ASTM_E_2737_-_10.pdf

Designation:E273710Standard Practice forDigital Detector Array Performance Evaluation and Long-Term Stability1This standard is issued under the fixed designation E2737;the number immediately following the designation 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()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice describes the evaluation of DDA systemsfor industrial radiology.It is intended to ensure that theevaluation of image quality,as far as this is influenced by theDDA system,meets the needs of users,and their customers,and enables process control and long term stability of the DDAsystem.1.2 This practice specifies the fundamental parameters ofDigital Detector Array(DDA)systems to be measured todetermine baseline performance,and to track the long termstability of the DDA system.1.3 The DDA system performance tests specified in thispractice shall be completed upon acceptance of the systemfrom the manufacturer and at intervals specified in this practiceto monitor long term stability of the system.The intent of thesetests is to monitor the system performance for degradation andto identify when an action needs to be taken when the systemdegrades by a certain level.1.4 The use of the gages provided in this standard ismandatory for each test.In the event these tests or gages arenot sufficient,the user,in coordination with the cognizantengineering organization(CEO)may develop additional ormodified tests,test objects,gages,or image quality indicatorsto evaluate the DDA system.Acceptance levels for theseALTERNATE tests shall be determined by agreement betweenthe user,CEO and manufacturer.1.5 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 determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E1025 Practice for Design,Manufacture,and MaterialGrouping Classification of Hole-Type Image Quality In-dicators(IQI)Used for RadiologyE1316 Terminology for Nondestructive ExaminationsE1742 Practice for Radiographic ExaminationE2002 Practice for Determining Total Image Unsharpness inRadiologyE2445 Practice for Performance Evaluation and Long-TermStability of Computed Radiography SystemsE2597 Practice for Manufacturing Characterization of Digi-tal Detector ArraysE2698 Practice for Radiological Examination Using DigitalDetector ArraysE2736 Guide for Digital Detector Array Radiology3.Terminology3.1 Definitionsthe definition of terms relating to gammaand X-radiology,which appear in Terminology E1316,PracticeE2597,Guide E2736,and Practice E2698 shall apply to theterms used in this practice.3.2 Definitions of Terms Specific to This Standard:3.2.1 digital detector array(DDA)systeman electronicdevice that converts ionizing or penetrating radiation into adiscrete array of analog signals which are subsequently digi-tized and transferred to a computer for display as a digitalimage corresponding to the radiologic energy pattern impartedupon the input region of the device.The conversion of theionizing or penetrating radiation into an electronic signal maytranspire by first converting the ionizing or penetrating radia-tion into visible light through the use of a scintillating material.1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.01 onRadiology(X and Gamma)Method.Current edition approved April 15,2010.Published June 2010.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 These devices can range in speed from many seconds perimage to many images per second,up to and in excess ofreal-time radioscopy rates(usually 30 frames per seconds).3.2.2 active DDA areathe active pixelized region of theDDA,which is recommended by the manufacturer as usable.3.2.3 signal-to-noise ratio(SNR)quotient of mean valueof the intensity(signal)and standard deviation of the intensity(noise).The SNR depends on the radiation dose and the DDAsystem properties.3.2.4 contrast-to-noise ratio(CNR)quotient of the differ-ence of the signal levels between two material thicknesses,andstandard deviation of the intensity(noise)of the base material.The CNR depends on the radiation dose and the DDA systemproperties.3.2.5 contrast sensitivityrecognized contrast percentageof the material to examine.It depends on 1/CNR.3.2.6 spatial resolution(SR)the spatial resolution indi-cates the smallest geometrical detail,which