Replacing Cesium-137 Research Irradiators

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.


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

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 hereContact the Office of Radiological Security at Learn more about this initiative here.

More questions? Read on.

Are the alternative X-ray devices effective for blood irradiation?

  • The reliability of X-ray devices has improved significantly since the machines were first introduced and X-ray irradiators now offer a direct replacement for Cesium-137 irradiators. Read about Mount Sinai's positive experience replacing their research and blood irradiators with x-ray technology in this report. Watch Dr. Colin Hill from the University of Southern California discuss why USC decided to change its cesium research irradiator to x-ray technology. And click here get to get more details about available alternative and emerging technologies.

  • What are the costs associated with replacement?

  • There are several types of costs to consider, including those associated with: purchasing, facility modification, operating, staff training, technology termination, and liability/insurance. This page provides a detailed overview of lifecycle costs and liability considerations. The worksheet template found within the document can help you decide if replacing cesium-137 irradiators with X-ray technology is the right step for you.

  • How long does the replacement process take?

  • The length of the replacement process can vary, depending on several factors including: your facility requirements, your local licensing procedures, and the manufacturer. This chart from the Cesium Irradiator Replacement Project illustrates the potential steps involved in the replacement process. You can use it to help define a timeline for your own site.

  • What do institutions that have replaced their irradiators have to say?

  • After replacing both their research and blood irradiators with X-ray technology, Mount Sinai Health System in New York says that their transition has been very successful. The X-ray blood irradiators have shown superior capability over their aging cesium-137 counterparts. Click here to read the full story of about Mount Sinai's experience making the switch to X-ray technology.

    Other decision makers in the United States and around the world have taken steps to eliminate the risk of dirty bombs through cesium-137 irradiator replacement. Visit this page to learn more about these leaders taking steps to eliminate radiological risks.

  • Click here to return to the Preventing a Dirty Bomb resources page.

    November 20, 2018

    Cesium-137 research irradiator owners can take steps to eliminate risks by switching to alternative technology.