Answer to Question #11300 Submitted to "Ask the Experts"
Category: Instrumentation and Measurements
The following question was answered by an expert in the appropriate field:
My husband was a medical researcher who used cesium irradiators. He died of brain cancer in 2011. A co-worker gave me several boxes of his personal belongings that had been at his workplace. I recently discovered what appears to be a rusted piece of machinery. How can I confirm that this is not contaminated and poses no threat to me or my two young children? Any guidance is appreciated.
Please accept my condolences for the loss of your husband. Not directly related to your question but perhaps worth noting is the fact that while radiation is known to increase the cancer risk for a number of cancer types, possible incidental exposure from the gamma radiation emitted by the cesium source(s) of interest would not yield any significant risk of brain cancer.
Regarding the nature of the cesium irradiators in common use, an important fact you should know is that typical cesium irradiators use sources that are sealed in an appropriate container to prevent loss of radioactive cesium from the source into surrounding areas and materials; by law, the facility licensed to possess and/or use the irradiators is required to perform leak-testing on the devices on a regular basis to demonstrate that the source containment is in tact and no radioactive material is leaking from the source. Additionally, by design, the sources in the irradiators are not accessible directly by personnel. Samples to be irradiated are loaded into the irradiators and moved by remote mechanisms to the source-irradiate position (in some cases the source is moved, also remotely). Given these considerations, and assuming your husband was handling and operating the irradiators in a fashion consistent with manufacturers' and administrative requirements, it should not have been possible for your husband to have removed any part of the irradiator that might have been inadvertently contaminated. Also any material that might have been purposely irradiated in the irradiator would not be radioactive upon removal—i.e., the gamma radiation from the cesium does not induce radioactivity in the irradiated material.
In view of the above I would have no reason to suspect that the piece of metal you refer to would be contaminated with radioactive cesium. If, for whatever reason, you suspect that some action might have been taken or that some event at your husband's work facility might have resulted in a release of radioactive material and that the piece of metal you describe was involved somehow then, at least for your peace of mind, you could attempt to have the metal monitored with a gamma-sensitive radiation detector. If you or someone you know does not have access to such a detector I would suggest that you attempt to contact someone in the radiation control program in your state and explain your concerns. Here is a link to a map that gives the contact information for each responsible individual in every state in the country. Another possibility, if you live reasonably close to a moderate-to-large university, is to identify and contact the radiation safety officer (RSO) at the university. (All universities that use radiation sources in education and/or research and/or medical applications will have an RSO.)
I do not think you have anything to be concerned about. Best wishes.
George Chabot, PhD