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1、NORME INTERNATIONALE INTERNATIONAL STANDARD CE1 IEC 1262-5 Premire dition First edition 1994-07 Appareils lectromdicaux - Caractristiques des intensificateurs lectro-optiques dimage radiologique - Partie 5: Dtermination de lefficacit quantique de dtection Medical electrical equipment - Characteristi
2、cs of electro-optical X-ray image intensifiers - Part 5: Determination of the detective quantum efficiency Numro de rfrence Reference number CEI/IEC 1262-5: 1994 Copyright International Electrotechnical Commission Provided by IHS under license with IECLicensee=IHS Employees/1111111001, User=Wing, Be
3、rnie Not for Resale, 03/10/2007 02:44:03 MSTNo reproduction or networking permitted without license from IHS -,-,- Numros des publications Depuis le ler janvier 1997, les publications de la CE1 sont numrotes partir de 60000. Publications consolides Les versions consolides de certaines publications d
4、e la CE1 incorporant les amendements sont disponibles. Par exemple, les numros ddition 1.0, 1.1 et 1.2 indiquent respectivement la publication de base, la publication de base incorporant lamendement 1, et la publication de base incorporant les amendements 1 et 2. Validit de la prsente publication Le
5、 contenu technique des publications de la CE1 est constamment revu par la CE1 afin quil reflete ltat actuel de la technique. Des renseignements relatifs la date de re- confirmation de la publication sont disponibles dans le Catalogue de la CEI. Les renseignements relatifs des questions ltude et des
6、travaux en cours entrepris par le comit technique qui a tabli cette publication, ainsi que la liste des publications tablies, se trouvent dans les documents ci-dessous: Site web de la CEP Catalogue des publications de la CE1 Publi annuellement et mis jour rgulirement (Catalogue en ligne)* Disponible
7、 la fois au site web de la CEI et comme priodique imprim Bulletin de la CE1 Terminologie, symboles graphiques et littraux En ce qui concerne la terminologie gnrale, le lecteur se reportera la CE1 60050: Vocabulaire Electro- technique International (VEI). Pour les symboles graphiques, les symboles li
8、ttraux et les signes dusage gnral approuvs par la CEI, le lecteur consultera la CE1 60027: Symboles littraux a utiliser en lectrotechnique, la CE1 6041 7: Symboles graphiques utilisables sur le matriel. Index, relev et compilation des feuilles individuelles. et la CE1 60617: Symboles graphiques pour
9、 schmas. * Voir adresse 4 t e web, sur la page de titre. Numbering As from 1 January 1997 all IEC publications are issued with a designation in the 60000 series. Consolidated publications Consolidated versions of some IEC publications including amendments are available. For example, edition numbers
10、1 .O, 1.1 and 1.2 refer, respectively, to the base publication, the base publication incor- porating amendment 1 and the base publication incorporating amendments 1 and 2. Validity of this publication The technical content of IEC publications is kept under constant review by the IEC, thus ensuring t
11、hat the content reflects current technology. Information relating to the date of the reconfirmation of the publication is available in the IEC catalogue. Information on the subjects under consideration and work in progress undertaken by the technical com- mittee which has prepared this publication,
12、as well as the list of publications issued, is to be found at the following IEC sources: IEC web site* Catalogue o f IEC publications Published yearly with regular updates (On-line catalogue)* Available both at the IEC web site* and as a printed periodical IEC Bulletin Terminology, graphical and let
13、ter symbols For general terminology, readers are referred to I EC 60 050: International Electrotechnical Vocabulary (IEV). For graphical symbols, and letter symbols and signs approved by the IEC for general use, readers are referred to publications IEC 60027: Letter symbols to be used in electrical
14、technology, IEC 60417: Graphical symbols for use on equipment. Index, survey and compilation of the single sheets and IEC 60617: Graphical symbols for diagrams. * See web site address on title page. Copyright International Electrotechnical Commission Provided by IHS under license with IECLicensee=IH
15、S Employees/1111111001, User=Wing, Bernie Not for Resale, 03/10/2007 02:44:03 MSTNo reproduction or networking permitted without license from IHS -,-,- NORME I NTE RN AT1 ON ALE INTERNATIONAL STANDARD CE1 IEC 1262-5 Premire dition First edition 1994-07 Appareils lectromdicaux - Caractristiques des i
16、ntensificateurs lect ro-op t iq ues d i mage radio log que - Partie 5: Dtermination de I e f f icaci t quantique de dtection Medical electrical equipment - Characteristics of electro-optical X-ray image intensifiers - Part 5: Determination of the detective quantum efficiency CE1 1994 Droits de repro
17、duction reserves - Copyright - all rights reserved Auwne partie de cette publication ne peut tre reproduite ni utilise sous quelque form que soit et par aucun pro- cd. lectronique ou mcanique. y compris !a photocope et les microfilms. sans laccord crrl de Iditeur No part of this publication may be r
18、eproduced or ulilued in any form or by any means. electronic or mechanical. including photocopying and microfilm, without permission in writing from the publisher. Bureau Central de ia Commission Eiectrotechnique Internationale 3, rue de Varem any IEC National Committee interested in the subject dea
19、lt with may participate in this preparatory work. International, governmental a d non-governmental organizations liaising with the IEC also participate in this preparation. The IEC collaborates dosely with the Intemational Organization for Standardization (ISO) in accordance with conditions determin
20、ed by agreement between the two organizations. 2) The formal decisions or agreements of the IEC on technical matters, prepared by technical committees on which all the National Committees having interest therein are represented, express, as nearly as possible, an intemational consensus of opinion on
21、 the subjects dealt with. 3) They have the form of recommendations for international use published in the form of standards, technical reports or guides and they are accepted by the National Cornmittees in that sense. 4) In order to promote international unification, IEC National Cornmittees underta
22、ke to apply IEC International Standards transparently to the maximum extent possible in their national and regional standards. Any divergence behiveen the IEC Standard a d the corresponding national or regional standard shall be clearly indicated in the latter. International Standard IEC 1262-5 has
23、been prepared by sub-committee 628: Diagnostic imaging equipment, of IEC technical committee 62: Electrical equipment in medical practice. The text of this standard is based on the following documents: Report on voting I DIS I Full information on the voting for approval of this standard can be found
24、 in the Report on voting indicated in the above table. Annexes A, B, C and D are for information only. In this standard, the following print types are used: - Requirements, compliance with which can be tested, and definitions: in roman type. - Explanations, advice, introductions, general statements,
25、 and exceptions: in smaller type. - Test specifications: in italic type. - TERMS USED MROUGHOCTT MIS STANDARD WHICH HAVE BEEN DEFINED IN 3.1 AND IN ANNEX A: SW CAPITALS. Copyright International Electrotechnical Commission Provided by IHS under license with IECLicensee=IHS Employees/1111111001, User=
26、Wing, Bernie Not for Resale, 03/10/2007 02:44:03 MSTNo reproduction or networking permitted without license from IHS -,-,- - 6 - 1262-5 O CEI:1994 INTRODUCTION LEFFICACITE DE QUANTIQUE DE DETECTION (DQE) est une mesure de la qualit de limage dun systme, tablie par comparaison de son rapport signal-b
27、ruit (SNR) de sortie avec son SNR dentre. Pour les systmes linaires de formation dimages, il est possible danalyser le SNR et le OQE en fonction de signaux sinusodaux variables. La prsente norme donne des spcifications dtailles pour la spatiales et temporelles proches de zro. L a mthode utilise est
28、lanalyse du spectre de scintillation (SSA). dtermination du DQE des INTENSIFICATEURS ELECTRO-OPTIQUES DIMAGE RADIOLOGIQUE a des frquences L a SOURCE DE RAYONNEMENT dentre est le radionuclide 241Am qui est prfrable a une SOURCE DE RAYONNEMENT X parce que outre son absence de drive et de fluctuations
29、priodiques lentre, il produit un rayonnement gamma sur une plage nergtique radiologiquement intressante. Le signal du lu minophore de sortie de IINTENSIFICATEUR ELECTRO-OPTIQUE DIMAGE RADIOLOGIQUE est intgr sur une surface grande par rapport limage de la source. De plus, la mthode SSA ncessite lintg
30、ration de pratiquement toute lnergie des photons lumineux en sortie de IINTENSIFICATEUR ELECTRO-OPTIQUE DIMAGE RADIOLOGIQUE imputable labsorption dun seul photon de rayonnement gamma. Ces caractristiques donnent une mesure proche de zro pour les frquences spatiales comme pour les frquences temporell
31、es. La prsente norme ne spcifie la mesure du DQE qu proximit du CENTRE DU CHAMP DENTREE. Dautre part, la mthode SSA nest pas recommande pour un INTENSIFICATEUR ELECTRO-OPTIQUE DIMAGE RADIOLOGIQUE dont la dcroissance de lmittance du luminophore de sortie est considrablement plus lente que celle dun l
32、uminophore P-20. Gnralement, lorsquun seul photon de rayonnement gamma est absorb, lintensit de limpulsion lumineuse correspondante, 1 ms aprs le dbut de limpulsion, devrait tre infrieure 10 % de lintensit maximale. Cela suppose que lintervalle de temps entre le dbut de limpulsion et lintensit maxim
33、ale est beaucoup plus petit que 1 ms. Etant donn que la mthode SSA ncessite une intgration de lmittance due aux photons individuels de rayonnement gamma, les luminophores ayant une dcroissance considrablement plus lente ncessitent des vitesses de comptage des photons de rayonnement gamma trs faibles
34、, qui peuvent devenir comparables aux vitesses de comptage du bruit de fond. II est reconnu quil existe dautres mthodes de mesure du DQE par exemple lanalyse par paquets dimpulsions, lanalyse du bruit r.m.s. et lestimation de labsorption quantique partir des D - Bibliographie). Les mthodes qui fourn
35、issent des rsultats de mesure de DQE cohrents, dans la limite de prcision de la mesure, avec les rsultats obtenus par la mthode de la prsente norme, sont tout aussi acceptables. CaaCtiStiqUeS physiques de IINTENSIFICATEUR ELECTRO-OPTIQUE DIMAGE RADIOLOGIQUE (Voir annexe Copyright International Elect
36、rotechnical Commission Provided by IHS under license with IECLicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/10/2007 02:44:03 MSTNo reproduction or networking permitted without license from IHS -,-,- 1262-5 O IEC:l994 -7- INTRODUCTION DETECTIVE QUANTUM EFFICIENCY (DQE) is a m
37、easure of the imaging quality of a system based on a comparison of the signal-to-noise ratio (SNR) at its output to the SNR at its input. For linear imaging systems, SNR and DQE can be conveniently analysed in terms of sinusoidally varying signals. This standard gives detailed specifications for the
38、 determination of the DQE of ELECTRO-OPTICAL X-RAY IMAGE INTENSIFIERS near zero frequency for both spatial and temporal frequencies. The method employed is scintillation spectrum analysis (SSA). The source of input radiation is the radionuclide *“Am, which is preferred over an X-RAY SOURCE because o
39、f the radionuclides freedom from drift and periodic fluctuations in its output while providing gamma-rays in a radiologically interesting energy range. The signal at the output phosphor of the ELECTRO-OPTICAL X-RAY IMAGE INTENSIFIER is integrated over an area that is large compared to the image of t
40、he source. Additionally, the SSA method requires integration of essentially all of the optical photon energy at the These characteristics result in a measurement near zero for both spatial and temporal frequencies. ELECTRO-OPTICAL X-RAY IMAGE INTENSIFIER Output attributable 10 the absorption Of a Si
41、ngle Qamma-ray photon. This standard Specifies the measurement Of DQE only near the CENTRE OF THE ENTRANCE FIELD. Also, the SSA method is not recommended for an ELECTRO-OPTICAL X-RAY IMAGE INTENSIFIER with output phosphor radiance decay that is considerably slower than that for a P-20 phosphor. Gene
42、rally, upon absorption of a single gamma-ray photon, the resulting light pulse intensity at 1 ms after the onset of the pulse should be less than 10 % of the peak intensity. This assumes that the time interval between pulse onset and peak intensity is much shorter than 1 ms. Since the SSA method ent
43、ails integrating the radiance due to individual gamma-ray photons, phosphors having appreciably slower decay would necessitate the use of very low gamma-ray photon count rates which can become comparable to background count rates. It is recognized that other methods of DQE measurement are available,
44、 e.g., pulse-burst analysis, r.m.s. noise analysis, and estimation of quantum absorption from physical characteristics of the ELECTRO-OPTICAL X-RAY IMAGE iNTENsiFiER (see annex D - Bibliography). Methods that provide measurements of DQE that agree within measurement accuracy with measurements obtain
45、ed by the method of this standard are equally acceptable. Copyright International Electrotechnical Commission Provided by IHS under license with IECLicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/10/2007 02:44:03 MSTNo reproduction or networking permitted without license from
46、 IHS -,-,- -8- 1262-5 O CEI:1994 APPAREILS LECTROMDICAUX - CARACTRISTIQUES DES INTENSIFICATEURS ELECTRO-OPTIQUES DIMAGE RADIOLOGIQUE - Partie 5: Dtermination de lefficacit quantique de dtection 1 Domaine dapplication La prsente Norme internationale sapplique aux INTENSIFICATEURS ELECTRO-OPTIQUES DIM
47、AGE RADIOLOGIQUE destins une utilisation mdicale en tant que composants dEQUIPEMENTS A RAYONNEMENT X de diagnostic. La prsente Norme internationale dcrit une mthode de dtermination RADIOLOGIQUE par analyse du spectre damplitude des impulsions de scintillation de photons unitaires de rayonnement gamm
48、a. La mthode de la prsente norme ne sapplique quaux INTENSIFICATEURS ELECTRO-OPTIQUES DIMAGE RADIOLOGIQUE ayant des vitesses de dcroissance de lmittance de sortie sensiblement gales ou suprieures celles dun luminophore P-20. de IEFFICACITE QUANTIQUE DE DETECTION (DQE) des INTENSIFICATEURS ELECTRO-OPTIQUE DIMAGE 2 Rfrence notmatie La norme suivante contient des dispositions qui, par suite de la rfrence qui y est faite