看这张表，做一次牙检查所接受的射线，比坐一小时飞机还低。
上图来自 http://www.drplitt.com/dental-x-ray-safety/
另外请看下述报道
Four bitewing X-rays, which is what many people get in a routine exam, give about .005 millisieverts of radiation, according to the American College of Radiology. That's about the same amount of radiation you get in a normal day from the sun and other sources.
from https://www.cnn.com/2011/09/15/health/living-well/dental-x-rays/index.html
https://www.123dentist.com/how-safe-are-dental-x-rays/
