Answer to Question #12924 Submitted to "Ask the Experts"

Category: Medical and Dental Patient Issues — Diagnostic X Ray and CT

The following question was answered by an expert in the appropriate field:


I have had two computed tomography (CT) scans in five years, along with a few x rays of my arm this week. Can you put my mind at rest? I am concerned about the radiation exposure and possible future cancer development. Are two CT scans over five years a concern? Can I do anything to reduce future possible cancer?


I want to start by reassuring you that any additional risk of cancer due to the radiation exposure is negligible, if it exists at all. For radiation doses below about 100 mSv above natural background, we don't have good evidence of any health risks to people. 

Our cells are very good at repairing damage caused by radiation or other factors. We are all exposed to radiation from natural background radiation sources as well as chemicals every day and our bodies repair the damage very well. Even though we are receiving more radiation during our lives because of the use of CT scans and other medical imaging, we are expected to live longer, in part because of the improved medical care possible with the new imaging technologies.

If your physician recommends CT scans in the future, I recommend that you discuss your concerns and the benefits of the imaging compared to the risk of the radiation exposure. It is important to recognize that there can be risks due to the decision to not have the x ray or CT scan, such as the need for a more invasive diagnostic procedure or failure to catch disease at a more treatable stage. Your physician should be able to discuss the options and the risks of each with you.

You should not be concerned about the radiation you have received from CT scans and x rays. The risk is very, very low or zero and the benefits from getting the right diagnosis and treatment are definite.

Deirdre H. Elder, MS, CHP, CMLSO

Answer posted on 20 May 2019. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.