1、Medical electrical equipment Characteristics of digital X-rayimaging devices Part 1-3: Determination of the detective quantum efficiency Detectors used in dynamic imagingBS EN 62220-1-3:2008raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI British S
2、tandardsNational forewordThis British Standard is the UK implementation of EN 62220-1-3:2008. It isidentical to IEC 62220-1-3:2008.The UK participation in its preparation was entrusted by Technical CommitteeCH/62, Electromedical equipment in medical practice, to SubcommitteeCH/62/2, Diagnostic imagi
3、ng equipment.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application. BSI 2009ISBN 978 0 580 55495 7ICS 11.040.50BRITISH
4、STANDARDBS EN 62220-1-3:2008Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of the StandardsPolicy and Strategy Committee on 30 April 2009Amendments issued since publicationAmd. No. Date Text affectedEUROPEAN STA
5、NDARD EN 62220-1-3 NORME EUROPENNE EUROPISCHE NORM September 2008 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2008 CENELEC -
6、 All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 62220-1-3:2008 E ICS 11.040.50 English version Medical electrical equipment - Characteristics of digital X-ray imaging devices - Part 1-3: Determination of the detective quantum efficiency -
7、Detectors used in dynamic imaging (IEC 62220-1-3:2008) Appareils lectromdicaux - Caractristiques des dispositifs dimagerie numrique rayonnement X - Partie 1-3: Dtermination de lefficacit quantique de dtection - Dtecteurs utiliss en imagerie dynamique(CEI 62220-1-3:2008) Medizinische elektrische Gert
8、e - Merkmale digitaler Rntgenbildgerte - Teil 1-3: Bestimmung der detektiven Quanten-Ausbeute - Bildempfnger fr dynamische Bildgebung (IEC 62220-1-3:2008) This European Standard was approved by CENELEC on 2008-07-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which
9、 stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member. This European S
10、tandard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the na
11、tional electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Swe
12、den, Switzerland and the United Kingdom. EN 62220-1-3:2008 - 2 - Foreword The text of document 62B/694/FDIS, future edition 1 of IEC 62220-1-3, prepared by SC 62B, Diagnostic imaging equipment, of IEC TC 62, Electrical equipment in medical practice, was submitted to the IEC-CENELEC parallel vote and
13、 was approved by CENELEC as EN 62220-1-3 on 2008-07-01. The following dates were fixed: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2009-04-01 latest date by which the national standards conflicting with
14、 the EN have to be withdrawn (dow) 2011-07-01 In this standard, terms printed in SMALL CAPITALS are used as defined in IEC/TR 60788, in Clause 3 of this standard or in other IEC publications referenced in the Index of defined terms. Where a defined term is used as a qualifier in another defined or u
15、ndefined term it is not printed in SMALL CAPITALS, unless the concept thus qualified is defined or recognized as a “derived term without definition”. NOTE Attention is drawn to the fact that, in cases where the concept addressed is not strongly confined to the definition given in one of the publicat
16、ions listed above, a corresponding term is printed in lower-case letters. In this standard, certain terms that are not printed in SMALL CAPITALS have particular meanings, as follows: “shall“ indicates a requirement that is mandatory for compliance; “should“ indicates a strong recommendation that is
17、not mandatory for compliance; “may“ indicates a permitted manner of complying with a requirement or of avoiding the need to comply; “specific“ is used to indicate definitive information stated in this standard or referenced in other standards, usually concerning particular operating conditions, test
18、 arrangements or values connected with compliance; “specified“ is used to indicate definitive information stated by the manufacturer in accompanying documents or in other documentation relating to the equipment under consideration, usually concerning its intended purposes, or the parameters or condi
19、tions associated with its use or with testing to determine compliance. This European Standard has been prepared under a mandate given to CENELEC by the European Commission and the European Free Trade Association and covers essential requirements of EC Directive MDD (93/42/EEC). See Annex ZZ. Annexes
20、 ZA and ZZ have been added by CENELEC. _ BS EN 62220-1-3:2008- 3 - EN 62220-1-3:2008 Endorsement notice The text of the International Standard IEC 62220-1-3:2008 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following notes ha
21、ve to be added for the standards indicated: IEC 62220-1 NOTE Harmonized as EN 62220-1:2004 (not modified). IEC 62220-1-2 NOTE Harmonized as EN 62220-1-2:2007 (not modified). IEC 61262-5 NOTE Harmonized as EN 61262-5:1994 (not modified). _ EN 62220-1-3:2008 - 4 - Annex ZA (normative) Normative refere
22、nces to international publications with their corresponding European publications The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (in
23、cluding any amendments) applies. NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies. Publication Year Title EN/HD Year IEC 60336 -1)Medical electrical equipment - X-ray tube assemblies for medical diagnosis - Characteristi
24、cs of focal spots EN 60336 20052)IEC/TR 60788 2004 Medical electrical equipment - Glossary of defined terms - - IEC 61267 1994 Medical diagnostic X-ray equipment - Radiation conditions for use in the determination of characteristics EN 612673) 1994 ISO 12232 1998 Photography - Electronic still-pictu
25、re cameras - Determination of ISO speed - - 1)Undated reference. 2)Valid edition at date of issue. 3) IEC 61267:2005 is harmonised as EN 61267:2006 (not modified). BS EN 62220-1-3:2008- 5 - EN 62220-1-3:2008 Annex ZZ (informative) Coverage of Essential Requirements of EC Directives This European Sta
26、ndard has been prepared under a mandate given to CENELEC by the European Commission and the European Free Trade Association and within its scope the standard covers all relevant essential requirements as given in Annex I of the EC Directive 93/42/EEC Compliance with this standard provides one means
27、of conformity with the specified essential requirements of the Directive concerned. WARNING: Other requirements and other EC Directives may be applicable to the products falling within the scope of this standard. 2 62220-1-3 IEC:2008 CONTENTS INTRODUCTION.6 1 Scope.7 2 Normative references .7 3 Term
28、s and definitions .8 4 Requirements .10 4.1 Operating conditions .10 4.2 X-RAY EQUIPMENT .10 4.3 RADIATION QUALITY .10 4.4 TEST DEVICE.11 4.5 Geometry 12 4.6 IRRADIATION conditions 14 4.6.1 General conditions 14 4.6.2 AIR KERMA measurement 15 4.6.3 LAG EFFECTS.16 4.6.4 IRRADIATION to obtain the CONV
29、ERSION FUNCTION 16 4.6.5 IRRADIATION for determination of the NOISE POWER SPECTRUM and LAG EFFECTS .16 4.6.6 IRRADIATION with TEST DEVICE in the RADIATION BEAM.17 4.6.7 Overview of all necessary IRRADIATIONS .18 5 Corrections of RAW DATA .18 6 Determination of the DETECTIVE QUANTUM EFFICIENCY 19 6.1
30、 Definition and formula of DQE(u,v) .19 6.2 Parameters to be used for evaluation 19 6.3 Determination of different parameters from the images20 6.3.1 Linearization of data 20 6.3.2 The LAG EFFECTS corrected NOISE POWER SPECTRUM (NPS) .20 6.3.3 Determination of the MODULATION TRANSFER FUNCTION (MTF)2
31、4 7 Format of conformance statement 24 8 Accuracy 25 Annex A (informative) Determination of LAG EFFECTS26 Annex B (informative) Calculation of the input NOISE POWER SPECTRUM 29 Bibliography30 Index of defined terms 32 Figure 1 TEST DEVICE .12 Figure 2 Geometry for exposing the DIGITAL X-RAY IMAGING
32、DEVICE in order to determine the CONVERSION FUNCTION, the NOISE POWER SPECTRUM and the MODULATION TRANSFER FUNCTION behind the TEST DEVICE.14 Figure 3 Image acquisition sequence to determine the NOISE POWER SPECTRUM and LAG EFFECTS17 Figure 4 Geometric arrangement of the ROIs.21 Figure A.1 Power spe
33、ctral density of white noise s and correlated signal g (only positive frequencies are shown)27 BS EN 62220-1-3:200862220-1-3 IEC:2008 3 Table 1 RADIATION QUALITY (IEC 61267:1994) for the determination of DETECTIVE QUANTUM EFFICIENCY and corresponding parameters .11 Table 2 Necessary IRRADIATIONS 18
34、Table 3 Parameters mandatory for the application of this standard 20 BS EN 62220-1-3:2008 6 62220-1-3 IEC:2008 INTRODUCTION DIGITAL X-RAY IMAGING DEVICES are increasingly used in medical diagnosis and will widely replace conventional (analogue) imaging devices such as screen-film systems or analogue
35、 X-RAY IMAGE INTENSIFIER television systems in the future. It is necessary, therefore, to define parameters that describe the specific imaging properties of these DIGITAL X-RAY IMAGING DEVICES and to standardize the measurement procedures employed. There is growing consensus in the scientific world
36、that the DETECTIVE QUANTUM EFFICIENCY (DQE) is the most suitable parameter for describing the imaging performance of an X-ray imaging device. The DQE describes the ability of the imaging device to preserve the signal-to-NOISE ratio from the radiation field to the resulting digital image data. Since
37、in X-ray imaging, the NOISE in the radiation field is intimately coupled to the AIR KERMA level, DQE values can also be considered to describe the dose efficiency of a given DIGITAL X-RAY IMAGING DEVICE. NOTE 1 In spite of the fact that the DQE is widely used to describe the performance of imaging d
38、evices, the connection between this physical parameter and the decision performance of a human observer is not yet completely understood 1, 3.1)NOTE 2 IEC 61262-5 specifies a method to determine the DQE of X-RAY IMAGE INTENSIFIERS at nearly zero SPATIAL FREQUENCY. It focuses only on the electro-opti
39、cal components of X-RAY IMAGE INTENSIFIERS, not on the imaging properties as this standard does. As a consequence, the output is measured as an optical quantity (luminance), and not as digital data. Moreover, IEC 61262-5 prescribes the use of a RADIATION SOURCE ASSEMBLY, whereas this standard prescr
40、ibes the use of an X-RAY TUBE. The scope of IEC 61262-5 is limited to X-RAY IMAGE INTENSIFIERS and does not interfere with the scope of this standard. The DQE is already widely used by manufacturers to describe the performance of their DIGITAL X-RAY IMAGING DEVICE. The specification of the DQE is al
41、so required by regulatory agencies (such as the Food and Drug Administration (FDA) for admission procedures. However, there is presently no standard governing either the measurement conditions or the measurement procedure, with the consequence that values from different sources may not be comparable
42、. This standard has therefore been developed in order to specify the measurement procedure together with the format of the conformance statement for the DETECTIVE QUANTUM EFFICIENCY of DIGITAL X-RAY IMAGING DEVICES. In the DQE calculations proposed in this standard, it is assumed that system respons
43、e is measured for objects that attenuate all energies equally (task-independent) 5. This standard will be beneficial for manufacturers, users, distributors and regulatory agencies. It is the third document out of a series of three related standards: Part 1, which is intended to be used in RADIOGRAPH
44、Y, excluding MAMMOGRAPHY and RADIOSCOPY. Part 1-2, which is intended to be used for MAMMOGRAPHY. the present Part 1-3, which is intended to be used for dynamic imaging detectors. These standards can be regarded as the first part of the family of IEC 62220 standards describing the relevant parameters
45、 of DIGITAL X-RAY IMAGING DEVICES. 1)Figures in square brackets refer to the bibliography. BS EN 62220-1-3:200862220-1-3 IEC:2008 7 MEDICAL ELECTRICAL EQUIPMENT CHARACTERISTICS OF DIGITAL X-RAY IMAGING DEVICES Part 1-3: Determination of the detective quantum efficiency Detectors used in dynamic imag
46、ing 1 Scope This part of IEC 62220 specifies the method for the determination of the DETECTIVE QUANTUM EFFICIENCY (DQE) of DIGITAL X-RAY IMAGING DEVICES as a function of AIR KERMA and of SPATIAL FREQUENCY for the working conditions in the range of the medical application as specified by the MANUFACT
47、URER. The intended users of this part of IEC 62220 are manufacturers and well equipped test laboratories. This Part 1-3 is restricted to DIGITAL X-RAY IMAGING DEVICES that are used for dynamic imaging such as, but not exclusively, direct and indirect flat panel-detector based systems. It is not reco
48、mmended to use this part of IEC 62220 for digital X-RAY IMAGE INTENSIFIER-based systems. NOTE 1 This negative recommendation is based on the low frequency drop, vignetting and geometrical distortion present in these devices which may put severe limitations on the applicability of the measurement met
49、hods described in this standard. This part of IEC 62220 is not applicable to: DIGITAL X-RAY IMAGING DEVICES intended to be used in mammography or in dental radiography; COMPUTED TOMOGRAPHY; and systems in which the X-ray field is scanned across the patient. NOTE 2 The devices noted above are excluded because they contain many parameters (for instance, beam qualities, geometry, time dependence, etc.) which differ from those important for d
