1、 CENELEC EN*b1262-4 94 = 3404583 0355533 642 BRITISH STANDARD Characteristics of electro-optical X-ray image intensifiers for medical electrical equipment BS EN Part 4. Determination of the image distortion The European Standard EN 61262-4 : 1994 has the status of a British Standard 61262-4 : 1995 I
2、EC 1262-4 : 1994 CENELEC EN+b12b2-4 94 m 3404583 0155534 589 m BS EN 61262-4 : 1996 This British Standard, having been prepared under the direction of the Health and Environment Sector Board, was published under the authority of the Standards Board and comes into effect on 15 May 1995 O BSI 1995 Com
3、mittees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee HCC/72, Image intensifiers, upon which the following bodies were represented: Association of X-ray Equipment Manufacturers (BEAMA Ltd.) British Institute of Radiology College o
4、f Radiographers Institute of Physical Sciences in Medicine (Ipsm) Amendments issued since publication Amdo No- I Date I lk* affected The following BSI references relate to the work on this standard: Committee reference HCC/72 Draft for comment 94/501344 DC ISBN O 580 24051 7 CENELEC EN*h3262-4 74 34
5、04583 0355535 415 BS EN 61262-4 : 1995 Contents Committees responsible Inside front cover National foreword ii Foreword 2 7kxt Of EN 61262-5 4 i CENELEC EN*b3262-4 74 = 3404583 0355536 353 BS EN 61262-4 : 1995 National foreword This British Standard has been prepared by Bchnical Committee HCC/72 and
6、 is the English language version of EN 61262-4 : 1994 Medical ekctrical equipment - CharacWt.ics of electro-optical X-ray image int.emers part 4: Determination of the image distortion, published by the European Committee for Electrotechnical Standardization (CENELEC). It is identical with IEC 1262-4
7、 published by the International Electrotechnical Commission (IEC). It supersedes BS 6801 : 1986 which is withdrawn. Cross-references Publication referred to Corresponding British Standard BS 6641 : 1985 Glossary of medical radiology temzs HD 501 S1 (LEC 788 : 1984) Additional information. The follow
8、ing print types are used in this standard. Requirements, with which compliance can be tested, and definitions: in roman type. Explanations, advice, general statements, exceptions and references: in smaer type. lst procedures: in italic type. lrms defined in clause 3 of this standard and in annex A:
9、in SMALL CAPITALS. For the purposes of this British Standard, any references to IEC page numbers in the text should be ignored. Compliance with a British Standard does not of itself confer immunity from legal obligations. ii CENELEC EN+bL262-4 94 3404583 0355537 298 = EUROPEAN STANDARD EUROPISCHE NO
10、RM NORMEEUROPENNE EN 61262-4 September 1994 ICs 11.040.50 Descriptors: Medical electrical equipment, image intensifier, X-ray, distortion Supersedes HD 515 Sl : 1989 English version Medical electrical equipment - Characteristics of electro-optical X-ray image intensifiers Part 4: Determination of th
11、e image distortion (IEC 1262-4 : 1994) Appareils lectromdicaux - Caractristiques des intensificateurs von elektronenoptischen lectro-optiques d?image radiologique Rntgenbildverstrkern Partie 4: Dtermination de la distorsion Medizinische elektrische Gerte - Merkmale Ri1 4: Bestimmung der Bildverzeich
12、nung d?image (IEC 1262-4 : 1994) (CE1 1262-4 1994) This European Standard was approved by CENELEC on 1994-07-05. CENELEC members are bound to comply with the CENKENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any
13、 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 Standard exists in three official versions (English, French, German). A version in any other language made
14、 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 national electrotechnical committees of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Icelan
15、d, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Centrai Secretariat: rue de St
16、assart 35, B-1050 Brussels O 1994 Copyright reserved to CENELEC members Ref. No. EN 61262-4 : 1994 E CENELEC EN+b12b2-4 94 m 3404583 0155538 124 m Page 2 EN 61262-4 : 1994 Foreword The text of document 62J3(C0)115, as prepared by Subcommittee 62B, Diagnostic imaging equipment, of IEC Technical Commi
17、ttee 62, Electrical equipment in medical practice, was submitted to the IEC-CENELEC paraiel vote in January 1994. The reference document was approved by CENELEC as EN 61262-4 on 5 July 1994. This European Standard replaces HD 515 S1 : 1989. The following dates were fixed: - latest date of publicatio
18、n of an identical national standard (dop) 1995-07-01 - latest date of withdrawal of conflicting national standards (dow) 1995-07-01 For products which have complied with HD 515 S1 : 1989 before 1995-07-01, as shown by the manufacturer or by a certification body, this previous standard may continue t
19、o apply for production until 2000-07-01. 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. CENELEC EN*bLZbZ- 94 E 3404583 0355539 Ob0 E Page 3 EN 61262-
20、4 : 1994 CONTENTS page FOREWORD 2 INTRODUCTION 4 Cbuse 1 Scope . 5 2 Normative reference 5 3 Terminology . 5 3.1 Definitions 5 3.2 Degree of requirements and reading instructions 7 4 Requirements 7 4.1 Testset-up . 7 4.2 X-RAY IMAGE INTENSIFIER . Operating conditions 8 4.3 Input radiation . 8 4.4 TE
21、STDEVICE 8 4.5 Measurement equipment 8 5 Determination Of the IMAGE DISTORTION 8 . 5.1 Not used . 8 5.2 Not used . 8 5.3 Not used . 8 5.4 Determination 9 5.4.1 Determination Of the DIFFERENTiAL RADIAL IMAGE DISTORTION 9 5.4.2 Determination of the INTEGRAL IMAGE DISTORTION g 6 PreSWltatiOn Of the IMA
22、GE DISTORTION . 9 7 Statement of compliance 10 Figure 1 . Suggested TEST DEVICE for the determination of the IMAGE DISTORTION 11 Annex A . Terminology . Index of terms . Annex ZA . Other international publications quoted in this standard with the references of the relevant European publications . 12
23、 1 3 CENELEC EN*bLZb2-4 94 m 3404583 0355540 882 m Page 4 EN 61262-4 : 1994 INTRODUCTION The IMAGE DISTORTION is a functional performance characteristic which describes deviations from a similarity representation of an image in the ENTFIANCE PLANE to the OUTPUT IMAGE of an ELECTFIO-OPTICAL X-RAY IMA
24、GE INTENSIFIER. It will however be assumed that angular distortions like the S-shaped distortion magnetic shielding since the X-RAY IMAGE INTENSIFIER itself is by construction very nearly axially symmetrical. Of a straight line through the CENTRE OF THE ENTRANCE FIELD can be reduced to a Small Size
25、by adequate 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. Page 5 EN 61262-4 : 1994 MEDICAL ELECTRICAL EQUIPMENT - CHARACTERISTICS OF
26、 ELECTRO-OPTICAL X-RAY IMAGE INTENSIFIERS - Part 4: Determination of the image distortion 1 Scope This International Standard applies to ELECTRO-OPTICAL X-RAY IMAGE INTENSIFIERS for medical use, as components of diagnostic X-RAY EQUIPMENT. This International Standard describes a method of determinin
27、g the IMAGE DISTORTION Of X-RAY IMAGE INTENSIFIERS. 2 Normative reference The following standard contains provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the edition indicated was valid. All standards are subject to
28、revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IEC 788: 1984, Medical Rad
29、iology - Terminology 3 Terminology 3.1 Definitions For the purposes of this Intemational Standard, the following definitions apply together with those given in IEC 788. The definitions given below take preference over those given in IEC 788 when differences occur. 3.1.1 xR/. An abbreviation for ELEC
30、TRO-OPTICAL X-RAY IMAGE INTENSIFIER. 3.1.2 ENTRANCE PLANE: The plane perpendicular to the axis of symmetry of the XRII and 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 di
31、ameter of the field in the ENTRANCE PLANE that can be used at a specified SED for the transmission of an X-RAY PATTERN. For 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 occurr
32、ing with .the largest ENTRANCE FIELD SIZE. 3.1.5 SOURCE TO ENTRANCE PLANE DISTANCE (abbreviation SED): The distance between the FOCAL SPOT Of the X-RAY TUBE and the ENTRANCE PLANE Of the XRII. CENELEC ENxbL2b2-4 94 m 3404583 0255542 b55 m Page 6 EN 61262-4 : 1994 3.1 -6 CENTRE OF THE OUTPUT IMAGE: T
33、he centre of the smallest circle circumscribing the OUTPUT IMAGE. 3.1.7 CENTFIE OF THE ENTRANCE FELD: That point in the ENTRANCE PLANE which is imaged at the CENTRE OF THE OUTPUT IMAGE. 3.1.8 CENTFIAL AXIS: The line perpendicular to the ENTRANCE PLANE passing through the CENTRE OF THE ENTRANCE FIELD
34、. 3.1.9 CENTML MAGNlFCA77ON: As a characteristic Of XRllS, th8 ratio Of the length in the OUTPUT IMAGE to the actual length of a small object placed in the ENTRANCE PME symmetrically about the CENTWU. AXIS. 3.1.10 IMAGE D/sroRnm: As a characteristic of an XRII, variation of the magnification of the
35、image of an object. IMAGE DISTORTION is expressed with respect to a reference magnification (CENTRAL (INTEGRAL IMAGE DISTORTION) of the object. MAGNIFICATION) and as a function Of either position (DIFFERENTIAL RADIAL IMAGE DISTORTION) O Size 3.1.1 1 DmmwnAL RADIAL IMAGE DISTORTION l): image distorti
36、on for a small, radially oriented TEST DEVICE of constant length placed in any position in the ENTRANCE PME. DIFFERENTIAL MAL IMAGE DISTORTION iS a function Of position Of this TEST DEVICE in the E“CE PLANE. 3.1.12 /mGmL IMAGE DIS TORT ION): IMAGE DISTORTION for a circular TEST DEVICE placed in the
37、ENTRANCE PLANE symmetrically about the CENTRAL AXIS. INTEGRAL IMAGE lflomm is a function of the radius of this circular TEST DEVICE. 3.1.13 LOCAL mDm MAGNIFICATION): As a characteristic of XRIIs, the ratio of the length in the OUTPUT IMAGE to the actual length o a small TEST DEVICE placed in the ENT
38、RANCE PLANE symmetrically about a given point and oriented radially to the CENTRAL Axis. LOCAL RADIAL MAGNIFICATION is a function Of position Of this TEST DEVICE in the ENTRANCE PLANE. 3.1.14 ImGRAf MAGNIRCATION): As a characteristic of XRIIs. the ratio of the diameter in the OUTPUT IMAGE to the act
39、ual diameter of a circular TEST DEVICE placed in the ENTRANCE PME symmetrically about the cm AXIS. INTEGRAL MAGNIFICATION is a function of the radius Of this circular TEST DEVICE. 1 to-axis points. the LOCAL nmu WIRCATKW is. in general. not equal b aie loai magnificstion. since the LOCAL MAGNIFICATI
40、ON (bl COI$ldOn wilh the CENTRAL MAGNIFICATION, to which t is referred) iS Used to detSIlnifW the MF- FERENTUL IMAGE MSTORTION, H is necessary to Mude the adjective Radial In definitions 3.1.1 1 and 3.1.13. In the case of and tangential is unnecessary since they are the same in the radial and tangen
41、tial directions. MAGNIFICATION (3.1.14). and hence also MITEGRAL IMAGE OISTOR (3.1 .l2), a distinction beween radal CENELEC ENxb32b2-4 94 I 3404583 0355543 591 I Page 7 EN 61262-4 : 1994 3.2 Degree of requirements and reading instructions In this International Standard the auxiliary verb: - “shall“
42、- “ShOld“ - “may“ implies that compliance with a requirement is mandatory for compliance with the standard: implies that compliance with a requirement is strongly recommended but is not mandatory for compliance with the standard; implies that compliance with a requirement is permitted to be accompli
43、shed in a particular manner for compliance with the st andard; and the following words have the meaning: - “specific“ - “specified“ when used in combination with parameters or conditions: refers to a particular value or standardized arrangement, usually to those required in an IEC standard or a lega
44、l requirement; see IEC 788, rm-74-01. 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; see IEC 788. rm-74-02. - “designed for“ when used in standards to chara
45、cterize equipment, devices, components or arrangements: designates an intended and usually apparent purpose or use for the product. 4 Requirements 4.1 Test Set-up a) The SED shall be 100 cm i 1 cm. b) The FOCAL SPOT Of the X-RAY TUBE shall be on the CENTRAL AXIS. c) The TEST DEVICE shall be placed i
46、n a plane as close as possible to, but not more than 10 mm in front Of, and parallel 10. the ENTRANCE PLANE. For the determination of the LOCAL RADIAL wGNiFicAnoN, the line of hash marks on the TEST DEVICE shall pass through the CENTRE OF THE ENTRANCE .FIELD. For the determination of the CENTRAL MAG
47、NIFICATION, the TEST DEVICE shall be placed symmetrically t0 the CENTRE OF THE ENTRANCE FIELD. The departure from Symmetry with reSpect t0 the CENTRE OF THE ENTRANCE FIELD shall not exceed 2 % Of the ENTRANCE FIELD SIZE. CENELEC EN*bL262-4 94 = 3404583 0355544 428 Page 8 EN 61262-4 : 1994 4.2 X-RAY
48、IMAGE imNsiFiER - Operating conditions a) The XRII shall be operated under the conditions for NORMAL USE as specified by the manufacturer. b) Not used. c) In the case of multiple-field XRIIs, the measurement shall be made for the largest specified EANCE FIELD SIE. Measurements for other ENTRANCE FIE
49、LD 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 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 mad
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