Quick Facts

Over the years we have answered many, many questions about gamma. Here are some facts to help you broaden your understanding of gamma.

What is the difference between sterilization, disinfection and disinfestation?

Sterilization: The goal is that there will be no viable micro-organisms which could cause infection in a patient. Sterility Assurance Level (SAL) is the probability of a viable micro-organism surviving the irradiation process. For a product to be labeled “sterile,” it must achieve the required SAL for its application; for example, for products that come into contact with compromised human tissue, there can be no more than a one in one million chance of a micro-organism surviving.
Disinfection: The goal is to decrease contamination. The outcome of irradiation is less strict than sterilization but must meet regulatory or manufacturers requirements for consumer safety for food and products.
Disinfestation: The goal is to prevent the spread of agricultural pests such as fruit flies into new geographies. This is mostly relevant to fruit and vegetables imported from tropical or subtropical countries. The dose required to kill pests is much less than the doses required to inactivate micro-organisms.

What is irradiated with gamma rays?

Hundreds of products and materials have been irradiated. Here’s just a small sample.
  • Medical devices
  • Medical supplies
  • Packaging components
  • Medical tissue
  • Spices
  • Ground beef
  • Frozen seafood
  • Produce for import/export
  • Nuclear reactor parts
  • Specialized orthopedics
  • Cosmetics
  • Gemstones
  • Dog chews   

How many irradiators has Nordion built?

Not only does Nordion provide Cobalt-60 to companies that sterilize products, we also manufacture irradiation systems. There are over 200 large-scale irradiation facilities in operation in 45 countries and more than 120 have been built by Nordion.

How does an irradiator work?

Watch this video to see how an irradiator works.

How many medical devices are irradiated in a year?

In the US alone, 200 million cubic feet of medical devices are irradiated each year. To put that number into perspective, the average 40-pound bag of garden mulch is approximately equal to 1 cubic foot. So, imagine 200 million of those.

Why does Cobalt have a blue glow?

When not in use, Cobalt-60 is placed in a pool of de-ionized water, which acts as a shield from the radiation. The radiation gives off a blue glow underwater, known as the Cherenkov Effect, named after the Russian scientist who studied the phenomenon. It’s caused by charged particles travelling faster than the speed that light normally travels through water. The blue glow is the optical equivalent of a sonic boom.

Why is gamma ‘green’?

The impact we all have on the environment is a key consideration for organizations today. Nordion facilities follow strict environmental requirements which we meet and often exceed. Gamma operations use significantly less natural resources than those of EtO and E-Beam because the amount of electricity to run a gamma plant is much smaller and natural gas is not required as is the case with EtO. Irradiator license applicants have a categorical exclusion from having to conduct an environmental impact study, granted by the USNRC. Categorical exclusions are granted to those projects which meet the criteria: “after first finding that the category of actions does not individually or cumulatively have a significant effect on the human environment.”
Learn more on the USNRC website.

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