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Gamma Irradiation

The gamma irradiation process uses Cobalt 60 radiation to kill microorganisms on a variety of different products. Processing with gamma yields quick turnaround time, easily penetrating packaging and product, and is ideal for many types of materials.

History of gamma irradiation

  • 1895 – W.C. Roentgen discovers X-rays
  • 1896 – A.H. Becquerel observes radiation emitted from uranium
  • 1897 – J. Thompson discovers the electron
  • 1898 – Marie & Pierre Curie discover several radioactive elements and first use the terms “radioactive” and “radio activity”
  • 1963 – The first gamma irradiator in the US was installed in New Jersey for the processing of medical devices

How does gamma irradiation work?
High-energy photons are emitted from an isotope source (Cobalt 60) producing ionization (electron disruptions) throughout a product. In living cells, these disruptions result in damage to the DNA and other cellular structures. These photon-induced changes at the molecular level cause the death of the organism or render the organism incapable of reproduction. The gamma process does not create residuals or impart radioactivity in processed products.

What is gamma irradiation used for?
This process can effectively sterilize a wide variety of products composed of different materials, with varying densities, configurations and orientations.

Gamma radiation is ideal for:

  • Sterilization of single-use medical supplies such as syringes, implants, catheters, IV sets, surgical gloves, gauze and more
  • Elimination of organisms from pharmaceuticals such as ointments and solutions
  • Microbial reduction on consumer products
  • For a complete list of products commonly treated with gamma radiation, please see Technical Tip # 4

What is a typical gamma processing cycle?

  • The product arrives on a truck and is unloaded at the processing facility.
  • The product is received by lot and product code that is entered into the STERIS Isomedix Operating Data Management System (ODMS) which provides for run generation, scheduling, processing, certification and release of product for shipment
  • The product is loaded into the carrier/tote per established configurations, dosimeters are placed, and the product is exposed to the radiation field (Cobalt 60 source rack)
  • Dosimeters are analyzed after irradiation of the product is complete, to confirm that the required dose has been delivered
  • All documentation and processing history records are reviewed, and if they are acceptable and Customer specifications are met, the product is released and shipped for use or further distribution