Eating oysters weekly does not equate to receiving the same radiation dose as a CT scan. The comparison between consuming oysters and undergoing a CT scan involves two very different types of exposure: radiation from medical imaging versus potential ingestion of naturally occurring radioactive elements or contaminants in seafood.
Oysters are filter feeders that can accumulate various substances from their environment, including trace amounts of naturally occurring radioactive materials (NORM) like radium or cesium isotopes, as well as bacteria and pollutants. However, the levels of any radioactive elements in oysters are generally very low and not comparable to the high doses of ionizing radiation delivered during a CT scan. A CT scan exposes the body to a controlled, relatively high dose of X-ray radiation in a short time, which is measured in millisieverts (mSv). In contrast, the radiation dose from eating oysters, even weekly, is negligible and far below any level of concern for radiation sickness or cancer risk.
The concern with oysters is more commonly related to bacterial contamination, such as Vibrio vulnificus, which can cause severe infections, especially if oysters are eaten raw or undercooked. This bacterium thrives in warm coastal waters and can accumulate in oysters, posing a health risk unrelated to radiation. The risk of bacterial infection from oysters is a food safety issue rather than a radiation exposure issue.
In rare cases, seafood has been found contaminated with radioactive isotopes due to environmental pollution or improper storage, but such events are exceptional and typically lead to recalls and warnings. These contamination levels are monitored by food safety authorities to prevent harmful exposure.
In summary, while oysters can contain trace radioactive elements naturally, the radiation dose from eating them weekly is minuscule compared to the dose from a CT scan. The main health risks from oysters are microbial rather than radiological.