More questions are emerging about the value of the screening intended to detect breast cancer.
In one of the most expansive studies to date, Canadian researchers found routine mammograms did not reduce breast cancer death rates.
They profiled nearly 90,000 women over 25 years and found the screening did not save lives. Nearly 25-percent of the time, the screenings led to false alarms.
Other researchers are calling this latest study flawed using 1980's technology.
Doctors admit mammograms are not perfect but they are one tool that can detect a problem.