ASTM E2698-10

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: E2698 − 10
Standard Practice for
Radiological Examination Using Digital Detector Arrays
This standard is issued under the fixed designation E2698; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 This practice establishes the minimum requirements for 2.1 ASTM Standards:
radiological examination for metallic and nonmetallic material E94 Guide for Radiographic Examination
E543 Specification forAgencies Performing Nondestructive
using a digital detector array (DDA) system.
Testing
1.2 The requirements in this practice are intended to control
E747 Practice for Design, Manufacture and Material Group-
the quality of radiologic images and are not intended to
ing Classification of Wire Image Quality Indicators (IQI)
establish acceptance criteria for parts or materials.
Used for Radiology
1.3 This practice covers the radiologic examination with
E1000 Guide for Radioscopy
DDAs including DDAs described in Practice E2597 such as a
E1025 Practice for Design, Manufacture, and Material
device that contains a photoconductor attached to a Thin Film
Grouping Classification of Hole-Type Image Quality In-
Transistor (TFT) read out structure, a device that has a
dicators (IQI) Used for Radiology
phosphor coupled directly to an amorphous silicon read-out
E1316 Terminology for Nondestructive Examinations
structure, and devices where a phosphor is coupled to a CMOS
E1647 Practice for Determining Contrast Sensitivity in Ra-
(Complementary metal–oxide–semiconductor) array, a Linear
diology
Detector Array (LDA) or a CCD (charge coupled device)
E1742 Practice for Radiographic Examination
crystalline silicon read-out structure.
E2002 Practice for DeterminingTotal Image Unsharpness in
Radiology
1.4 The DDA shall be selected for an NDT application
E2597 Practice for Manufacturing Characterization of Digi-
based on knowledge of the technology described in Guide
tal Detector Arrays
E2736, and of the selected DDA properties provided by the
E2736 Guide for Digital Detector Arrays
manufacturer in accordance with Practice E2597.
E2737 Practice for Digital Detector Array Performance
1.5 The requirements of this practice and Practice E2737
Evaluation and Long-Term Stability
shall be used together and both be approved by the CEO Level
2.2 AWS Documents:
3 in Radiography before inspection of production hardware.
AWSA2.4 Symbols forWelding and NondestructiveTesting
The requirements of Practice E2737 will provide the baseline
2.3 Aerospace Industries Association Document:
evaluation and long term stability test procedures for the DDA
NAS 410 Certification & Qualification of Nondestructive
system.
Test Personnel
1.6 The requirements in this practice shall be used when
2.4 Government Standards:
placing a DDAinto NDT service and, before being placed into
NIST Handbook 114 General Safety Standard for Installa-
service, an established baseline of system qualification shall be
tions Using Non-medical X-ray and Sealed Gamma Ray
performed in accordance with Practice E2737.
Sources, Energies up to 10 MeV
1.7 Techniques and applications employed with DDAs are
DoD Contracts any specifications called out on the DoDISS
diverse. This practice is not intended to be limiting or restric-
(Department of Defense Index of Specifications and
tive. Refer to Guides E94, E1000, E2736,Terminology E1316,
Practice E747 and E1025, Fed. Std. Nos. 21CFR 1020.40 and
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
29 CFR 1910.96 for a list of documents that provide additional
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
information and guidance.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Available from American Welding Society (AWS), 550 NW LeJeune Rd.,
Miami, FL 33126, http://www.aws.org.
1 4
This practice is under the jurisdiction of ASTM Committee E07 on Nonde- Available fromAerospace IndustriesAssociation ofAmerica, Inc. (AIA), 1000
structive Testing and is the direct responsibility of Subcommittee E07.01 on WilsonBlvd.,Suite1700,Arlington,VA22209-3928,http://www.aia-aerospace.org.
Radiology (X and Gamma) Method. Available from National Institute of Standards and Technology (NIST), 100
Current edition approved April 15, 2010. Published July 2010. Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http://www.nist.gov.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2698 − 10
Standards) cited in the solicitation. 3.2.11 window width and level—contrast (window width)
21-CFR-1020.40 Safety Requirements of Cabinet X-ray andbrightness(windowlevel)adjustmentofadigitalimageby
Systems changing how the Gray levels translate into displayed bright-
29-CFR-1910.96 Ionizing Radiation ness levels.
NCRP 144 Radiation Protection for Particle Accelerator
3.2.12 signal-to-noise ratio (SNR)—quotient of mean value
Facilities
of the intensity (signal) and standard deviation of the intensity
SMPTE RP 133 Specifications for Medical Diagnostic Im-
(noise). The SNR depends on the radiation dose and the DDA
agingTest Pattern forTelevision Monitors and Hard-Copy
system properties.
Recording Cameras
3.2.13 contrast-to-noise ratio (CNR)—quotient of the dif-
ference in the mean values of the intensity (signal) in an area
3. Terminology
in the object subtracted from the mean value of the intensity of
3.1 Definitions relating to the radiological examination,
the background, and standard deviation of the intensity (noise).
which appear in Terminology E1316, shall apply to the terms
The CNR depends on the radiation dose and quality, thickness/
used in this practice. attenuation of the object and the DDA system properties.
3.2 Definitions of Terms Specific to This Standard: 3.2.14 basic spatial resolution (SRb)—indicatesthesmallest
geometrical detail, which can be resolved using the DDA. It is
3.2.1 component—the part(s) or element of a system as-
similartotheeffectivepixelsize/pitchandcorrespondsto ⁄2of
sembled or processed to the extent specified by the drawing,
the measured unsharpness.
purchase order, or contract.
3.2.15 ghosting—residual signal or image from a prior
3.2.2 energy—a property of radiation that determines the
exposure in a current image. Signal or image can be negative
penetratingability.Inx-rayradiography,energymachinerating
or positive and may affect interpretation of the image.
is determined by kilo electron volts (keV), million electron
volts (MeV). In gamma ray radiography, energy is a charac-
3.2.16 bad pixel—a pixel identified with a performance
teristic of the source used.
outside of the specification range for a pixel of a DDA as
defined in Practice E2597.
3.2.3 like section—a separate section of material that is
similar in shape and cross section to the component or part
3.2.17 relevant cluster—a cluster with a cluster kernel pixel
being radiologically inspected, and is made of the same or (CKP), where there are fewer than five good neighboring
radiologically similar material.
pixels surrounding this pixel as defined in Practice E2597.A
CKP is a pixel that does not have sufficient good neighboring
3.2.4 material group—materials that have the same pre-
pixelstoperforminterpolation,andisthereforenotcorrectable.
dominant alloying elements and which can be examined using
the same IQI.Alisting of common material groups is given in
4. Significance and Use
Practice E1025.
4.1 This practice establishes the basic parameters for the
3.2.5 NDT facility—the facility or entity performing the
application and control of the digital radiologic method. This
radiologic examination.
practice is written so it can be specified on the engineering
3.2.6 digital detector array (DDA)—an electronic device
drawing, specification, or contract. It will require a detailed
that converts ionizing or penetrating radiation into a discrete
procedure delineating the technique or procedure requirements
array of analog signals which are subsequently digitized and
and shall be approved by the CEO.
transferred to a computer for display as a digital image
5. Basis of Application
correspondingtotheradiologicintensitypatternimpartedupon
the input region of the device. The conversion of the ionizing
5.1 The following items are subject to contractual agree-
or penetrating radiation into an electronic signal may transpire
ment between the parties using or referencing this standard.
by first converting the ionizing or penetrating radiation into
5.1.1 Personnel Qualification—If specified in the contrac-
visible light through the use of a scintillating material. These
tual agreement, personnel performing examinations to this
devices can range in speed from many minutes per image to
standard shall be qualified in accordance with a nationally or
many images per second, up to and in excess of real-time
internationally recognized NDT personnel qualification prac-
radioscopy rates.
tice or standard and certified by the employer or certifying
agency, as applicable. The practice or standard to be used and
3.2.7 digital driving level (DDL)—for computer graphics
its applicable revision shall be identified in the contractual
displayboards,thedigitalvaluethatcorrespondstoaparticular
agreement between the using parties.
monochrome grayscale level. A particular DDL “drives out” a
5.1.2 If specified in the contractual agreement, NDT agen-
particular visible shade of gray. For example, in an 8-bit
cies shall be qualified and evaluated as described in E543. The
display, a DDL assumes 256 values from 0 to 255.
N applicable edition of E543 shall be specified in the contract.
3.2.8 grayscale—2 signal levels for an N-bit system
N
3.2.9 gray level—one of 2 signal levels for an N-bit digital 6. Environment and Safety
system
6.1 The premises and equipment shall present no hazards to
3.2.10 mean gray level—the average of all the pixel gray the safety of personnel or property. NCRP 144, and/or NIST
levels in a given region of interest. Handbook 114 may be used as guides to ensure that radiologic
E2698 − 10
procedures are performed so that personnel shall not receive a 7.5.2 The minimum contrast as determined by the ratio of
radiationdosageexceedingthemaximumpermittedbythecity, the screen brightness at the maximum DDL compared to the
state, or national codes. screen brightness at the minimum DDL shall be 250:1.
7.5.3 The image display shall be capable of displaying
6.2 Environmental conditions conducive to human comfort
linear patterns of alternating pixels at full contrast in both the
and concentration will promote examination efficiency and
horizontal and vertical directions without aliasing.
reliability. A proper examination environment will take into
account temperature, humidity, dust, lighting, access, and 7.5.4 The display shall be free of discernable geometric
distortion.
noise.
7.5.5 The display shall be free of screen flicker, character-
6.3 Dust and dirt need to be kept to a minimum and the
ized by high frequency fluctuation of high contrast image
image display face needs to be cleaned often to prevent
details.
interference with interpretation.
7.5.6 The image display shall be capable of displaying a
7. Equipment
5 % DDL block against a 0 % DDL background and simulta-
7.1 Different examination system configurations are pos-
neously displaying a 95 % DDL block against a 100 %
sible. It is important that the user understands the advantages
background in a manner clearly perceptible to the user. An
and limitations of each (see Practice E2597 and Guide E2736).
image display test pattern, in accordance with the requirements
The provider and the user of the examination system should be
of SMPTE RP 133, shall be configured for the system display
fully aware of the capabilities and limitations of each system
resolution and aspect ratio.Alternate test patterns may be used
proposed.
providedtheyincludethefeaturesdescribedinSMPTERP133
required to perform the quality tests specified in this practice.
7.2 The DDA cannot be operated without computing hard-
7.5.7 The monitor shall be capable of discriminating the
ware and software for image acquisition, image display and
image storage/retrieval. horizontal and vertical low contrast (1 %) modulation patterns
at the display center and each of the four corner locations.
7.2.1 The software shall be capable of acquiring images
framebyframefromtheDDAandintegrating,oraveragingthe
7.6 Image Quality Indicators (IQI):
frames, or both.
7.6.1 IQIsshallbeinaccordancewitharecognizedstandard
7.2.2 The software shall perform an image calibration to
or approved by the Cognizant Engineering Organization. Hole
correcttheinhomogenitiesofthedetectorandtodetermineand
plate type indicators shall comply with Practice E1025 or
correctbadpixels(thatis,badpixelmap)asdefinedinPractice
Practice E1742, Annex 1. Wire type indicators shall be in
E2597.
accordance with Practice E747 and correlated to the hole type
7.3 The software to display resulting imagery from a DDA
penetrameters in accordance with Practice E747.
shall be capable to scale images in size (geometrical
7.6.2 TheIQIshallbeconstructedfrommaterialinthesame
magnification—zoom) and gray levels (window and level
material group (see Practice E1025) as the material to be
adjustment—brightness and contrast, for example from 16 bit
radiologically inspected. If an IQI material of the same
to 8 bit). Additional functions shall be required such as a line
material group is not available, a material that is radiologically
profile measurement, histogram, and statistics window for
less dense shall be used.
measuring an region of interest (ROI) (mean and standard
7.6.3 The use of alternative IQIs that are approved by the
deviation).
CEO shall be documented in a written procedure with the
7.4 The Digital Detector Array (DDA):
design, materials designation, and thickness identification or
7.4.1 Only DDAs shall be used in practice as established in
documented on a drawing and that drawing referenced in the
Guide E2736.
procedure.
7.4.2 Users shall comply with the manufacturers’ require-
7.6.4 The IQIs shall be procured or fabricated to the
ments of temperatures and humidity conditions for both
requirements of Practice E1025 or Practice E747 with a
operation and shipping.
manufacturer’scertificationofcompliancewithrespecttoalloy
7.4.3 The DDAshall be calibrated using the manufacturers’
and dimensions. Users shall visually inspect IQIs for damage
recommendation both for freque
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