Researchers reduce radiation dose to lens during neck CT examinations by 89%

A team of researchers from the National Institutes of Health was able to significantly reduce radiation dose to the lens and other radiosensitive organs during neck CT examinations by making straightforward modifications to both the imaging equipment and the patient’s positioning, according to a new study published in the American Journal of Roentgenology.

“The lens of the eye is one of the most radiosensitive tissues in the human body,” wrote author Choonsik Lee, PhD, Radiation Epidemiology Branch of the National Cancer Institute, and colleagues. “Radiation-induced cataracts are of concern to patients undergoing head or neck CT examinations and to radiologists, technicians, and other clinical staff involved in fluoroscopy procedures.”

The team’s modifications included reducing the scanning range and reducing the tube potential. In addition, neck positioning was updated using a head title. To test the effectiveness of these changes, the authors retrospectively analyzed data from 20 CT examinations before implementation of these new rules in October 2013 and 20 examinations after implementation.

Overall, the group’s modifications reduced the median dose to the lens by 89 percent. Reductions were also observed in the median doses to the brain (59 percent), pituitary gland (52 percent), globes (66 percent) and salivary glands (29 percent).

“The new scanning procedure made neck CT safer by reducing the lens dose per CT examination from 14.3 to 1.6 mGy,” the authors wrote. “Positioning the neck in extension will limit a patient's risk for radiation-induced cataracts, while still allowing the inclusion of critical neck structures in the CT study.”