Fact Sheet

Replacing Cesium-137 Research Irradiators

Part of Preventing a Dirty Bomb: Radiological Security for Hospitals and Research Centers

Replacing Cesium-137 Research Irradiators

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Hospitals and research centers in the United States and around the world are addressing concerns about radiological security, safety and liability by replacing blood irradiators that use radioactive cesium-137 with safe, effective, FDA-approved X-ray technology. 

In addition to the important health and safety concerns associated with a radiological attack, hospitals and research centers face considerable liability and reputation risks. Replacing cesium-137 sources with X-ray technology protects those without insurance to cover losses associated with acts of terrorism—losses that easily could cause financial devastation for an institution responsible for paying huge damages in the wake of a dirty bomb explosion using stolen material.  

If an institution chooses to continue using cesium-137 devices, those who oversee operations including radiation, health, safety and security department, have an obligation to ensure the devices are used in a safe and secure matter, compliant with state and/or federal regulations. They also must inform senior management about risks associated with the devices. End users, including doctors, technicians, and researchers, also should be informed about security risks and threats, and provided with information about alternative technologies.

Ready to switch to a safe technology? Here is where to start:

  1. Learn more about available alternative technologies: There are a more than 20 models of commercially available research irradiators that use X-ray technology. This detailed chart, created by the University of California, compares the irradiators to help you determine what can best meet your needs.
  2. Learn about your local regulations and requirements. Determine who oversees licenses and inspections of radiological devices in your state to find out what steps are necessary to terminate or amend your cesium-137 licenses. Regulators may also be able to inform you about solutions or replacement initiatives in your home state. Information about your local regulator, either at the state or federal level, is available through the U.S. Nuclear Regulatory Commission here.
  3. Find out if you qualify for federal funding help through the Cesium Irradiator Replacement Project. The Cesium Irradiator Replacement Project offered by the National Nuclear Security Administration’s Office of Radiological Security provides incentives for qualified sites to make the switch. These include:
  • Removal and disposal of the cesium-137 irradiator, saving the site approximately $100–$200k per irradiator.
  • A limited financial payment towards the purchase of the new non-radioisotopic device, up to 50% of the purchase price. The payment will be disbursed when the cesium device has been removed and the non-radioisotopic device has been installed.
  • Training, warranty/maintenance agreement costs, and spare part costs are the responsibility of the site.

Learn more about the Cesium Irradiator Replacement Project here. Contact the Office of Radiological Security at [email protected].


There were increasing regulations over security issues with our cesium irradiators...we needed to switch over to something that was more usable, has more flexibility, more people can do things with it, plus it has less liability." — Colin Hill, PhD, Professor Emeritus, University of Southern California, Keck School of Medicine in Los Angeles, California, on USC's switch to x-ray irradiators for research

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Treatment, Not Terror


Treatment, Not Terror

Recent terrorist attacks have renewed concerns that terrorists could use widely available radiological sources to carry out an attack. Reducing the use of high-risk sources can help reduce this potential threat from occurring.


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