1、Designation: F 792 08Standard Practice forEvaluating the Imaging Performance of Security X-RaySystems1This standard is issued under the fixed designation F 792; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis
2、ion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice applies to all X-ray based screeningsystems, with tunnel apertures up to 1 m wide 3 1 m high,whether it is a conve
3、ntional X-ray system or an explosivesdetection system (EDS) that provides a projection orprojection/scatter image for an operator to interpret.1.2 This practice applies to X-ray systems used for thescreening for prohibited items such as weapons, explosives,and explosive devices in baggage, packages,
4、 cargo, or mail.1.3 This practice establishes quantitative and qualitativemethods for evaluating the systems. This practice does notestablish minimum performance requirements for any particu-lar application.1.4 This practice relies upon the use of a standard test object(ASTM X-ray Test Object) to de
5、termine the applicable perfor-mance levels of the systems. The specific test object issubsequently described and referred to in this document as the“Test Object.”1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 This stand
6、ard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.22. Referenced Documents2.1 A
7、STM Standards:3B 258 Specification for Nominal Diameters and Cross-Sectional Areas of AWG Sizes of Solid Round Wires Usedas Electrical ConductorsE 1025 Practice for Design, Manufacture, and MaterialGrouping Classification of Hole-Type Image Quality Indi-cators (IQI) Used for RadiologyE 1316 Terminol
8、ogy for Nondestructive ExaminationsE 1647 Practice for Determining Contrast Sensitivity inRadiologyF 1039 Test Method for Measurement of Low LevelX-Radiation Used in X-Ray Security Screening Systems42.2 ASTM Adjuncts:30 Autocad Drawings52.3 Other Documents:Part 21 Code of Federal Regulations, Sectio
9、n 1020.40 Cabi-net X-ray Systems (United States)6Health seeTerminology E 1316).3.1.14 thin organic imagingthe ability of an X-ray systemto display, on a video monitor, thin organic material.3.1.15 useful organic differentiationthe ability of anX-ray system to penetrate through steel and differentiat
10、e on avideo monitor between organic materials of different effectiveatomic number.3.1.16 useful penetrationthe ability of an X-ray system topenetrate through aluminum and display, on a video monitor,wires that would otherwise be hidden by the aluminum.3.1.17 weapona device intended to do damage to p
11、erson-nel or equipment without harming the attacker, but requiringthe attacker to physically activate the device. Examples includegun, knife and hand grenade.3.1.18 wire displaythe ability of an X-ray system todisplay, on a video monitor, metal wires.4. Significance and Use4.1 This practice applies
12、to and establishes a method tomeasure the imaging performance of X-ray systems used forthe screening for prohibited items such as weapons, explosivesand explosive devices in baggage, packages, cargo or mail.4.2 This practice is intended for use by manufacturers toassess performance and by evaluators
13、 of security and contra-band screening X-ray systems to verify performance.4.3 This practice is intended to establish whether an X-raysystem meets the manufacturers specification or if the sys-tems performance has deteriorated over time.4.4 This practice may be used for manufacturing control,specifi
14、cation acceptance, service evaluation or regulatory stat-utes.4.5 This practice is intended for use at both the point ofmanufacture and where the system is operated. The latterincludes locations such as security checkpoints of transporta-tion terminals, nuclear power stations, correctional instituti
15、ons,corporate mailrooms, government offices and other securityareas.4.6 The most significant attributes of this practice are thedesign of a standard Test Object and standard methods fordetermining the performance levels of the system.4.7 In screening objects with X-ray systems video imagesare the pr
16、imary inputs provided to operators. The better thequality of these images, the better the potential performance ofthe operator.5. Test Object5.1 The following describes the ASTM X-ray Test Object(Fig. 1) to be used throughout the test procedures to determinethe applicable performance levels of a sys
17、tem. It was devel-oped to assess an X-ray based screening systems imagequality in 9 distinct areas.ADrawings Index for the Test Objectis provided in Table 1. Copies of the AutoCad drawings listedin Table 1 are available from ASTM International Headquar-ters.5.2 Test 1Wire DisplayTo determine how wel
18、l an X-raysystem displays wires, the test object incorporates a set ofunobstructed wires. The gauge of these wires provides asufficient range to characterize the systems ability to displaywires. These wires are laid out on the test object in a sinusoidalpattern. For details as to the type, quantity
19、and gauge of thewires or regarding the spacing between each wire refer to Fig.1.5.3 Test 2Useful PenetrationTo determine the usefulpenetration of an X-ray system, the test object incorporates aset of wires placed under aluminum that varies in thickness.The gauge of these wires and the thickness of t
20、he aluminumprovides sufficient range to characterize the systems UsefulPenetration. The wires shall be laid out on the test object, underan aluminum step wedge in a sinusoidal pattern. For details asto the type, quantity, gauge and spacing between the wires orregarding the thickness of the aluminum
21、refer to Fig. 1.5.4 Test 3Spatial ResolutionTo determine the spatialresolution of an X-ray system, the test object incorporates a setof narrowly spaced wires. The gauge of these wires and thespacing between them provides sufficient range to characterizethe systems Spatial Resolution. For details as
22、to the type,quantity, gauge or spacing between the wires refer to Fig. 1.5.5 Test 4Simple PenetrationTo determine the simplepenetration of an X-ray system, the test object incorporateslead digits placed on top of steel that varies in thickness. Thethickness of the steel provides sufficient range to
23、characterizethe systems Simple Penetration. For further details regardingthe test object refer to Fig. 1.5.6 Test 5Thin Organic ImagingTo determine the thinorganic imaging capability of an X-ray system, the test objectincorporates plastic of various thicknesses. The thickness ofthe plastic provides
24、sufficient range to characterize the sys-tems ability to image thin organic material. For detailsregarding the plastic samples refer to Fig. 1.5.7 Test 6IQI SensitivityTo determine the IQI sensitivityof an X-ray system, the test object incorporates a set offlat-bottom holes drilled into steel and pl
25、astic samples that varyin thickness. The diameter of these holes, the depth of theseholes, and the thickness of the steel and plastic samplesprovides sufficient range to characterize the systems IQIF792082Sensitivity. For details as to the diameter and depth of theseholes or regarding the thickness
26、of the steel and plastic refer toFig. 1.5.8 Test 7Organic/Inorganic DifferentiationTo deter-mine the organic/inorganic differentiation capability of anX-ray system, the test object incorporates a steel and plasticsample. For details regarding the steel and plastic samples referto Fig. 1.5.9 Test 8Or
27、ganic DifferentiationTo determine the or-ganic differentiation capability of an X-ray system, the testobject incorporates various samples of plastic. The plasticschosen shall have different effective atomic numbers butnominally identical attenuation. For details regarding theplastic samples refer to
28、 Fig. 1.5.10 Test 9Useful Organic DifferentiationTo determinethe useful organic differentiation of an X-ray system the testobject incorporates various samples of plastic placed on top ofsteel that varies in thickness. For details regarding the steel andplastic samples used in this test refer to Fig.
29、 1.6. Test Procedures6.1 The location and orientation of the test object in thefollowing procedures depends on the X-ray source and detectorarrangement. The position of the test object for these tests shallbe chosen to obtain the best displayed image possible. Addi-tional locations may be used as de
30、sired. The X-ray manufac-turer should be consulted to establish the optimum location.Also, to achieve the best video image practical it may benecessary to use enhancement features such as Zoom, HighPenetration, etc. This is an acceptable practice but for each test,the enhancement features used to me
31、et the requirement must berecorded. The results of the following tests are to be retained aspart of the system record and compared to performancerequirements or to previously recorded results.FIG. 1 ASTM X-Ray Test Object Assembly PlanF7920836.2 Wire DisplayScan the test object with the X-raysystem
32、and record on the Log Sheet (Fig. 2) the gauge of all thewires, in Test 1, that can be seen on the monitor.6.3 Useful PenetrationScan the test object with the X-raysystem and record on the Log Sheet (Fig. 2) the gauge of all thewires, in Test 2, that can be seen on the monitor.6.4 Spatial Resolution
33、Scan the test object with the X-raysystem and record on the Log Sheet (Fig. 2) which sets ofvertical and horizontal wires can be resolved.6.5 Simple PenetrationScan the test object with the X-raysystem and record on the Log Sheet (Fig. 2) the thicknesses ofsteel through which the lead numbers can be
34、 seen on themonitor.6.6 Thin Organic ImagingScan the test object with theX-ray system and record on the Log Sheet (Fig. 2) thethicknesses of the thin plastic object that can be seen on themonitor.6.7 IQI SensitivityScan the test object with the X-raysystem and record on the Log Sheet (Fig. 2) which
35、of the holesin the steel and the plastic steps can be seen.6.8 Organic/Inorganic DifferentiationScan the test objectand study the displayed image seen on the monitor. Observe ifthere is a response difference between the steel and plasticsamples. Record results on the Log Sheet (Fig. 2).6.9 Organic D
36、ifferentiationScan the test object with theX-ray system and study the displayed image seen on themonitor. Observe if there is a response difference betweensuccessive plastic samples. Record results on the Log Sheet(Fig. 2).6.10 Useful Organic DifferentiationScan the test objectwith the X-ray system
37、and study the displayed image seen onthe monitor. Record on the Log Sheet (Fig. 2) the thicknessesof steel through which there is a response difference betweensuccessive plastic samples.7. Evaluation Considerations7.1 GeneralUse of this practice does not guaranty that theX-ray system is operating pr
38、operly. It is not intended to replacethe X-ray systems diagnostics. If problems are experiencedwith the system they must be resolved prior to operation.7.2 Training RequirementsTo effectively conduct theevaluation of an X-ray system it is recommended that theevaluator be trained to operate the syste
39、m. The evaluator mustbe able to use all of the systems features to optimizeperformance and present the best picture practical.7.3 Test Object Location effective atomic number; explosivedevice; explosives; IQI; IQI sensitivity; organic differentiation;organic/inorganic differentiation; radiation cham
40、ber; radiationmonitor; scatter block; security system; simple penetration;spatial resolution; thin organic imaging; useful organic differ-entiation; useful penetration; weapons; wire display; X-rayASTM International takes no position respecting the validity of any patent rights asserted in connectio
41、n with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible
42、technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consid
43、eration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Bar
44、r Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).F792086
