Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started
My Medicine

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Cancer Health Center

Font Size

Are CT Scans Sometimes Too Risky?

Study Shows Radiation Doses From CT Scans Vary Widely
WebMD Health News

Dec. 14, 2009 -- Radiation doses from CT scans are often high and vary widely, and excessively high doses may contribute substantially to future cancers, a study shows.

CT scans are noninvasive medical tests that combine special X-ray equipment and computers to produce detailed cross sectional images of the body. The number of CT scans performed has exploded over the last three decades, growing from about 3 million yearly in 1980 to about 70 million in 2007.

The new study is published in the Archives of Internal Medicine. Study researcher Rebecca Smith-Bindman, MD, of the University of California San Francisco, says the idea for the research began "when I was looking at some individual scans; I was surprised at how high the radiation dose was. I thought it was time to start looking."

The new research comes in the wake of the discovery earlier this year that more than 200 stroke patients at Cedars-Sinai Medical Center in Los Angeles had received more than eight times the necessary radiation dose when undergoing CT scans. That, in turn, prompted the FDA to encourage CT facility personnel to review their protocols and be sure the values displayed on the control panel jibe with doses normally associated with the scan being performed.

In Smith-Bindman's study, researchers evaluated radiation doses given to 1,119 patients getting CT scans and found that ''the differences in radiation exposure were dramatic," she says. "The doses are on one hand higher than they should be, but also the variation [for the same procedure] is much higher than it should be."

The message from her research, Smith-Bindman says, is for doctors and patients not to panic but to become more aware of the issues. She says the findings also point to the need for more oversight of the scans.

Radiation From CT Scans

Smith-Bindman and her team evaluated CT scan patients who were getting care at four San Francisco area facilities in 2008. They calculated the radiation dose involved with each scan.

The doses varied widely between the different types of scans. The median doses (half higher, half lower) ranged from 2 millisieverts (the measures of radiation used in CT scans) for a routine head CT scan to 31 millisieverts for a multiple-phase abdomen and pelvic scan.

1 | 2 | 3

Today on WebMD

Colorectal cancer cells
New! I AM Not Cancer Facebook Group
Lung cancer xray
See it in pictures, plus read the facts.
sauteed cherry tomatoes
Fight cancer one plate at a time.
Ovarian cancer illustration
Real Cancer Perspectives
Jennifer Goodman Linn self-portrait
what is your cancer risk
colorectal cancer treatment advances
breast cancer overview slideshow
prostate cancer overview
lung cancer overview slideshow
ovarian cancer overview slideshow
Actor Michael Douglas