With no pain and little discomfort for patients, computed tomography (CT) scans provide physicians with a wealth of information, allowing them to more accurately diagnose and treat disease or injury.

Like most medical imaging procedures, CT scans expose patients to small amounts of radiation, which can add up over time. In the absence of national regulations regarding CT radiation doses, Duke researchers are investigating evidence-based ways to protect patients from excess radiation while maintaining the highest level of image quality.

Reducing Radiation Exposure, Preserving Image Quality

It sounds simple, but reducing exposure takes more than adjusting a knob -- there’s a direct relationship between dose and image quality: as radiation decreases, so does quality.

“If the dose is reduced to a level that the image quality is poor, you’re not doing any service to the patient,” says Ehsan Samei, PhD, professor of radiology, whose research focuses on finding the delicate balance between the two.

“Duke is one of the national leaders in the reduction of radiation dose, especially for pediatric patients,” Samei says.

For years Duke has used a color-coded system to ensure that children receive the right amount of radiation for their size and age. Now researchers hope to develop similar guidelines for all patients.

Using computer-simulated patients -- referred to as phantoms -- Samei and his team are determining the lowest dose needed to obtain high-quality images for any CT scan. Manipulating the phantoms provides data on patient variables such as height, weight, age, and gender.

Less than a year into a NIH-funded project (co-directed by Samei and Paul Segars, PhD), the results are already being used at Duke to optimize select CT procedures.

To further reduce radiation, Duke is transitioning to advanced-reconstruction CT machines, which provide more information than traditional scanners. “Because we take advantage of every iota of information that every snapshot is providing, we can reduce the radiation dose by 30 to 50 percent,” Samei says.

Duke currently has two advanced-reconstruction scanners and will add more over time, starting with the Duke Cancer Center and Duke Medicine Pavilion.

To monitor these efforts, Duke is tracking the amount of radiation used for all CT scans across the medical center. This comprehensive quality control tool ensures that protocol is being followed and allows researchers to independently “verify that we are doing what we think we are doing,” says Samei.