bone)
- MRIs that use magnetic waves instead of x-rays, and can detect and tract anomalies in soft tissue and bone (MRIs should not be used on individuals who have metal inside their bodies, as the powerful magnet could actually pull the metal out, or disrupt the function of the pacemaker or defibrillator.)