BS EN 60336-2005 Medical electrical equipment - X-ray tube assemblies for medical diagnosis - Characteristics of focal spots《医用电气设备 医疗诊断用X-射线管组件 焦点特性》.pdf

1、BRITISH STANDARD BS EN 60336:2005 Medical electrical equipment X-ray tube assemblies for medical diagnosis Characteristics of focal spots The European Standard EN 60336:2005 has the status of a British Standard ICS 11.040.50 BS EN 60336:2005 This British Standard was published under the authority of

2、 the Standards Policy and Strategy Committee on 13 October 2005 BSI 13 October 2005 ISBN 0 580 46478 4 National foreword This British Standard is the official English language version of EN 60336:2005. It is identical with IEC 60336:2005. It supersedes BS EN 60336:1995 which will be withdrawn on 1 J

3、une 2008. The UK participation in its preparation was entrusted by Technical Committee CH/62, Electromedical equipment in medical practice, to Subcommittee CH/62/2, Diagnostic imaging equipment, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained

4、 on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of t

5、he BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid en

6、quirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This docum

7、ent comprises a front cover, an inside front cover, the EN title page, pages 2 to 39 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEAN STANDARD EN 60336 NORME EUROPENNE

8、 EUROPISCHE NORM July 2005 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 2005 CENELEC - All rights of exploitation in any form

9、 and by any means reserved worldwide for CENELEC members. Ref. No. EN 60336:2005 E ICS 11.040.50 Supersedes EN 60336:1995English version Medical electrical equipment X-ray tube assemblies for medical diagnosis Characteristics of focal spots (IEC 60336:2005) Appareils lectromdicaux Gaines quipes pour

10、 diagnostic mdical - Caractristiques des foyers (CEI 60336:2005) Medizinische elektrische Gerte - Rntgenstrahler fr medizinische Diagnostik Kennwerte von Brennflecken (IEC 60336:2005) This European Standard was approved by CENELEC on 2005-06-01. CENELEC members are bound to comply with the CEN/CENEL

11、EC Internal Regulations which 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 CE

12、NELEC member. This European Standard 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 version

13、s. CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, S

14、weden, Switzerland and United Kingdom. EN 60336:2005 - 2 - Foreword The text of document 62B/554/FDIS, future edition 4 of IEC 60336, 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 was appro

15、ved by CENELEC as EN 60336 on 2005-06-01. This European Standard supersedes EN 60336:1995. 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) 2006-03-01 latest date by which the

16、national standards conflicting with the EN have to be withdrawn (dow) 2008-06-01 Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 60336:2005 was approved by CENELEC as a European Standard without any modification. In the official version, for Biblio

17、graphy, the following note has to be added for the standard indicated: IEC 60601-2-28 NOTE Harmonized as EN 60601-2-28:1993 (not modified). _ 3 EN 60336:2005 CONTENTS 1 Scope 5 2 Normative references .5 3 Terms and definitions .5 4 Determinations for the evaluation of the FOCAL SPOT characteristics

18、.5 4.1 Statement of the FOCAL SPOT characteristics.5 4.2 Longitudinal axis of the X-RAY TUBE ASSEMBLY.5 4.3 REFERENCE AXIS of the X-RAY TUBE ASSEMBLY 6 4.4 Direction of evaluation for the FOCAL SPOT length6 4.5 Direction of evaluation for the FOCAL SPOT width .6 5 FOCAL SPOT camera set-up 6 5.1 Over

19、view.6 5.2 Test equipment6 5.3 Test arrangement 8 5.4 Total uncertainty of the camera set-up .11 6 Production of RADIOGRAMS 11 6.1 Overview.11 6.2 Operating conditions11 6.3 Production of FOCAL SPOT SLIT RADIOGRAMS or FOCAL SPOT PINHOLE RADIOGRAMS.12 6.4 Statement of compliance13 7 Determination of

20、the LINE SPREAD FUNCTION .13 7.1 Overview.13 7.2 Measuring equipment and measuring arrangement.13 7.3 Measurement of the density distribution .14 7.4 Determination of the LINE SPREAD FUNCTION 14 7.5 Statement of compliance14 8 Determination of FOCAL SPOT dimensions.15 8.1 Overview.15 8.2 Measurement

21、 and determination 15 8.3 Specified NOMINAL FOCAL SPOT VALUES 16 8.4 Statement of compliance18 8.5 Marking of compliance.18 9 Determination of the MODULATION TRANSFER FUNCTION 18 9.1 Overview.18 9.2 Specified MODULATION TRANSFER FUNCTION18 9.3 Calculation of the MODULATION TRANSFER FUNCTION .19 9.4

22、Evaluation of compliance of the MTF20 9.5 Statement of compliance20 10 FOCAL SPOT STAR RADIOGRAMS .20 10.1 Overview.20 10.2 Test equipment21 11 STAR PATTERN RESOLUTION LIMIT.23 11.1 Overview.23 EN 60336:2005 4 11.2. Specified STAR PATTERN RESOLUTION LIMIT 23 11.3 Measurement 24 11.4 Determination of

23、 the STAR PATTERN RESOLUTION LIMIT 24 11.5 Evaluation and statement of compliance.25 12 BLOOMING VALUE26 12.1 Overview.26 12.2 Determination of the BLOOMING VALUE.26 12.3 Evaluation and statement of compliance.26 13 Alternate measurement methods.27Annex A (informative) Alignment to the REFERENCE AXI

24、S28 Annex B (informative) Application of digital X-ray image detectors for determination of the FOCAL SPOT characteristics 30 Annex C (informative) Historical background 31 Bibliography .36 Index of defined terms 37 Figure 1 Essential dimensions of the slit diaphragm7 Figure 2 Essential dimensions o

25、f the pinhole diaphragm .8 Figure 3 Position of the centre of the slit or pinhole diaphragm (marked as x in the figure) with respect to the REFERENCE AXIS.9 Figure 4 Reference dimensions and planes 10 Figure 5 Alignment of the optical densitometer slit 14 Figure 6 LINE SPREAD FUNCTION.15 Figure 7 Es

26、sential dimensions of the star test pattern .21 Figure 8 Essential dimensions of the star test pattern .22 Figure 9 Illustration of the zones of minimum modulation 24 Figure A.1 The REFERENCE AXIS and directions of evaluation .28 Figure A.2 Projection of the ACTUAL FOCAL SPOT on the IMAGE RECEPTION

27、PLANE .29 Figure C.1 The LSFs for a typical X-RAY TUBE with small FOCAL SPOT ( 0,3 mm) .32 Figure C.2 The LSFs for a typical X-RAY TUBE with large FOCAL SPOT (0,3 mm).32 Figure C.3 The corresponding MTFs for the LSFs in Figure C.2 33 Table 1 Enlargement for FOCAL SPOT RADIOGRAMs .11 Table 2 LOADING

28、FACTORS.12 Table 3 Maximum permissible values of FOCAL SPOT dimensions for NOMINAL FOCAL SPOT VALUES .17 Table 4 Standard magnifications for MODULATION TRANSFER FUNCTIONS 19 Table 5 Standard magnifications for STAR PATTERN RESOLUTION LIMIT .25 Table 6 LOADING FACTORS for the determination of the BLO

29、OMING VALUE .26 Table C.1 Methods for evaluation of specific aspects characterising the FOCAL SPOT35 5 EN 60336:2005 MEDICAL ELECTRICAL EQUIPMENT X-RAY TUBE ASSEMBLIES FOR MEDICAL DIAGNOSIS CHARACTERISTICS OF FOCAL SPOTS 1 Scope This International Standard applies to FOCAL SPOTs in medical diagnosti

30、c X-RAY TUBE assemblies for medical use, operating at X-RAY TUBE VOLTAGEs up to and including 200 kV. This International Standard describes the test methods for evaluating FOCAL SPOT character- istics and the means for indicating compliance. 2 Normative references The following referenced documents

31、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 (including any amendments) applies. IEC 60417-DB:2002: Graphical symbols for use on equipment 1) IEC 60613, Electrical,

32、thermal and loading characteristics of rotating anode X-ray tubes for medical diagnosis IEC 60788:2004, Medical electrical equipment Glossary of defined terms 3 Terms and definitions For the purposes of this document, the terms and definitions given in IEC 60788 together with the following apply. 3.

33、1 STAR PATTERN RESOLUTION LIMIT characteristic of the FOCAL SPOT of an X-RAY TUBE; highest spatial frequency that can be resolved under specific measuring conditions 4 Determinations for the evaluation of the FOCAL SPOT characteristics 4.1 Statement of the FOCAL SPOT characteristics The FOCAL SPOT c

34、haracteristics shall be stated for two normal directions of evaluation referred to as the length direction and width direction. An illustration for this clause can be found in Figure A.1. 4.2 Longitudinal axis of the X-RAY TUBE ASSEMBLY Generally, the longitudinal axis can be identified unambiguousl

35、y. If the X-RAY TUBE ASSEMBLY does not have an identifiable longitudinal axis or if it is specified otherwise by the 1)“DB“ refers to the IEC on-line database. EN 60336:2005 6 MANUFACTURER, the longitudinal axis shall be specified together with the FOCAL SPOT characteristics. 4.3 REFERENCE AXIS of t

36、he X-RAY TUBE ASSEMBLY If not specified otherwise, the REFERENCE AXIS is normal to the longitudinal axis and intersects both the centre of the ACTUAL FOCAL SPOT and the longitudinal axis of the X-RAY TUBE ASSEMBLY. 4.4 Direction of evaluation for the FOCAL SPOT length The direction of evaluation for

37、 the FOCAL SPOT length is normal to the REFERENCE AXIS in the plane given by the REFERENCE AXIS and the longitudinal axis of the X-RAY TUBE ASSEMBLY. 4.5 Direction of evaluation for the FOCAL SPOT width The direction of evaluation for the FOCAL SPOT width is normal to the longitudinal axis of the X-

38、 RAY TUBE ASSEMBLY and normal to the REFERENCE AXIS. 5 FOCAL SPOT camera set-up 5.1 Overview This clause deals with the design requirements of a camera for the production of FOCAL SPOT SLIT RADIOGRAMs to be used for the determination of FOCAL SPOT dimensions in accordance with Clause 8, and the dete

39、rmination of the modulation transfer function in accordance with Clause 9. This clause deals also with the design requirements of a camera for the production of FOCAL SPOT PINHOLE RADIOGRAMs. 5.2 Test equipment 5.2.1 SLIT CAMERA The diaphragm of the SLIT CAMERA shall be made from materials with high

40、 ATTENUATION properties and shall have dimensions as given in Figure 1. Suitable materials are for example: tungsten; tantalum; alloy of gold and 10 % platinum; alloy of tungsten and 10 % rhenium; alloy of platinum and 10 % iridium; 7 EN 60336:2005 Dimensions in millimetres Not drawn to scale 5 8 1

41、1,5 0,015 0,01 0,002 5 / 0,002 Axis of symmetry 0,002 IEC 526/05 Figure 1 Essential dimensions of the slit diaphragm EN 60336:2005 8 5.2.2 PINHOLE CAMERA The diaphragm of the PINHOLE CAMERA shall be constructed from materials with high ATTENUATION and shall have dimensions as given in Figure 2. Suit

42、able materials are for example: tungsten; tantalum; alloy of gold and 10 % platinum; alloy of tungsten and 10 % rhenium; alloy of platinum and 10 % iridium. Dimensions in millimetres Not drawn to scale 5 8 1 1,5 0,075 0,03 0,005 Axis of symmetry IEC 527/05 Figure 2 Essential dimensions of the pinhol

43、e diaphragm 5.2.3 RADIOGRAPHIC FILM FOCAL SPOT SLIT RADIOGRAMS or FOCAL SPOT PINHOLE RADIOGRAMS shall be made using fine- grain radiographic film, for example dental radiographic film, without INTENSIFYING SCREENS. 5.3 Test arrangement 5.3.1 Position of the slit or pinhole diaphragm normal to the RE

44、FERENCE AXIS The slit or pinhole diaphragm shall be positioned in such a way that the distance from its centre to the REFERENCE AXIS is within 0,2 mm per 100 mm of m (as indicated in Figure 3). 9 EN 60336:2005 REFERENCE PLANE IMAGE RECEPTION PLANE REFERENCE AXIS m (100 mm min.) 0,4 per 100 mm Centre

45、 of diaphragm x n Incident face of the slit or pinhole diaphragm EFFECTIVE FOCAL SPOT IEC 528/05 Figure 3 Position of the centre of the slit or pinhole diaphragm (marked as x in the figure) with respect to the REFERENCE AXIS 5.3.2 Position of the slit or pinhole diaphragm along the REFERENCE AXIS Th

46、e incident face of the slit or pinhole diaphragm shall be placed at a distance from the REFERENCE PLANE sufficient to ensure that the variation of the enlargement over the extension of the ACTUAL FOCAL SPOT does not exceed 5 % along the REFERENCE AXIS (see Figure 4). This is met when p 5 mm and k 5

47、mm per 100 mm of distance m; where k is the distance from the REFERENCE PLANE to the edge of the ACTUAL FOCAL SPOT farthest away from the slit or pinhole diaphragm; p is the distance from the REFERENCE PLANE to the edge of the ACTUAL FOCAL SPOT closest to the slit or pinhole diaphragm; m is the dist

48、ance from the REFERENCE PLANE to the incident face of the diaphragm; n is the distance from the incident face of the diaphragm to the IMAGE RECEPTION PLANE; E is the enlargement given by n/m . The distance from the FOCAL SPOT to the slit or pinhole diaphragm shall not be less than 100 mm. EN 60336:2

49、005 10 k p m n REFERENCE PLANE IMAGE RECEPTION PLANE REFERENCE AXIS Incident face of the slit or pinhole diaphragm EFFECTIVE FOCAL SPOT IEC 529/05 Figure 4 Reference dimensions and planes 5.3.3 Orientation of the slit or pinhole diaphragm The axis of symmetry (see Figures 1 and 2) shall be aligned with