1、BS ISO 15708-1:2017Non-destructive testing Radiation methods forcomputed tomographyPart 1: TerminologyBSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS ISO 15708-1:2017 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 15708-1:20
2、17. The UK participation in its preparation was entrusted to TechnicalCommittee WEE/46, Non-destructive testing.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Use
3、rs are responsible for its correctapplication. The British Standards Institution 2017. Published by BSI Standards Limited 2017ISBN 978 0 580 95774 1ICS 19.100Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of the
4、Standards Policy and Strategy Committee on 31 March 2017.Amendments/corrigenda issued since publicationDate Text affectedBS ISO 15708-1:2017 ISO 2017Non-destructive testing Radiation methods for computed tomography Part 1: TerminologyEssais non destructifs Mthodes par rayonnements pour la tomographi
5、e informatise Partie 1: TerminologieINTERNATIONAL STANDARDISO15708-1Second edition2017-02Reference numberISO 15708-1:2017(E)BS ISO 15708-1:2017ISO 15708-1:2017(E)ii ISO 2017 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2017, Published in SwitzerlandAll rights reserved. Unless otherwise specif
6、ied, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISO
7、s member body in the country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 15708-1:2017ISO 15708-1:2017(E)Foreword iv1 Scope . 12 Normative references 13 Terms and definiti
8、ons . 1 ISO 2017 All rights reserved iiiContents PageBS ISO 15708-1:2017ISO 15708-1:2017(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried ou
9、t through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO co
10、llaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different appr
11、oval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www. iso. org/ directives).Attention is drawn to the possibility that some of the elements of this document may be th
12、e subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/oron the ISO list of patent declarations received (see www. iso. org/ patents).A
13、ny trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the World Trade Organi
14、zation (WTO) principles in theTechnical Barriers to Trade (TBT) see the following URL: www .iso. org/ iso/ foreword. htmlThis document was prepared by the European Committee for Standardization (CEN) (as EN 16016-1) and was adopted, under a special “fast-track procedure”, by Technical Committee ISO/
15、TC 135, Non-destructive testing, Subcommittee SC 5, Radiographic testing, in parallel with its approval by the ISO member bodies.The first edition (ISO 15708-1:2002) having been cancelled and replaced by ISO 15708-2:2017, this second edition of ISO 15708-1 has been repurposed with a different title
16、and scope and takes into consideration developments in computed tomography (CT) and computational power over the preceding decade.A list of all parts in the ISO 15708 series can be found on the ISO website.iv ISO 2017 All rights reservedBS ISO 15708-1:2017INTERNATIONAL STANDARD ISO 15708-1:2017(E)No
17、n-destructive testing Radiation methods for computed tomography Part 1: Terminology1 ScopeThis document gives the definitions of terms used in the field of computed tomography (CT). It presents a terminology that is not only CT-specific but which also includes other more generic terms and definition
18、s spanning imaging and radiography. Some of the definitions represent discussion points aimed at refocusing their terms in the specific context of computed tomography.2 Normative referencesThere are no normative references in this document.3 Terms and definitionsFor the purposes of this document, th
19、e following terms and definitions apply.ISO and IEC maintain terminological databases for use in standardization at the following addresses: IEC Electropedia: available at h t t p :/ www .electropedia .org/ ISO Online browsing platform: available at h t t p :/ www .iso .org/ obp3.1absorptionphotoele
20、ctric absorptionmode of interaction between photons and matter whereby a photon is absorbed by an atom which then emits an electron whose kinetic energy is exactly equal to the energy-depleted photons electron-binding energyNote 1 to entry: See also Compton scattering (3.6).3.2angular incrementangul
21、ar spacing between adjacent CT projections (3.12)3.3artefactartificial feature which appears on the CT image (3.11) but does not correspond to a physical feature of the object3.4beam hardeningspectrum hardeningspectral change of a polychromatic beam caused by preferential attenuation of lower energy
22、 photonsNote 1 to entry: See also cupping effect (3.17). ISO 2017 All rights reserved 1BS ISO 15708-1:2017ISO 15708-1:2017(E)3.5calibration templatephantomknown reference object that is scanned to assess the performance of a CT system (3.15)3.6Compton scatteringmode of interaction between a photon a
23、nd an electron, where the photon is scattered with reduced energy, and the difference of energy is transferred to the electron, also known as inelastic scattering or incoherent scatteringNote 1 to entry: See also photoelectric absorption (3.1).3.7computed tomographyCTCT computed axial tomographyradi
24、ographic scanning technique that uses a number of CT projections (3.12) of an object at different angles in order to allow calculation of a CT image (3.11)3.8CT cone beamscanning mode wherein each CT projection (3.12) is built from a set of ray paths (3.24) emanating from a point source and divergin
25、g in two dimensions, thereby forming a cone3.9CT dataCT datasetCT projection (3.12) or CT image (3.11)3.10CT grey valuegrey levelnumerical value assigned to each voxel (3.30) in a CT image (3.11)Note 1 to entry: This value represents the average linear attenuation coefficient (3.20) of the object vo
26、lume for that voxel.3.11CT imagetomogram2D or 3D image of the CT grey values (3.10) obtained by reconstruction (3.25)3.12CT projection1D or 2D radiographic image3.13CT scanset of relative movements between sample, source and detector, and the acquisition necessary to obtain a set of CT projections (
27、3.12) that can be reconstructed into a CT image (3.11)3.14CT slice2D CT image (3.11) with a finite thickness along a given planeNote 1 to entry: See also slice thickness (3.29).2 ISO 2017 All rights reservedBS ISO 15708-1:2017ISO 15708-1:2017(E)3.15CT systemtomographequipment used to produce CT imag
28、es (3.11)3.16CT volume3D CT image (3.11)3.17cupping effectfeature due to beam hardening (3.4) in which the CT grey values (3.10) in a CT image (3.11) towards the centre of an homogeneous object are lower than those closer to the surface3.18density resolutionmeasure of the extent to which a CT image
29、(3.11) can be used to detect differences in the linear attenuation coefficient (3.20)3.19fan beam CTscanning mode wherein each CT projection (3.12) is built from a set of ray paths (3.24) emanating from a point source but considered to be diverging in only one dimension, thereby forming a fan3.20lin
30、ear attenuation coefficientX-ray attenuation (3.31) per unit path length of material at a given energyNote 1 to entry: It is often expressed in cm-1.3.21parallel beam CTscanning mode wherein each CT projection (3.12) is built from a set of parallel ray paths (3.24)3.22partial volume effecteffect due
31、 to the finite voxel size of CT images (3.11) where properties of different materials are averaged within a single voxel (3.30)3.23pixelbasic cell area in a 2D image or detectorNote 1 to entry: See also voxel (3.30).3.24ray pathpath that an X-ray travels from the source to a given detector pixel (3.
32、23)3.25reconstructionprocess of transforming a set of CT projections (3.12) into a CT image (3.11)3.26region of interestROIsub-volume within an object or a CT image (3.11) ISO 2017 All rights reserved 3BS ISO 15708-1:2017ISO 15708-1:2017(E)3.27region of interest CTlocal tomographyCT image (3.11) of
33、a region of interest (ROI) (3.26) of an object using a set of CT projections (3.12) in which parts outside the ROI are not imaged in all of the CT projections (3.12)3.28sinogramimage formed by stacking vertically a set of 1D CT projections (3.12) from a complete set of angular positions in order of
34、increasing projection angle3.29slice thicknesseffective thickness of the X-ray beam in 2D tomography (i.e. that part of the X-ray beam that reaches the detector) measured at the centre of the object3.30voxelvolume element of a CT image (3.11) to which a CT grey value (3.10) is assignedNote 1 to entr
35、y: It is the 3D equivalent of a pixel (3.23).3.31X-ray attenuationreduction in the intensity of X-rays as they pass through matter due to a combination of absorption and scatteringNote 1 to entry: See also linear attenuation coefficient (3.20).4 ISO 2017 All rights reservedBS ISO 15708-1:2017BS ISO
36、15708-1:2017ISO 15708-1:2017(E) ISO 2017 All rights reservedICS 19.100Price based on 4 pagesThis page deliberately left blankBSI is the national body responsible for preparing British Standards and other standards-related publications, information and services.BSI is incorporated by Royal Charter. B
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