1、BRITISH STANDARD BS EN 61685:2002 IEC 61685:2001 Ultrasonics Flow measurement systems Flow test object The European Standard EN 61685:2001 has the status of a British Standard ICS 17.120.01; 17.140 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBS EN 61685:2002 This British St
2、andard, having been prepared under the direction of the Electrotechnical Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 14 February 2002 BSI 14 February 2002 ISBN 0 580 38950 2 National foreword This British Standard is the o
3、fficial English language version of EN 61685:2001. it is identical with IEC 61685:2001 The UK participation in its preparation was entrusted to Technical Committee EPL/87, Ultrasonics, which has the responsibility to: A list of organizations represented on this committee can be obtained on request t
4、o its secretary. From 1 January 1997, all IEC publications have the number 60000 added to the old number. For instance, IEC 27-1 has been renumbered as IEC 60027-1. For a period of time during the change over from one numbering system to the other, publications may contain identifiers from both syst
5、ems. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards
6、Electronic Catalogue. 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 with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to un
7、derstand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document compr
8、ises a front cover, an inside front cover, the EN title page, pages 2 to 38, an inside back cover and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEAN STANDARD EN 61685 NORM
9、E EUROPENNE EUROPISCHE NORM October 2001 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 2001 CENELEC - All rights of exploitati
10、on in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 61685:2001 E ICS 17.140.50 English version Ultrasonics - Flow measurement systems - Flow test object (IEC 61685:2001) Ultrasons - Systmes de mesure de dbit - Montage pour essai de dbit (CEI 61685:2001) Ultraschall -
11、Durchflussmesssysteme - Durchfluss-Doppler-Prfobjekt (IEC 61685:2001) This European Standard was approved by CENELEC on 2001-09-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national
12、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 CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any
13、 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 versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic, Denmark, Finl
14、and, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.EN 58616:2001 - 2 - Foreword The text of document 87/202/FDIS, future edition 1 of IEC 61685, prepared by IEC TC 87, Ultrasonics, was submitted to th
15、e IEC-CENELEC parallel vote and was approved by CENELEC as EN 61685 on 2001-09-01. 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) 2002-06-01 latest date by which the national
16、 standards conflicting with the EN have to be withdrawn (dow) 2004-09-01 Annexes designated “normative“ are part of the body of the standard. Annexes designated “informative“ are given for information only. In this standard, annexes B and ZA are normative and annexes A, C, D, E and F are informative
17、. Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 61685:2001 was approved by CENELEC as a European Standard without any modification. _ Page2 EN61685:2001 58616 (1002:CEI)E 3 CONTENTS INTRODUCTION 5 1 Scope 6 2 Normative references. 6 3 Definitions
18、 6 4 List of symbols12 5 General outline of flow Doppler test object.13 6 Specification of the flow Doppler test object.13 6.1 General .13 6.2 Blood-mimicking fluid (BMF) 14 6.3 Tube15 6.4 Tissue-mimicking material (TMM).16 6.5 Geometry.16 7 Precautions to prevent changes in the composition of the b
19、lood-mimicking fluid (BMF) .16 8 Specifications for labelling.17 Annex A (informative) Rationale concerning the position of this standard 18 Annex B (normative) Formulae relating various quantities .21 Annex C (informative) Rationale for the numerical values chosen in this standard .22 Annex D (info
20、rmative) Description of an example flow Doppler test object.24 Annex E (informative) Schematic diagram of a possible flow circuit.33 Annex F (informative) Measuring methods 34 Annex ZA (normative) Normative references to international publications with their corresponding European publicatins38 Bibl
21、iography 35 Figure 1 Three configurations for Doppler flow test objects .13 Figure D.1 The main elements of a flow test object .25 Figure D.2 Backscattering coefficient of BMF as a function of frequency .27 Figure D.3 Attenuation of TMM ( ) and BMF ( ) as a function of frequency .27 Figure D.4 Atten
22、uation of ultrasound by material of tube wall, as a function of frequency28 Figure D.5 Deformation of velocity spectrum of parabolic flow by attenuation due to tube wall (wall thickness 1,5 mm).29 Figure D.6 Backscattering coefficient of two samples of TMM as a function of frequency30 Figure D.7 The
23、 quotient of attenuation by TMM (1-way passage) and frequency as a function of frequency.30 Figure D.8 Testing for penetration depth.32 Figure E.1 Schematic diagram of a possible flow circuit, showing the place of the flow Doppler test object 33 Page3 EN61685:2001 4 58616 (1002:CEI)E Table 1 Typical
24、 ranges of parameters for blood at 37 C, where f is the acoustic- working frequency in hertz.14 Table 2 Specification of blood-mimicking fluid (BMF) 14 Table 3 Parameters of tissue-mimicking material (TMM) .16 Table A.1 Parameters concerning CW Doppler .19 Table A.2 Additional parameters concerning
25、pulsed Doppler and colour flow .20 Page4 EN61685:2001 58616 (1002:CEI)E 5 INTRODUCTION The purpose of this International Standard is to establish a flow Doppler test object for the acceptance testing, quality assurance testing and clinical calibration of Doppler systems, working at a frequency betwe
26、en 2 MHz and 10 MHz. As the response of Doppler systems depends on the signal level and on the spectral contents of the signal, it is desirable to test some aspects of a Doppler system with a test object that mimics the in vivo situation. A flow Doppler test object is particularly useful for testing
27、 the influence of the size and the depth of the blood vessel on the signal recorded by a Doppler system; testing the response of a Doppler system with a spectrum of blood velocities typical of the in vivo situation. This flow test object is not intended as a phantom mimicking clinical conditions. Th
28、e basis of this International Standard is given by IEC Technical Report 61206:1993 Ultrasonics Continuous Wave Doppler systems Test procedures. In annex A the position of this standard in relation to IEC 61206 and IEC 61895 is described. This standard only declares parameters that can be measured wi
29、th the test object. Measurement methods are given in IEC 61206 and IEC 61895. This International Standard deals only with the flow Doppler test object in a restricted sense, i.e. the section in which the ultrasonic measurements are performed. Where the whole of the set-up is meant, the phrase flow r
30、ig is used. The prescriptions of this International Standard define the ultrasonic properties and the flow pattern in the measurement section of the flow test object. For other aspects of the flow rig (i.e. generating and measuring flows) standard engineering practice has to be followed. The flow co
31、nditions are simplified as much as possible: a steady flow through a straight tube with a circular cross-section. Generalisation of the flow conditions to other geometries and time dependent flows is required in order to test some instrument functions. This generalisation is not undertaken in this I
32、nternational Standard. In annex D, an example flow Doppler test object is described which complies with the requirements of this International Standard. Compliance with this International Standard can also be fulfilled by measuring the properties of the materials to be used, and complying with the v
33、alues given in this International Standard. In literature 1, 2 the nomenclature about the primary measurand of Doppler systems is confused. Doppler frequency and velocity occur on equal footing. In velocity often a correction for Doppler angle has been included. To avoid this ambiguity, in this Inte
34、rnational Standard the term Doppler frequency is preferred. In case a Doppler system is declared to measure velocity, it is intended that measured values are converted to Doppler frequency, using acoustic working frequency and, if applicable, Doppler angle. Page5 EN61685:2001 6 58616 (1002:CEI)E ULT
35、RASONICS FLOW MEASUREMENT SYSTEMS FLOW TEST OBJECT 1 Scope This International Standard specifies parameters for a flow Doppler test object representing a blood vessel of known diameter at a certain depth in human tissue, carrying a steady flow. This International Standard establishes a flow Doppler
36、test object which can be used to assess various aspects of the performance of Doppler diagnostic equipment. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, s
37、ubsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references,
38、 the latest edition of the normative document referred to applies. Members of IEC and ISO maintain registers of currently valid International Standards. IEC 61206:1993, Ultrasonics Continuous-wave Doppler systems Test procedures IEC 61102:1991, Measurement and characterisation of ultrasonic fields u
39、sing hydrophones in the frequency range 0,5 MHz to 15 MHz IEC 61895:1999, Ultrasonics Pulsed Doppler diagnostic systems Test procedures to determine performance 3 Definitions For the purposes of this International Standard, the following definitions apply: 3.1 3 dB Doppler frequency frequency at whi
40、ch the power per unit frequency in the Doppler spectrum is half (3 dB) of the maximum value 3.2 3 dB sample volume volume of a region in space for which the Doppler system gives a response to a point Doppler target that is above 3 dB from the maximal response, taking account of the effects of both t
41、ransmission and reception Unit: cubic millimetre, mm 3 3.3 3 dB sample volume length largest dimension of the 3 dB sample volume in the direction of the beam alignment axis (see 3.5 of IEC 61102) Unit: millimetre, mm Page6 EN61685:2001 58616 (1002:CEI)E 7 3.4 3 dB sample volume width largest value o
42、f the dimension of the 3 dB sample volume along an axis which is perpendicular to the beam alignment axis. In case the Doppler system has a scan plane, the axes are taken in the scan plane and perpendicular to the scan plane Unit: millimetre, mm 3.5 acoustic-working frequency frequency of an acousti
43、c signal based on the output observed by a hydrophone placed in an acoustic field: it is the arithmetic mean of the two frequencies at which the amplitude of the acoustic pressure spectrum is 3 dB below the peak amplitude conforms to 3.4.2 of IEC 61102 Unit: hertz, Hz 3.6 aliasing false indication o
44、f signal frequency as a result of sampling at too low a frequency NOTE The threshold for aliasing depends on pulse repetition frequency and a possible base line shift. 3.7 average frequency of the Doppler spectrum parameter estimated by clinical Doppler systems for the short-time average in a Dopple
45、r spectrum, ignoring the contributions from noise NOTE The average frequency of the Doppler spectrum is generally determined for a small time interval, typically 2 ms to 20 ms). Unit: hertz, Hz 3.8 axial response range depth range in tissue over which a signal from a specific target plus noise is at
46、 least 3 dB above the noise level see 2.4.1 of IEC 61206 Unit: millimetre, mm 3.9 blood-mimicking fluid (BMF) fluid which simulates blood acoustically and is moved at a known flow rate through the flow Doppler test object 3.10 channel separation ratio of the signal level in the signal channel corres
47、ponding to the movement in the test object (the desired output voltage) and the signal level in the opposite channel (the undesired output voltage) NOTE Channel separation is to be quoted in decibels as twenty times the logarithm of the desired output to the undesired output voltage. see 2.6.1 of IE
48、C 61206 Unit: decibel, dB Page7 EN61685:2001 8 58616 (1002:CEI)E 3.11 colour display spatial resolution minimum separation in space for which two separate moving point targets or line targets can be resolved NOTE The colour display spatial resolution is measured in three directions: 1) along the bea
49、m alignment axis, 2) the direction perpendicular to the scan plane and 3) the direction in the scan plane perpendicular to the beam alignment axis. Unit: millimetre, mm 3.12 dead zone boundary boundary of the region close to the transducer in which the system is insensitive to movement 3.13 depth of measurement distance from the surface of the tissue-mimicking material to the centre of the tube. In case various atte
