ASTM E1695-20e1 PDF

Full title and description

Standard Test Method for Measurement of Computed Tomography (CT) System Performance — ASTM E1695-20e1 provides procedures and analysis methods for determining overall CT system performance, specifically spatial resolution and contrast sensitivity in X‑ray and γ‑ray computed tomography volumes. The method uses image analysis of reconstructed slices from a uniform cylinder/disk phantom to derive Modulation Transfer Function (MTF) and Contrast Discrimination Function (CDF).

Abstract

This test method defines a repeatable procedure to quantify CT system image quality through two principal measurements: spatial resolution (via MTF from edge analysis of a reconstructed cylinder/disk) and contrast sensitivity (via CDF using low‑contrast features and noise statistics at the phantom center). Results are intended for system performance characterization, acceptance testing and routine quality assurance of industrial and research CT systems using X‑ray or gamma sources.

General information

• Status: Published / Active.
• Publication date: June 1, 2020 (designation E1695‑20; editorial change e1 added subsequently).
• Publisher: ASTM International.
• ICS / categories: 11.040.50 (Radiographic equipment / nondestructive testing imaging).
• Edition / version: E1695‑20e1 — 2020 edition (with editorial amendment e1).
• Number of pages: 13 pages.

Scope

This standard specifies measurements and analysis techniques to determine spatial resolution and contrast sensitivity of computed tomography systems used for nondestructive evaluation. It is applicable to X‑ray and gamma‑ray CT systems and is based on reconstructed image slices of a uniform cylinder or disk phantom; it does not replace component‑level tests for individual system elements (X‑ray tubes, detectors, gamma sources), which are covered in separate guides and practices. Units are SI by convention and users remain responsible for safety and regulatory compliance.

Key topics and requirements

• Measurement of spatial resolution using edge analysis to derive the Modulation Transfer Function (MTF).
• Assessment of contrast sensitivity via Contrast Discrimination Function (CDF) using low‑contrast features and noise statistics.
• Use of a uniform cylinder/disk phantom and standardized reconstruction slices for repeatability.
• Image analysis procedures to extract edge sharpness, noise metrics, and contrast values.
• Guidance on reporting results, units (SI), and limitations (scope excludes component‑only performance tests and specific safety requirements).

Typical use and users

Used for acceptance testing, routine quality assurance, benchmark comparisons and system performance tracking. Typical users include nondestructive testing (NDT) laboratories, CT system manufacturers and service providers, aerospace and defense inspection teams, research institutions using industrial CT, and accreditation/QA personnel responsible for imaging performance verification.

Related standards

Complementary and related ASTM documents include system/component guides and practices such as Guide E1000 and Practices E2737 and E2002 (component/system-level NDT guidance), plus other radiology and NDT practices for contrast and radiographic quality. Users often consult these related documents for broader QA programs and component‑level testing requirements.

Keywords

computed tomography, CT system performance, spatial resolution, modulation transfer function, contrast sensitivity, contrast discrimination function, CT phantom, nondestructive testing, radiographic equipment, image quality

FAQ

Q: What is this standard?

A: ASTM E1695‑20e1 is a Standard Test Method for Measurement of Computed Tomography (CT) System Performance that specifies procedures to quantify spatial resolution and contrast sensitivity of X‑ray and gamma CT systems.

Q: What does it cover?

A: It covers measurement methods using a uniform cylinder/disk phantom and image analysis to derive MTF (spatial resolution) and CDF (contrast sensitivity), plus guidance on reporting results and units. It does not substitute for individual component tests of tubes, detectors, or sources.

Q: Who typically uses it?

A: CT system manufacturers, NDT inspection labs, aerospace/defense inspection teams, research institutions, and QA/accreditation personnel who need a repeatable method to assess or compare CT image quality.

Q: Is it current or superseded?

A: The E1695‑20e1 edition (approved June 1, 2020, with editorial amendment e1 added afterward) is the 2020 revision of the standard and supersedes earlier editions; it is listed as the current published test method. Users should check for any later revisions or amendments before relying on the document for regulatory or contractual work.

Q: Is it part of a series?

A: It sits within ASTM’s nondestructive testing and radiographic standards collection and is typically used alongside related guides and practices (for example Guide E1000 and Practices E2737 / E2002) that cover component testing and broader QA procedures.

Q: What are the key keywords?

A: Computed tomography, CT performance, MTF, contrast sensitivity, CDF, CT phantom, radiographic imaging, nondestructive testing.