The reports presented at the annual meeting of the Radiological Society of North America say the recommendations may lead to missed cancer for women in their 40s and a decrease in mammography screening.
In 2009, the U.S. Preventive Services Task Force ignited a controversy when it recommended against routine screening for most women in their 40s and advised less frequent screening for older women.
That's out of step with advice from other groups urging women to get yearly mammograms starting at age 40.
And another study says women don't have to worry about the tiny amount of radiation that's emitted during a mammogram. Researchers used sensors placed around the body to confirm radiation to areas near the breast do not result in an increased risk of cancer.
Researchers claim the dose is so low that lead shielding of other parts of the body, including the thyroid, is unnecessary.
"Number one, the thyroid collars can get in the way of the mammogram pictures, and number two, that the dose is very, very low," said Dr. Alison Chetlen, a radiologist at Penn. St. Medical Center. "We know that the thyroid gland isn't exposed directly to the x-ray beam. The scatter radiation dose from a mammogram to the thyroid is very low."
Researchers also stress that after age 30 the thyroid gland is far less sensitive to radiation.