Module 14: Design Development and Certification of Medical Devices

17/11/2023

GAMMA RAYS [ISO 11137: 1, 2, 3 ]

– Does not involve high temperatures / high humidity / high pressure

– Reasonably rapid

– Typically uses 60 Cobalt source to provide a specific “dose” – Placement near to the source

Masterclass: Lecture 11

The Organisation for Professionals in Regulatory Affairs

33

GAMMA STERILISATION

 Ionizing radiation causes excitations, ionisations and, where water is present, free radical formation.  Free radicals are powerful oxidising (OH, HO2) and reducing (H) agents, capable of damaging essential molecules in living cells.  All three processes cause disintegration of essential cell constituents such as enzymes and the DNA. This results in cell death.  The most biologically damaging forms of gamma radiation occur in the gamma ray window, between 3MeV and 10MeV.  Cobalt-60 emits gamma radiation at the 1.17MeV and 1.33MeV level, - below the most effective range.

Masterclass: Lecture 11

The Organisation for Professionals in Regulatory Affairs

34

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