EN 61675-1:2014

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Naprave za slikanje z radionuklidi - Karakteristike in preskusni pogoji - 1. del: Pozitronska emisijska tomografija (IEC 61675-1:2013)Dispositifs d'imagerie par radionucléides - Caractéristiques et conditions d'essai - Partie 1: Tomographes à émission de positrons (IEC 61675-1:2013)Radionuclide imaging devices - Characteristics and test conditions - Part 1: Positron emission tomographs (IEC 61675-1:2013)11.040.50Radiografska opremaRadiographic equipmentICS:Ta slovenski standard je istoveten z:EN 61675-1:2014SIST EN 61675-1:2016en01-oktober-2016SIST EN 61675-1:2016SLOVENSKI
STANDARDSIST EN 61675-1:1998/A1:2008SIST EN 61675-1:19981DGRPHãþD

EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 61675-1
June 2014 ICS 11.040.50
Supersedes
EN 61675-1:1998
English Version
Radionuclide imaging devices - Characteristics and test conditions - Part 1: Positron emission tomographs (IEC 61675-1:2013)
Dispositifs d'imagerie par radionucléides - Caractéristiques et conditions d'essai - Partie 1: Tomographes à émission de positrons (CEI 61675-1:2013)
Bildgebende Systeme in der Nuklearmedizin - Merkmale und Prüfbedingungen - Teil 1: Positronen-Emissions-Tomographen (IEC 61675-1:2013) This European Standard was approved by CENELEC on 2013-10-30. 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 standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CENELEC 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 CEN-CENELEC Management Centre has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung CEN-CENELEC Management Centre: Avenue Marnix 17,
B-1000 Brussels © 2014 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 61675-1:2014 E SIST EN 61675-1:2016

Foreword The text of document 62C/550/CDV, future edition 2 of IEC 61675-1, prepared by IEC/SC 62C, "Equipment for radiotherapy, nuclear medicine and radiation dosimetry", of IEC TC 62, "Electrical equipment in medical practice " was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN 61675-1:2014. The following dates are fixed: • latest date by which the document has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2014-12-13 • latest date by which the national standards conflicting with the document have to be withdrawn (dow) 2016-10-30
This document supersedes EN 61675-1:1998. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent rights. Endorsement notice The text of the International Standard IEC 61675-1:2013 was approved by CENELEC as a European Standard without any modification. SIST EN 61675-1:2016

- 3 - EN 61675-1:2014 Annex ZA
(normative) Normative references to international publications with their corresponding European publications The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
NOTE
When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies.
Publication Year Title EN/HD Year
IEC/TR 60788 2004 Medical electrical equipment - Glossary of defined terms - -
IEC 61675-1 Edition 2.0 2013-09 INTERNATIONAL STANDARD NORME INTERNATIONALE Radionuclide imaging devices – Characteristics and test conditions –
Part 1: Positron emission tomographs
Dispositifs d'imagerie par radionucléides – Caractéristiques et conditions d'essai –
Partie 1: Tomographes à émission de positrons
INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE W ICS 11.040.50 PRICE CODE CODE PRIX ISBN 978-2-8322-1119-9
– 2 – 61675-1 © IEC:2013 CONTENTS FOREWORD . 4 INTRODUCTION . 6 1 Scope . 7 2 Normative references . 7 3 Terms and definitions . 7 4 Test methods . 13 4.1 General . 13 4.2 SPATIAL RESOLUTION . 13 4.2.1 General . 13 4.2.3 Method . 14 4.2.4 Analysis . 15 4.2.5 Report . 17 4.3 Tomographic sensitivity. 18 4.3.1 General . 18 4.3.2 Purpose . 18 4.3.3 Method . 18 4.3.4 Analysis . 19 4.3.5 Report . 20 4.4 Uniformity . 20 4.5 Scatter measurement . 20 4.5.1 General . 20 4.5.2 Purpose . 20 4.5.3 Method . 20 4.5.4 Analysis . 21 4.5.5 Report . 22 4.6 PET COUNT RATE PERFORMANCE . 23 4.6.1 General . 23 4.6.2 Purpose . 23 4.6.3 Method . 23 4.6.4 Analysis . 24 4.6.5 Report . 26 4.7 Image quality and quantification accuracy of source ACTIVITY concentrations . 26 4.7.1 General . 26 4.7.2 Purpose . 26 4.7.3 Method . 27 4.7.4 Data analysis . 31 4.7.5 Report . 34 5 ACCOMPANYING DOCUMENTS . 35 5.1 General . 35 5.2 Design parameters . 35 5.3 Configuration of the tomograph . 36 5.4 SPATIAL RESOLUTION . 36 5.5 Sensitivity . 36 5.6 SCATTER FRACTION . 36 5.7 COUNT RATE performance . 36 SIST EN 61675-1:2016

61675-1 © IEC:2013 – 3 – 5.8 Image quality and quantification accuracy of source ACTIVITY concentrations . 36 Bibliography . 37 Index of defined terms . 38
Figure 1 – Evaluation of FWHM . 16 Figure 2 – Evaluation of EQUIVALENT WIDTH (EW) . 17 Figure 3 – Scatter phantom configuration and position on the imaging bed . 19 Figure 4 – Evaluation of SCATTER FRACTION . 22 Figure 5 – Cross-section of body phantom . 27 Figure 6 – Phantom insert with hollow spheres . 28 Figure 7 – Image quality phantom and scatter
phantom position for whole body scan acquisition . 29 Figure 8 – Placement of ROIs in the phantom background . 32
– 4 – 61675-1 © IEC:2013 INTERNATIONAL ELECTROTECHNICAL COMMISSION ____________
RADIONUCLIDE IMAGING DEVICES –
CHARACTERISTICS AND TEST CONDITIONS –
Part 1: Positron emission tomographs
FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations. 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user. 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter. 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any services carried out by independent certification bodies. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 61675-1 has been prepared by subcommittee 62C: Equipment for radiotherapy, nuclear medicine and radiation dosimetry, of IEC technical committee 62: Electrical equipment in medical practice. This second edition replaces the first edition of IEC 61675-1, published in 1998. This edition constitutes a technical revision. Requirements have been changed regarding the following technical aspects: – SPATIAL RESOLUTION; – sensitivity measurement; – SCATTER FRACTION; – COUNT RATE performance; – image quality. SIST EN 61675-1:2016

61675-1 © IEC:2013 – 5 – The text of this standard is based on the following documents: CDV Report on voting 62C/550/CDV 62C/561/RVC
Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. In this standard, the following print types are used: – Requirements and definitions: roman type. – Test specifications: italic type. – Informative material appearing outside of tables, such as notes, examples and references: in smaller type. Normative text of tables is also in a smaller type. – TERMS DEFINED IN CLAUSE 3 OF IEC 60601-1, IN THIS PARTICULAR STANDARD OR AS NOTED: SMALL CAPITALS. References to clauses within this standard are preceded by the term “clause” followed by the clause number. References to subclauses within this particular standard are by number only. In this standard, the conjunctive “or” is used as an “inclusive or” so a statement is true if any combination of the conditions is true. The verbal forms used in this standard conform to usage described in Annex H of the ISO/IEC Directives, Part 2. For the purposes of this standard, the auxiliary verb: – “shall” means that compliance with a requirement or a test is mandatory for compliance with this standard; – “should” means that compliance with a requirement or a test is recommended but is not mandatory for compliance with this standard; – “may” is used to describe a permissible way to achieve compliance with a requirement or test. The committee has decided that the contents of this publication will remain unchanged until the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to the specific publication. At this date, the publication will be
• reconfirmed, • withdrawn, • replaced by a revised edition, or • amended.
– 6 – 61675-1 © IEC:2013 INTRODUCTION Further developments of POSITRON EMISSION TOMOGRAPHS allow most of the tomographs to be operated in fully 3D acquisition mode. To comply with this trend, this standard describes test conditions in accordance with this acquisition characteristic. In addition, today a POSITRON EMISSION TOMOGRAPH often includes X-RAY EQUIPMENT for COMPUTED TOMOGRAPHY (CT). For this standard PET-CT hybrid devices are considered to be state of the art, dedicated POSITRON EMISSION TOMOGRAPHS not including the X-ray component being special cases only. The test methods specified in this part of IEC 61675 have been selected to reflect as much as possible the clinical use of POSITRON EMISSION TOMOGRAPHS. It is intended that the tests be carried out by MANUFACTURERS, thereby enabling them to declare the characteristics of POSITRON EMISSION TOMOGRAPHS in the ACCOMPANYING DOCUMENTS. This standard does not indicate which tests will be performed by the MANUFACTURER on an individual tomograph. SIST EN 61675-1:2016

61675-1 © IEC:2013 – 7 – RADIONUCLIDE IMAGING DEVICES –
CHARACTERISTICS AND TEST CONDITIONS –
Part 1: Positron emission tomographs
1 Scope This part of IEC 61675 specifies terminology and test methods for declaring the characteristics of POSITRON EMISSION TOMOGRAPHS. POSITRON EMISSION TOMOGRAPHS detect the ANNIHILATION RADIATION of positron emitting RADIONUCLIDEs by COINCIDENCE DETECTION. No test has been specified to characterize the uniformity of reconstructed images, because all methods known so far will mostly reflect the noise in the image. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. 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 60788:2004 and the following apply. 3.1
tomography radiography of one or more layers within an object [SOURCE: IEC 60788:2004, rm-41-15] 3.1.1
transverse tomography TOMOGRAPHY that slices a three-dimensional object into a stack of OBJECT SLICES which are considered as being two-dimensional and independent from each other and at which the IMAGE PLANES are perpendicular to the SYSTEM AXIS 3.1.2
emission computed tomography ECT imaging method for the representation of the spatial distribution of incorporated RADIONUCLIDES in selected two-dimensional slices through the object 3.1.2.1 projection transformation of a three-dimensional object into its two-dimensional image or of a two-dimensional object into its one-dimensional image, by integrating the physical property which determines the image along the direction of the PROJECTION BEAM SIST EN 61675-1:2016

– 8 – 61675-1 © IEC:2013 Note 1 to entry: This process is mathematically described by line integrals in the direction of PROJECTION (along the LINE OF RESPONSE) and called radon-transform. 3.1.2.2 projection beam beam that determines the smallest possible volume in which the physical property which determines the image is integrated during the measurement process Note 1 to entry: Its shape is limited by SPATIAL RESOLUTION in all three dimensions. Note 2 to entry: The PROJECTION BEAM mostly has the shape of a long thin cylinder or cone. In POSITRON EMISSION TOMOGRAPHY, it is the sensitive volume between two detector elements operated in coincidence. 3.1.2.3 projection angle angle at which the PROJECTION is measured or acquired 3.1.2.4 sinogram two-dimensional display of all one-dimensional PROJECTIONs of an OBJECT SLICE, as a function of the PROJECTION ANGLE Note 1 to entry: The PROJECTION ANGLE is displayed on the ordinate, the linear projection coordinate is displayed on the abscissa. 3.1.2.5 object slice physical property that correspondes to a slice in the object and that determines the measured information and which is displayed in the tomographic image 3.1.2.6 image plane a plane assigned to a plane in the OBJECT SLICE Note 1 to entry: Usually the IMAGE PLANE is the midplane of the corresponding OBJECT SLICE. 3.1.2.7 system axis axis of symmetry, characterized by geometrical and physical properties of the arrangement of the system Note 1 to entry: For a circular POSITRON EMISSION TOMOGRAPH, the SYSTEM AXIS is the axis through the centre of the detector ring. For tomographs with rotating detectors it is the axis of rotation. 3.1.2.8 tomographic volume juxtaposition of all volume elements which contribute to the measured PROJECTIONs for all PROJECTION ANGLES 3.1.2.8.1 transverse field of view dimensions of a slice through the TOMOGRAPHIC VOLUME, perpendicular to the SYSTEM AXIS Note 1 to entry: For a circular TRANSVERSE FIELD OF VIEW, it is described by its diameter. Note 2 to entry: For non-cylindrical TOMOGRAPHIC VOLUMES the TRANSVERSE FIELD OF VIEW may depend on the axial position of the slice. 3.1.2.8.2 axial field of view AFOV field which is characterized by dimensions of a slice through the TOMOGRAPHIC VOLUME, parallel to and including the SYSTEM AXIS SIST EN 61675-1:2016

61675-1 © IEC:2013 – 9 – Note 1 to entry: In practice, it is specified only by its axial dimension, given by the distance between the centre of the outmost defined IMAGE PLANEs plus the average of the measured AXIAL RESOLUTION. 3.1.2.8.3 total field of view field which is characterized by dimensions (three-dimensional) of the TOMOGRAPHIC VOLUME 3.1.3
positron emission tomography PET EMISSION COMPUTED TOMOGRAPHY utilizing the ANNIHILATION RADIATION of positron emitting RADIONUCLIDES by COINCIDENCE DETECTION 3.1.3.1 positron emission tomograph tomographic device, which detects the ANNIHILATION RADIATION of positron emitting RADIONUCLIDES by COINCIDENCE DETECTION 3.1.3.2 annihilation radiation ionizing radiation that is produced when a particle and its antiparticle interact and cease to exist 3.1.3.3 coincidence detection method which checks whether two opposing detectors have detected one photon each simultaneously Note 1 to entry: By this method the two photons are concatenated into one event. Note 2 to entry: The COINCIDENCE DETECTION between two opposing detector elements serves as an electronic collimation to define the corresponding PROJECTION BEAM or LINE OF RESPONSE (LOR), respectively. 3.1.3.4 coincidence window time interval during which two detected photons are considered as being simultaneous 3.1.3.5 line of response LOR axis of the PROJECTION BEAM Note 1 to entry: In PET, it is the line connecting the centres of two opposing detector elements operated in coincidence. 3.1.3.6 total coincidences sum of all coincidences detected 3.1.3.6.1 true coincidence result of COINCIDENCE DETECTION of two gamma events originating from the same positron annihilation 3.1.3.6.2 scattered true coincidence TRUE COINCIDENCE where at least one participating photon was scattered before the COINCIDENCE DETECTION SIST EN 61675-1:2016

– 10 – 61675-1 © IEC:2013 3.1.3.6.3
unscattered true coincidence difference between TRUE COINCIDENCES and SCATTERED TRUE COINCIDENCES 3.1.3.6.4 random coincidence result of a COINCIDENCE DETECTION in which participating photons do not originate from the same positron annihilation. 3.1.3.7 singles rate COUNT RATE measured without COINCIDENCE DETECTION, but with energy discrimination 3.1.4
two-dimensional reconstruction image reconstruction at which data are rebinned prior to reconstruction into SINOGRAMS, which are the PROJECTION data of transverse slices which are considered as being independent of each other and being perpendicular to the SYSTEM AXIS 3.1.5
three-dimensional reconstruction image reconstruction at which the LINES OF RESPONSE are not restricted to being perpendicular to the SYSTEM AXIS so that a LINE OF RESPONSE may pass several transverse slices 3.2
image matrix matrix in which each element corresponds to the measured or calculated physical property of the object at the location described by the coordinates of this MATRIX ELEMENT 3.2.1
matrix element smallest unit of an IMAGE MATRIX, which is assigned in location and size to a certain volume element of the object (VOXEL) 3.2.1.1 pixel MATRIX ELEMENT in a two-dimensional IMAGE MATRIX 3.2.1.2 trixel MATRIX ELEMENT in a three-dimensional IMAGE MATRIX 3.2.2
voxel volume element in the object which is assigned to a MATRIX ELEMENT in a two- or three-dimensional IMAGE MATRIX Note 1 to entry: The dimensions of the VOXEL are determined by the dimensions of the corresponding MATRIX ELEMENT via the appropriate scale factors and by the systems SPATIAL RESOLUTION in all three dimensions. 3.3
point spread function PSF scintigraphic image of a POINT SOURCE SIST EN 61675-1:2016

61675-1 © IEC:2013 – 11 – 3.3.1
physical point spread function two-dimensional POINT SPREAD FUNCTION in planes perpendicular to the PROJECTION BEAM at specified distances from the detector Note 1 to entry: The PHYSICAL POINT SPREAD FUNCTION characterizes the purely physical (intrinsic) imaging performance of the tomographic device and is independent of for example sampling, image reconstruction and image processing. A PROJECTION BEAM is characterized by the entirety of all PHYSICAL POINT SPREAD FUNCTIONs as a function of distance along its axis. 3.3.2
axial point spread function profile passing through the peak of the PHYSICAL POINT SPREAD FUNCTION in a plane parallel to the sYSTEM AXIS 3.3.3
transverse point spread function reconstructed two-dimensional POINT SPREAD FUNCTION in a tomographic IMAGE PLANE Note 1 to entry: In TOMOGRAPHY, the TRANSVERSE POINT SPREAD FUNCTION can also be obtained from a LINE SOURCE located parallel to the SYSTEM AXIS. 3.4
spatial resolution ability to concentrate the count density distribution in the image of a POINT SOURCE to a point 3.4.1
transverse resolution SPATIAL RESOLUTION in a reconstructed plane perpendicular to the SYSTEM AXIS 3.4.1.1 radial resolution TRANSVERSE RESOLUTION along a line passing through the position of the source and the SYSTEM AXIS 3.4.1.2 tangential resolution TRANSVERSE RESOLUTION in the direction orthogonal to the direction of RADIAL RESOLUTION 3.4.2
axial resolution SPATIAL RESOLUTION along a line parallel to the SYSTEM AXIS Note 1 to entry: AXIAL RESOLUTION only applies for tomographs with sufficiently fine axial sampling fulfilling the sampling theorem. 3.4.3
equivalent width
EW width of the rectangle that has the same area and the same height as the response function 3.4.4
full width at half maximum FWHM for a bell shaped curve, distance parallel to the abscissa axis between the points where the ordinate has half of its maximum value [SOURCE: IEC 60788:2004, rm-73-02 SIST EN 61675-1:2016

– 12 – 61675-1 © IEC:2013 3.5
recovery coefficient measured (image) ACTIVITY concentration of an active volume divided by the true ACTIVITY concentration of that volume, neglecting ACTIVITY calibration factors Note 1 to entry: For the actual measurement, the true ACTIVITY concentration is replaced by the measured ACTIVITY concentration in a large volume. 3.6
slice sensitivity ratio of COUNT RATE as measured on the SINOGRAM to the ACTIVITY concentration in the phantom Note 1 to entry: In PET, the measured counts are numerically corrected for scatter by subtracting the SCATTER FRACTION. 3.7
volume sensitivity sum of the individual SLICE SENSITIVITIES 3.8
count rate characteristic function giving the relationship between observed COUNT RATE and TRUE COUNT RATE [SOURCE: IEC 60788:2004, rm-34-21 3.8.1
count loss difference between measured COUNT RATE and TRUE COUNT RATE, which is caused by the finite RESOLVING TIME of the instrument 3.8.2
count rate number of counts per unit of time 3.8.3
true count rate COUNT RATE that would be observed if the RESOLVING TIME of the device were zero [SOURCE: IEC 60788:2004,
rm-34-20] 3.9
scatter fraction SF ratio between SCATTERED TRUE COINCIDENCES and the sum of SCATTERED plus UNSCATTERED TRUE COINCIDENCES for a given experimental set-up 3.10
point source RADIOACTIVE SOURCE approximating a δ-function in all three dimensions 3.11
line source straight RADIOACTIVE SOURCE approximating a δ-function in two dimensions and being constant (uniform) in the third dimension SIST EN 61675-1:2016

61675-1 © IEC:2013 – 13 – 3.12
calibration the process to establish the relation between COUNT RATE per volume element locally in the image and the corresponding ACTIVITY concentration in the object for object sizes not requiring RECOVERY CORRECTION
Note 1 to entry: In order to have this CALIBRATION fairly independent of the object under study, the application of proper corrections to the data, e.g. ATTENUATION, scatter, COUNT LOSS, radioactive decay, detector normalization, RANDOM COINCIDENCES (PET), and branching ratio (PET) is mandatory. The independency of the object is required to scale clinical images in terms of kBq/ml or standardized uptake values (SUV). 3.13
PET count rate performance relationship between the measured COUNT RATE of TRUE COINCIDENCES, RANDOM COINCIDENCES, TOTAL COINCIDENCES, and noise equivalent count rate versus ACTIVITY 4 Test methods 4.1 General For all measurements, the tomograph shall be set up according to its normal mode of operation, i.e. it shall not be adjusted specially for the measurement of specific parameters. If the tomograph is specified to operate in different modes influencing the performance parameters, for example with different axial acceptance angles, with and without septa, with TWO-DIMENSIONAL RECONSTRUCTION and THREE-DIMENSIONAL RECONSTRUCTION, the test results shall be reported for every mode of operation. The tomograph configuration (e.g. energy thresholds, axial acceptance angle, reconstruction algorithm) shall be chosen according to the MANUFACTURER’s recommendation and clearly stated. If any test cannot be carried out exactly as specified in this standard, the reason for the deviation and the exact conditions under which the test was performed shall be stated clearly.
It is postulated that a POSITRON EMISSION TOMOGRAPH is capable of measuring RANDOM COINCIDENCES and performing the appropriate correction. In addition, a POSITRON EMISSION TOMOGRAPH shall provide corrections for scatter, ATTENUATION, COUNT LOSS, branching ratio, radioactive decay, and CALIBRATION. The test phantoms shall be centred within the tomograph’s AXIAL FIELD OF VIEW, if not specified otherwise. 4.2 SPATIAL RESOLUTION 4.2.1 General SPATIAL RESOLUTION measurements describe partly the ability of a tomograph to reproduce the spatial distribution of a tracer in an object in a reconstructed image. The measurement is performed by imaging POINT SOURCES in air and reconstructing images, using a sharp reconstruction filter. Although this does not represent the condition of imaging a PATIENT, where tissue scatter is present and limited statistics require the use of a smooth reconstruction filter and/or iterative reconstruction methods, the measured SPATIAL RESOLUTION provides an objective comparison between tomographs.
4.2.2 Purpose The purpose of this measurement is to characterize the ability of the tomograph to recover small objects. The TRANSVERSE RESOLUTION is characterized by the width of the reconstructed TRANSVERSE POINT SPREAD FUNCTIONS of radioactive POINT SOURCES. The width of the spread function is measured by the FULL WIDTH AT HALF MAXIMUM (FWHM) and the EQUIVALENT WIDTH (EW). SIST EN 61675-1:2016

– 14 – 61675-1 © IEC:2013 The AXIAL RESOLUTION is defined for tomographs with sufficiently fine axial sampling (volume detectors) and could be measured with a stationary POINT SOURCE. These systems (fulfilling the sampling theorem in the axial direction) are characterized by the fact that the AXIAL POINT SPREAD FUNCTION of a stationary POINT SOURCE would not vary if the position of the source is varied in the axial direction for half the axial sampling distance. 4.2.3 Method 4.2.3.1 General For all systems, the SPATIAL RESOLUTION shall be measured in the transverse IMAGE PLANE in two directions (i.e. radially and tangentially). In addition, for those systems having sufficiently fine axial sampling, the AXIAL RESOLUTION also shall be measured. The TRANSVERSE FIELD OF VIEW and the IMAGE MATRIX size determine the PIXEL size in the transverse IMAGE PLANE. In order to measure accurately the width of the spread function, its FWHM should span at least 5 PIXELs.
For volume imaging systems, the TRIXEL size, in both the transverse and axial dimensions, should be made close to one fifth of the expected FWHM,
4.2.3.2 RADIONUCLIDE The RADIONUCLIDE for the measurement shall be 18F, with an ACTIVITY such that the percent COUNT LOSS is less than 5 % or the RANDOM COINCIDENCE rate is less than 5 % of the TOTAL COINCIDENCE rate. 4.2.3.3 RADIOACTIVE SOURCE distribution 4.2.3.3.1 General POINT SOURCES shall be used. 4.2.3.3.2 Source positioning Tomographs shall use POINT SOURCES, suspended in air to minimize scatter, for measurements of TRANSVERSE RESOLUTION.
Resolution measurements shall be made on two planes perpendicular to the LONG AXIS of the tomograph, one at the centre of the AXIAL FIELD OF VIEW and the second on a plane offset from the central plane by 3/8 of the AXIAL FIELD OF VIEW (i.e., one-eighth of the AXIAL FIELD OF VIEW from the end of the tomograph). On each plane sources shall be positioned at 1 cm, 10 cm, and 20 cm from the SYSTEM AXIS (the 20 cm location shall be omitted if it is not covered by the TRANSVERSE FIELD OF VIEW).
The sources shall be positioned on either the horizontal or vertical line intersecting the SYSTEM AXIS, so that the radial and tangential directions are aligned with the image grid
4.2.3.4 Data collection Data shall be collected for all sources in all of the six positions specified in 4.2.3.3.2, either singly or in groups of multiple sources, to minimize the data acquisition time. At least one hundred thousand counts for each POINT SOURCE shall be acquired.
4.2.3.5 Data processing Filtered backprojection reconstruction using a ramp filter with the cutoff at the Nyquist frequency of the PROJECTION data or its 3D equivalent shall be employed for all SPATIAL RESOLUTION data. No resolution enhancement methods shall be used.
Results obtained using alternate reconstruction algorithms may be reported in addition to the filtered backprojection results, provided that the alternate reconstruction methods and their parameters are described in sufficient detail to reproduce the study results. SIST EN 61675-1:2016

61675-1 © IEC:2013 – 15 – 4.2.4 Analysis The RADIAL RESOLUTION and the TANGENTIAL RESOLUTION shall be determined by forming one-dimensional response functions. These response functions are created by taking profiles from the TRANSVERSE POINT SPREAD FUNCTION through the reconstructed 3D-image of each POINT SOURCE in radial and tangential directions passing through the peak of the distribution. The width of each profile shall be two times the expected FWHM in both directions perpendicular to the direction of the analysis.
The AXIAL RESOLUTION of the POINT SOURCE measurements is determined by forming one-dimensional response functions (AXIAL POINT SPREAD FUNCTIONs), which result from taking profiles through the reconstructed 3D-image in the axial direction passing through the peak of the distribution. The width of each profile shall be two times the expected FWHM in both directions perpendicular to the direction of the analysis.
Each FWHM shall be determined by linear interpolation between adjacent PIXELS at half the maximum PIXEL value, which is the peak of the response function (see Figure 1). The maximum PIXEL value Cm shall be determined by a parabolic fit using the peak point and its two nearest neighbours. Values shall be converted to millimetre units by multiplication with the appropriate PIXEL width. SIST EN 61675-1:2016

– 16 – 61675-1 © IEC:2013
ABFWHMMaximum valueHalf-maximum valueXAXBXiXi+1Ci+1Ci Ci+1 Xi+1 IEC
2407/13
NOTE A and B are the points where the interpolation count curve cuts the line of half-maximum value. Then FWHM = XB – XA. Figure 1 – Evaluation of FWHM Each EQUIVALENT WIDTH (EW) shall be measured from the corresponding response function. EW is calculated from Equation (1):
∑=iPWCiEWmxC (1) where ∑iC is the sum of the counts in the profile between the limits defined by 1/20 Cm on either side of the peak; Cm
is the maximum PIXEL value; SIST EN 61675-1:2016

61675-1 © IEC:2013 – 17 – PW
is the PIXEL width in millimetres (see Figure 2).
Maximum value CmEWXiXi+1Ci+1Ci Ci+1 Xi+1 Maximum value Cm IEC
2408/13
NOTE EW is given by the width of that rectangle having the area of the LINESPREAD FUNCTION and its maximum value Cm. ()∑×=mCPWiCEW The PIXEL width PW is xi+1 – xi. The areas shaded differently are equal. Figure 2 – Evaluation of EQUIVALENT WIDTH (EW) 4.2.5 Report RADIAL RESOLUTION, TANGENTIAL RESOLUTION, and AXIAL RESOLUTION (FWHM and EW) for each POINT SOURCE position shall be calculated and reported. Transverse and axial PIXEL dimensions shall be reported.
If special reconstruction methods were used, the results of the tests should be reported together with the exact description of the methodology.
– 18 – 61675-1 © IEC:2013 4.3 Tomographic sensitivity 4.3.1 General Tomographic sensitivity is a parameter that characterizes the rate at which coincidence events are detected in the presence of a RADIOACTIVE SOURCE in the limit of low ACTIVITY where COUNT LOSSES and RANDOM COINCIDENCES are negligible. The measured rate of TRUE COINCIDENCES for a given distribution of the RADIOACTIVE SOURCE depends upon many factors, including the detector material, size and packing fraction, tomograph ring diameter, axial acceptance window and septa geometry, ATTENUATION, scatter, dead-time, and energy thresholds. 4.3.2 Purpose The purpose of this measurement is to determine the detected rate of UNSCATTERED TRUE COINCIDENCES per unit of ACTIVITY concentration for a standard volume source, i.e. a cylindrical phantom of given dimensions. 4.3.3 Method 4.3.3.1 General The tomographic sensitivity test places a specified volume of radioactive solution of known ACTIVITY concentration in the TOTAL FIELD OF VIEW of the POSITRON EMISSION TOMOGRAPH and observes the resulting COUNT RATE. The system’s sensitivity is calculated from these values. The test is critically dependent upon accurate assays of ACTIVITY as measured in a dose calibrator or well counter. It is difficult to maintain an absolute CALIBRATION with such devices to accuracies finer than 10 %. Absolute reference standards using positron emitters should be considered if higher degrees of accuracy are required. The last frame of the PET COUNT RATE PERFORMANCE test (4.6) can also be used to determine the SLICE SENSITIVITY and VOLUME SENSITIVITY. 4.3.3.2 RADIONUCLIDE The RADIONUCLIDE used for these measurements shall be 18F. The amount of ACTIVITY used shall be such that the percentage of COUNT LOSSES is less than 2 %.
4.3.3.3 RADIOACTIVE SOURCE distribution The test phantom is a solid right circular cylinder composed of polyethylene with a specific density of (0,96 ± 0,01) g/cm3, with an outside diameter of (203 ± 3) mm, and with an overall length of (700 ± 5) mm. A (6,5 ± 0,3) mm hole is drilled parallel to the central axis of the cylinder, at a radial distance of (45 ± 1) mm. For ease of fabrication and handling, the cylinder may consist of several segments that are assembled together during testing. However, in both design and assembly of the completed phantom one must insure a tight fit between adjacent segments, as even very small gaps will allow narrow axial regions of scatter-free radiation. The test phantom LINE SOURCE insert is a clear polyethylene or polyethylene coated plastic tube (800 ± 5) mm in length, with an inside diameter of (3,2 ± 0,2) mm and an outside diameter of (4,8 ± 0,2) mm.
The test phantom LINE SOURCE insert shall be filled with water well mixed with the measured amount of ACTIVITY to a length of (700 ± 5) mm and sealed at both ends. This LINE SOURCE shall be inserted into the hole of the test phantom such that the ACTIVITY of the LINE SOURCE matches the length of the polyethylene phantom. The test phantom with LINE SOURCE is mounted on the standard patient bed supplied by the MANUFACTURER and rotated such that the LINE SOURCE insert is positioned nearest to the patient bed (see Figure 3). The phantom shall be centred in the TRANSVERSE FIELD OF VIEW and to within 5 mm or if the phantom cannot be centred in the TRANSVERSE FIELD OF VIEW by elevation of the patient bed alone, additional SIST EN 61675-1:2016

61675-1 © IEC:2013 – 19 – mounting means as foam blocks placed outside the AXIAL FIELD OF VIEW can be used. In this case the actual mounting means and the actual table elevation shall be reported.
203 mm Centre 6,5 mm hole Bed top 45 mm IEC
2409/13
The 6,5 mm hole is for insertion of the LINE SOURCE. Figure 3 – Scatter phantom configuration and position on the imaging bed 4.3.3.4 Data collection Each coincident event between individual detectors shall be taken into account only once. Data shall be assembled into SINOGRAMs. All events shall be assigned to the transverse slice passing the midpoint of the corresponding LINE OF RESPONSE. At least 500 000 true coincident counts shall be acquired.
4.3.3.5 Data processing The ACTIVITY concentration in the phantom shall be corrected for decay to determine the average ACTIVITY concentration, aave, during the data acquisition time, Tacq, by the following Equation (2):
−−−=ln2exp1ln2expln211/2acq1/20calacq1/2calaveTTTTTTTVAa (2) where V
is the volume of the phantom; Acal
is the ACTIVITY times branching ratio ("positron activity") measured at time Tcal; T0
is the acquisition start time; T1/2
is the RADIOACTIVE HALF-LIFE of the RADIONUCLIDE. No corrections for detector normalization, COUNT LOSS, SCATTERED TRUE COINCIDENCES, and ATTENUATION shall be applied. The data shall be corrected for RANDOM COINCIDENCES. 4.3.4 Analysis All PIXELS in the SINOGRAM located further than 25 cm from the SYSTEM AXIS shall be set to zero.
– 20 – 61675-1 © IEC:2013 The total counts Ci,tot on each slice i shall be obtained by summing all PIXELs in the corresponding SINOGRAM. The SLICE SENSITIVITY Si for unscattered events shall be found by the following Equation (3):
()aveacqtot,1aSFTCSiii−= (3) where SFi is the corresponding SCATTER FRACTION (see 4.5). The VOLUME SENSITIVITY, Stot, shall be the sum of Si over all slices of the tomograph within the AXIAL FIELD OF VIEW. 4.3.5 R
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