Non-destructive testing - Radiation methods for Computed tomography - Part 2: Principles, equipment and samples (ISO 15708-2:2017)

ISO 15708-2:2017 specifies the general principles of X-ray computed tomography (CT), the equipment used and basic considerations of sample, materials and geometry.
It is applicable to industrial imaging (i.e. non-medical applications) and gives a consistent set of CT performance parameter definitions, including how those performance parameters relate to CT system specifications.
ISO 15708-2:2017 deals with computed axial tomography and excludes other types of tomography such as translational tomography and tomosynthesis.

Zerstörungsfreie Prüfung - Durchstrahlungsverfahren für Computertomografie - Teil 2: Grundlagen, Geräte und Proben (ISO 15708-2:2017)

Dieses Dokument legt die allgemeinen Grundlagen der Röntgencomputertomographie (CT) sowie die ange-wendeten Geräte und grundsätzliche Überlegungen zu Proben, Materialien und Geometrie fest.
Es gilt für die industrielle Bildgebung (d. h. nicht medizinische Anwendungen) und bietet einen einheitlichen Satz von Festlegungen zu CT Leistungsparametern, einschließlich der Art des Zusammenhangs dieser Leistungsparameter mit den Spezifikationen des CT Systems.
Dieses Dokument befasst sich mit der axialen Computertomographie und schließt weitere Arten der Tomo-graphie, wie z. B. Translationstomographie und Tomosynthese, aus.

Essais non destructifs - Méthodes par rayonnements pour la tomographie informatisée - Partie 2: Principes, équipements et échantillons (ISO 15708-2:2017)

Le présent document spécifie les principes généraux de la tomographie informatisée (TI) par rayonnement X, l'équipement utilisé ainsi que les considérations de base relatives à l'échantillon, aux matériaux et à la géométrie.
Il est applicable à l'imagerie industrielle (c'est-à-dire aux applications non médicales) et donne un ensemble cohérent de définitions des paramètres de performance de la TI, y compris la façon dont ces paramètres sont reliés aux spécifications du système TI.
Le présent document traite de la tomographie axiale informatisée et exclut les autres types de tomographie, tels que la tomographie par translation et la tomosynthèse.

Neporušitvene preiskave - Sevalne metode za računalniško tomografijo - 2. del: Načela, oprema in vzorci (ISO 15708-2:2017)

Standard ISO 15708-2:2017 določa splošna načela rentgenske računalniške tomografije (CT), uporabljeno opremo in temeljne zamisli glede vzorcev, materialov in geometrije.
Uporablja se za slikanje v industriji (npr. v nemedicinske namene) in podaja dosleden sklop definicij podatkov delovanja računalniške tomografije, vključno s tem, kako so podatki delovanja povezani s specifikacijami sistema računalniške tomografije.
Standard ISO 15708-2:2017 obravnava računalniško aksialno tomografijo in izključuje druge vrste tomografij, kot so translacijska tomografija in tomosinteza.

General Information

Status
Published
Publication Date
02-Apr-2019
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
03-Apr-2019
Completion Date
03-Apr-2019

RELATIONS

Buy Standard

Standard
EN ISO 15708-2:2019
English language
24 pages
sale 10% off
Preview
sale 10% off
Preview

e-Library read for
1 day

Standards Content (sample)

SLOVENSKI STANDARD
SIST EN ISO 15708-2:2019
01-julij-2019
Nadomešča:
SIST EN 16016-2:2012
Neporušitvene preiskave - Sevalne metode za računalniško tomografijo - 2. del:
Načela, oprema in vzorci (ISO 15708-2:2017)
Non-destructive testing - Radiation methods for Computed tomography - Part 2:
Principles, equipment and samples (ISO 15708-2:2017)

Zerstörungsfreie Prüfung - Durchstrahlungsverfahren für Computertomografie - Teil 2:

Grundlagen, Geräte und Proben (ISO 15708-2:2017)

Essais non destructifs - Méthodes par rayonnements pour la tomographie informatisée -

Partie 2: Principes, équipements et échantillons (ISO 15708-2:2017)
Ta slovenski standard je istoveten z: EN ISO 15708-2:2019
ICS:
19.100 Neporušitveno preskušanje Non-destructive testing
SIST EN ISO 15708-2:2019 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN ISO 15708-2:2019
---------------------- Page: 2 ----------------------
SIST EN ISO 15708-2:2019
EN ISO 15708-2
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2019
EUROPÄISCHE NORM
ICS 19.100 Supersedes EN 16016-2:2011
English Version
Non-destructive testing - Radiation methods for Computed
tomography - Part 2: Principles, equipment and samples
(ISO 15708-2:2017)

Essais non destructifs - Méthodes par rayonnements Zerstörungsfreie Prüfung - Durchstrahlungsverfahren

pour la tomographie informatisée - Partie 2: Principes, für Computertomografie - Teil 2: Grundlagen, Geräte

équipements et échantillons (ISO 15708-2:2017) und Proben (ISO 15708-2:2017)
This European Standard was approved by CEN on 11 February 2019.

CEN 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 CEN

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 CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 15708-2:2019 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 15708-2:2019
EN ISO 15708-2:2019 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

---------------------- Page: 4 ----------------------
SIST EN ISO 15708-2:2019
EN ISO 15708-2:2019 (E)
European foreword

The text of ISO 15708-2:2017 has been prepared by Technical Committee ISO/TC 135 "Non-destructive

testing” of the International Organization for Standardization (ISO) and has been taken over as

EN ISO 15708-2:2019 by Technical Committee CEN/TC 138 “Non-destructive testing” the secretariat of

which is held by AFNOR.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by October 2019, and conflicting national standards shall

be withdrawn at the latest by October 2019.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN 16016-2:2011.

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,

France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,

Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
Endorsement notice

The text of ISO 15708-2:2017 has been approved by CEN as EN ISO 15708-2:2019 without any

modification.
---------------------- Page: 5 ----------------------
SIST EN ISO 15708-2:2019
---------------------- Page: 6 ----------------------
SIST EN ISO 15708-2:2019
INTERNATIONAL ISO
STANDARD 15708-2
Second edition
2017-02
Non-destructive testing — Radiation
methods for computed tomography —
Part 2:
Principles, equipment and samples
Essais non destructifs — Méthodes par rayonnements pour la
tomographie informatisée —
Partie 2: Principes, équipements et échantillons
Reference number
ISO 15708-2:2017(E)
ISO 2017
---------------------- Page: 7 ----------------------
SIST EN ISO 15708-2:2019
ISO 15708-2:2017(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, Published in Switzerland

All rights reserved. Unless otherwise specified, 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’s member body in the country of

the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 15708-2:2019
ISO 15708-2:2017(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 General principles ............................................................................................................................................................................................... 1

4.1 Basic principles....................................................................................................................................................................................... 1

4.2 Advantages of CT ................................................................................................................................................................................... 2

4.3 Limitations of CT ................................................................................................................................................................................... 2

4.4 Main CT process steps ...................................................................................................................................................................... 3

4.4.1 Acquisition ............................................................................................................................................................................ 3

4.4.2 Reconstruction .................................................................................................................................................................. 4

4.4.3 Visualization and analysis ........................................................................................................................................ 4

4.5 Artefacts in CT images ...................................................................................................................................................................... 4

5 Equipment and apparatus .......................................................................................................................................................................... 5

5.1 General ........................................................................................................................................................................................................... 5

5.2 Radiation sources ................................................................................................................................................................................. 6

5.3 Detectors ...................................................................................................................................................................................................... 6

5.4 Manipulation ............................................................................................................................................................................................. 7

5.5 Acquisition, reconstruction, visualization and storage system ..................................................................... 7

6 CT system stability .............................................................................................................................................................................................. 7

6.1 General ........................................................................................................................................................................................................... 7

6.2 X-Ray Stability .......................................................................................................................................................................................... 8

6.3 Manipulator stability ......................................................................................................................................................................... 8

7 Geometric alignment........................................................................................................................................................................................ 8

8 Sample considerations ................................................................................................................................................................................... 9

8.1 Size and shape of sample ............................................................................................................................................................... 9

8.2 Materials (including table voltage/thickness of penetration) ....................................................................... 9

Annex A (informative) CT system components .......................................................................................................................................11

Bibliography .............................................................................................................................................................................................................................17

© ISO 2017 – All rights reserved iii
---------------------- Page: 9 ----------------------
SIST EN ISO 15708-2:2019
ISO 15708-2:2017(E)
Foreword

ISO (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 out

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 collaborates 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 approval 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 the 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/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any 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 ISO’s adherence to the World Trade Organization (WTO) principles in the

Technical Barriers to Trade (TBT) see the following URL: www . i so .org/ iso/ foreword .html.

This document was prepared by the European Committee for Standardization (CEN) (as EN 16016-2)

and was adopted, under a special “fast-track procedure”, by Technical Committee ISO/TC 135, Non-

destructive testing, Subcommittee SC 5, Radiographic testing, in parallel with its approval by the ISO

member bodies.

This second edition of ISO 15708-2 cancels and replaces ISO 15708-1:2002, of which it forms the subject

of a technical revision. It 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 reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 15708-2:2019
INTERNATIONAL STANDARD ISO 15708-2:2017(E)
Non-destructive testing — Radiation methods for
computed tomography —
Part 2:
Principles, equipment and samples
1 Scope

This document specifies the general principles of X-ray computed tomography (CT), the equipment used

and basic considerations of sample, materials and geometry.

It is applicable to industrial imaging (i.e. non-medical applications) and gives a consistent set of CT

performance parameter definitions, including how those performance parameters relate to CT system

specifications.

This document deals with computed axial tomography and excludes other types of tomography such as

translational tomography and tomosynthesis.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 15708-1:2017, Non-destructive testing — Radiation methods for computed tomography — Part 1:

Terminology

ISO 15708-3:2017, Non-destructive testing — Radiation methods for computed tomography — Part 3:

Operation and interpretation

ISO 15708-4:2017, Non-destructive testing — Radiation methods for computed tomography — Part 4:

Qualification

ISO 9712, Non-destructive testing — Qualification and certification of NDT personnel

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 15708-1 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
4 General principles
4.1 Basic principles

Computed tomography (CT) is a radiographic inspection method which delivers three-dimensional

information on an object from a number of radiographic projections either over cross-sectional planes

(CT slices) or over the complete volume. Radiographic imaging is possible because different materials

© ISO 2017 – All rights reserved 1
---------------------- Page: 11 ----------------------
SIST EN ISO 15708-2:2019
ISO 15708-2:2017(E)

have different X-ray attenuation coefficients. In CT images, the X-ray linear attenuation coefficients

are represented as different CT grey values (or in false colour). For conventional radiography the

three-dimensional object is X-rayed from one direction and an X-ray projection is produced with the

corresponding information aggregated over the ray path. In contrast, multiple X-ray-projections of an

object are acquired at different projection angles during a CT scan. From these projection images the

actual slices or volume are reconstructed. The fundamental advantage compared to radiography is the

preservation of full volumetric information. The resulting CT image (2D-CT slice or 3D-CT volume), is a

quantitative representation of the X-ray linear attenuation coefficient averaged over the finite volume

of the corresponding volume element (voxel) at each position in the sample.

The linear attenuation coefficient characterizes the local instantaneous rate at which X-rays are

attenuated as they propagate through the object during the scan. The attenuation of the X-rays as they

interact with matter is the result of several different interaction mechanisms: Compton scattering and

photoelectric absorption being the predominant ones for X-ray CT. The linear attenuation coefficient

depends on the atomic numbers of the corresponding materials and is proportional to the material

density. It also depends on the energy of the X-ray beam.
4.2 Advantages of CT

This radiographic method can be an excellent examination technique whenever the primary goal is

to locate and quantify volumetric details in three dimensions. In addition, since the method is X-ray

based it can be used on metallic and non-metallic samples, solid and fibrous materials and smooth and

irregularly surfaced objects.

In contrast to conventional radiography, where the internal features of a sample are projected onto a

single image plane and thus are superposed on each other, in CT images the individual features of the

sample appear separate from each other, preserving the full spatial information.

With proper calibration, dimensional inspections and material density determinations can also be made.

Complete three-dimensional representations of examined objects can be obtained either by

reconstructing and assembling successive CT slices (2D-CT) or by direct 3D CT image (3D-CT)

reconstruction. Computed tomography is thus valuable in the industrial application areas of non-

destructive testing, 2D and 3D metrology and reverse engineering.
CT has several advantages over conventional metrology methods:
— acquisition without contact;
— access to internal and external dimensional information;
— a direct input to 3D modelling especially of internal structures.

In some cases, dual energy (DE) CT acquisitions can help to obtain information on the material density

and the average atomic number of certain materials. In the case of known materials the additional

information can be traded for improved discrimination or improved characterization.

4.3 Limitations of CT

CT is an indirect test procedure and measurements (e.g. of the size of material faults; of wall thicknesses

must be compared with another absolute measurement procedure, see ISO 15708-3). Another potential

drawback of CT imaging is the possible occurrence of artefacts (see 4.5) in the data. Artefacts limit

the ability to quantitatively extract information from an image. Therefore, as with any examination

technique, the user must be able to recognize and discount common artefacts subjectively.

Like any imaging system, a CT system can never reproduce an exact image of the scanned object. The

accuracy of the CT image is dictated largely by the competing influences of the imaging system, namely

spatial resolution, statistical noise and artefacts. Each of these aspects is discussed briefly in 4.4.1. A

more complete description will be found in ISO 15708-3.
2 © ISO 2017 – All rights reserved
---------------------- Page: 12 ----------------------
SIST EN ISO 15708-2:2019
ISO 15708-2:2017(E)

CT grey values cannot be used to identify unknown materials unambiguously unless a priori information

is available, since a given experimental value measured at a given position may correspond to a broad

range of materials.

Another important consideration is to have sufficient X-ray transmission through the sample at all

projection angles (see 8.2) without saturating any part of the detector.
4.4 Main CT process steps
4.4.1 Acquisition

During a CT scan, multiple projections are taken in a systematic way: the images are acquired from a

number of different viewing angles. Feature recognition depends, among other factors, on the number

of angles from which the individual projections are taken. The CT image quality can be improved if the

number of projections of a scan is increased.

As all image capture systems contain inherent artefacts, CT scans usually begin with the capture of

offset and gain reference images to allow flat field correction; using black (X-rays off) and white (X-rays

on with the sample out of the field of view) images to correct for detector anomalies. The capture of

reference images for distortion correction (pin cushion distortion in the case of camera-based detector

systems with optical distortion), and centre of rotation correction can also take place at this stage. Each

subsequent captured image for the CT data set has these corrections applied to it. Some systems can be

configured to either the X-ray settings or enhance the image to ensure that the background intensity

level of the captured images remains constant throughout the duration of the CT scan.

The quality of a CT image depends on a number of system-level performance factors, with one of the

most important being spatial resolution.

Spatial resolution is generally quantified in terms of the smallest separation at which two features can

be distinguished as separate entities. The limits of spatial resolution are determined by the design and

construction of the system and by the resolution of and number of CT projections. The resolution of the

CT projection is limited by the maximum magnification that can be used while still imaging all parts of

the sample at all rotation angles.

It is important to notice that the smallest feature that can be detected in a CT image is not the same

as the smallest that can be resolved spatially. A feature considerably smaller than a single voxel can

affect the voxel to which it corresponds to such an extent that it appears with a visible contrast so that

it can be easily detected with respect to adjacent voxels. This phenomenon is due to the “partial-volume

effect”.

Although region-of-interest CT (local tomography) can improve spatial resolution in specified regions

of larger objects, it introduces artefacts (due to incomplete data) which can sometimes be reduced with

special processing.

Radiographic imaging as used for CT examination is always affected by noise. In radiography this

noise arises from two sources: (1) intrinsic variation corresponding to photon statistics related to

the emission and detection of photons and (2) variations specific to instruments and processing used.

Noise in CT projections is often amplified by the reconstruction algorithm. In the CT images statistical

noise appears as a random variation superimposed on the CT grey value of each voxel and limits density

resolution.

Although statistical noise is unavoidable, the signal-to-noise ratio can be improved by increasing the

number of projections and/or time of exposure for each of them, the intensity of the X-ray source or the

voxel size. However, some of these measures will decrease spatial resolution. This trade-off between

spatial resolution and statistical noise is inherent in computed tomography.
© ISO 2017 – All rights reserved 3
---------------------- Page: 13 ----------------------
SIST EN ISO 15708-2:2019
ISO 15708-2:2017(E)
4.4.2 Reconstruction

A CT scan initially produces a number of projections of an object. The subsequent reconstruction

of the CT image from these individual projections is the main step in computed tomography, which

distinguishes this examination technique from other radiographic methods.

The reconstruction software may apply additional corrections to the CT projections during

reconstruction, e.g. reduction of noise, correction of beam hardening and/or scattered radiation.

Depending on the CT system, either individual CT slices or 3D CT images are reconstructed.

4.4.3 Visualization and analysis

This step includes all operations and data manipulations, for extracting the desired information from

the reconstructed CT image.

Visualisation can either be performed in 2D (slice views) or in 3D (volume). 2D visualisation allows the

user to examine the data slice-wise along a defined axis (generally it can be an arbitrary path).

For 3D imaging, the CT volume or selected surfaces derived from it, are used for generating the desired

image according to the optical model underlying the algorithm. The main advantage of this type of

visualisation is that the visual perception of the image corresponds well with the natural appearance of

the object for the human eye, although features may appear superimposed in the 2D-representation on

a screen.

During visualisation, additional artefacts of different origin can occur, especially in the 3D imaging

of the CT volume. Such artefacts due to sampling, filtering, classification and blending within the

visualisation software are dependent on the hardware and software used, as well as the visualisation

task at hand. Therefore such artefacts are not included in the definition of artefacts as found in 4.5.

Nevertheless, the user should be aware that misinterpretation of the data might also occur in this

process step.

To highlight features of interest during visualisation different digital filter operations can be performed.

A characteristic of all these operations is that although they enhance one or more properties of the data,

they simultaneously deteriorate other properties (for example: highlighting the edges deteriorates

recognition of inner structures of an object). Therefore digital filters should always be used cautiously

for specific tasks, being aware which benefits and which detriments they are associated with.

A computer used for 3D visualisation should be able to process the complete volume of interest in the

main memory. The corresponding monitor should have a resolution, a dynamic range and settings

sufficient for the given visualisation task. Adequate vision of the personnel is to be ensured in

accordance with ISO 9712.
4.5 Artefacts in CT images

An artefact is an artificial feature which appears on the CT image but does not correspond to a physical

feature of the sample. Artefacts result from different origins; they can be classified into artefacts

arising from the measurement itself and the equipment (artefacts due to a finite beam width, scattered

radiation, instabilities and detector peculiarities) and artefacts inherent to the method (e.g. beam

hardening). Artefacts can also be divided into acquisition artefacts (e.g. scattered radiation, ring

artefacts) and reconstruction artefacts (e.g. cone beam artefacts). Some artefacts can be eliminated

by using an appropriate measurement technique with suitable parameters, while others can only be

reduced in their extent. Artefacts may be detrimental for specific measurement or analysis tasks, but

may have no impact on certain other analyses. With this fact in mind, the type and extent of artefacts in

a data set has to be evaluated in the context of the corresponding analysis task.

Noise and the partial volume effect are not considered as artefacts in this standard.

More details are given in ISO 15708-3:2017, 5.5.
4 © ISO 2017 – All rights reserved
---------------------- Page: 14 ----------------------
SIST EN ISO 15708-2:2019
ISO 15708-2:2017(E)
5 Equipment and apparatus
5.1 General

In relation to performance, a CT system can be considered as comprising four main components: the

X-ray source, detector, sample manipulation stages (the latter including any mechanical structure that

influences image stability) and reconstruction/visualisation system.

Generally the source and detector will be fixed while the sample rotates in the beam to acquire the

necessary set of projections. In scanners for example designed for in vivo animal studies or for imaging

large structures, the source and detector may
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.