IEC 62220-1-3-2008 Medical electrical equipment - Characteristics of digital X-ray imaging devices - Part 1-3 Determination of the detective quantum efficiency .pdf

1、 IEC 62220-1-3 Edition 1.0 2008-06 INTERNATIONAL STANDARD NORME INTERNATIONALE Medical electrical equipment Characteristics of digital X-ray imaging devices Part 1-3: Determination of the detective quantum efficiency Detectors used in dynamic imaging Appareils lectromdicaux Caractristiques des dispo

2、sitifs dimagerie numrique rayonnement X Partie 1-3: Dtermination de lefficacit quantique de dtection Dtecteurs utiliss en imagerie dynamique IEC 62220-1-3:2008 THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2008 IEC, Geneva, Switzerland All rights reserved. Unless otherwise specified, no part of

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17、 NORME INTERNATIONALE Medical electrical equipment Characteristics of digital X-ray imaging devices Part 1-3: Determination of the detective quantum efficiency Detectors used in dynamic imaging Appareils lectromdicaux Caractristiques des dispositifs dimagerie numrique rayonnement X Partie 1-3: Dterm

18、ination de lefficacit quantique de dtection Dtecteurs utiliss en imagerie dynamique INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE V ICS 11.040.50 PRICE CODE CODE PRIX ISBN 2-8318-9826-9 2 62220-1-3 IEC:2008 CONTENTS FOREWORD.4 INTRODUCTION.6 1 Scope.7 2 Normati

19、ve references .7 3 Terms 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 IRRADIATI

20、ON to obtain the CONVERSION 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 QUANT

21、UM EFFICIENCY 19 6.1 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 data20 6.3.2 The LAG EFFECTS corrected NOISE POWER SPECTRUM (NPS) .20 6.3.3 Determination of the MODULATION TRANSF

22、ER FUNCTION (MTF)24 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 DIGI

23、TAL X-RAY IMAGING 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 Fi

24、gure A.1 Power spectral density of white noise s and correlated signal g (only positive frequencies are shown)27 62220-1-3 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 Ta

25、ble 3 Parameters mandatory for the application of this standard 20 4 62220-1-3 IEC:2008 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ MEDICAL ELECTRICAL EQUIPMENT CHARACTERISTICS OF DIGITAL X-RAY IMAGING DEVICES Part 1-3: Determination of the detective quantum efficiency Detectors used in dynamic imag

26、ing FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in

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32、ir national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter. 5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any equipment declar

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35、wn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not

36、 be held responsible for identifying any or all such patent rights. International Standard IEC 62220-1-3 has been prepared by subcommittee 62B: Diagnostic imaging equipment, of IEC technical committee 62: Electrical equipment in medical practice. The text of this standard is based on the following d

37、ocuments: FDIS Report on voting 62B/694/FDIS 62B/702/RVD Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. 62220-1-3 IEC:2008 5 A lis

38、t of all parts of the IEC 62220 series, published under the general title Medical electrical equipment Characteristics of digital X-ray imaging devices, can be found on the IEC website. In this standard, terms printed in SMALL CAPITALS are used as defined in IEC 60788, in Clause 3 of this standard o

39、r in other IEC publications referenced in the Index of defined terms. Where a defined term is used as a qualifier in another defined or undefined term it is not printed in SMALL CAPITALS, unless the concept thus qualified is defined or recognized as a “derived term without definition”. NOTE Attentio

40、n is drawn to the fact that, in cases where the concept addressed is not strongly confined to the definition given in one of the publications 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 me

41、anings, as follows: “shall“ indicates a requirement that is mandatory for compliance; “should“ indicates a strong recommendation that is 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

42、definitive information stated in this standard or referenced in other standards, usually concerning particular operating conditions, test arrangements or values connected with compliance; “specified“ is used to indicate definitive information stated by the manufacturer in accompanying documents or i

43、n other documentation relating to the equipment under consideration, usually concerning its intended purposes, or the parameters or conditions associated with its use or with testing to determine compliance. The committee has decided that the contents of this publication will remain unchanged until

44、the maintenance result date indicated on the IEC web site under “http:/webstore.iec.ch“ in the data related to the specific publication. At this date, the publication will be reconfirmed; withdrawn; replaced by a revised edition, or amended. 6 62220-1-3 IEC:2008 INTRODUCTION DIGITAL X-RAY IMAGING DE

45、VICES are increasingly used in medical diagnosis and will widely replace conventional (analogue) imaging devices such as screen-film systems or analogue X- RAY IMAGE INTENSIFIER television systems in the future. It is necessary, therefore, to define parameters that describe the specific imaging prop

46、erties of these DIGITAL X-RAY IMAGING DEVICES and to standardize the measurement procedures employed. There is growing consensus in the scientific world that the DETECTIVE QUANTUM EFFICIENCY (DQE) is the most suitable parameter for describing the imaging performance of an X-ray imaging device. The D

47、QE 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 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

48、 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 devices, the connection between this physical parameter and the decision performance of a human observer is not yet completely understood 1, 3. 1)N

49、OTE 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-optical 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 612