IEEE/ANSI N42.45-2021

This document establishes standard test methods and test objects for measuring the imaging performance of x-ray computed tomography (CT) security-screening systems. The quality of data for automated analysis is the primary concern. This document does not address the system’s ability to use this image data to automatically detect explosives or other threat materials, nor is it intended for vendor-to-vendor comparisons of threat-detection performance. This standard does not purport to address radiation safety and health practices associated with CT security-screening systems; users are advised to determine the applicability of regulatory limitations prior to use. Four annexes are included. Annex A is a bibliography (informative). Annex B (normative) provides mechanical drawings of the imaging test objects that compose the test article. A sample test report form is given in Annex C (informative). Finally, Annex D (informative) offers statistical guidance on multiple scans, summary statistics, and comparison of results.

Security screening systems are generally used to scan parcels, including luggage, for the presence of illicit items such as explosives, drugs, or other contraband. Many of the screening systems currently used, particularly in transportation security applications, are based on CT imaging technology. Generally, as the parcel is transported through the system, the system collects a CT image of the parcel. These data are then subjected to automated analysis to determine whether a threat may be present or the parcel is considered clear. If the automated analysis determines a threat may be present, the image is often presented to a system operator who can override the automated decision, clearing the parcel, or referring it for further processing such as opening it and manually searching for threats.

Revision Standard - Active. Standard test methods for the evaluation of image quality of computed tomography security-screening systems are established in this document. The quality of data for automated analysis is the primary concern. The system’s ability to use this image data to automatically detect explosives or other threat materials, which is typically verified by an appropriate regulatory body, is not addressed in this standard.