Answer to Question #12965 Submitted to "Ask the Experts"
Category: Medical and Dental Patient Issues
The following question was answered by an expert in the appropriate field:
I had a computerized tomography scan of the abdomen with barium contrast. What is my effective dose?
The best way to estimate the effective dose is using the dose-length product (DLP) given in milligray centimeters (mGy cm). If you provide the DLP from your scan, I can calculate the effective dose.
It's important to note that effective dose is a metric of relative risk to a population, not a dose to an individual. So, it is not your effective dose. The baseline cancer risk in the United States is around 40%, i.e., the risk of getting cancer from all sources. You don't have a 40% risk of cancer. Instead, in a group of 1,000 random people, 400 are expected to get cancer. It's a subtle but important distinction. Think about it this way: your neighbor smokes tobacco products and works in a coal mine. You exercise and eat broccoli and blueberries every day. The two of you don't have the same cancer risk, but you both are in the group of 1,000 people from which there will be 400 cancers.
Kent Lambert, CHP, FHPS