ASTM F3094-2014 Standard Test Method for Determining Protection Provided by X-ray Shielding Garments Used in Medical X-ray Fluoroscopy from Sources of Scattered X-Rays《散射X射线来源的医用X射.pdf

1、Designation: F3094 14Standard Test Method forDetermining Protection Provided by X-ray ShieldingGarments Used in Medical X-ray Fluoroscopy from Sourcesof Scattered X-Rays1This standard is issued under the fixed designation F3094; the number immediately following the designation indicates the year ofo

2、riginal adoption or, in the case of revision, the year of last revision. 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 test method establishes a procedure for measuringthe re

3、lative reduction in the intensity of X-radiation providedby shielding garments to the human user under conditionssimulating actual use.1.2 This test method provides a condition simulating X-raysgenerated between 60 and 130 kV that are scattered through anangle of 90 by a water equivalent material.1.

4、3 This test method applies to both leaded and no-leadedradiation protective materials.1.4 This test method provides a method for inclusion ofsecondary radiations generated within the protective materialinto a more realistic evaluation of radiation protection.1.5 The values given in SI units are to b

5、e regarded asstandard. No other units of measurement are included in thisstandard.1.6 This 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 d

6、etermine the applica-bility of regulatory limitations prior to use. Some specifichazards statements are given in Section 7.2. Referenced Documents2.1 ASTM Standards:2F1494 Terminology Relating to Protective ClothingF2547 Test Method for Determining the Attenuation Prop-erties in a Primary X-ray Beam

7、 of Materials Used toProtect Against Radiation Generated During the Use ofX-ray Equipment2.2 IEC Standard:3IEC 61331-1 Ed. 2.0 Protective Devices Against DiagnosticMedical X-radiation: Part 1 Determination of Attenua-tion Properties of Materials3. Terminology3.1 Definitions:3.1.1 attenuation, nfor r

8、adiological protective material,the fractional reduction in the intensity of the X-ray beamresulting from the interactions between the X-ray beam and theprotective material when the X-ray beam passes through theprotective material.3.1.1.1 DiscussionIt is important to note that the measure-ment of at

9、tenuation (as specified by Test Method F2547)specifically excludes the contribution of secondary radiationfrom the measurement. The present standard provides amethod for incorporating those contributions of radiation doseto the wearer of protective garments. (See 3.1.10.)3.1.2 coeffcient of variatio

10、nthe ratio of the standarddeviation of a sample to the sample mean.3.1.3 exposure, nfor radiological purposes the amount ofionization charge of one sign produced in a defined volume ofdry air at standard temperature and pressure, caused byinteraction with X-rays. Exposure is expressed in units ofcou

11、lombs/kg of air in SI units. An older unit called theRoentgen (R) is also used, where1R=2.58 10-4C/kg.3.1.4 fluorescent radiation, na form of secondary radia-tion following photoelectric collisions between X-rays andorbital electrons of heavier elements such as those used inprotective materials, whe

12、reupon electron rearrangements at theatomic level result in the emission of one or more fluorescentphotons.3.1.4.1 DiscussionMeasurements to include fluorescentradiation are important because they may contribute to theradiation exposure to the wearer of radiation protective gar-ments.1This test meth

13、od is under the jurisdiction ofASTM Committee F23 on PersonalProtective Clothing and Equipment and is the direct responsibility of SubcommitteeF23.70 on Radiological Hazards.Current edition approved July 1, 2014. Published July 2014. DOI: 10.1520/F309414.2For referenced ASTM standards, visit the AST

14、M 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.3Available from International Electrotechnical Commission (IEC), 3, rue deVaremb, P.O. Box 131, CH-1211 Ge

15、neva 20, Switzerland, http:/www.iec.ch.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.5 half-value layer (HV), nthe thickness of 99.9 % purealuminum in millimetres (commonly designated mm Al) thatreduces the intensity of an X-ray

16、 beam by one half of its initialvalue.3.1.5.1 DiscussionHVL is commonly used to designatethe penetrating ability of an X-ray beam containing manyX-ray energies (as is the case with standard X-ray sources). Ahigher value ofAl in mmAl would indicate a more penetratingX-ray beam. Note that HVL may also

17、 be specified in materialsother than Al, although only Al is used in this document.3.1.6 ionization chambera device that measures the elec-trical charge liberated during the ionization of air molecules byelectromagnetic radiation (X-rays for the purposes of this testmethod), expressed in units of co

18、ulombs per kg of air.3.1.6.1 DiscussionThe measurement of exposure is de-fined for an air ionization chamber. The chamber used in thismethod must be of a flat, parallel-plate design.3.1.7 kilovolts, or kilovolts peak (kV or kVp), nfor thepurposes of radiological protection, the maximum electricalpot

19、ential across an X-ray tube during exposure.3.1.7.1 DiscussionThe kV or kVp determines the maxi-mum photon energy in kilo-electron volts (keV) of an X-raybeam; standard X-ray beams contain many photon energiesmost of which are less than this maximum value.3.1.8 lead equivalencyfor radiological prote

20、ctive materialthe thickness in millimetres (commonly designated mm Pb) ofgreater than 99.9 % purity that provides the same attenuation asa given protective material.3.1.8.1 DiscussionRadiation protective materials are com-monly made with little or no lead thus lead equivalence willvary with X-ray en

21、ergy and with the composition of theprotective material. Lead equivalence should be specified at aspecific energy. This test method specifies a method fordetermining the attenuation in pure lead materials but does notrequire a specific lead equivalence. If lead equivalence isspecified, it should be

22、specified at a single scatter equivalentcondition.3.1.9 primary X-rays, nthe X-rays emitted from the targetof an X-ray tube subjected to an accelerating potential suffi-cient to cause X-ray emission.3.1.9.1 DiscussionPrimary X-rays are distinguished fromsecondary X-rays emitted from a material expos

23、ed to primaryX-rays. Secondary X-rays are generally less penetrating thanprimary X-rays.3.1.10 protection rating, nfor the purposes of radiologicalprotection in this test method, the percentage of exposure at theskin surface of the wearer of the protective garment relative tothe exposure on that sur

24、face in the absence of the protectivegarment, measured under scatter equivalent conditions for aparticular radiation quality.3.1.11 scatter equivalent conditionsspecific primaryX-ray spectra defined in terms of kV and HVL that simulateradiation scattered from a water equivalent medium measuredat 90

25、to the beam incidence on that medium.43.1.11.1 DiscussionMeasuring the actual degree of pro-tection from scattered X-rays provided by radiation protectivegarments under real world conditions is technically difficultand subject to large uncertainties. Actual scatter intensities aretoo low and measure

26、ments have excessively high uncertaintieswhen evaluated in practical conditions. The scatter equivalentconditions describe conditions that conservatively approximatethe energies of 90 scatter produced when a water medium(body of a human or animal) is exposed to Test Method F2547beam qualities. Use o

27、f the surrogate primary beams providesconditions that are practical to test under field conditions.3.1.12 scatter radiation, na form of secondary radiationwhere X-radiation is deflected to a changed direction with orwithout a loss in energy by collisions between X-ray photonsand orbital electrons of

28、 atoms in the path of the X-rays;scattering events in medical procedures mainly occur with lossof energy due to the Compton Effect such that the averageenergies of scattered X-rays are less than that of the directprimary beam.3.1.13 secondary radiation, nradiation that is produced ina material by sc

29、attering or emission when the material isexposed to a source of X-rays.3.1.13.1 DiscussionSecondary radiation is of importancebecause: (1) the hazard to medical X-ray fluoroscopy workersis principally from X-rays scattered from the patient and othermaterials within the primary X-ray beam, (2) fluore

30、scentradiation produced within the protective material can contrib-ute to the radiation exposure to the wearer of the radiationprotective garments.3.1.14 standard sample dimensionstest samples and leadstandards cut to an area suited to the measurement setup in Fig.1, ideally by using a template.3.1.

31、14.1 DiscussionIt may be desired to test finishedprotective clothing that are not cut to standard sample dimen-sions using this test method.This may be done, but may requirea special test jig to support the material in proper orientationand configuration to meet this test method. Such a procedure is

32、not described in this test method.3.1.15 wave form ripple, nfor radiological purposes thepeak to peak variation in the voltage potential applied to theX-ray tube during exposure. Greater voltage ripple (common inolder X-ray generators) tends to reduce the intensity andpenetrating ability of the resu

33、lting X-ray beam compared tounits with little or no voltage ripple.3.2 Some definitions are reproduced for convenience fromTest Method F2547. For definitions of other terms related toprotective clothing used in this test method, refer to Terminol-ogy F1494.4McCaffrey, J. P., Tessier, F., and Shen, H

34、., “Radiation Shielding Materials andRadiation Scatter Effects for Interventional Radiology (IR) Physicians,” Med. Phys.,Vol 39 (7), July 2012.F3094 1424. Summary of Test Method4.1 A primary X-ray beam with a standardized X-rayspectrum and a constant intensity with the conditions listed inTable 1 fo

35、r the scatter equivalent conditions employed tomeasure the attenuation in test samples using the inversebroad-beam conditions in Fig. 1.4.2 Attenuation can be measured for scatter equivalentenergies corresponding to all primary beam energies as definedby Test Method F2547; however, it is recommended

36、 that threemeasurements be used in standard reports. These measure-ments correspond to most common fluoroscopic conditions at80 kV, a high kV condition for a standard fluoroscope at 100kV, and a condition corresponding to scatter produced from CTscanning at 130 kV. These scatter equivalent condition

37、s corre-spond to direct beam measurement at 70, 85, and 105 kV withfiltrations adjusted to achieve HVLs of 3.4, 4.0, and 5.1 mmAlrespectively.5. Significance and Use5.1 This test method is designed to provide a standardizedprocedure to ensure comparable results betweenmanufacturers, testing laborato

38、ries, and users.5.2 This test method attempts to realistically quantify theradiation protection provided by radiation protective garmentsunder real world conditions for workers primarily exposed toscattered radiation in medical fluoroscopy work.5.3 This test method is designed to simulate exposureco

39、nditions to radiation scattered from the body of the patientundergoing fluoroscopy through an angle of 90 from theprimary X-ray beam.5.4 The test method is designed to include contributions ofradiation dose to the wearer from secondary radiation emittedfrom the shielding material.6. Apparatus6.1 Pri

40、mary X-ray Beam SourceA variable power X-raygenerator coupled to a tungsten anode X-ray tube with thefollowing characteristics:6.1.1 Wave form ripple cannot exceed 3 %, and may notemploy capacitor discharge methods where the voltage poten-tial falls more than 5 % during the test exposure.6.2 kV Moni

41、toringKilovoltage shall be actively measuredduring testing with an invasive or non-invasive kV measuringdevice capable of measuring potential within 0.5 kV of theactual tube.6.2.1 The coefficient of variation in voltage potential cannotexceed 0.05 in four consecutive exposures using the potentialset

42、ting(s) for testing.6.3 Exposure Measurement:6.4 An ionization chamber and electrometer capable ofmeasuring from 0.258 to 1290 C/kg (1 mR to 5 R) andcalibrated for use with X-rays generated under conditionsspecified by Test Method F2547.6.5 The coefficient of variation in exposure cannot exceed0.05

43、in four consecutive exposures when measured through 0.5mm of Pb.6.6 NoiseDetector signal measured under the same con-ditions (integration time) of the measurement but withoutX-rays shall not be more than 1 % of the minimum measure-ment recorded through any test material.6.7 Test SetupThe apparatus m

44、ay use either a vertically orhorizontally directed X-ray beam provided that the geometryconforms to that described in Fig. 1.6.7.1 Beam defining apertures.6.7.1.1 Beam apertures designated 1 and 3 in Fig. 1 arenormally incorporated into most medical X-ray system colli-mator assemblies. If such an ap

45、paratus is used they need not beadded. Aluminum filtration needed to adjust the HVL to testconditions may be added through a slot provided on somecollimators or may be positioned on the output surface of thecollimator.1. Diaphragm2. Beam filtration3. Diaphragm4. Measuring diaphragm5. Test material6.

46、 Flat air ionization measuring chamber1. IEC 61331-1 Ed. 2.0 Protective Devices Against Diagnostic MedicalX-radiation, Part 1: Determination of Attenuation Properties2. McCaffrey, J.P., Tessier, F., and Shen, H., “Radiation Shielding Materials andRadiation Scatter Effects for Interventional Radiolog

47、y (IR) Physicians, Med. Phys.,Vol 39 (7), 2012, pp. 45374546.FIG. 1 Test SetupTABLE 1 Standard X-ray Qualities (Columns 1 and 2) and ScatterEquivalent Qualities4Direct Beam 90 Scatter EquivalentkV HVL (mm Al) kV HVL (mm Al)60 2.9 50 2.670 3.3 60 2.980 4.0 70 3.490 4.3 75 3.7100 5.2 85 4.0110 5.5 90

48、4.3120 6.3 100 4.5130 6.7 105 5.1F3094 1436.7.1.2 The collimator should be adjusted so that all dimen-sions of the field at aperture 4 exceed the dimensions of thataperture on all sides by at least 1 cm.6.7.1.3 Aperture 4 should be constructed of lead with athickness of at least 2 mm with external d

49、imensions at least 2.5cm larger than the largest dimensions of the ionization chamberon all chamber margins.6.7.2 Geometry:6.7.2.1 Aperture 4 should be positioned so that its distanceto the X-ray tube focus (a in Fig. 1) is at least five times thediameter of the opening (d).6.7.2.2 The spacing between test material and the ionizationchamber (b) shall not exceed 5 mm during measurements.6.7.2.3 Spacing between the X-ray detector and any othersurface along the direction of the X-ray beam shall be 700 mmor more.7. Hazards7.1 Workers performi