How Much Radiation Exposure Occurs with a CT Scan? X-ray? Sunlight?

A common concern now is how much radiation exposure occurs with common radiological testing such as x-rays and CT scans, especially given the small increased risk of cancer with accumulated exposure over years.

Of note, ultrasounds and MRI scans do not emit radiation. MRI scans use magnets while ultrasounds use sound waves in order to obtain imaging information.

So, here's a chart comparing such tests with common environmental radiation exposure such as sunlight. Information taken from www.X-RayRisk.com:

Radiation	Amount
Sunlight (high-altitude city)	6 mSv per year
Sunlight (sea-level city)	3.1 mSv per year
Frequent Flyer	1 - 6.7 mSv
Single Airflight coast-to-coast	0.01 - 0.03 mSv
Smoke 20 cigarettes per day	53 mSv
CT Chest	7 mSv
CT Head	2 mSv
Nuclear Stress Test (Technicium)	9.4 mSv
Nuclear Stress Test (Thallium)	40.7 mSv
Barium Swallow	5 mSv
Mammogram	0.4 mSv
Chest X-ray	0.1 mSv
Dental X-ray (Bitewing)	0.02 mSv