A computed tomography scan, or CT scan, is generally considered to be a fairly safe medical procedure, but it can lead to some unwanted effects. Due to the use of radiation and the fact that multiple images are taken from different angles which leads to multiple exposures, there is concern that the scans can contribute to the formation of cancer later in life. There is also concern about potential harm to the fetus from radiation if a pregnant woman is given a CT scan, so the procedure is not recommended unless the benefit outweighs the risk. One of the most usual side effects of a CT scan concerns the contrast material. Some people have a reaction to the iodine used, which can cause allergic symptoms ranging from itching to hives to trouble breathing.
One of the potential effects of a CT scan that usually causes the most concern is cancer. Exposure to radiation can sometimes contribute to the formation of cancer, though it does not always do so. Typically, cancer will form well after the radiation exposure, and is much more likely if the dose of radiation is high or occurs multiple times. CT scans do expose the body to radiation, and at higher levels than a regular X ray. They are an important diagnostic tool, however, so the potential risk of having them needs to be weighed against the potential benefits in terms of diagnosing and treating certain conditions.
Pregnant women may be particularly concerned about the effects of a CT scan. Radiation exposure might be harmful to the developing tissues of the fetus. Again, the potential risks need to be weighed against the benefits of giving a CT scan to an expectant mother. There may be other diagnostic tests that can be used that are just as effective, which should probably be considered first. New mothers should also be cautious if they are breastfeeding, as the contrast material can be transferred to an infant in the day or two following the procedure.
The majority of people who complain of negative effects of a CT scan are those with allergies to the contrast materials used to improve the images of certain organs and blood vessels. Though relatively rare, some people can have a bad reaction to the iodine in them. For some, the reaction is fairly mild and includes an itchy rash or hives. Other people may have more severe, potentially dangerous reactions that make it difficult for them to breathe.