BELLEVILLE, Ill. (AP) — Illinois regulators have suspended the breast-imaging operations of a radiology center in Belleville following a review that found major quality problems.

The Belleville News-Democrat reports that more than 2,000 patients of Belleville Imaging are receiving letters telling them they need to have their mammograms reviewed. Some may need repeat mammograms.

Mammograms are tests that screen for breast cancer. They’re also used to check patients who were treated for breast cancer in the past.

Officials say Belleville Imaging failed to meet quality standards established by the American College of Radiology as required by Illinois. The American College of Radiology’s report states the facility’s practice posed a “serious risk to human health.”

That worries patient Mary Nettleton of Belleville. She had three exams during the period the facility was reviewed.