ASTM E2445 E2445M-2014 Standard Practice for Performance Evaluation and Long-Term Stability of Computed Radiography Systems《计算机射线照相系统资格和长期稳定性的标准实施规程》.pdf
《ASTM E2445 E2445M-2014 Standard Practice for Performance Evaluation and Long-Term Stability of Computed Radiography Systems《计算机射线照相系统资格和长期稳定性的标准实施规程》.pdf》由会员分享,可在线阅读,更多相关《ASTM E2445 E2445M-2014 Standard Practice for Performance Evaluation and Long-Term Stability of Computed Radiography Systems《计算机射线照相系统资格和长期稳定性的标准实施规程》.pdf(21页珍藏版)》请在麦多课文档分享上搜索。
1、Designation: E2445/E2445M 14Standard Practice forPerformance Evaluation and Long-Term Stability ofComputed Radiography Systems1This standard is issued under the fixed designation E2445/E2445M; the number immediately following the designation indicates the yearof original adoption or, in the case of
2、revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice describes the evaluation of ComputedRadiology (CR) systems for industrial radiolog
3、y. It is intendedto ensure that the evaluation of image quality, as far as this isinfluenced by the CR system, meets the needs of users of thisstandard, and their customers, and enables process control andlong-term stability of the CR system.1.2 This practice specifies the fundamental parameters ofC
4、R systems to be measured to determine baseline performance,and to track the long term stability of the system. These testsare for applications up to 320kV. When greater than 320kV orwhen a gamma source is used, these tests may still be used tocharacterize a system, but may need to be modified as agr
5、eedbetween the user and cognizant engineering organization(CEO).1.3 The CR 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 t
6、hesetests is to monitor the system performance degradation and toidentify when an action needs to be taken when the systemdegrades by a certain level.1.4 The use of gauges2provided in this standard is manda-tory for each test. In the event these tests or gauges are notsufficient, the user, in coordi
7、nation with the CEO shall developadditional or modified tests, test objects, gauges, or imagequality indicators to evaluate the CR system.Acceptance levelsfor theseALTERNATE tests shall be determined by agreementbetween the user and CEO.1.5 The values stated in either SI units or inch-pound unitsare
8、 to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.6 This standard does not purport to address all
9、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:3E746 Practice for Dete
10、rmining Relative Image Quality Re-sponse of Industrial Radiographic Imaging SystemsE1316 Terminology for Nondestructive ExaminationsE1647 Practice for Determining Contrast Sensitivity in Ra-diologyE2002 Practice for Determining Total Image Unsharpness inRadiologyE2007 Guide for Computed RadiographyE
11、2033 Practice for Computed Radiology (PhotostimulableLuminescence Method)E2446 Practice for Classification of Computed RadiologySystems3. Terminology3.1 DefinitionsThe definition of terms relating to gamma-and X-radiology, which appear in Terminology E1316, GuideE2007, and Practice E2033 shall apply
12、 to the terms used in thispractice.3.2 Definitions of Terms Specific to This Standard:3.2.1 aliasingartifacts that appear in an image when thespatial frequency of the input is higher than the output iscapable of reproducing.1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-stru
13、ctive Testing and is the direct responsibility of Subcommittee E07.01 onRadiology (X and Gamma) Method.Current edition approved Oct. 1, 2014. Published October 2014. Originallyapproved in 2005. Last previous edition approved in 2010 as E2445/E2445M-05(2010). DOI:10.1520/E2445_E2445M-14.2The sole sou
14、rce of supply of the apparatus shown in Appendix X2 known to thecommittee at this time is Rockwell CollinsARINC, 1300 Thomas Drive, PanamaCity Beach, FL 32408, Phone: 405-605-7095, ARINC part number A0295224002(USAF design) or A0295224003 (NAVAIR design). The NAVAIR design includestwo additional tes
15、t targets that are not used in this test standard. If you are aware ofalternative suppliers, please provide this information to ASTM InternationalHeadquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend.13For referenced A
16、STM 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 Conshoh
17、ocken, PA 19428-2959. United States13.2.1.1 DiscussionThis will often appear as jagged orstepped sections in a line or as moir patterns (see Fig. 1).3.2.2 bandinglinear striping aligned parallel to the IPtransport direction, which may be caused by improper scannernormalization (see Fig. 2).3.2.3 com
18、puted radiology system (CR system)a completesystem of a storage phosphor imaging plate (IP) type, corre-sponding read out unit (scanner or reader) including pertinentequipment settings (for example, sampling resolution, laserpower, photomultiplier tube (PMT) gain, etc.), image acquisi-tion and proce
19、ssing software, and image display monitor.3.2.4 CR phantoma device containing an arrangement oftest targets used to evaluate the image quality of a CR system,as well as monitoring the image quality of the chosen system.3.2.5 customerthe company, government agency, or otherauthority responsible for t
20、he design, or end user, of the systemor component for which radiographic examination is required,also known as the Cognizant Engineering Organization (CEO).3.2.6 fadingthe reduction of intensity of the stored imagein the imaging plate over time.3.2.7 gainoverall signal amplification of the scannings
21、ystem.3.2.8 laser beam jittera lack of smooth movement of thelaser scanning device, which results in jagged scan lines on theimage (see Fig. 3).3.2.9 linear pixel valuea numerical value of a pictureelement (pixel) of the digital image, which is proportional tothe radiation dose.3.2.9.1 DiscussionExa
22、mple: for conversion of 12 bit logto 16 bit linear:PV16 bit linear5 65535 310SPV12 bit log10242 4D(1)The linear pixel value is zero if the radiation dose iszero.3.2.10 long-term stabilityperformance measurements of aCR system over the life-cycle of the devices, used to evaluaterelative system perfor
23、mance over time.3.2.11 manufacturerCR system manufacturer, supplier forthe user of the CR system.3.2.12 PMTphotomultiplier tube or other light capturedevice used by the specific scanner.3.2.13 PMT non-linearitydeviation from a linear responseof the PMT at high light input values or from step changes
24、 inlight.3.2.13.1 DiscussionAt high light input values the PMTmay under-respond, also the PMT may over-shoot or under-shoot in response to a step change in light (see Fig. 4).3.2.14 scan column dropouta zero PV linear image arti-fact created parallel to the transport direction when the path ofthe sc
- 1.请仔细阅读文档,确保文档完整性,对于不预览、不比对内容而直接下载带来的问题本站不予受理。
- 2.下载的文档,不会出现我们的网址水印。
- 3、该文档所得收入(下载+内容+预览)归上传者、原创作者;如果您是本文档原作者,请点此认领!既往收益都归您。
下载文档到电脑,查找使用更方便
5000 积分 0人已下载
下载 | 加入VIP,交流精品资源 |
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- ASTME2445E2445M2014STANDARDPRACTICEFORPERFORMANCEEVALUATIONANDLONGTERMSTABILITYOFCOMPUTEDRADIOGRAPHYSYSTEMS

链接地址:http://www.mydoc123.com/p-531136.html