BS EN 61262-4-1995 Characteristics of electro-optical X-ray image intensifiers for medical electrical equipment - Determination of the image distortion《医用电气设备X射线图像增强仪电光特性 图像失真测定》.pdf

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1、BRITISH STANDARD BSEN 61262-4:1995 IEC1262-4: 1994 Characteristics of electro-optical X-ray image intensifiers for medical electrical equipment Part 4: Determination of the image distortion The European Standard EN61262-4:1994 has the status of a BritishStandardBSEN61262-4:1995 This BritishStandard,

2、 having been prepared under the directionof the Health and Environment Sector Board, waspublished under the authorityof the Standards Boardand comes into effect on 15May1995 BSI01-2000 The following BSI references relate to the work on this standard: Committee referenceHCC/72 Draft for comment 94/50

3、1344DC ISBN 0 580 24051 7 Committees responsible for this British Standard The preparation of this BritishStandard was entrusted to Technical CommitteeHCC/72, Image intensifiers, upon which the following bodies were represented: Association of X-ray Equipment Manufacturers (BEAMA Ltd.) British Insti

4、tute of Radiology College of Radiographers Institute of Physical Sciences in Medicine (Ipsm) Amendments issued since publication Amd. No. Date CommentsBSEN61262-4:1995 BSI 01-2000 i Contents Page Committees responsible Inside front cover National foreword ii Foreword 2 Text of EN61262-4 3 List of re

5、ferences Inside back coverBSEN61262-4:1995 ii BSI 01-2000 National foreword This BritishStandard has been prepared by Technical CommitteeHCC/72 and is the English language version of EN61262-4:1994 Medical electrical equipment Characteristics of electro-optical X-ray image intensifiers Part4: Determ

6、ination of the image distortion, published by the European Committee for Electrotechnical Standardization (CENELEC). It is identical with IEC1262-4 published by the International Electrotechnical Commission (IEC). It supersedes BS6801:1986 which is withdrawn. Additional information. The following pr

7、int types are used in this standard. Requirements, with which compliance can be tested, and definitions: inromantype. Explanations, advice, general statements, exceptions and references: insmaller type. Test procedures: in italic type. Terms defined in clause3 of this standard and in Annex A: in SMA

8、LL CAPITALS. For the purposes of this BritishStandard, any references to IEC page numbers in the text should be ignored. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance wit

9、h a British Standard does not of itself confer immunity from legal obligations. Cross-references Publication referred to Corresponding British Standard HD501S1 (IEC788:1984) BS6641:1985 Glossary of medical radiology terms Summary of pages This document comprises a front cover, an inside front cover,

10、 pagesi andii, theEN title page, pages2 to8, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM

11、EN61262-4 September1994 ICS11.040.50 Supersedes HD515S1:1989 Descriptors: Medical electrical equipment, image intensifier, X-ray, distortion English version Medical electrical equipment Characteristics of electro-optical X-ray image intensifiers Part 4: Determination of the image distortion (IEC1262

12、-4:1994) Appareils lectromdicaux Caractristiques des intensificateurs lectro-optiques dimage radiologique Partie 4: Dtermination de la distorsion dimage (CEI1262-4:1994) Medizinische elektrische Gerte Merkmale von elektronenoptischen Rntgenbildverstrkern Teil4: Bestimmung der Bildverzeichnung (IEC12

13、62-4:1994) This EuropeanStandard was approved by CENELEC on1994-07-05. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliogr

14、aphical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member. This EuropeanStandard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of

15、 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 national electrotechnical committees of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands,

16、 Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. 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 1994 Copyright r

17、eserved to CENELEC members Ref.No.EN61262-4:1994 EEN61262-4:1994 BSI 01-2000 2 Foreword The text of document62B(CO)115, as prepared by Subcommittee62B, Diagnostic imaging equipment, of IEC Technical Committee62, Electrical equipment in medical practice, was submitted to the IEC-CENELEC parallel vote

18、 in January1994. The reference document was approved by CENELEC as EN61262-4 on5 July1994. This European Standard replaces HD515S1:1989. The following dates were fixed: For products which have complied with HD515S1:1989 before1995-07-01, as shown by themanufacturer or by a certification body, this p

19、revious standard may continue to apply for production until2000-07-01. Annexes designated “normative” are part of the body of the standard. Annexes designated “informative” are given only for information. In this standard, Annex A is informative and Annex ZA is normative. Contents Page Foreword 2 In

20、troduction 3 1 Scope 3 2 Normative reference 3 3 Terminology 3 3.1 Definitions 3 3.2 Degree of requirements and reading instructions 4 4 Requirements 4 4.1 Test set-up 4 4.2 X-RAY IMAGE INTENSIFIER Operating conditions 4 4.3 Input radiation 5 4.4 TEST DEVICE 5 4.5 Measurement equipment 5 5 Determina

21、tion of the IMAGE DISTORTION 5 5.1 Not used 5 5.2 Not used 5 5.3 Not used 5 5.4 Determination 5 5.4.1 Determination of the DIFFERENTIAL RADIAL IMAGE DISTORTION 5 5.4.2 Determination of the INTEGRAL IMAGE DISTORTION 5 6 Presentation of the IMAGE DISTORTION 5 7 Statement of compliance 6 Annex A (infor

22、mative) Terminology Index of terms 7 Annex ZA (normative) Other international publications quoted in this standard with the references of the relevant European publications 8 Figure 1 Suggested TEST DEVICE for the determination of the IMAGE DISTORTION 6 latest date of publication ofan identical nati

23、onal standard (dop)1995-07-01 latest date of withdrawal ofconflicting national standards (dow)1995-07-01EN61262-4:1994 BSI 01-2000 3 Introduction The IMAGE DISTORTION is a functional performance characteristic which describes deviations from a similarity representation of an image in the ENTRANCE PL

24、ANE to the OUTPUT IMAGE of an ELECTRO-OPTICAL X-RAY IMAGE INTENSIFIER. It will however be assumed that angular distortions like the S-shaped distortion of a straight line through the CENTRE OF THE ENTRANCE FIELD can be reduced to a small size by adequate magnetic shielding since the X-RAY IMAGE INTE

25、NSIFIER itself is by construction very nearly axially symmetrical. Therefore this standard will be confined to radial distortion. A slight S-shaped distortion may persist in spite of the shielding. Its influence on the measurement of magnification, described below, is negligible. 1 Scope This Intern

26、ationalStandard applies to ELECTRO-OPTICAL X-RAY IMAGE INTENSIFIERS for medical use, as components of diagnostic X-RAY EQUIPMENT. This InternationalStandard describes a method of determining the IMAGE DISTORTION of X-RAY IMAGE INTENSIFIERS. 2 Normative reference The following standard contains provi

27、sions which, through reference in this text, constitute provisions of this InternationalStandard. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this InternationalStandard are encouraged to investigate the possib

28、ility of applying the most recent edition of the standard indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. IEC788:1984, Medical Radiology Terminology. 3 Terminology 3.1 Definitions For the purposes of this InternationalStandard, the following def

29、initions apply together with those given in IEC788. The definitions given below take preference over those given in IEC788 when differences occur. 3.1.1 XRII an abbreviation for ELECTRO-OPTICAL X-RAY IMAGE INTENSIFIER 3.1.2 ENTRANCE PLANE the plane perpendicular to the axis of symmetry of the XRII a

30、nd grazing the part of the XRII, including its housing, that protrudes most in the direction of the RADIATION SOURCE 3.1.3 Not used. 3.1.4 ENTRANCE FIELD SIZE for an XRII, the diameter of the field in the ENTRANCE PLANE that can be used at a specified SED for the transmission of an X-RAY PATTERN. Fo

31、r an XRII with more than one magnification mode, the ENTRANCE FIELD SIZE for each of the magnification modes shall correspond to the same diameter of the XRII OUTPUT IMAGE occurring with the largest ENTRANCE FIELD SIZE 3.1.5 SOURCE TO ENTRANCE PLANE DISTANCE (abbreviation SED) the distance between t

32、he FOCAL SPOT of the X-RAY TUBE and the ENTRANCE PLANE of the XRII 3.1.6 CENTRE OF THE OUTPUT IMAGE the centre of the smallest circle circumscribing the OUTPUT IMAGE 3.1.7 CENTRE OF THE ENTRANCE FIELD that point in the ENTRANCE PLANE which is imaged at the CENTRE OF THE OUTPUT IMAGE 3.1.8 CENTRAL AX

33、IS the line perpendicular to the ENTRANCE PLANE passing through the CENTRE OF THE ENTRANCE FIELD 3.1.9 CENTRAL MAGNIFICATION as a characteristic of XRIIs, the ratio of the length in the OUTPUT IMAGE to the actual length of a small object placed in the ENTRANCE PLANE symmetrically about the CENTRAL A

34、XIS 3.1.10 IMAGE DISTORTION as a characteristic of an XRII, variation of the magnification of the image of an object. IMAGE DISTORTION is expressed with respect to a reference magnification (CENTRAL MAGNIFICATION) and as a function of either position (DIFFERENTIAL RADIAL IMAGE DISTORTION) or size (I

35、NTEGRAL IMAGE DISTORTION) of the objectEN61262-4:1994 4 BSI 01-2000 3.1.11 DIFFERENTIAL RADIAL IMAGE DISTORTION 1) image distortion for a small, radially oriented TEST DEVICE of constant length placed in any position in the ENTRANCE PLANE DIFFERENTIAL RADIAL IMAGE DISTORTION is a function of positio

36、n of this TEST DEVICE in the ENTRANCE PLANE 3.1.12 INTEGRAL IMAGE DISTORTION 1) IMAGE DISTORTION for a circular TEST DEVICE placed in the ENTRANCE PLANE symmetrically about the CENTRAL AXIS INTEGRAL IMAGE DISTORTION is a function of the radius of this circular TEST DEVICE 3.1.13 LOCAL RADIAL MAGNIFI

37、CATION 1) as a characteristic of XRIIs, the ratio of the length in the OUTPUT IMAGE to the actual length of a small TEST DEVICE placed in the ENTRANCE PLANE symmetrically about a given point and oriented radially to the CENTRAL AXIS LOCAL RADIAL MAGNIFICATION is a function of position of this TEST D

38、EVICE in the ENTRANCE PLANE 3.1.14 INTEGRAL MAGNIFICATION 1) as a characteristic of XRIIs, the ratio of the diameter in the OUTPUT IMAGE to the actual diameter of a circular TEST DEVICE placed in the ENTRANCE PLANE symmetrically about the CENTRAL AXIS INTEGRAL MAGNIFICATION is a function of the radi

39、us of this circular TEST DEVICE 3.2 Degree of requirements and reading instructions In this InternationalStandard the auxiliary verb: and the following words have the meaning: 4 Requirements 4.1 Test set-up a) The SED shall be100cm 1cm. b) The FOCAL SPOT of the X-RAY TUBE shall be on the CENTRAL AXI

40、S. c) The TEST DEVICE shall be placed in a plane as close as possible to, but not more than10mm in front of, and parallel to, the ENTRANCE PLANE. For the determination of the LOCAL RADIAL MAGNIFICATION, the line of hash marks on the TEST DEVICE shall pass through the CENTRE OF THE ENTRANCE FIELD. Fo

41、r the determination of the CENTRAL MAGNIFICATION, the TEST DEVICE shall be placed symmetrically to the CENTRE OF THE ENTRANCE FIELD. The departure from symmetry with respect to the CENTRE OF THE ENTRANCE FIELD shall not exceed2% of the ENTRANCE FIELD SIZE. 4.2 X-RAY IMAGE INTENSIFIER Operating condi

42、tions a) The XRII shall be operated under the conditions for NORMAL USE as specified by the manufacturer. 1) At off-axis points, the LOCAL RADIAL MAGNIFICATION is, in general, not equal to the local tangential magnification. Since the LOCAL RADIAL MAGNIFICATION (in conjunction with the CENTRAL MAGNI

43、FICATION, to which it is referred) is used to determine the DIFFERENTIAL RADIAL IMAGE DISTORTION, it is necessary to include the adjective “Radial” in definitions3.1.11 and3.1.13. In the case of INTEGRAL MAGNIFICATION (3.1.14), and hence also INTEGRAL IMAGE DISTORTION (3.1.12), a distinction between

44、 radial and tangential is unnecessary since they are the same in the radial and tangential directions. “shall” implies that compliance with a requirement is mandatory for compliance with the standard; “should” implies that compliance with a requirement is strongly recommended but is not mandatory fo

45、r compliance with the standard; “may” implies that compliance with a requirement is permitted to be accomplished in a particular manner for compliance with the standard; “specific” when used in combination with parameters or conditions:refers to a particular value or standardized arrangement, usuall

46、y to those required in an IEC standard or a legal requirement; seeIEC788, rm-74-01. “specified” when used in combination with parameters or conditions: refers to a value or arrangement to be chosen for the purpose under consideration and indicated usually in the ACCOMPANYING DOCUMENTS; seeIEC788, rm

47、-74-02. “designed for” when used in standards to characterize equipment, devices, components or arrangements: designates an intended and usually apparent purpose or use for the product.EN61262-4:1994 BSI 01-2000 5 b) Not used. c) In the case of multiple-field XRIIs, the measurement shall be made for

48、 the largest specified ENTRANCE FIELD SIZE. Measurements for other ENTRANCE FIELD SIZES are optional. 4.3 Input radiation The combination of the ATTENUATION EQUIVALENT of the TEST DEVICE and the RADIATION QUALITY used for the determination of the values of magnification shall be such that the image

49、of the TEST DEVICE has a high contrast. The radiation intensity shall be sufficient to obtain an image at a low noise level. 4.4 TEST DEVICE The TEST DEVICE shall consist of a thin X-RADIATION transparent panel with X-RADIATION absorbing markings along which distance measurements can be made. Horizontal and vertical equidistant hash marks shall be used for the measurement of the CENTRAL and LOCAL RADIAL MAGNIFICATION. Circular markings shall be used for the measurement of INTEGRAL MAGNIFICATION: This avoids measurement difficultie