Opinion Paper/CommentaryTime to Reject the Linear-No Threshold Hypothesis and Accept Thresholds and Hormesis A Petition to the U.S. Nuclear Regulatory CommissionMarcus, Carol S. PhD, MDAuthor Information From the David Geffen School of Medicine at the University of California at Los Angeles, Los Angeles, CA. Received for publication March 12, 2015; revision accepted March 26, 2015. Conflicts of interest and sources of funding: none declared. Reprints: Carol S. Marcus, PhD, MD, David Geffen School of Medicine at the University of California at Los Angeles, 1877 Comstock Avenue, Los Angeles, CA 90025-5014. E-mail: firstname.lastname@example.org. Clinical Nuclear Medicine: July 2015 - Volume 40 - Issue 7 - p 617-619 doi: 10.1097/RLU.0000000000000835 Buy Metrics Abstract On February 9, 2015, I submitted a petition to the U.S. Nuclear Regulatory Commission (NRC) to reject the linear-no threshold (LNT) hypothesis and ALARA as the bases for radiation safety regulation in the United States, using instead threshold and hormesis evidence. In this article, I will briefly review the history of LNT and its use by regulators, the lack of evidence supporting LNT, and the large body of evidence supporting thresholds and hormesis. Physician acceptance of cancer risk from low dose radiation based upon federal regulatory claims is unfortunate and needs to be reevaluated. This is dangerous to patients and impedes good medical care. A link to my petition is available: http://radiationeffects.org/wp-content/uploads/2015/03/Hormesis-Petition-to-NRC-02-09-15.pdf, and support by individual physicians once the public comment period begins would be extremely important. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.