Many of us grew up in an era of perpetual fear about the threat of nuclear war and were warned repeatedly about the dangers of radiation in any setting – including in lifesaving circumstances, like a computed tomography scan in a hospital. But new evidence suggests those warnings were ill-founded, and may have had an unfortunate negative impact on patient care.

The model used to estimate cancer risk from exposure to low-dose radiation is called the Linear No-Threshold model. Devised in the 1950s, this model assumes that a person's risk for developing cancer from ionizing radiation is directly proportional to the level of radiation exposure he or she received. In other words, the LNT model holds that radiation exposure is always harmful at any dose above zero – the only variable is the extent to which it is harmful.

The problem is that the LNT model was developed based only on extremely high, acute exposures to radiation from atomic bombs. The effects of these extreme radiation doses were plotted on a graph, and then a straight line back to zero was drawn without any validation and/or additional research on how human cells react to low levels of radiation exposure. As it turns out, newer research shows cells actually heal themselves after exposure to low levels of radiation. For example, there is no evidence of higher cancer rates in nuclear power plant workers, who are routinely exposed to significantly higher levels of radiation, levels still considered to be low, than the general public.

Unfortunately, the LNT model has contributed to a widely-held perception that radiation does more harm than good for patients who depend on advanced imaging to obtain correct diagnoses. Concerns over low doses of radiation from CT and X-ray scans are not only misguided, but may lead to more deaths from missed or delayed diagnosis than would be derived from radiation exposure.

Radiation exposure was cited in recent U. S. Preventive Service Task Force screening recommendations for CT colonography and mammography. MedPAC and the Centers for Medicare & Medicaid Services have also held the supposed negative effects of low-dose radiation against medical imaging technologies. The result? Policies that limit access to imaging and may lower the possibility that diseases will be detected early, when they are easier to treat. Patients should not be victims of the unfounded fears driving these guidelines.

Science and technology are the bedrock of American innovation, particularly in the field of medicine. Why, then, should regulators continue to rely on an outdated model that only serves to limit progress in medical technology? The LNT model may have once played an important role by providing a measuring stick at a time when none other existed, but that era is long gone.

Evaluating the risks and benefits of low-dose radiation exposure through an updated model driven by new research is essential for providing patients the best care. The medical community is leading the charge to enhance all aspects of patient safety. For example, the Choosing Wisely® campaign is sparking a national dialogue on avoiding wasteful or unnecessary medical tests, treatments and procedures. Physicians are guided by evidence-based Appropriate Use Criteria to inform medical imaging decisions. In addition, the American College of Radiology has an accreditation process to ensure physicians interpreting scans have met stringent education and training standards, technologists operating equipment are certified by the appropriate body and imaging equipment is surveyed regularly and takes optimal images.

The notion that all radiation is harmful has been embedded in our psyche through unfounded fears that have been propagated by misinformed messaging. As we continue to move toward a more personalized approach to medicine, dependent on standards that support transparency, we must finally and decisively abandon the LNT model. Only then will we be able to begin work on repairing its damaging effects that, for the sake of our patients, we cannot afford to let linger any longer.