Radiation in CT Scans

No matter how much we try to avoid it, small doses of radiation seem to be everywhere - from computer monitors, television sets, and airport body scanners to nuclear power plants, smoke detectors, and dental x-rays. According to the latest estimates, an average person in the U.S. receives an effective dose (the radiation risk averaged over the entire body) of about 3 millisievert (mSv) per year just from natural sources and cosmic radiation. Remember, these natural “background” radiation doses vary widely from one part of the country to another.

What Can Patients Do to Help Themselves?

Radiation exposure should be limited whenever possible. Still, when a CT scan is deemed critical, patients should get it. "Those [radiation] doses just are not really significant at this point compared to the benefit of extending lives, saving lives and improving the quality of lives," says Dr. Ellenbogen of the American College of Radiology, also a radiologist atSouthwest Diagnostic Imaging Center in Dallas.

While you can’t go back in time to calculate the doses of radiation received in the past, you can certainly take steps moving forward. For example, many are now only considering procedures such as dental X-rays and additional CT scans if there is a cause for concern – not just for preventive reasons anymore.

Radiation Exposure Estimates

The chart below is a comparison of effective radiation dose with background radiation exposure. The effective doses are typical values for an average-sized adult, and the actual dose can vary substantially, based on a person’s size for instance.

CT procedure:	Estimated effective radiation dose:	Comparable to natural background radiation for:	* Risk level from examination:
ABDOMINAL REGION:
Abdomen and Pelvis	10 mSv	3 years	Low
Abdomen and Pelvis, repeated with & without contrast material	20 mSv	7 years	Moderate
Colonography	10 mSv	3 years	Low
CENTRAL NERVOUS SYSTEM:
Head	2 mSv	8 months	Very Low
Head, repeated with and without contrast material	4 mSv	16 months	Low
Spine	6 mSv	2 years	Low
CHEST:
Chest	7 mSv	2 years	Low
Chest Low Dose	1.5 mSv	6 months	Very Low
HEART:
Coronary Computed Tomography Angiography (CTA)	12 mSv	4 years	Low
Cardiac CT for Calcium Scoring	3 mSv	1 year	Low
Risk Level *Approximate additional risk of fatal cancer from exam (adult): Negligible: less than 1 in 1,000,000 Minimal: 1 in 1,000,000 to 1 in 100,000 Very Low: 1 in 100,000 to 1 in 10,000 Low: 1 in 10,000 to 1 in 1000 Moderate: 1 in 1000 to 1 in 500
Chart derived from: http://www.radiologyinfo.org/en/safety/index.cfm?pg=sfty_xray

Remember, there are ways radiation exposure can be fine-tuned to help lower radiation levels. Those who use radiology equipment must be adequately trained in equipment operation and radiation safety principles to protect the patients and personnel that are subject to exposure.

Call me with any questions you may have about CT safety or CT equipment.


Posted by: 

Charla Hurst
General Operations Manager

Charla@ClermontRadiology.com
352-241-6100
www.ClermontRadiology.com