Name: ASTM E1647-16(2022) - Standard Practice for Determining Contrast Sensitivity in Radiology
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Abstract

Standard Practice for Determining Contrast Sensitivity in Radiology

SIGNIFICANCE AND USE
5.1 The contrast sensitivity gauge measures contrast sensitivity independent of the imaging system spatial resolution limitations. The thickness recess dimensions of the contrast sensitivity gauge are large with respect to the unsharpness limitations of most imaging systems. Four levels of contrast sensitivity are measured: 4 %, 3 %, 2 %, and 1 %.
5.2 The contrast sensitivity gauge is intended for use in conjunction with a high-contrast resolution measuring gauge, such as Practice E2002, ISO 19232 – 5 Duplex Wire Image Quality Indicator7, or a line-pair gauge. Such gauges measure system unsharpness essentially independent of the imaging system's contrast sensitivity. Such measurements are appropriate for the qualification and performance monitoring of radiographic and radioscopic imaging systems with film, realtime devices, Computed Radiography (CR) and Digital Detector Arrays (DDA).
5.3 Radioscopic/radiographic system performance may be specified by combining the measured contrast sensitivity expressed as a percentage with the unsharpness expressed in millimetres of unsharpness. For the duplex wire image quality indicator, the unsharpness is equal to twice the wire diameter. For the line pair gauge, the unsharpness is equal to the reciprocal of the line-pair/mm value. As an example, an imaging system that exhibits 2 % contrast sensitivity and images the 0.1 mm paired wires of the duplex wire IQI (equivalent to imaging 5 line-pairs/millimeter resolution on a line-pair gauge) performs at a 2 %–0.2 mm sensitivity level. A standard method of evaluating overall radioscopic system performance is given in Practice E1411 and in EN 13068–1. A conversion table from duplex wire read out to lp/mm can be found in Practice E2002. For CR system performance evaluation, this contrast sensitivity gauge is used in Practice E2445.
SCOPE
1.1 This practice covers the design and material selection of a contrast sensitivity measuring gauge used to determine the minimum change in material thickness or density that may be imaged without regard to unsharpness limitations.
1.2 This practice is applicable to transmitted-beam radiographic imaging systems (film, radioscopy, computed radiography, and digital detector array image detectors) utilizing X-ray and gamma ray radiation sources.
1.3 The values stated in inch-pound units are to be regarded as standard. The SI units given in parentheses are for information only.
1.4 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. For specific safety statements, see NIST/ANSI Handbook 114 Section 8, Code of Federal Regulations 21 CFR 1020.40 and 29 CFR 1910.96.
1.5 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.

General Information

Status

Published

Publication Date

30-Nov-2022

ICS

11.040.50 - Radiographic equipment

Technical Committee

E07 - Nondestructive Testing

Drafting Committee

E07.01 - Radiology (X and Gamma) Method

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ASTM E1647-16(2022) - Standard Practice for Determining Contrast Sensitivity in Radiology

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ASTM E1647-16(2022) - Standard...

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.
Designation: E1647 − 16 (Reapproved 2022)
Standard Practice for
1
Determining Contrast Sensitivity in Radiology
This standard is issued under the ﬁxed designation E1647; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope B161Speciﬁcation for Nickel Seamless Pipe and Tube
B164Speciﬁcation for Nickel-Copper Alloy Rod, Bar, and
1.1 Thispracticecoversthedesignandmaterialselectionof
Wire
a contrast sensitivity measuring gauge used to determine the
B166Speciﬁcation for Nickel-Chromium-Aluminum Alloy,
minimum change in material thickness or density that may be
Nickel-Chromium-IronAlloys,Nickel-Chromium-Cobalt-
imaged without regard to unsharpness limitations.
Molybdenum Alloy, Nickel-Iron-Chromium-Tungsten
1.2 This practice is applicable to transmitted-beam radio-
Alloy, and Nickel-Chromium-Molybdenum-CopperAlloy
graphic imaging systems (ﬁlm, radioscopy, computed
Rod, Bar, and Wire
radiography, and digital detector array image detectors) utiliz-
E747PracticeforDesign,ManufactureandMaterialGroup-
ing X-ray and gamma ray radiation sources.
ing Classiﬁcation of Wire Image Quality Indicators (IQI)
1.3 Thevaluesstatedininch-poundunitsaretoberegarded
Used for Radiology
as standard.The SI units given in parentheses are for informa-
E1025Practice for Design, Manufacture, and Material
tion only.
Grouping Classiﬁcation of Hole-Type Image Quality In-
1.4 This standard does not purport to address all of the
dicators (IQI) Used for Radiography
safety concerns, if any, associated with its use. It is the
E1255Practice for Radioscopy
responsibility of the user of this standard to establish appro-
E1316Terminology for Nondestructive Examinations
priate safety, health, and environmental practices and deter-
E1411Practice for Qualiﬁcation of Radioscopic Systems
mine the applicability of regulatory limitations prior to use.
E1734Practice for Radioscopic Examination of Castings
For speciﬁc safety statements, see NIST/ANSI Handbook 114
E1742Practice for Radiographic Examination
Section 8, Code of Federal Regulations 21 CFR 1020.40 and
E2002Practice for Determining Image Unsharpness and
29 CFR 1910.96.
Basic Spatial Resolution in Radiography and Radioscopy
1.5 This international standard was developed in accor-
E2445Practice for Performance Evaluation and Long-Term
dance with internationally recognized principles on standard-
Stability of Computed Radiography Systems
ization established in the Decision on Principles for the
3
Development of International Standards, Guides and Recom-
2.2 Federal Standards:
mendations issued by the World Trade Organization Technical
21CFR 1020.40 Safety Requirements for Cabinet X-ray
Barriers to Trade (TBT) Committee.
Systems
29CFR 1910.96 Ionizing Radiation
2. Referenced Documents
4
2.3 NIST/ANSI Standards:
2
2.1 ASTM Standards:
NIST/ANSI Handbook 114General Safety Standard for
B139/B139MSpeciﬁcation for Phosphor Bronze Rod, Bar,
Installations Using Non-Medical X-ray and Sealed
and Shapes
Gamma Ray Sources, Energies to 10 MeV
B150/B150MSpeciﬁcation forAluminum Bronze Rod, Bar,
5
2.4 ISO Standard:
and Shapes
ISO 19232–5Duplex Wire Image Quality Indicator
1
This practice is under the jurisdiction of ASTM Committee E07 on Nonde-
structive Testing and is the direct responsibility of Subcommittee E07.01 on
3
Radiology (X and Gamma) Method. AvailablefromU.S.GovernmentPrintingOfficeSuperintendentofDocuments,
Current edition approved Dec. 1, 2022. Published December 2022. Originally 732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http://
approved in 1994. Last previous edition approved in 2016 as E1647–16. DOI: www.access.gpo.gov.
4
10.1520/E1647-16R22. AvailablefromAmericanSocietyforNondestructiveTesting(ASNT),P.O.Box
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 28518, 1711Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org.
5
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Available from International Organization for Standardization (ISO), ISO
Standards volume information, refer to the standard’s Document Summary page on Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,
the ASTM website. Geneva, Switzerland, http://www.iso.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E1647 − 16 (2022)
6
2.5 Other Standards:
...

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SIGNIFICANCE AND USE
4.1 This practice is intended to be used by the DDA user to measure and record the baseline performance of an acquired DDA in order to monitor its performance throughout its service as an imaging system. This practice is not intended to be used as an “acceptance test” of a DDA.
4.2 This practice defines the tests to be performed and their required intervals. Also defined are the methods of tabulating results that DDA users will complete following initial baselining of the DDA system. These tests will also be performed periodically at the stated required intervals to evaluate the DDA system to determine if the system remains within acceptable operational limits as established in this practice and defined between the user and CEO.
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SCOPE
1.1 This practice covers the baseline and periodic performance evaluation of Digital Detector Array (DDA) systems used for industrial radiography. It is intended to ensure that the evaluation of image quality, as far as this is influenced by the DDA system, meets the needs of users, and their customers, and enables process control to monitor long-term stability of the DDA system.
1.2 This practice specifies the fundamental parameters of DDA systems to be measured to determine baseline performance, and to track the long-term stability of the DDA system.
1.3 The DDA system tests specified in this practice shall be completed upon acceptance of the system from the manufacturer to baseline the performance of the DDA. Periodic performance testing shall then be used to monitor long-term stability of the system in order to identify when an action needs to be taken due to system degradation beyond a certain defined level.
1.4 Two types of phantoms, the duplex plate and the five-groove wedge, are used for testing as specified herein. The use of these two types of phantoms is not intended to exclude the use of other phantom configurations. In the event the tests or phantoms specified herein are not sufficient or appropriate, the user, in coordination with the cognizant engineering organization (CEO) may develop additional or modified tests, test objects, phantoms, or image quality indicators to evaluate the DDA system performance. Acceptance levels for these ALTERNATE test methods shall be determined by agreement between the user and CEO.
1.5 The user of this practice shall consider that higher energies than 450 keV may require different test methods or modifications to the test methods described here. This practice is not intended for usage with isotopes.
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Standard Guide for Digital Neutron Radiography

SIGNIFICANCE AND USE
4.1 Purpose—Practices to be employed for the radiographic examination of materials and components with neutrons using digital neutron detectors are outlined herein. They are intended as a guide for the assessment of a digital neutron radiograph’s characteristics. For information on neutron beam lines for imaging and film neutron radiography, refer to Guide E748.
4.2 Limitations—Acceptance standards have not been established for any material or production process. Neutron radiography, whether performed by means of a reactor, an accelerator, subcritical assembly, or radioactive source, will be consistent in sensitivity and spatial resolution only if the consistency of all details of the technique, such as neutron source, collimation, geometry, imaging system, etc., are maintained. This guide is limited to the use of digital neutron detectors in combination with neutron conversion materials for image recording. This guide is intended for use with thermal and cold neutron spectrums. The production of thermal neutron radiographs by employing the use of film and appropriate conversion screens is covered in Guide E748.
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SCOPE
1.1 This guide covers the evaluation, qualification, and quantification of digital neutron images. These images can be acquired by many methods, including: neutron sensitive imaging plates (Computed Radiography – CR), Digital Detector Arrays – DDA’s (amorphous silicon, CMOS, CCD, etc.), micro-channel plates, neutron sensitive fluoroscopes, neutron sensitive scintillators coupled to optical cameras, digitized radiographic films, and linear diode arrays.
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1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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SIGNIFICANCE AND USE
4.1 This standard provides a guide for the other DDA standards (see Practices E2597, E2698, and E2737). It is not intended for use with computed radiography apparatus. Figure 1 describes how this standard is interrelated with the aforementioned standards.
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SCOPE
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SIGNIFICANCE AND USE
5.1 Principal Advantage of Compton Scatter Tomography—The principal advantage of CST is the ability to perform three-dimensional X-ray examination without the requirement for access to the back side of the examination object. CST offers the possibility to perform X-ray examination that is not possible by any other method. The CST sub-surface slice image is minimally affected by examination object features outside the plane of examination. The result is a radioscopic image that contains information primarily from the slice plane. Scattered radiation limits image quality in normal radiographic and radioscopic imaging. Scatter radiation does not have the same detrimental effect upon CST because scatter radiation is used to form the image. In fact, the more radiation the examination object scatters, the better the CST result. Low subject contrast materials that cannot be imaged well by conventional radiographic and radioscopic means are often excellent candidates for CST. Very high contrast sensitivities and excellent spatial resolution are possible with CST tomography.
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SCOPE
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SIGNIFICANCE AND USE
4.1 This practice provides a means to compare DDAs on a common set of technical measurements, realizing that in practice, adjustments can be made to achieve similar results even with disparate DDAs, given geometric magnification, or other industrial radiologic settings that may compensate for one shortcoming of a device.
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SCOPE
1.1 This practice describes the evaluation of Digital Detector Arrays (DDAs), and assures that one common standard exists for quantitative comparison of DDAs so that an appropriate DDA is selected to meet NDT requirements.
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Note 1: Further information on application of DDAs is contained in Guide E2736 and Practices E2698 and E2737.
1.3 The results reported based on this practice should be based on a group of at least three individual detectors for a particular model number.
1.4 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.
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5.1 This guide will aid the purchaser in generating a CT system specification. This guide covers the conversion of purchaser's requirements to system components that must occur for a useful CT system specification to be prepared.
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5.4 This guide is applicable to purchasers needing to procure a CT system for a specific examination application.
SCOPE
1.1 This guide covers guidelines for translating application requirements into computed tomography (CT) system requirements/specifications and establishes a common terminology to guide both purchaser and supplier in the CT system selection process. This guide is applicable to the purchaser of both CT systems and scan services. Computed tomography systems are complex instruments, consisting of many components that must correctly interact in order to yield images that repeatedly reproduce satisfactory examination results. Computed tomography system purchasers are generally concerned with application requirements. Computed tomography system suppliers are generally concerned with the system component selection to meet the purchaser's performance requirements. This guide is not intended to be limiting or restrictive, but rather to address the relationships between application requirements and performance specifications that must be understood and considered for proper CT system selection.
1.2 Computed tomography (CT) may be used for new applications or in place of radiography or radioscopy, provided that the capability to disclose physical features or indications that form the acceptance/rejection criteria is fully documented and available for review. In general, CT has lower spatial resolution than film radiography and is of comparable spatial resolution with digital radiography or radioscopy unless magnification is used. Magnification can be used in CT or radiography/radioscopy to increase spatial resolution but concurrently with loss of field of view.
1.3 Computed tomography (CT) systems use a set of transmission measurements made along a set of paths projected through the object from many different directions. Each of the transmission measurements within these views is digitized and stored in a computer, where they are subsequently conditioned (for example, normalized and corrected) and reconstructed, typically into slices of the object normal to the set of projection paths by one of a variety of techniques. If many slices are reconstructed, a three dimensional representation of the object is obtained. An in-depth treatment of CT principles is given in Guide E1441.
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SIGNIFICANCE AND USE
4.1 The major factors affecting the quality of a CT image are total image unsharpness (UTimage), contrast (Δµ), and random noise (σ). Geometrical and detector unsharpness limit the spatial resolution of a CT system, that is, its ability to image fine structural detail in an object. Random noise and contrast response limit the contrast sensitivity of a CT system, that is, its ability to detect the presence or absence of features in an object. Spatial resolution and contrast sensitivity may be measured in various ways. In this test method, spatial resolution is quantified in terms of the modulation transfer function (MTF), and contrast sensitivity is quantified in terms of the contrast discrimination function (CDF). The relationship between contrast sensitivity and spatial resolution describing the resolving and detecting capabilities is given by the contrast-detail-diagram (CDD metric, see also Guide E1441 and Practice E1570). This test method allows the purchaser or the provider of CT systems or services, or both, to measure and specify spatial resolution and contrast sensitivity and is a measure for system stability over time and performance acceptability.
SCOPE
1.1 This test method provides instruction for determining the spatial resolution and contrast sensitivity in X-ray and γ-ray computed tomography (CT) volumes. The determination is based on examination of the CT volume of a uniform cylinder of material. The spatial resolution measurement (Modulation Transfer Function) is derived from an image analysis of the sharpness at the edges of the reconstructed cylinder slices. The contrast sensitivity measurement (Contrast Discrimination Function) is derived from an image analysis of the contrast and the statistical noise at the center of the cylinder slices.
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1.5 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.
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.