Overview
ISO 15708-1:2024 - Non-destructive testing (NDT) - Radiation methods for computed tomography - Part 1: Vocabulary is the third edition of the ISO vocabulary specific to computed tomography (CT) used in NDT. This standard defines and clarifies terminology used across CT imaging, radiography and related radiation methods. It consolidates CT-specific terms (e.g., CT image, CT projection, voxel) alongside more generic imaging terms (e.g., absorption, Compton scattering), helping professionals use consistent language in CT inspection, reporting and standards work.
Key topics
The document provides authoritative, standardized definitions for terms that underpin CT-based non-destructive testing:
- Fundamental radiation interactions: absorption (photoelectric absorption) and Compton scattering
- CT acquisition concepts: CT projection, CT scan, angular increment, ray path, sinogram
- Scanning geometries and modes: cone beam CT, fan beam CT, parallel beam CT
- Image and voxel concepts: CT image (tomogram), CT grey value, voxel, pixel, CT slice, CT volume, slice thickness
- Image quality effects: beam hardening, cupping effect, partial volume effect, density resolution
- Metrology and workflow terms: calibration template (phantom), reconstruction, region of interest (ROI), local tomography (region of interest CT)
- Measurement fundamentals: X-ray attenuation, linear attenuation coefficient
The 2024 edition corrects and refocuses several definitions (notably terms 3.8, 3.9, 3.20 and 3.27) and contains no normative references. The vocabulary is intended to be used with ISO and IEC terminology resources (ISO Online Browsing Platform and IEC Electropedia).
Applications and who uses it
ISO 15708-1:2024 is designed for anyone working with CT in non-destructive testing and industrial imaging:
- NDT engineers and CT operators standardizing inspection language and procedures
- Equipment manufacturers and software developers ensuring consistent feature naming (voxel, CT grey value, reconstruction)
- Quality managers and inspectors writing test reports, specifications and acceptance criteria
- Standards writers, auditors and regulators harmonizing terminology across documents and audits
- Trainers and educators developing CT and radiography curricula
Practical uses include: preparing inspection procedures, defining procurement specifications, specifying acceptance criteria, ensuring interoperability between CT systems and software, and improving clarity in technical reports.
Related standards and resources
- ISO 15708 series (other parts cover methods and requirements)
- ISO Online Browsing Platform and IEC Electropedia for standardized terminology and cross-references
- ISO/IEC Directives (editorial guidance used in drafting this document)
Using ISO 15708-1:2024 helps organizations and practitioners achieve consistent, unambiguous CT terminology-critical for reliable industrial computed tomography, accurate NDT reporting, and international collaboration.