Moderate Doses of Radiation Therapy to Unaffected Breast May Prevent Second Breast Cancers (image) Columbia University Medical Center Share Print E-Mail Caption Breast-cancer rates in breast cancer-prone mice whose mammary glands were treated with different doses of prophylactic mammary irradiation (PMI ), compared with mice whose mammary glands were not treated. At moderate PMI doses of 12 or 16 Gy -- much lower than that used to treat the affected breast -- the breast cancer rate was reduced by about three-fold. Credit Lab of David J. Brenner, Ph.D./Columbia University Medical Center. Usage Restrictions May be used only in the context of this news. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.