Cardiac CT involves radiation, although the amount used is considered small. Depending on the type of CT scan you have, the amount of radiation is similar to the amount you’re naturally exposed to over 1–5 years.
There is a small chance that cardiac CT will cause cancer because of the radiation. The risk is higher for people younger than 40 years old. New cardiac CT methods are available that reduce the amount of radiation used during the test.
Cardiac CT scans are painless. Some people have side effects from the contrast dye that might be used during the scan. An itchy feeling or a rash may appear after the contrast dye is injected. Normally, neither side effect lasts for long, so medicine often isn't needed.
If you do want medicine to relieve the symptoms, your doctor may prescribe an antihistamine. This type of medicine is used to help stop allergic reactions.
Although rare, it is possible to have a serious allergic reaction to the contrast dye. This reaction may cause breathing problems. Doctors use medicine to treat serious allergic reactions.