A significant difference between CT and MRI scans is that CT scans expose patients to ionizing radiation, while an MRI does not. The amount of radiation used during this test is higher than the amount used in an x-ray. There are a number of factors that determine the impact of the radiation from a CT scan: the dose of the radiation the frequency of exposure a patient’s age a patient’s gender the size of the patient the specific design of the scanner being used The low level of radiation that a patient is exposed to during a CT scan is measured in units called millisieverts (mSv). According to the United States Nuclear Regulatory Committee, a person’s average annual exposure from natural sources is 3.1msv. During a CT scan of the head, a patient is exposed to 2mSv; less than the yearly amount of natural exposure.2 This is acceptable because the human body can naturally repair this amount of radiation damage in one year.

If your consultant physician has asked for a CT, then there is probably need for one. Also, he/she would have analysed the risks/rewards ratio. CT is better in diagnosing bone related issues, in addition to soft tissue problems, than an MRI. Although it is true that multiple exposure to medical radiation (including CT) can slightly increase the chance of developing Cancers, the risk is very slight, and most often almost nil. As far as Contrast is concerned, it is safe to use unless you have a known allergic history or are a kidney/liver/cardiac patient.