When working with ionizing radiation or radioactive materials, it is a federal regulatory requirement that all reasonable efforts be made to maintain exposure to ionizing radiation as far below the dose limits as practical.  ALARA translates as "As Low As Reasonably Achievable" and not only needs to be an integral part of all tasks that involve the use of radiation or radioactive materials but also used as the guiding principle to stay consistent with the purpose for which the activity is undertaken.


There are three major principles that assist in maintaining ALARA and can help prevent both unnecessary exposure and overexposure: time, distance and shielding.


  • Time: Minimize the time spent near a radiation source to only what it takes to get the job done
  • Distance: maximize your distance from a radiation source as much as you can. The greater the distance, the lower the dose
  • Shielding: put something between you and the radiation source.


A common example of how these three principles work together is an x-ray at a doctor’s office. The radiation technician goes behind a barrier while taking the x-ray image to protect them from the repeated daily exposure to radiation.

“Not long after the discovery of ionizing radiation, it became clear that exposure to high doses of such radiation was detrimental to human health. After the bombings that ended World War II, the United States moved toward further investment in both nuclear weaponry and nuclear energy for civilians. The Nuclear Regulatory Commission, laid out increasingly stringent safeguards to protect both civilians and nuclear workers. This effort culminated in the ALARA (As Low As Reasonably Achievable) protocol, which eventually became adopted as the gold standard of nuclear safety.”

Michael Baumer ,March 14, 2015 (http://large.stanford.edu/courses/2015/ph241/baumer2/)

ALARA insures that any work with ionizing radiation or radioactive materials is consistent with the purpose for which the licensed activity is undertaken and that all safety precautions are taken to protect workers.


Watch for more blogs from us on ALARA. You should also check out the RaySafe i3 Real-time Dosimeter which helps people monitor and modify their behavior to reduce radiation exposure.

Large Image


Medium Image

H1 Title: 
ALARA - Keeping Radiation Exposure to a Minimum
Preview Summary: 
ALARA is the guiding principle for all tasks that involve ionizing radiation or radioactive materials. Learn more about the regulatory requirements for ALARA in the first blog of this multi-part series.
I would like to learn more