[TheOtherHobbes]

Modern dental x-rays are basically negligible for most patients, although not for dentists who do them daily, even though they're well away from the beam - which is why they have to hide when they take them.

Less negligible are CT scans, which can expose you to multiples of the average annual background dose in a few minutes.

That's still relatively low level exposure. But there isn't really a safe minimum exposure level, and it's certainly not something you'd want to have regularly.

[copperx]

Aren't CT scans equivalent to about 3,000 chest X-Rays? It sounds pretty bad if you're young.

[Teknoman117]

Not quite that bad. These days a chest CT scan (~7 mSv) is worth about 70 chest x-rays (0.1 mSv).

That's 2 years (CT) and 10 days (x-ray) of exposure to sea level background radiation respectively.