Gamma Irradiation Processing

The gamma irradiation process uses Cobalt 60 radiation for a variety of applications, including sterilization, decontamination and materials modification. Gamma irradiation offers good penetration of dense products and is ideal for many types of materials and their packaging.

What is Gamma Irradiation?

Cobalt-Glow-4The gamma irradiation process uses Cobalt 60 radiation to kill microorganisms on a variety of different products in a specially designed cell. Gamma radiation is generated by the decay of the radioisotope Cobalt 60, with the resultant high energy photons being an effective sterilant. A key characteristic of gamma irradiation is the high penetration capability, which allows for delivery of target radiation dose to areas of products that may be higher in density.

The unit of absorbed dose is kiloGray, expressed as kGy. Delivery and absorption of dose by product is determined by product density, packaging size, dose rate, exposure time and facility design.

What is Gamma Irradiation Used For?

The gamma irradiation process can effectively treat a wide variety of products composed of different materials, with varying densities, configurations and orientations. Some examples of products processed include:

  • Medical devices
  • Pharmaceuticals
  • Combination drug/device products
  • Tissue-based and biological products
  • Animal retail products
  • Archives
  • Cosmetics and toiletries
  • Horticultural supplies
  • Packaging materials

For a comprehensive list of products commonly treated by gamma irradiation, please see Technical Tip # 4

What are the Benefits of Gamma Irradiation?

Gamma irradiation is safe, reliable and highly effective at treating a wide variety of products with varying densities. With the ability to penetrate products while sealed in their final packaging, gamma irradiation supports the manufacturing and distribution process by facilitating final packaged products as well as raw material needs, ensuring full sterility of the product.


Gamma sterilization is supported by the internationally recognized consensus standard, ISO 11137, which describes the approach to validating a dose to achieve a defined sterility assurance level (SAL).

Gamma Irradiation Support Services:

In addition to irradiation sterilization, STERIS AST provides our Customers with laboratory testing and technical support solutions at every stage of the sterilization design process, from product development through routine processing.

Our Radiation TechTeam® guides Customers through the irradiation validation process, provides solutions for unique project needs, and supports routine processing through quarterly dose audits.

The Radiation Technology Center (RTC) supports our Customers with radiation test activities such as product trials, dose establishment and dose verification. The RTC provides high-precision dose delivery for validation, dose mapping, dose audit, and research purposes.

Our testing services provide Customers with validation support and microbial testing of their products proceed with irradiation. As part of our complete radiation validation program, we will develop a protocol, assemble all testing and validation data, summarize results and make recommendations based on your product, as well as provide on-going support through a dedicated Radiation TechTeam Project Manager. Go here to learn more about our testing services available.

View our TechTeam Resources to learn more about the gamma irradiation process.

Gamma Irradiation Summary

Gamma Icon


Gamma irradiation exposes products to a Cobalt 60 radiation field

Technology Variables

  • Time in Cell
  • Isotope Load
  • Product Conveyance

Product Considerations

    • Compatible with most materials
    • Good penetration on dense products

Possible Effects


On certain materials, embrittlement, discoloration, change in viscosity due to irradiation

Exposure Time


    • (time varies based on dose requirements)


As a global leading sterilization and contamination control specialist, STERIS AST has over 40 years experience in providing safe and effective gamma irradiation sterilization.

Contact our team of experts to find out more about our Global Contract Sterilization, Testing and Validation Services.