IEC 63073-1:2020

IEC 63073-1 ®
Edition 1.0 2020-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Dedicated radionuclide imaging devices – Characteristics and test conditions –
Part 1: Cardiac SPECT
Dispositifs d'imagerie par radionucléides dédiés – Caractéristiques et
conditions d'essai –
Partie 1: SPECT pour scintigraphie cardiaque

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IEC 63073-1 ®
Edition 1.0 2020-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Dedicated radionuclide imaging devices – Characteristics and test conditions –

Part 1: Cardiac SPECT
Dispositifs d'imagerie par radionucléides dédiés – Caractéristiques et

conditions d'essai –
Partie 1: SPECT pour scintigraphie cardiaque

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 11.040.50 ISBN 978-2-8322-8967-9

– 2 – IEC 63073-1:2020 © IEC 2020
CONTENTS
CONTENTS . 2
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Test methods . 7
4.1 General . 7
4.2 Detector characteristics . 8
4.2.1 General . 8
4.2.2 Energy resolution and LOW-ENERGY-TAIL RATIO measurement . 8
4.2.3 Shield leakage . 9
4.2.4 COUNT RATE performance . 10
4.2.5 System sensitivity . 12
4.2.6 Non-uniformity for each CARDIAC DETECTOR HEAD . 14
4.2.7 SCATTER FRACTION . 14
4.3 Characteristics of tomographic images . 16
4.3.1 CENTRE OF ROTATION (COR) . 16
4.3.2 REFERENCE POINT localization in the reconstructed FOV . 16
4.3.3 Accuracy of tomographic system sensitivity modelling . 17
4.3.4 Tomographic SPATIAL NON-LINEARITY. 19
4.3.5 Tomographic SPATIAL RESOLUTION . 21
4.3.6 Image quality assessment using a heart phantom . 23
5 Additional testing . 26
6 ACCOMPANYING DOCUMENTS . 27
Bibliography . 28
Index of defined terms . 29

Figure 1 – Small shielded liquid source . 10
Figure 2 – Transverse slice of phantom used for measuring COUNT RATE performance . 11
Figure 3 – Evaluation of SCATTER FRACTION . 15
Figure 4 – Calculation of FWHM and measurement of the location of the maximum
value. 17
Figure 5 – Transaxial view of the 7 LINE SOURCE Phantom . 18
Figure 6 – Transaxial view of the 7 LINE SOURCE phantom centred within a 140 mm
diameter water-filled cylinder . 22
Figure 7 – Placement of ROIs in SHORT AXIS view of myocardium . 25
Figure 8 – Placement of ROIs in LONG AXIS view of myocardium . 26

Table 1 – Relative ACTIVITY concentration of compartments of the anthropomorphic
phantom . 24

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
DEDICATED RADIONUCLIDE IMAGING DEVICES –
CHARACTERISTICS AND TEST CONDITIONS –

Part 1: Cardiac SPECT
FOREWORD
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rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 63073-1 has been prepared by subcommittee 62C: Equipment for
radiotherapy, nuclear medicine and radiation dosimetry, of IEC technical committee 62:
Electrical equipment in medical practice.
The text of this document is based on the following documents:
CDV Report on voting
62C/740/CDV 62C/765/RVC
Full information on the voting for the approval of this document can be found in the report on
voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 4 – IEC 63073-1:2020 © IEC 2020
In this document, the following print types are used:
– terms defined in Clause 3 of this document or listed in the index of defined terms:
SMALL CAPITALS.
The requirements are followed by specifications for the relevant tests.
A list of all parts in the IEC 63073 series, published under the general title Dedicated
radionuclide imaging devices – Characteristics and test condtions, can be found on the IEC
website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates that it
contains colours which are considered to be useful for the correct understanding of its
contents. Users should therefore print this document using a colour printer.

INTRODUCTION
The test methods specified in this part of IEC 63073 have been selected to reflect as much as
possible the clinical use of GAMMA CAMERAS that are dedicated to cardiac SINGLE PHOTON
EMISSION COMPUTED TOMOGRAPHY (SPECT). It is intended that the test methods are carried out
by manufacturers thereby enabling them to describe the characteristics of the systems on a
common basis.
– 6 – IEC 63073-1:2020 © IEC 2020
DEDICATED RADIONUCLIDE IMAGING DEVICES –
CHARACTERISTICS AND TEST CONDITIONS –

Part 1: Cardiac SPECT
1 Scope
This document specifies terminology and test methods for describing the characteristics of
SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY (SPECT) systems designed specifically for
tomographic cardiac imaging. This includes dedicated systems or general purpose systems with
dedicated sub-systems which are not included in the scope of IEC 61675-2.
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.
IEC 61675-2:2015, Radionuclide imaging devices – Characteristics and test conditions – Part 2:
Gamma cameras for planar, wholebody, and SPECT imaging
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
3.1
REFERENCE POINT
defined 3D position in the FOV of the camera, specified by the manufacturer, or, if not specified
by the manufacturer, assumed to be the centre of the FOV of the camera
3.2
BAD PIXEL
detector pixel that has been physically or electronically turned off such that gamma rays which
interact in that BAD PIXEL are not recorded by the camera
3.3
CARDIAC DETECTOR HEAD
assembly of detector components associated with a single COLLIMATOR
3.4
CARDIAC DETECTOR HEAD ELEMENT
smallest discrete unit of the CARDIAC DETECTOR HEAD that is able to provide distinct energy,
spatial, and timing information about detected photons

3.5
CCFOV
central volume of the field of view of a cardiac camera, located within a radius of 7 cm from the
REFERENCE POINT
3.6
CUFOV
field of view of a cardiac camera for which the summed counts for a LINE SOURCE segment are
at least 50 % of the summed counts measured with the camera with the LINE SOURCE segment
positioned within the CCFOV
3.7
CARDIAC ORIENTATION
image coordinate system specified in reference to the axes of the heart
3.8
SHORT AXIS
SA
in the CARDIAC ORIENTATION, the plane perpendicular to the long-axis of the heart
3.9
LONG AXIS
LA
in the CARDIAC ORIENTATION, a plane parallel to the long-axis of the heart
3.10
HORIZONTAL LONG AXIS
HLA
in the CARDIAC ORIENTATION, the LONG AXIS plane that most closely bisects both the left ventricle
and the right ventricle of the heart
3.11
VERTICAL LONG AXIS
VLA
in the CARDIAC ORIENTATION, the LONG AXIS plane, that is perpendicular to the HORIZONTAL LONG
AXIS
3.12
LOW-ENERGY-TAIL RATIO
ratio of the counts measured in an ENERGY WINDOW Of width 2 × E centred at energy E
FWHM peak
– 2 × E divided by the counts measured in an ENERGY WINDOW Of width 2 × E centred
FWHM FWHM
at an energy of E , where E is the peak energy of the radioisotope being measured and
peak peak
E is the energy resolution of the detector
FWHM
4 Test methods
4.1 General
Before the measurements are performed, the tomographic system shall be adjusted by the
procedure normally used by the manufacturer for an installed unit and shall not be adjusted
specially for the measurement of specific parameters. If any test cannot be carried out exactly
as specified in the standard, the reason for the deviation and the exact conditions under which
the test was performed shall be stated clearly.
Unless otherwise specified, each CARDIAC DETECTOR HEAD in the system shall be characterized
by a full data set.
– 8 – IEC 63073-1:2020 © IEC 2020
Unless otherwise specified, SPECT characterization shall be provided for an acquisition
covering the minimal rotation required to obtain a complete set of data (e.g. 120° for a three-
headed rotating-gantry system). If a rotating-gantry tomograph is specified to operate in a non-
circular orbiting mode influencing the performance parameters, test results for the non-circular
orbiting mode shall be reported in addition.
Unless otherwise specified, measurements are carried out at COUNT RATES not exceeding
40 000 counts per second on each CARDIAC DETECTOR HEAD and not exceeding 120 000 counts
per second for the system.
4.2 Detector characteristics
4.2.1 General
Evaluation of detector characteristics for cardiac systems are performed extrinsically (with
COLLIMATORS in place). Additionally, for systems that allow the removal of the COLLIMATOR,
intrinsic detector characteristics shall be specified and tested in accordance with IEC 61675-2.
4.2.2 Energy resolution and LOW-ENERGY-TAIL RATIO measurement
4.2.2.1 General
Energy resolution describes the ability of the detector to properly identify the energy of the
detected photons. Due to incomplete charge collection, the detector material in some cardiac
systems may have an increased fraction of photons detected with reduced energy. The effect
is characterized by measuring the LOW-ENERGY-TAIL RATIO.
An energy spectrum is determined for each CARDIAC DETECTOR HEAD.
4.2.2.2 Purpose
The energy resolution is measured to characterize the ability of a GAMMA CAMERA to separate
photons with different energies.
4.2.2.3 Method
Measure an energy spectrum in low scatter configuration using an irradiation of the entire
CARDIAC DETECTOR HEAD. This measurement is performed separately for each CARDIAC DETECTOR
HEAD.
4.2.2.4 RADIONUCLIDE
99m 57
The sources are Tc and Co.
4.2.2.5 RADIOACTIVE SOURCE DISTRIBUTION
A LINE SOURCE with internal diameter of < 1,2 mm is placed so as to illuminate the entire CARDIAC
DETECTOR HEAD. The COUNT RATE shall not exceed 40 000 counts per second.
4.2.2.6 Data collection
For each CARDIAC DETECTOR HEAD, the pulse height spectrum is obtained with a channel width
less than or equal to 5 % of the expected photopeak FWHM. The number of counts in the peak
channel is greater than 10 000. The spectrum is obtained over the entire usable energy range
of the detector.
4.2.2.7 Data processing
For the energy spectrum, the channel numbers are expressed in terms of energy by scaling the
channel number by the difference in peak energies of the two RADIONUCLIDES divided by the
difference in their measured peak channel positions.
4.2.2.8 Data analysis
For each CARDIAC DETECTOR HEAD, the energy resolution, E , is the FWHM of the full energy
FWHM
absorption peak with a peak energy, E , closest to the expected photopeak energy.
peak
For each CARDIAC DETECTOR HEAD, the LOW-ENERGY-TAIL RATIO, Q , is defined as:

tail
Q = Z / Z (1)
tail tail peak
where
Z is the sum of counts from the averaged energy spectrum in the ENERGY WINDOW
peak
centred on the energy peak E with the width of 2 × E ;
peak FWHM
Z is the sum of counts from the averaged energy spectrum in the ENERGY WINDOW
tail
centred on the energy E – 2 × E with the width of 2 × E .
peak FWHM FWHM
4.2.2.9 Report
The energy resolution, expressed as a percentage of the peak energy, and the LOW-ENERGY-
TAIL RATIO are reported for each CARDIAC DETECTOR HEAD. The mean and standard deviation of
the energy resolution and LOW-ENERGY-TAIL RATIO for the entire system is also reported if the
system has more than 5 CARDIAC DETECTOR HEADS.
4.2.3 Shield leakage
4.2.3.1 General
The DETECTOR SHIELD prevents the detection of unwanted photons originated from outside the
entrance field of view of the COLLIMATOR.
4.2.3.2 Purpose
The purpose of this test is to identify the locations of the highest leakage and its magnitude.
4.2.3.3 Method
The complete surface of cardiac camera system is swept with a collimated source searching for
the maximum leakage COUNT RATES at the rear and the side of the DETECTOR SHIELD and the
joints (particularly the joint between the COLLIMATOR And the DETECTOR SHIELD), if it is
accessible.
4.2.3.4 RADIONUCLIDE
99m
The source is Tc.
4.2.3.5 RADIOACTIVE SOURCE DISTRIBUTION
A small collimated source, as illustrated in Figure 1, with d not larger than 20 mm and t not less
than 10 mm, totally filled with the RADIONUCLIDE

– 10 – IEC 63073-1:2020 © IEC 2020
4.2.3.6 Data collection
The source is placed in contact with the external surface of the DETECTOR SHIELD and the joints
if accessible. The entire surface of the DETECTOR SHIELD is swept and the system COUNT RATES
measured during a clinical acquisition mode. For systems with a rotating gantry, the data
collection is performed at a single gantry angle.
4.2.3.7 Data processing
The maximum leakage COUNT RATES at the rear and the side of the DETECTOR SHIELD, normalized
to the source ACTIVITY, are recorded. Also the maximum leakage COUNT RATE at joints in the
shield, normalized to the source ACTIVITY, is recorded.
4.2.3.8 Data analysis
The normalized leakage COUNT RATES are divided by the sensitivity of the system as measured
in 4.2.5.
4.2.3.9 Report
The three normalized maximum leakage COUNT RATES expressed as a percentage of the
sensitivity measured in 4.2.5, and the locations at which they were measured, are reported.
Dimensions in millimetres
Figure 1 – Small shielded liquid source
NOTE See 4.2.3.5 for recommended values for d and t.
4.2.4 COUNT RATE performance
4.2.4.1 General
COUNT RATE performance depends in a complex manner on the spatial distribution of ACTIVITY
and scattering materials, which therefore should simulate clinical imaging situations. Therefore
the tests are conducted with COLLIMATOR and scattering material.

COUNT RATE performance measures the relationship between the registered COUNT RATE and
ACTIVITY, i.e. the COUNT RATE CHARACTERISTIC. The COUNT RATE CHARACTERISTIC describes the
constancy of the GAMMA CAMERA sensitivity at different ACTIVITY levels and is highly dependent
on the set-up of the measurement conditions.
4.2.4.2 Purpose
The procedure described here is designed to evaluate deviations from the linear relationship
between COUNT RATE and ACTIVITY, caused by COUNT LOSSES, over a clinically relevant range of
COUNT RATES.
4.2.4.3 Method
Measurements of the COUNT RATE are performed at various ACTIVITY levels. The variation of
ACTIVITY is normally achieved by RADIOACTIVE decay. No correction is made for COUNT LOSSES
and scatter. Each measured count is taken into account only once.
4.2.4.4 RADIONUCLIDE
99m
The RADIONUCLIDE for the measurement is Tc with ENERGY WINDOW Of 140 keV ± 10 %.
4.2.4.5 RADIOACTIVE SOURCE distribution
A cylindrical phantom (Figure 2) with a LINE SOURCE insert is used. The phantom is filled with
non-radioactive water as a scatter medium. The LINE SOURCE of at least 7 cm in length is
inserted and positioned on the central axis of the cylinder. The LINE SOURCE is centred on the
REFERENCE POINT of the system and aligned with the patient inferior-superior axis.
Dimensions in millimetres
Figure 2 – Transverse slice of phantom used for measuring COUNT RATE performance
4.2.4.6 Data collection
A COUNT RATE CHARACTERISTIC (measured COUNT RATE versus incident COUNT RATE or ACTIVITY)
is to be measured by acquiring a series of images over time (e.g. frames). The variation of
ACTIVITY is accomplished by RADIOACTIVE decay with measurements continuing over
approximately 10 RADIOACTIVE HALF-LIVES. The time per frame is less than one-half of the

– 12 – IEC 63073-1:2020 © IEC 2020
RADIOACTIVE HALF-LIFE with the exception of the last three frames, which can be longer. The
initial amount of ACTIVITY is chosen to be 2 GBq ± 10 %.
A background acquisition is performed.
4.2.4.7 Data processing
The total counts acquired in each image is processed. Background correction is performed for
all frames.
The average of the decaying ACTIVITY, A , during the data acquisition interval for time frame i,
ave,i
T , is determined by the following equation:
acq,i
T
T −T  
1 T
cal 0,i acq,i
12/
exp ln2 1 exp ln2 (2)
AA −−
 
ave,i cal 
 
ln2 TT T
acq,i 1/ 2 1/ 2
 

where
A is the ACTIVITY Measured at time T ;
cal cal
T is the acquisition start-time of the time frame i;
0,i
T is the RADIOACTIVE HALF-LIFE of the RADIONUCLIDE in use.
1/2
From the above measurements, plot the COUNT RATE CHARACTERISTIC (i.e. measured COUNT RATE
versus ACTIVITY).
The conversion factor between ACTIVITY and COUNT RATE Without COUNT LOSS is determined from
each of the three frames with lowest ACTIVITY and averaged. Care is taken to acquire enough
counts in these frames to ensure a statistical precision of 1 % or better.
4.2.4.8 Data analysis
The measured COUNT RATE is plotted against the TRUE COUNT RATE.
4.2.4.9 Report
The ACTIVITY is specified as the total amount of ACTIVITY within the phantom.
Report the graph showing the COUNT RATE CHARACTERISTIC. Report the maximum observed
COUNT RATE and the ACTIVITY at which it is measured. Report the maximum percent deviation
observed from the TRUE COUNT RATE and the ACTIVITY at which it is measured.
4.2.5 System sensitivity
4.2.5.1 General
SYSTEM SENSITIVITY is a parameter that characterizes the effectiveness of a system to identify
the radiation emitted from a RADIOACTIVE SOURCE, i.e. the rate at which events are detected in
the presence of a RADIOACTIVE SOURCE with low ACTIVITY where COUNT LOSSES are negligible.
The measured COUNT RATE for a given ACTIVITY and RADIONUCLIDE depends on many factors,
including the detector material, its size and thickness, the size and shape of the RADIOACTIVE
SOURCE including its absorption and scatter properties, and instrument’s dead time, energy
thresholds and COLLIMATOR.
=
4.2.5.2 Purpose
The purpose of this measurement is to determine the detected rate of events per unit of ACTIVITY
for a standard volume source of given dimensions at a specified location and for a specified
COLLIMATOR. Variation in sensitivity between detectors in a multi-detector system can introduce
artefacts in a reconstructed image and so is also measured.
4.2.5.3 Method
The SYSTEM SENSITIVITY test places a known amount of ACTIVITY of a specified RADIONUCLIDE at
a specified REFERENCE POINt for the camera and observes the resulting COUNT RATE. From these
values the SYSTEM SENSITIVITY and the sensitivity variation between detectors are calculated.
The test is critically dependent upon accurate assays of ACTIVITY as measured in a dose
calibrator or well counter as well as the source position.
4.2.5.4 RADIONUCLIDE
99m
The RADIONUCLIDE used for this measurement is Tc and the ENERGY WINDOW is
140 keV ± 10 %.
4.2.5.5 RADIOACTIVE SOURCE distribution
The RADIOACTIVE SOURCE is a 1 ml ± 10 % sphere. The RADIOACTIVE SOURCE is placed at the
REFERENCE POINT of the camera.
4.2.5.6 Data collection
Counts are acquired until a minimum of 10 000 counts are recorded in each CARDIAC DETECTOR
HEAD. The acquisition duration is recorded. For pixelated detectors, BAD PIXEL corrections are
enabled.
4.2.5.7 Data processing
The ACTIVITY in the phantom shall be corrected for decay to determine the average ACTIVITY,
A , during the data acquisition time interval, T , by the following equation
ave acq
 T 
   
A T T −T
acq
cal cal 0
1/2
 
A = exp ln2 1− exp− ln2
  (3)
ave  
 
ln2 T T T
acq  1/ 2   1/ 2 
 
where
A is the ACTIVITY measured at time T ;
cal cal
T is the acquisition start time;
T is the RADIOACTIVE HALF-LIFE of the RADIONUCLIDE.
1/2
4.2.5.8 Data analysis
The SENSITIVITY S for each CARDIAC DETECTOR HEAD i is then found by S = C / A , where C

i i i ave i
is the COUNT RATE measured in CARDIAC DETECTOR HEAD i. The SENSITIVITY S is expressed in
i
−1 −1
counts ⋅ s ⋅ MBq . For each CARDIAC DETECTOR HEAD, the percent deviation from the
manufacturer provided expected value, ΔS , is calculated. The SYSTEM SENSITIVITY is the sum
i
of S over all CARDIAC DETECTOR HEADS.
i
4.2.5.9 Report
The following values are reported:

– 14 – IEC 63073-1:2020 © IEC 2020
For each CARDIAC DETECTOR HEAD i: S , ΔS , mean and standard deviation in ΔS .
i i i
For the cardiac system: the total system sensitivity S, and percent deviation of S from the
manufacturer provided expected value.
4.2.6 Non-uniformity for each CARDIAC DETECTOR HEAD
NON-UNIFORMITY OF RESPONSE is assessed for each CARDIAC DETECTOR HEAD according to
manufacturer specified procedures. The manufacturer specified procedure is described and the
values determined by the procedure are reported.
4.2.7 SCATTER FRACTION
4.2.7.1 General
The scattering of primary gamma rays results in events with false information for radiation
source localization. Variations in design and implementation cause emission tomographs to
have different sensitivities to scattered radiation. The purpose of this procedure is to measure
the relative SYSTEM SENSITIVITY to scattered radiation, expressed by the SCATTER FRACTION (SF).
It is recognized that access to PROJECTION data is not available on all systems. If PROJECTION
data are unavailable, the SCATTER FRACTION should be estimated according to the manufacturer-
specified protocol and the exact protocol used is reported along with the SCATTER FRACTION.
4.2.7.2 Purpose
Unscattered events are assumed to lie within a 2 × FWHM wide strip centred on the image of
the LINE SOURCE. This region width is chosen because the scatter value is insensitive to the
exact width of the region, and a negligible number of unscattered events lie more than one
FWHM from the line image.
4.2.7.3 RADIONUCLIDE
99m
The RADIONUCLIDE used for this measurement is Tc and the ENERGY WINDOW is 140
keV ± 10 %.
4.2.7.4 RADIOACTIVE SOURCE distribution
A cylindrical phantom (Figure 2) with a LINE SOURCE insert is used. The phantom is filled with
non-radioactive water as a scatter medium. The LINE SOURCE of at least 7 cm in length is
inserted and positioned on the central axis of the cylinder. The LINE SOURCE is centred on the
REFERENCE POINT of the system and aligned with the patient inferior-superior axis.
4.2.7.5 Data collection
The measurement is performed by imaging the LINE SOURCE within a water-filled test phantom
using a standard clinical protocol for cardiac tomographic imaging. A total of 10 million counts
are acquired in the PROJECTION data.
4.2.7.6 Data processing
The PROJECTION data are not reconstructed and are not corrected for scatter or ATTENUATION.
4.2.7.7 Data analysis
Each PROJECTION is summed in the axial direction to create a profile. The counts in the PIXELS
at ±1 × FWHM from the peak of the profile, C and C respectively, are obtained (see Figure
L,i R,i
3). Linear interpolation is used to find the count levels at ±1 × FWHM from the peak of the

profile. The average of the two count levels C and C is multiplied by the fractional number
L,i R,i
of PIXELS between the edges of the 2 × FWHM wide strip, with the product added to the counts
in the PIXELS outside the strip, to yield the number of scattered counts C , for the PROJECTION
s,i
i. The total counts (scattered plus unscattered) C is the sum of the counts in the profile of
tot,i
PROJECTION i.
The SCATTER FRACTION SF for each PROJECTION, i, is calculated as follows:
i
SF = C / C (4)
i s,i tot,i
The mean and standard deviation of SF are calculated.
i
The system SCATTER FRACTION SF is calculated as follows
SF = Ʃ C / Ʃ C (5)
i s,i i tot,i
4.2.7.8 Report
The mean and the standard deviation the set of SF values are reported. The value SF is also
i
reported as the system SCATTER FRACTION.

NOTE In the summed PROJECTION profile, the scatter is estimated by the counts outside the 2 × FWHM wide strip
plus the area of the LSF below the line C – C .
L,i R,i
Figure 3 – Evaluation of SCATTER FRACTION

– 16 – IEC 63073-1:2020 © IEC 2020
4.3 Characteristics of tomographic images
4.3.1 CENTRE OF ROTATION (COR)
Measurement of COR is critical to tomographic performance of cardiac cameras with rotating
gantries. For cameras with rotating gantries, the COR shall be specified and tested in
accordance with IEC 61675-2.
4.3.2 REFERENCE POINT localization in the reconstructed FOV
4.3.2.1 General
The REFERENCE POINT defines a reproducible spatial location within the FOV of the system.
NOTE Accurate knowledge of the REFERENCE POINT location in the reconstructed image space is crucial for
reproducible measurement of system performance.
4.3.2.2 Purpose
To measure the precision of positioning a POINT SOURCE at the REFERENCE POINT.
4.3.2.3 Method
A POINT SOURCE is placed in the camera FOV and the manufacturer specified procedure is used
to position the POINT SOURCE at the REFERENCE POINT. The position of the POINT SOURCE in the
reconstructed image volume is measured. The procedure is repeated 10 times. Prior to each
repetition, the POINT SOURCE is removed and replaced in the FOV, and the camera is reset to
its starting position.
4.3.2.4 RADIONUCLIDE
99m
THe RADIONUCLIDE used for this measurement is Tc and the ENERGY WINDOW is
140 keV ± 10 %.
4.3.2.5 RADIOACTIVE SOURCE distribution
The source is a 1 ml spherical source. It is measured in air.
4.3.2.6 Data collection
The camera is positioned according to the manufacturer specified cardiac protocol to align the
POINT SOURCE with the REFERENCE POINT. A standard cardiac tomographic acquisition is
performed and at least 1 million counts are acquired total in the PROJECTION data.
4.3.2.7 Data processing
The image volume for each acquisition is reconstructed according to the manufacturer-specified
default reconstruction for clinical cardiac myocardial perfusion imaging.
4.3.2.8 Data analysis
Each image volume is summed in the 2 orthogonal directions to generate a 1 dimensional
summed profile of the POINT SOURCE. The location of the peak is determined as indicated in
Figure 4 (position E). The process is repeated to determine the location in the axial, coronal,
and sagittal directions.
The means and standard deviation of the location in the three orthogonal directions are
calculated.
A and B are the points where the interpolated curve cuts the line of half maximum value. The maximum value is
calculated as the maximum value of a quadratic curve fit to the maximum measured value and the two adjacent
measured values. The location of the maximum value, E, is also determined from the quadratic fit.
FWHM = X – X
B A
Figure 4 – Calculation of FWHM and measurement of the location of the maximum value
4.3.2.9 Report
The means and standard deviation of the location in the three orthogonal directions are
reported.
4.3.3 Accuracy of tomographic system sensitivity modelling
4.3.3.1 General
Image reconstruction requires knowledge of the system geometry. The system geometry of
dedicated cardiac cameras may be complex. Inconsistencies between the assumed and actual
system geometry can lead to artefacts affecting the uniformity of reconstructed images.
4.3.3.2 Purpose
The accuracy of tomographic system sensitivity modelling measurements provide information
about the consistency, over the FOV of the camera, of the counts in the reconstructed image of
a small source.
– 18 – IEC 63073-1:2020 © IEC 2020
4.3.3.3 Method
The accuracy of tomographic system sensitivity modelling is determined from the deviations in
the measured ACTIVITY concentration in the image of the LINE SOURCES of a multi-line-source
phantom.
4.3.3.4 RADIONUCLIDE
99m
The RADIONUCLIDE used for this measurement is Tc and the ENERGY WINDOW is
140 keV ± 10 %.
4.3.3.5 RADIOACTIVE SOURCE distribution
The RADIOACTIVE SOURCE is a set of 7 LINE SOURCES with an internal diameter of < 1,2 mm and
a length of at least 7 cm, arranged as indicated in Figure 5. The multi-line source phantom is
measured in air. The ACTIVITY concentration in each LINE SOURCE is the same.
Dimensions in millimetres
Figure 5 – Transaxial view of the 7 LINE SOURCE Phantom
4.3.3.6 Data collection
4.3.3.6.1 Set A (CCFOV)
Three measurements are made, one with the lines parallel to each of the axial, coronal and
sagittal axis of the image space. For each measurement, the central line of the multi-line source
phantom is centred on the REFERENCE POINT of the camera. Counts are acquired until a minimum
of 10 million counts are recorded in total by the camera.
NOTE The data for these measurements can be used in 4.3.4.6.1.
4.3.3.6.2 Set B (CUFOV)
Following each measurement with the phantom centred on the REFERENCE POINT (Set A), the
phantom is displaced in the direction of the LINE SOURCE axis until all of the LINE SOURCES extend
at least to the edge of the manufacturer-specified FOV and if possible to 1 cm beyond the edge
of the FOV. Counts are acquired until a minimum of 10 million counts are recorded in total by
the camera. The measurement is repeated for the opposite displacement such that both edges
of the FOV in the direction of the LINE SOURCE axis are measured.
NOTE The data for these measurements can be used in 4.3.4.6.2.

4.3.3.7 Data processing
Image volumes are reconstructed according to the manufacturer-specified default
reconstruction for clinical cardiac myocardial perfusion imaging.
For each of the three 3D reconstructed volumes in data set A, the data are summed in the
direction parallel to the LINE SOURCE axis over a length extending not more than 10 mm in the
direction of the LINE SOURCE axis. The summed 2D images corresponding to the LINE SOURCE
segment at each end of the LINE SOURCES are discarded. For each of the remaining summed 2D
images and for each of the 7 LINE SOURCES, the image is summed in the two orthogonal
directions over a width of between 2 cm and 4 cm centred on the LINE SOURCE axis to generate
the total counts in the image associated with each LINE SOURCE segment.
For each of the six 3D reconstructed volumes in data set B, the same processing is repeated
over the length of the LINE SOURCES visible in the reconstructed volume.
4.3.3.8 Data analysis
4.3.3.8.1 Sensitivity map analysis in the CCFOV
Calculate the mean, minimum, maximum and standard deviation of the counts measured for the
LINE SOURCE segments in the CCFOV.
4.3.3.8.2 Dimensions of the CUFOV
Determine the distances from the REFERENCE POINT in each of the orthogonal directions (axial,
sagittal, and coronal) of the locations of the LINE SOURCE segments for which the summed counts
are at least 50 % of the mean value of the summed counts in the LINE SOURCE segments located
in the CCFOV.
4.3.3.8.3 Sensitivity map analysis in the CUFOV
Calculate the mean, minimum, maximum and standard deviation of the counts measured for the
LINE SOURCE segments in the CUFOV.
4.3.3.9 Report
The mean, minimum, maximum and standard deviation of the counts measured for the LINE
SOURCE segment are reported separately for the segments in the CCFOV and CUFOV. The
locations of the LINE SOURCE segment with the minimum and maximum count measurement are
reported. The dimensions of the CUFOV with respect to the REFERENCE POINT are reported.
4.3.4 Tomographic SPATIAL NON-LINEARITY
4.3.4.1 General
Spatial linearity describes the ability of the system to r
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