1、Designation: F 2547 06Standard Test Method forDetermining the Attenuation Properties in a Primary X-rayBeam of Materials Used to Protect Against RadiationGenerated During the Use of X-ray Equipment1This standard is issued under the fixed designation F 2547; the number immediately following the desig
2、nation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method establishes p
3、rocedures for measuringthe attenuation of X-rays by protective materials at acceleratingpotentials from 60 to 130 kVp.1.2 This test method provides attenuation values of primarybeam X-radiation.1.3 This test method applies to both leaded and non-leadedradiation protective clothing materials.1.4 This
4、 standard 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.2. Referenced Documents
5、2.1 ASTM Standards:2F 1494 Terminology Relating to Protective Clothing3. Terminology3.1 Definitions:3.1.1 attenuation, nFor radiological protective material,the reduction in the intensity of the X-ray beam resulting fromthe interactions between the X-ray beam and the protectivematerial that occur wh
6、en the X-ray beam passes through theprotective material.3.1.1.1 DiscussionIn this test method, the attenuation iscalculated as 1 minus the ratio of the measured exposure witha protective material in the beam to the measured exposurewithout the protective material in the beam at a specificacceleratin
7、g potential. Multiplying the resulting value by 100gives percent attenuation.Attenuation percent!5S1exposure with sampleexposure without sampleD3 100(1)3.1.2 lead equivalency, nFor radiological protective ma-terial, the thickness in millimetres of lead (commonly desig-nated mmPb) of greater than 99.
8、9 percent purity that providesthe same attenuation as a given protective material.3.1.2.1 DiscussionThis test method provides the attenua-tion of the material and not the lead equivalency. Determininglead equivalency would require testing lead of known thicknessand purity, and comparing the attenuat
9、ion of the protectivematerial with the attenuation of the lead. Although leadequivalency has been the standard for reporting protectivematerial capability, the drafters of this test method believe it isnot feasible to obtain adequate standard lead samples forreporting lead equivalency values.3.1.3 s
10、econdary radiation, nradiation outside the primaryX-ray beam.3.1.4 scatter radiation, na form of secondary radiationresulting from the interaction of the primary X-ray beam andthe target (for example, protective material being tested or apatient undergoing a medical procedure).3.1.5 half-value layer
11、 (HVL), nthe thickness of alumi-num, in millimetres (commonly designated mmAl), that re-duces the intensity of the X-ray beam by one half.3.1.5.1 DiscussionThe HVL is dependent on the energyof the X-ray beam and, therefore, is different for X-raysproduced at different accelerating potentials.3.1.6 k
12、ilovolts, peak (kVp), nthe maximum electricalpotential across an X-ray tube during an exposure, expressed inkilovolts.3.1.7 exposure, nfor radiological purposes, the amount ofionization in air at standard conditions caused by interactionwith X-rays, expressed in units of Roentgen (R) or milliroent-g
13、en (mR).3.1.8 wave form ripple, nfor radiological purposes, thepeak-to-peak variation in the output voltage of the X-raygenerator.1This test method is under the jurisdiction of ASTM Committee F23 onProtective Clothing and is the direct responsibility of Subcommittee F23.70 onRadiological Hazards.Cur
14、rent edition approved June 1, 2006. Published June 2006.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copy
15、right ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.9 ionization chamber, na device that measures theelectrical charge liberated during the ionization of air mol-ecules by electromagnetic radiation (X-rays for the purposes ofthis test met
16、hod), expressed in units of coulombs per kilogramof air.3.1.10 shielding, nfor radiological purposes, any materialor obstruction that attenuates radiation to protect personnel orequipment from the effects of ionizing radiation.3.1.11 coeffcient of variation, nthe ratio of the standarddeviation of a
17、sample to the sample mean.3.1.12 For definitions of other terms related to protectiveclothing used in this test method, refer to Terminology F 1494.4. Summary of Test Method4.1 A primary X-ray beam with a standardized energyspectrum and constant intensity is configured to pass throughthe test set-up
18、.An ionization chamber, calibrated for the energyrange of X-rays produced at accelerating potentials between 60to 130 kVp, is used to measure the exposure in the primarybeam with and without the material specimen positionedbetween the X-ray source and the ionization chamber. Theexposure is directly
19、proportional to the intensity of the X-raybeam. The attenuation provided by the material specimen isdefined as the percentage of the original beam intensity that isremoved by the material specimen.4.2 The attenuation of the sample is determined at an X-rayenergy in the range produced by an accelerat
20、ing potential from60 to 130 kVp.5. Significance and Use5.1 This test method is intended to provide a standardizedtest procedure of protective materials to ensure comparableresults among manufacturers and users.5.2 This test method involves measurement of the attenua-tion of X-rays by protective clot
21、hing material at an acceleratingpotential (kVp) between 60 and 130 kVp. These energies areconsidered to be representative of those commonly used duringmedical diagnosis and treatment.5.3 The reporting of the attenuation at a specific X-rayenergy is intended to allow the end user organization to asse
22、ssthe attenuating properties of the protective clothing material atthat energy level.6. Apparatus6.1 Primary X-ray Beam SourceA variable power highfrequency X-ray generator coupled with X-ray tube equippedwith Tungsten anode with the following characteristics:6.1.1 The wave form ripple does not exce
23、ed three percent.6.1.2 The coefficient of variation for the exposure does notexceed 0.05 as determined using four consecutive exposures.6.1.3 The coefficient of variation for kVp does not exceed0.05 determined using four consecutive test measurements atthe kVp setting used in testing.6.2 An invasive
24、 or non-invasive kVp measuring devicecapable of measuring the kVp accuracy within 0.5 kVp.6.3 An ionization chamber and electrometer capable ofmeasuring from 1 mR to 5 R.6.4 Shielding material may be used around apparatus toimprove precision.7. Hazards7.1 All individuals performing tests using this
25、test methodshall wear X-ray protective clothing or be positioned behindstationary shielding when the X-ray beam is activated.8. Sampling and Test Specimens8.1 Test specimens may come from protective materialsheets or from protective material obtained from garments.8.1.1 Specimens may be single sheet
26、s or multiple sheetstested as a stack, as appropriate for the application.8.2 Randomly select a total of five specimens from thematerial or protective clothing sample for evaluation.8.3 Test specimens shall have a circular or square shapewith an area sufficient for testing.9. Preparation of Apparatu
27、s9.1 Measure and document the kVp accuracy for each kVpsetting used in the testing prior to every testing session.9.2 Measure and document the exposure reproducibility ofthe combination of tube current and exposure time used in thetesting prior to every testing session.9.2.1 If the length of the tes
28、ting session exceeds one hourmeasure and document kVp accuracy at least once each hour.9.3 Measure and document HVL for the kVp setting used inthe testing at the beginning of the testing session.9.4 Measure and document the kVp accuracy for the kVpsetting used in the testing at the end of the testin
29、g session.10. Calibration and Standardization10.1 The kVp meter and ionization chamber shall be cali-brated not less than annually to NIST-traceable standards.10.2 At the desired kVp setting determine the half-valuelayer in millimetres of type 1100 aluminum (mm Al). Thehalf-value layer shall fall wi
30、thin 0.1 mm Al of the valuespecified in Table 1.10.3 The focal spot size shall be as small as practicable.11. Conditioning11.1 There are no special conditioning requirements for thetest.12. Procedure12.1 Set the X-ray accelerating potential to the desired kVpfor the X-ray beam source.12.2 Set the di
31、stance between the focal spot to the specimenat 400 mm 1534 in. and the distance between the ionizationchamber and the specimen at 1000 mm 3938 in.TABLE 1 Half-Value Layers at Different X-ray Energy Levels60kVp 70 kVp 80 kVp 90 kVp 100 kVp 110 kVp 120 kVp 130 kVp2.9 mm Al 3.3 mm Al 4.0 mm Al 4.3 mm
32、Al 5.2 mm Al 5.5 mm Al 6.3 mm Al 6.7 mm AlF254706212.3 Ensure that the closest source of back-scatter (such asa table top or the floor) is not less than 450 mm 1734 in. fromthe ionization chamber.12.4 Set the X-ray field dimensions to match the dimensionsof the ionization chamber.12.4.1 Ensure that
33、the X-ray field does not exceed the sizeof the specimen.12.5 Conduct one exposure measurement without a speci-men in the X-ray beam and record the exposure reading fromthe exposure meter.12.6 Place a specimen in the field.12.7 Perform two exposure measurements with the speci-men in the X-ray beam an
34、d record the exposure readings fromthe exposure meter.12.7.1 The exposure measurements acquired with the speci-men in the beam shall not vary by more than three percent.12.8 Conduct a post-specimen exposure measurement withno specimen in the X-ray beam.12.8.1 The second no-specimen exposure measurem
35、entshall not vary from pre-specimen exposure by more than threepercent.12.9 Repeat measurements for remaining specimens.13. Calculations13.1 Calculate the arithmetic mean (simple average) expo-sure with no specimen in the X-ray beam for all no-specimenmeasurements. This value becomes the mean exposu
36、re (nospecimen).13.2 Calculate the mean of the exposures with a specimen inthe X-ray beam for all measurements involving a specimen.This value is the mean exposure (with specimen).13.3 Calculate the attenuation for the protective clothingmaterial.14. Report14.1 State that the test was conducted as d
37、irected in TestMethod F 2547 - 06.14.2 Provide the following information with each test set:14.2.1 Test InformationDate of testing, place of testing,name of individual(s) performing the testing, equipment(manufacturer and model of X-ray generator and X-ray tube)used in testing, test parameters (kVp,
38、 HVL Al mm, current,exposure time)14.2.2 Sample IdentificationDescription of the materialtested (indicate, as applicable and available: manufacturer, typeof material, presence of coatings, number of sheets, otheridentifying data).14.2.3 The attenuation for each of the five samples and themean attenu
39、ation.15. Precision and Bias15.1 PrecisionThe precision of the procedure in this testmethod is being determined.15.2 BiasNo information can be presented on the bias forthe procedure in this test method, for measuring the X-rayattenuation of protective clothing materials, because no mate-rial having
40、an accepted reference value is available at this time.16. Keywords16.1 attenuation; protective material; radiation protectiveclothing; X-rayASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this
41、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 technical committee and must be reviewed every five years
42、 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 consideration at a meeting of theresponsible technical committe
43、e, 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 Barr 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).F2547063
