ASTM E1000-98(2009)
(Guide)Standard Guide for Radioscopy
Standard Guide for Radioscopy
SIGNIFICANCE AND USE
Radioscopy is a versatile nondestructive means for examining an object. It provides immediate information regarding the nature, size, location, and distribution of imperfections, both internal and external. It also provides a rapid check of the dimensions, mechanical configuration, and the presence and positioning of components in a mechanism. It indicates in real-time the presence of structural or component imperfections anywhere in a mechanism or an assembly. Through manipulation, it may provide three-dimensional information regarding the nature, sizes, and relative positioning of items of interest within an object, and can be further employed to check the functioning of internal mechanisms. Radioscopy permits timely assessments of product integrity, and allows prompt disposition of the product based on acceptance standards. Although closely related to the radiographic method, it has much lower operating costs in terms of time, manpower, and material.
Long-term records of the radioscopic image may be obtained through motion-picture recording (cinefluorography), video recording, or “still” photographs using conventional cameras. The radioscopic image may be electronically enhanced, digitized, or otherwise processed for improved visual image analysis or automatic, computer-aided analysis, or both.
SCOPE
1.1 This guide is for tutorial purposes only and to outline the general principles of radioscopic imaging.
1.2 This guide describes practices and image quality measuring systems for real-time, and near real-time, nonfilm detection, display, and recording of radioscopic images. These images, used in materials examination, are generated by penetrating radiation passing through the subject material and producing an image on the detecting medium. Although the described radiation sources are specifically X-ray and gamma-ray, the general concepts can be used for other radiation sources such as neutrons. The image detection and display techniques are nonfilm, but the use of photographic film as a means for permanent recording of the image is not precluded.
Note 1—For information purposes, refer to Terminology E 1316.
1.3 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 and health practices and determine the applicability of regulatory limitations prior to use. For specific safety precautionary statements, see Section 6.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: E1000 − 98 (Reapproved 2009)
Standard Guide for
Radioscopy
This standard is issued under the fixed designation E1000; 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 E1316Terminology for Nondestructive Examinations
E2002PracticeforDeterminingTotalImageUnsharpnessin
1.1 Thisguideisfortutorialpurposesonlyandtooutlinethe
Radiology
general principles of radioscopic imaging.
2.2 National Council on Radiation Protection and Measure-
1.2 This guide describes practices and image quality mea-
ment (NCRP) Standards:
suring systems for real-time, and near real-time, nonfilm
NCRP49 Structural Shielding Design and Evaluation for
detection, display, and recording of radioscopic images. These
Medical Use of X Rays and Gamma Rays of Energies up
images, used in materials examination, are generated by
to 10 MeV
penetrating radiation passing through the subject material and
NCRP 51 Radiation Protection Design Guidelines for
producing an image on the detecting medium. Although the
0.1–100 MeV Particle Accelerator Facilities
described radiation sources are specifically X-ray and gamma-
NCRP91,(supercedes NCRP 39) Recommendations on
ray, the general concepts can be used for other radiation
Limits for Exposure to Ionizing Radiation
sources such as neutrons. The image detection and display
2.3 Federal Standard:
techniques are nonfilm, but the use of photographic film as a
Fed. Std. No.21-CFR1020.40 Safety Requirements for
means for permanent recording of the image is not precluded.
Cabinet X-Ray Machines
NOTE 1—For information purposes, refer to Terminology E1316.
1.3 This standard does not purport to address all of the
3. Summary of Guide
safety concerns, if any, associated with its use. It is the
3.1 This guide outlines the practices for the use of radio-
responsibility of the user of this standard to establish appro-
scopicmethodsandtechniquesformaterialsexaminations.Itis
priate safety and health practices and determine the applica-
intended to provide a basic understanding of the method and
bility of regulatory limitations prior to use. For specific safety
the techniques involved. The selection of an imaging device,
precautionary statements, see Section 6.
radiation source, and radiological and optical techniques to
achieve a specified quality in radioscopic images is described.
2. Referenced Documents
2.1 ASTM Standards:
4. Significance and Use
E142Method for Controlling Quality of Radiographic Test-
3 4.1 Radioscopy is a versatile nondestructive means for
ing (Withdrawn 2000)
examining an object. It provides immediate information re-
E747Practice for Design, Manufacture and Material Group-
garding the nature, size, location, and distribution of
ing Classification of Wire Image Quality Indicators (IQI)
imperfections, both internal and external. It also provides a
Used for Radiology
rapid check of the dimensions, mechanical configuration, and
E1025 Practice for Design, Manufacture, and Material
thepresenceandpositioningofcomponentsinamechanism.It
Grouping Classification of Hole-Type Image Quality In-
indicates in real-time the presence of structural or component
dicators (IQI) Used for Radiology
imperfections anywhere in a mechanism or an assembly.
Through manipulation, it may provide three-dimensional in-
This guide is under the jurisdiction ofASTM Committee E07 on Nondestruc-
formation regarding the nature, sizes, and relative positioning
tive Testing and is the direct responsibility of Subcommittee E07.01 on Radiology
of items of interest within an object, and can be further
(X and Gamma) Method.
employed to check the functioning of internal mechanisms.
CurrenteditionapprovedJune1,2009.PublishedJuly2009.Originallyapproved
in 1989. Last previous edition approved in 2003 as E1000-98 (2003). DOI:
Radioscopy permits timely assessments of product integrity,
10.1520/E1000-98R09.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from NCRP Publications, 7010 Woodmont Ave., Suite 1016,
the ASTM website. Bethesda, MD 20814.
3 5
The last approved version of this historical standard is referenced on AvailablefromStandardizationDocumentsOrderDesk,Bldg.4SectionD,700
www.astm.org. Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1000 − 98 (2009)
and allows prompt disposition of the product based on accep- X-ray generator (keVcp) source. Concurrent with image-
tance standards. Although closely related to the radiographic intensifier developments, direct X ray to television-camera
method, it has much lower operating costs in terms of time, tubes capable of high sensitivity and resolution on low-density
manpower, and material. materialsweremarketed.Becausetheyrequireacomparatively
high X-ray flux input for proper operation, however, their use
4.2 Long-term records of the radioscopic image may be
has been limited to examination of low-density electronic
obtained through motion-picture recording (cinefluorography),
components, circuit boards, and similar applications. The
video recording, or “still” photographs using conventional
development of low-light level television (LLLTV) camera
cameras. The radioscopic image may be electronically
tubes, such as the isocon, intensifier orthicon, and secondary
enhanced, digitized, or otherwise processed for improved
electron conduction (SEC) vidicon, and the advent of
visualimageanalysisorautomatic,computer-aidedanalysis,or
advanced, low-noise video circuitry have made it possible to
both.
use television cameras to scan conventional, high-resolution,
low-light-output fluorescent screens directly. The results are
5. Background
comparable to those obtained with the image intensifier.
5.1 Fluorescence was the means by which X rays were
5.3 In recent years (circa 1980’s) new digital radiology
discovered, but industrial fluoroscopy began some years later
techniques have been developed. These methods produce
with the development of more powerful radiation sources and
directly digitized representations of the X-ray field transmitted
improved screens. Fluoroscopic screens typically consist of
by an examination article. Direct digitization enhances the
phosphors that are deposited on a substrate. They emit light in
signal-to-noiseratioofthedataandpresentstheinformationin
proportion to incident radiation intensity, and as a function of
a form directly suitable for electronic image processing and
the composition, thickness, and grain size of the phosphor
enhancement, and storage on magnetic tape. Digital radio-
coating. Screen brightness is also a function of the wavelength
scopic systems use scintillator-photodetector and phosphor-
of the impinging radiation. Screens with coarse-grained or
photodetector sensors in flying spot and fan beam-detector
thick coatings of phosphor, or both, are usually brighter but
array arrangements.
have lower resolution than those with fine grains or thin
coatings, or both. In the past, conventional fluorescent screens
5.4 All of these techniques employ television presentation
limited the industrial applications of fluoroscopy. The light
and can utilize various electronic techniques for image
output of suitable screens was quite low (on the order of 0.1
enhancement, image storage, and video recording. These
−3 2
millilambertor0.343×10 cd/m )andrequiredabout30min
advanced imaging devices, along with modern video process-
for an examiner to adapt his eyes to the dim image. To protect
ing and analysis techniques, have greatly expanded the versa-
the examiner from radiation, the fluoroscopic image had to be
tility of radioscopic imaging. Industrial applications have
viewed through leaded glass or indirectly using mirror optics.
become wide-spread: production examination of the longitudi-
Such systems were used primarily for the examination of
nal fusion welds in line pipe, welds in rocket-motor housings,
light-alloy castings, the detection of foreign material in
castings, transistors, microcircuits, circuit-boards rocket pro-
foodstuffs, cotton and wool, package inspection, and checking
pellant uniformity, solenoid valves, fuses, relays, tires and
weldmentsinthinorlow-densitymetalsections.Thechoiceof
reinforced plastics are typical examples.
fluoroscopy over radiography was generally justified where
5.5 Limitations—Despite the numerous advances in RRTI
time and cost factors were important and other nondestructive
technology, the sensitivity and resolution of real-time systems
methods were not feasible.
usually are not as good as can be obtained with film. In
5.2 It was not until the early 1950’s that technological radiography the time exposures and close contact between the
advances set the stage for widespread uses of industrial film and the subject, the control of scatter, and the use of
fluoroscopy. The development of the X-ray image intensifier screens make it relatively simple to obtain better than 2%
provided the greatest impetus. It had sufficient brightness gain
penetrameter sensitivity in most cases. Inherently, because of
tobringfluoroscopicimagestolevelswhereexaminationcould statistical limitations dynamic scenes require a higher X-ray
be performed in rooms with somewhat subdued lighting, and
flux level to develop a suitable image than static scenes. In
without the need for dark adaption. These intensifiers con- addition, the product-handling considerations in a dynamic
tained an input phosphor to convert the X rays to light, a imaging system mandate that the image plane be separated
photocathode (in intimate contact with the input phosphor) to from the surface of the product resulting in perceptible image
convert the light image into an electronic image, electron unsharpness. Geometric unsharpness can be minimized by
accelerating and focusing electrodes, and a small output employing small focal spot (fractions of a millimetre) X-ray
phosphor.Intensifierbrightnessgainresultsfromboththeratio sources, but this requirement is contrary to the need for the
of input to output phosphor areas and the energy imparted to high X-ray flux density cited previously. Furthermore, limita-
the electrons. Early units had brightness gains of around 1200 tions imposed by the dynamic system make control of scatter
to 1500 and resolutions somewhat less than high-resolution and geometry more difficult than in conventional radiographic
conventional screens. Modern units utilizing improved phos- systems. Finally, dynamic radioscopic systems require careful
phors and electronics have brightness gains in excess of alignment of the source, subject, and detector and often
10 000× and improved resolution. For example, welds in steel expensive product-handling mechanisms. These, along with
thicknesses up to 28.6 mm (1.125 in.) can be examined at 2% the radiation safety requirements peculiar to dynamic systems
plaque penetrameter sensitivity using a 160 constant potential usuallyresultincapitalequipmentcostsconsiderablyinexcess
E1000 − 98 (2009)
ofthatforconventionalradiography.Thecostsofexpendables, phosphors used in ordinary fluorescent screens. Typical mate-
manpower, product-handling and time, however, are usually rials used are sodium iodide (thallium-activated), cesium
significantly lower for radioscopic systems. iodide (thallium-activated) and sodium iodide (cesium-
activated). These single crystal materials can be obtained in
6. Safety Precautions
very large sizes (up to 30-cm or 12-in. diameter is not
6.1 The safety procedures for the handling and use of uncommon)andcanbemachinedintovarioussizesandshapes
as required. Thickness of 2 to 100 mm (0.08 to 4 in.) are
ionizing radiation sources must be followed. Mandatory rules
and regulations are published by governmental licensing customary.
agencies, and guidelines for control of radiation are available
8.4 X Ray to Electron Conversion—Radioscopic Systems—
in publications such as the Fed. Std. No.21-CFR 1020.40.
X-ray photons of sufficient energy have the ability to release
Careful radiation surveys should be made in accordance with
loosely bound electrons from the inner shells of atoms with
regulations and codes and should be conducted in the exami-
which they collide. These photoelectrons have energies pro-
nation area as well as adjacent areas under all possible
portional to the original X-ray photon and can be utilized in a
operating conditions.
variety of ways to produce images, including the following
useful processes.
7. Interpretation and Reference Standards
8.4.1 Energizing of Semiconductor Junctions—The resis-
7.1 Reference radiographs produced by ASTM and accep-
tance of a semiconductor, or of a semiconductor junction in a
tance standards written by other organizations may be em-
device such as a diode or transistor, can be altered by adding
ployed for radioscopic examination as well as for radiography,
free electrons. The energy of an X-ray photon is capable of
provided appropriate adjustments are made to accommodate
freeing electrons in such materials and can profoundly affect
for the differences in the fluoroscopic images.
the operation of the device. For example, a simple silicon
“solar cell” connected to a microammeter will produce a
8. Radioscopic Devices, Classification
substantial current when exposed to an X-ray source.
8.1 The most commonly used electromagnetic radiation in
8.4.1.1 If an array of small semiconductor devices is ex-
radioscopyisproducedbyX-raysources.Xraysareaffectedin
posedtoanX-raybeam,andtheperformanceofeachdeviceis
various modes and degrees by passage through matter. This
sampled, then an image can be produced by a suitable display
providesveryusefulinformationaboutthematterthathasbeen
of the data. Such arrays can be linear or two-dimensional.
traversed. The detection of these X-ray photons in such a way
Linear arrays normally require relative motion between the
that the information they carry can be used immediately is the
object and the array to produce a useful real-time image. The
prime requisite of radioscopy. Since there are many ways of
choice depends upon the application.
detecting the presence of X rays, their energy and flux density,
8.4.2 Affecting Resistance of Semiconductors—The most
there are a number of possible systems. Of these, only a few
common example of this is the X-ra
...
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