“一年做42次才会有影响”？不太可能

http://abcnews.go.com/Health/CancerPreventionAndTreatment/story?id=3927117&page=1

引用：

Although the image is a big improvement over conventional X-rays, the radiation dose that patients receive is also much higher. Researchers say an abdominal CT scan exposes patients to 50 times more radiation than an X-ray of the same region does.

http://abcnews.go.com/Health/WellnessNews/story?id=6801216&page=1

http://Radiation%20is%20commonly%20measured%20in%20units%20called%20millisieverts,%20or%20mSv.%20Authors%20studied%20almost%202,000%20patients%20who%20had%20a%20cardiac%20CTA,%20and%20they%20found%20that%20the%20average%20radiation%20dose%20from%20these%20CT%20scans%20was%2012%20mSv.

我做实验常年用放射性同位素，被告知存在健康风险，但是我一年接受的辐射剂量不会超过2 mSv，还不到一次CT的1/6.所以说，一年可以做42次CT，有点不可思议。