Significance and Use
4.1 Operational qualification (OQ) will be used to demonstrate that the irradiator, as installed, is capable of operating and delivering dose to product being irradiated with defined acceptance criteria by determining dose distribution and magnitude through dose mapping exercises and relating these distributions to process parameters.
4.2 The principle objectives of OQ are to:
4.2.1 Establish the dose distribution and create a baseline PQ grid for mapping actual product,
4.2.2 Establish the relationship for dose uniformity ratio (DUR) as a function of density,
4.2.3 Establish the relationship for cycle time (CT) as a function of density and source activity, and
4.2.4 Establish the relationship for minimum dose (kGy) as a function of density, cycle time and source activity.
4.3 OQ exercises could augment or replace PQ exercises. It is the facility’s responsibility to document the rationale when using OQ data for PQ purposes.
4.4 A design of experiments approach may help rationalize the types of OQ tests needed. For some irradiator changes, the minimum number of densities may be different depending on the degree of anticipated change in dose distribution. These decisions should be covered through a documented change control process. See ISO/ASTM 52701.
4.5 This guide is not intended to address OQ requirements in research or experimental irradiators.
4.6 An irradiation facility is able to process different process load configurations. For example, an irradiation container may be designed to accommodate boxes, sacks and drums. It is important to consider OQ studies that characterize the irradiator for different irradiation geometries.
4.7 The bulk density, dimensions and atomic composition are important properties in dose mapping. See Appendix X2 for examples of materials for potential use in OQ studies.
Scope
1.1 This document provides guidance on operational qualification (OQ) tests to meet the OQ requirements defined in ISO 11137-1, ISO 14470, ISO/ASTM 51702, and ISO/ASTM 52303 for gamma irradiators.
1.1.1 The types of OQ tests are discussed to help the user gain an increased understanding of operational aspects of their irradiator and determine which OQ tests are appropriate for the assessment of irradiator change.
1.1.2 The facility should assess the rationale for the OQ tests chosen and for the ones that have been deemed to be unnecessary.
1.2 Specific requirements for OQ are dependent on the application of the irradiation process and are not within the scope of this guide. For example, requirements for OQ when sterilizing healthcare products can be found in ISO 11137-1.
1.3 A change to the irradiator is a component of the change control process. The OQ testing following the irradiator change is determined as part of the change control documentation and should include rationale to support decision(s) on which tests are required to be completed.
1.4 For an OQ study following an irradiator change, the required OQ tests are defined procedurally with established acceptance criteria. (The OQ tests in the appendixes have examples of defined acceptance criteria with a rationale for the acceptance.) When multiple tests are used in the assessment of change, no individual OQ test should be solely relied upon; rather, the composite of OQ test results should be used to help provide a clear justification for the conclusion regarding irradiator change.
1.5 Many calculations in this guide were completed using Microsoft Excel (for example, ANOVA, t-test, p-value), but numerous other software tools are commercially available.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
