Download Dual slice CT scanner comparison report

July 2002
Evaluation Report
NUMBER
MDA 02060
Dual Slice CT Scanner Comparison Report
Version 7
MDA 02060
MDA Evaluation Report
ImPACT report
© Crown Copyright
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ImPACT – Imaging Performance Assessment of CT Scanners
Dual Slice CT Scanner Comparison Report
Version 7.12, July 2002
A report comparing the specification and imaging performance of the following CT
scanners:
Manufacturer
Scanner model
GE
NX/i
GE
NX/i Pro
Philips
Mx8000D
Siemens
Somatom Emotion Duo
Toshiba
Asteion Dual
Compiled and prepared by members of the ImPACT group
www.impactscan.org
© 2002, Crown Copyright
Table of Contents
TABLE OF CONTENTS .........................................................................................2
INTRODUCTION.....................................................................................................3
Purpose of this report ........................................................................................................ 3
Comparison methods......................................................................................................... 3
Specification comparison...................................................................................................... 3
Scanner performance ........................................................................................................... 3
Scanners covered in this report........................................................................................ 4
SPECIFICATION COMPARISON...........................................................................5
SCANNER PERFORMANCE .................................................................................8
Introduction ......................................................................................................................... 8
Dose efficiency.................................................................................................................... 9
Head scanning...................................................................................................................... 9
Body scanning ...................................................................................................................... 9
Spatial resolution.............................................................................................................. 10
Limiting resolution............................................................................................................... 10
Geometric efficiency ........................................................................................................ 11
Clinical scan tables .......................................................................................................... 12
Standard brain .................................................................................................................... 12
Standard abdomen ............................................................................................................. 12
Helical abdomen ................................................................................................................. 12
Inner ear (1mm) .................................................................................................................. 12
High resolution spine .......................................................................................................... 12
APPENDIX 1: EXTENDED SPECIFICATION COMPARISON.............................13
Scanner gantry.................................................................................................................. 13
Patient couch .................................................................................................................... 14
X-ray generator ................................................................................................................. 15
X-ray tube .......................................................................................................................... 15
Detection system .............................................................................................................. 16
System start-up and calibration ...................................................................................... 16
Scan parameters............................................................................................................... 17
Helical scanning ............................................................................................................... 17
Scan projection radiograph (SPR) .................................................................................. 18
Manufacturers’ performance data................................................................................... 19
Factors affecting image quality....................................................................................... 20
Operator’s console ........................................................................................................... 21
Main computer .................................................................................................................. 22
Image storage.................................................................................................................... 23
Image reconstruction ....................................................................................................... 24
3D reconstruction ............................................................................................................. 25
Optional features .............................................................................................................. 26
Installation requirements ................................................................................................. 27
Independent workstation ................................................................................................. 28
Image transfer and connectivity...................................................................................... 29
APPENDIX 2: IMAGE QUALITY ASSESSMENT AND Q....................................30
APPENDIX 3: MANUFACTURERS’ COMMENTS...............................................31
Response from GE Medical Systems ............................................................................. 32
Response from Philips Medical Systems....................................................................... 33
Response from Siemens Medical Solutions .................................................................. 34
APPENDIX 4: IMPACT AND THE MDA...............................................................35
Background ....................................................................................................................... 35
ImPACT .............................................................................................................................. 35
MDA support to purchasers and users .......................................................................... 35
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ImPACT Dual Slice CT Scanner Comparison v 7.12
Introduction
Purpose of this report
In January 2000, the UK government announced the funding for the replacement, over a
three-year period, of all non-helical CT scanners in use in England.
ImPACT has produced comparison reports for each phase of the purchase. The primary
aim of these reports is to aid the equipment selection process by providing comparisons of
CT scanners that are currently on the market. The previous set of ‘Blue Cover’ comparison
reports generally available was from Phase 3 of CIP (MDA 01048(single slice),
01049(dual), 01050(quad)). A limited edition of ‘Blue Cover’ reports from Phase 6 of CIP
was also produced and these are available on request (MDA 02020(single slice),
02023(dual), 02021(quad), 02022(8/16 slice)).
The scope of this report is limited to CT scanners that are capable of acquiring two sets of
attenuation data per tube rotation, known as ‘dual’ or ‘two slice’ scanners. Single slice and
four, eight and sixteen slice scanners are covered in separate reports.
The scanners included in the report are those that are currently on the market, and in
particular, that will generally be considered for purchase by NHS hospitals in the UK.
Comparison methods
The data given in this report are representative of the scanners as of April 2002, and are
liable to change as the performance of individual scanner models is changed and upgraded.
In particular, optional features such as workstations and software packages may be listed as
standard for the scanner replacement programme, but may not be included in other, separate
scanner purchases.
There are two main areas for comparison of the scanners: specification and performance
Specification comparison
The specification comparison is presented in two sections. The first is a side-by-side
summary comparison of the specification of each scanner, workstation and related
equipment, showing the parameters that are considered to be most important for interscanner comparison. An extended version of the first, giving greater detail can be found in
Appendix 1 – Extended Specification Comparison.
Scanner performance
This section presents the results of ImPACT’s imaging and dose performance assessment of
each of the scanners. Although manufacturers generally publish image and dose
characteristics of their scanners, different measurement techniques and phantoms often
make it very difficult to compare results from one scanner against another. The ImPACT
performance assessments utilise standard techniques, and allow a fair, like-with-like
comparison.
ImPACT Dual Slice CT Scanner Comparison v 7.12
3
Introduction
Scanners covered in this report
At the time of writing, there are five manufacturers of medical CT scanners; (in alphabetical
order) GE Medical Systems, Philips Medical Systems, Shimadzu, Siemens AG and Toshiba
Medical Systems. Of these, GE, Philips, Siemens and Toshiba produce dual slice scanners.
The scanner models in this report are listed in the table below.
Manufacturer
Scanner model
GE
NX/i
GE
NX/i Pro
Philips
Mx8000D
Siemens
Somatom Emotion Duo
Toshiba
Asteion Dual
The GE NX/i and NX/i Pro are very similar, the main difference being the larger tube and
generator on the NX/i Pro. The specification comparison section lists them in a single
column, with the differences shown where relevant. The performance data comes from an
assessment of an NX/i Pro, but the NX/i has identical imaging performance.
Philips acquired Marconi Medical in October 2001. The Philips Mx8000D was formerly
marketed as the Marconi Mx8000D.
The Philips Mx8000D and the Toshiba Asteion Dual have not yet been evaluated by
ImPACT, therefore no imaging performance measurements are available. The limiting
resolution data for the Mx8000D came from the assessment of the Marconi Mx8000 (a four
slice scanner), which is also applicable to the Mx8000D.
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ImPACT Dual Slice CT Scanner Comparison v 7.12
Specification comparison
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
Generation
3rd
3rd
3rd
3rd
Aperture (cm)
70
70
70
72
Maximum scan field of view (cm)
50
50
50
2 x 1, 2, 3, 4, 5, 6,
7, 10, [2 x 0.5]
2 x 0.5,1, 2.5,
5, 8, 10
50
2 x 1, 1.5, 2.5,
3, 4, 5. 1 x 6, 8
10
224 x 65 (or 42
just for cradle)
243 x 67.5
222 x 68
200 x 47
162
200
153
182
Vertical movement range out of
gantry (cm)
40 - 95
48 - 100.8
45 - 83
30 - 87
Maximum weight on couch (kg)
180
200
200
205
42 or 53.2
60
40
36
Scanner gantry
Nominal slice widths for axial
scans (mm)
2 x 0.5, 1, 2, 3, 4,
5, 8, 10
Couch
Length and width (cm)
Horizontal movement range (cm)
Tube and generator
Generator power rating (kW)
Anode heat capacity (MHU)
3.5 [6.3]
6.5
3.5 MHU
4.0 (nominal)
(claimed
equivalent to 6.5)
Maximum anode cooling rate
(kHU/min)
820 [840]
735
700
864
Guaranteed tube life
200,000 rotations 160,000 rotations
130,000 seconds
200,000 rotations
of scanning
Detection system
Number of elements along z-axis
2
2
2
22
Effective length of each element
at isocentre (mm)
2 x 10
2 x 10
2x5
4 x 0.5, 18 x 1
Total effective length of detector
array at isocentre (mm)
20
20
10
20
Yes (4). Aim to
launch shortly
Yes, 4 or 16
slices/rotation
available now.
Yes
Yes (4). (not
'forklift', 3 - 4
days)
Future option for more slices /
rotation
ImPACT Dual Slice CT Scanner Comparison v 7.12
5
Specification comparison
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
System start-up and calibration
Power-on to warm-up time (mins)
3 from fully off, 1
from standby
6 from fully off,
approx. 2 from
standby
11 from fully off,
5 from standby
2 from fully off,
0 from standby
Tube warm-up time from 'cold' to
operating temperature (mins)
2
2-3
3
2 (0 in an
emergency)
Total time from fully off to
scanning in an emergency (mins)
5
8-9
5 (without
check up)
2
Scan times (s)
* = Partial scans
0.53*, 0.8, 1,
1.5, 2, 3
[0.46*, 0,7, 1,
1,5, 2, 3]
0.3*, 0.5, 0.75, 1,
1.5, 2
0.5*, 0.67*, 0.8,
1, 1.5
0.5*, 0.75, 1, 1.5,
2, 3
Helical pitches (range and
increment)
1.5 and 3
(0.75 and 1.5)
0.5 to 4 (0.25 to 1 to 4 (0.5 to 2) 1.25 to 3 (0.63 to
2) (0.1 steps)
(freely selectable) 1.5) (0.25 steps)
Scanning
Maximum continuous scan time
(s)
120
100
100
100
Operator's console
Number of monitors at console
Control methods
1 standard ,
(acquisition/
2 (patient set up
review and
and acquisition/
processing). 2nd
image review,
recon and filming) optional (shared
database)
2 (acquisition/
review and
processing)
Mouse, keyboard Mouse, keyboard Mouse, keyboard
Mouse, cursor,
keyboard
1
Image storage
36
72
18 GByte system
disk, 2 x 18
GByte data disk
45
MOD (standard)
MOD (standard),
CD-R (standard)
MOD and CD-R
(standard)
Rewritable MOD
(standard)
60 (with IBO)
23
45
50 prospective,
65 retro.
48
23
45
35 prospective,
50 retro.
Simultaneous scanning and
reconstruction
Yes
Yes
Yes
Yes
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ImPACT Dual Slice CT Scanner Comparison v 7.12
Total hard disk storage capacity
supplied as standard (Gbytes)
Archive options
Image reconstruction
Minimum time taken (secs) for
the 30th image of a series to
appear for:
standard axial brain scan
helical abdomen scan
Specification comparison
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
3D reconstruction
3D reconstruction software
MIPs, SSD,
MIPs, SSD,
MIPs, SSD,
MIPs, SSD,
volume rendering, volume rendering, volume rendering, volume rendering,
MPR, virtual
MPR, virtual
MPR, virtual
MPR, virtual
endoscopy
endoscopy
endoscopy
endoscopy
Additional facilities
Independent workstation
Standard
Standard
Standard
Standard
Contrast injector
Optional
Optional
Optional
Optional
Contrast media bolus tracking
Standard
Standard
Standard
Standard
CT fluoroscopy software and
hardware
Optional
Optional
Optional
Optional
Hard-copy imaging device
Optional
Optional
Optional
Optional
Bone mineral densitometry
Optional
Optional
Optional
Optional
CT angiography
Standard
Standard
Standard
Standard
Dental
Optional
Optional
Optional
Optional
Radiotherapy CT simulation
software
Standard
Optional
Optional
Optional
Prospective ECG-triggered
cardiac software
N/A
Optional
Optional
Optional
Retrospective ECG-gated
cardiac software
Optional
Optional
N/A
Optional
Storage SCU and
DICOM service classes provided
SCP,
by CT console (SCP and SCU)
query/retrieve
Storage SCU and
SCP,
query/retrieve,
print
Storage SCU and
SCP,
query/retrieve,
print, modality
worklist
Storage SCU and
print (standard),
storage SCP and
modality worklist
(optional)
DICOM service classes provided Storage SCU and
by Independent workstation
SCP,
(SCP and SCU)
query/retrieve
Storage SCU and Storage SCU and Storage SCU and
SCP,
SCP,
SCP, print,
query/retrieve,
query/retrieve,
query/retrieve
print
print
(standard)
Image transfer/connectivity
Speed of scanner/workstation
connections to local area
networks (Mbits/s)
100
100
ImPACT Dual Slice CT Scanner Comparison v 7.12
100
100
7
Scanner performance
Introduction
In order to compare the performance of CT scanners, the ImPACT evaluation programme
has developed a range of assessment techniques. These were described in detail in
MDA/98/25, Type Testing of CT Scanners: Methods and Methodology for Assessing
Imaging Performance and Dosimetry. The results of this testing are presented in this
section, which consists of data regarding different aspects of scanner performance.
The dose efficiency section looks at the overall image quality of the scanner relative to the
radiation dose delivered to the patient, for both head and body scanning. This is presented
in terms of the ImPACT Q value.
Spatial resolution compares the ability of the scanners to reproduce fine detail within an
image, usually referred to as the high contrast spatial resolution. This is presented as the
MTF50 and MTF10 values (known as MTF50 and MTF10) for the limiting clinical resolution
of the scanner.
Geometric efficiency examines the z-axis dose utilisation of the scanners. This is expressed
as the ratio of the imaged slice thickness to the x-ray beam thickness. In general, scanners
with a high geometric efficiency will not produce large patient doses, particularly for
narrow slice thicknesses, where geometric efficiencies are normally lowest.
Clinical scan tables lists the measured image quality and dose parameters for the standard
ImPACT clinical scans.
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ImPACT Dual Slice CT Scanner Comparison v 7.12
Scanner performance
Dose efficiency
Dose efficiency is a term used to describe the quality of a scanner's images relative to the
radiation dose to the patient. It can be expressed in a number of ways. ImPACT normally
use the 'Q-value', which combines measurements of noise, high contrast resolution, slice
thickness and dose to produce an imaging figure of merit (see Appendix 2).
The Q2 values presented in this section are for head and body imaging. The imaging
parameters used for these scans are chosen to minimise slight variations that occur for
different kV, slice thicknesses, scan times and reconstruction algorithm, by using standard
values where possible:
kV: 120 kV or 130 kV when this is the ‘standard’ operating kV for the scanner
Slice thickness: 2 x 5 mm for head, 1 x 10 or 2 x 10 mm for body, depending on the
capabilities of the scanner.
Scan time: 1.5 or 2 s for head, 1s for body.
Reconstruction algorithm: the algorithm chosen for each scanner is the one that most
closely matches the average ‘standard’ head and body algorithm (MTF50 of 3.4 c/cm,
MTF10 of 6.0 c/cm).
Reconstruction field of view: 250 mm (head) and 380 mm (body).
The mAs setting that would result in a CTDIw of 50 mGy for head and 15 mGy for body
scanning is listed. Z-sensitivity, image noise at 50 or 15 mGy and MTF values are also
shown.
Head scanning
Recon mAs for z-sens
algorithm 50mGy (mm)
GE NX/i
Std+
337
5.0
Siemens Emotion Duo
H40
235
4.6
MEAN
286
4.8
Scanner
Noise
(%)
0.30
0.32
0.31
MTF50
(c/cm)
3.3
3.5
3.4
MTF10
(c/cm)
6.2
5.7
6.0
Noise
(%)
1.3
1.3
1.3
MTF50
(c/cm)
3.6
3.3
3.4
MTF10
(c/cm)
6.0
6.1
6.1
Q2
7.1
6.3
6.7
Body scanning
Recon mAs for z-sens
algorithm 15mGy (mm)
Siemens Emotion Duo
B30
151
9.5
GE NX/i
Detl
229
9.4
MEAN
190
9.4
Scanner
ImPACT Dual Slice CT Scanner Comparison v 7.12
Q2
2.1
2.1
2.1
9
Scanner performance
Spatial resolution
The spatial resolution figures given below show the capabilities of the scanners to
reproduce fine detail within an image.
Limiting resolution looks at the highest spatial resolution that can be achieved with the
scanner, using a clinical reconstruction algorithm.
Limiting resolution
Scanner
Marconi Mx8000D
Siemens Emotion Duo
GE NX/i
Recon.
filter
E
U90
Edge
MTF50
(lp/cm)
8.9
7.6
10.2
MTF10
(lp/cm)
17.8
13.4
12.1
The scan parameters used for limiting resolution table are those that produce the highest
spatial resolution i.e. fine focal spot, long (>1 s) scan time, sharpest reconstruction
algorithm, small reconstruction field of view.
10
ImPACT Dual Slice CT Scanner Comparison v 7.12
Scanner performance
Geometric efficiency
Geometric efficiency is a measure of the scanners dose utilisation in the z-axis. This is
expressed as the ratio of the axial imaged slice section thickness relative to the z-axis dose
profile. For optimum imaging, the geometric efficiency should be 1, but it is often less,
especially for narrow beam collimations where post-patient collimation may be necessary to
bring the imaged slice thickness closer to the nominal value. Geometric efficiency values
of greater than 1 are due to the accuracy limits of the measurements.
The data is presented in the form of a table and a graph. The table gives geometric
efficiency values both for the setting closest to 2 x 1 mm slice thickness and also, where
applicable, for the slice narrower than 1 mm. The graph presents data for all slice widths,
showing how geometric efficiency varies with nominal imaged slice width. The total zsensitivity figure is measured using fused slices.
Slice
Total zImaged
Thickness
sensitivity
width (mm)
(mm)
(mm)
GE NX/i
2x1
1.2
2.3
Siemens Emotion Duo
2x1
1.1
2.1
Scanner
Dose
profile
(mm)
2.2
2.1
Geometric
efficiency
1.07
1.03
1.2
1.0
0.8
0.6
GE NX/i
0.4
Siemens Emotion Duo
0.2
0.0
0
2
4
6
8
10
Nominal Imaged Slice Width (mm)
ImPACT Dual Slice CT Scanner Comparison v 7.12
11
Scanner performance
Clinical scan tables
These are a sub-set of the standard ImPACT clinical scan tables for a range of examination
types. It should be noted that exposure parameters listed were those suggested by the
manufacturer, but in practice they will vary from site to site. In particular, the settings for
mA and scan time, which define patient dose, may vary widely from one centre to another.
Standard brain
Head scan reconstructed to show low contrast brain detail. Listed alphabetically.
Scanner
Scan Slice FOV Conv. CTDIW z-sens. Noise MTF50 MTF10
time (s) (mm) (mm) Filter (mGy) (mm)
(%) (c/cm) (c/cm)
240
2.0 2 x 10 250 Std+
35
9.4
0.26
3.3
6.2
255
1.5 1 x 10 250 H20
54
9.5
0.18
3.0
5.1
45
9.4
0.22
3.2
5.7
kVp mAs
GE NX/i
120
Siemens Emotion Duo 130
MEAN
Standard abdomen
Axial abdomen scan. Listed alphabetically.
Scanner
Scan Slice FOV Conv. CTDIW z-sens. Noise MTF50 MTF10
time (s) (mm) (mm) Filter (mGy) (mm)
(%) (c/cm) (c/cm)
175
0.7 2 x 10 380 Std+
11
9.4
1.2
2.7
4.8
120
0.8 1 x 10 380 B30
12
9.5
1.4
3.6
6.0
12
9.4
1.3
3.2
5.4
kVp mAs
GE NX/i
120
Siemens Emotion Duo 130
MEAN
Helical abdomen
Helical abdomen scan. Listed alphabetically.
Scanner
Scan Slice FOV Conv. CTDIW z-sens. Noise MTF50 MTF10
time (s) (mm) (mm) Filter (mGy) (mm)
(%) (c/cm) (c/cm)
175
0.7
10.00 380 Std+
8
10.4
1.1
2.5
4.5
120
0.8
10
380 B30
12
10.1
1.3
3.6
6.0
10
10.3
1.2
3.0
5.2
kVp mAs
GE NX/i
120
Siemens Emotion Duo 130
MEAN
Inner ear (1mm)
High contrast inner ear exam. Listed alphabetically.
Scanner
Scan Slice FOV Conv. CTDIW z-sens. Noise MTF50 MTF10 MTF10
time (s) (mm) (mm) Filter (mGy) (mm)
(%) (c/cm) (c/cm) as mm
100
1.0
2 x 1 120 Edge
16
1.2
8.4
10.2
12.1
0.41
135
1.5
2 x 1 120 U90
28
1.1
7.6
7.6
13.4
0.37
16
1.2
8.4
10.2
12.1
0.41
kVp mAs
GE NX/i
120
Siemens Emotion Duo 130
MEAN
High resolution spine
High contrast spine examination. Listed alphabetically.
Scanner
GE NX/i
120
Siemens Emotion Duo 130
MEAN
12
Scan Slice FOV Conv. CTDIW z-sens. Noise MTF50 MTF10 MTF10
(%) (c/cm) (c/cm) as mm
time (s) (mm) (mm) Filter (mGy) (mm)
170
1.0
2 x 3 120 Bone
12
3.1
14
7.5
10.1
0.50
165
1.5 2 x 1.5 120 U90
17
1.5
23
7.7
11.4
0.44
14
2.3
19
7.6
10.8
0.47
kVp mAs
ImPACT Dual Slice CT Scanner Comparison v 7.12
Appendix 1: Extended specification comparison
Scanner gantry
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
3rd
3rd
3rd
3rd
Low voltage
Low voltage
Low voltage
Low voltage
70
70
70
72
18, 25, 35, 50
25 and 50
50
18, 24, 32, 40, 50
2 x 1, 2, 3, 4, 5, 6,
7, 10, [2 x 0.5]
2 x 0.5,1, 2.5,
5, 8, 10
2 x 1, 1.5,
2.5, 3, 4, 5.
1 x 6, 8 ,10
2 x 0.5, 1, 2, 3, 4,
5, 8, 10
Tilt range (degrees)
± 30
± 30
± 30
± 30
Type of positioning lights
Laser
Laser
Laser
Laser
Generation
Slipring
Aperture (cm)
Scan fields of view (cm)
Nominal slice widths for axial
scans (mm)
ImPACT Dual Slice CT Scanner Comparison v 7.12
13
Appendix 1: Extended specification comparison
Patient couch
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
Carbon fibre
Carbon fibre
Carbon fibre
Carbon fibre
224 x 65 (or 42
just for cradle)
243 x 67.5
222 x 68
200 x 47
162
200
153
182
Horizontal movement speeds
(mm/sec)
20, 100
0.5 - 100
1 - 100
10, 100
Accuracy/reproducibility of table
positioning (mm)
± 0.25
± 0.25
± 0.5
± 0.25
(i) without table top extension
162
165
153
144
(ii) with table top extension(s)
162
187
153
155
Vertical movement range out of
gantry (cm)
40 - 95
48 - 100.8
45 - 83
30 - 87
Vertical movement range in
gantry (cm)
81 - 95
86 - 100.8
18.6
73 - 87
Minimum couch top height
outside gantry (cm)
40
48
45
30
Maximum weight allowed on
couch (kg)
205
200
200
500
Maximum weight on couch which
still achieves stated performance
specifications (kg)
180
200
200
205
Couch top
Material
Length and width (cm)
Horizontal movement
Horizontal movement range (cm)
Scannable horizontal range (cm):
Vertical movement
Weight bearing properties
14
ImPACT Dual Slice CT Scanner Comparison v 7.12
Appendix 1: Extended specification comparison
X-ray generator
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
High frequency
High frequency
High frequency
High frequency
Location
Rotation
assembly
Rotation
assembly
Rotation
assembly
Rotation
assembly
Power rating (kW)
42 or 53.2
60
40
36
kV settings available
80, 120, 140
90, 120, 140
80, 110, 130
80, 100, 120, 135
mA range and step size
10 - 350 [10 440] (5mA
steps)
28 - 500
(<1mA steps)
30 - 240
(1mA steps)
10 - 400
(10mA steps)
Max. mA allowed for each kV
80kV:350
[400]mA
120kV:
350 [440]mA
140kV:
300 [380]mA
90 kV: 500 mA
120 kV: 500 mA
140 kV: 425 mA
80 kV: 228 mA
110 kV: 236 mA
130 kV: 240 mA
80-120 kV:
400 mA
135 kV: 350 mA
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
GE 3.5 MHU
[5.2 / 6.3 MHU]
Marconi DFS
Siemens Dura
352
Toshiba Helicool
0.5x0.7 / 1.0x1.0
[0.6x0.7 / 0.9x0.9]
0.7 x 1
1.2 x 1.5
0.4 x 0.8
0.7 x 0.8
0.9 x 1.3
1.7 x 1.6
6.2 (at 140kV)
[6.32 (at 80kV)]
> 5.5
6.4mm (at 80kV)
> 1 (inh) + 1.5
Anode heat capacity (MHU)
3.5 [6.3]
6.5
3.5 MHU
4.0 (nominal)
(claimed
equivalent to 6.5)
Maximum anode cooling rate
(kHU/min)
820 [840]
735
700
864
Method of cooling
Oil to air
Oil to air
Oil to air
Oil to air with
liquid metal
bearings
Type
X-ray tube
Type and make
Focal spot size(s) (mm), quoted
to IEC 336/93 standard
Total filtration (inherent + beam
shaping filter) at central axis (mm
Al equivalent)
Guaranteed tube life
200,000 rotations 160,000 rotations
ImPACT Dual Slice CT Scanner Comparison v 7.12
130,000 seconds
200,000 rotations
of scanning
15
Appendix 1: Extended specification comparison
Detection system
GE NX/i
[and NX/i Pro]
Detector type
Philips
Mx8000D
Solid state
Solid state (High
(HiLight / Lumex) speed ceramic)
Siemens
Emotion Duo
Toshiba
Asteion Dual
Solid state (Ultra
Fast Ceramic)
Solid state
789 (plus 23
reference
elements)
672 (plus 2
reference
elements)
2 x 672
896 (plus 1 pair
ref detectors)
Number of elements along z-axis
2
2
2
22
Effective length of each element
at isocentre (mm)
2 x 10
2 x 10
2x5
4 x 0.5, 18 x 1
Total effective length of detector
array at isocentre (mm)
20
20
10
20
Yes (4). Aim to
launch shortly
Yes, 4 or 16
slices/rotation
available now.
Yes
Yes (4). (not
'forklift', 3 - 4
days)
Number of detectors per row
Future option for more
slices/rotation
System start-up and calibration
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
Power-on to warm-up time (mins)
3 from fully off, 1
from standby
6 from fully off,
approx. 2 from
standby
11 from fully off,
5 from standby
2 from fully off,
0 from standby
Tube warm-up time from 'cold' to
operating temperature (mins)
2
2-3
3
2 (0 in an
emergency)
Included in 2 mins
tube warm-up
3
2
1
Included in tube
warm up, no
additional cals.
are normally
required
1 per week
Advised 2 hrs
post switch on
1 per week
2
2
Up to 20
8-9
5 (without
check up)
2
Time to perform detector
calibrations at warm-up (mins)
Recommended frequency for any
additional calibration by the
radiographer
Time to perform these additional
5 mins but not
calibrations (mins)
normally required
Total time from fully off to
scanning in an emergency (mins)
16
5
ImPACT Dual Slice CT Scanner Comparison v 7.12
Appendix 1: Extended specification comparison
Scan parameters
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
4.8 - 50
2.5 - 50 (0.1
steps)
5 - 50
0 - 50
Nominal slice widths (mm) and
number of simultaneous slices
(axial scans)
* = Optional
2 x 0.5*, 2 x 1,
2 x 2, 2 x 3,
2 x 5, 2 x 7,
2 x 10, 9 + 1
2 x 0.5, 2 x 1,
2 x 2.5, 2 x 5,
2 x 8, 2 x 10
2 x 1, 2 x 1.5,
2 x 2.5, 2 x 4,
2 x 5. 1 x 6,
1 x 8, 1 x 10
2 x 0.5, 2 x 1,
2 x 2, 2 x 3, 2 x 4,
2 x 5, 2 x 8, 2 x
10
Scan times for axial scans (s)
* = partial scans
0.53*, 0.8, 1,
1.5, 2, 3
[0.46*, 0,7, 1,
1,5, 2, 3]
0.3*, 0.5, 0.75, 1,
1.5, 2
0.5*, 0.67*, 0.8,
1, 1.5
0.5*, 0.75, 1, 1.5,
2, 3
kV settings available
80, 120, 140
90, 120, 140
80, 110, 130
80, 100, 120, 135
10 - 350 [10 440] (5mA steps)
28 - 500
(1mA steps)
30 - 240
(1 mA steps)
10 - 400
(10mA steps)
80kV:350
[400]mA
120kV:
350 [440]mA
140kV:
300 [380]mA
90 kV: 500 mA
120 kV: 500 mA
140 kV: 425 mA
80 kV: 228 mA
110 kV: 236 mA
130 kV: 240 mA
80-120 kV:
400 mA
135 kV: 350 mA
Reconstruction fields of view
(cm)
mA range and step size
Max. mA allowed for each kV
Helical scanning
Rotation times for helical
scanning (s)
Pitches available for routine
scanning (range and increment)
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
0.8, 1. 1.5
[0.7,1,1.5]
0.5, 0.75, 1, 1.5
0.8, 1, 1.5
0.75, 1, 1.5
1.5 and 3
(0.75 and 1.5)
0.5 to 4 (0.25 to 1 to 4 (0.5 to 2) 1.25 to 3 (0.63 to
2) (0.1 steps)
(freely selectable) 1.5) (0.25 steps)
1.5 and 3
0.5, 0.75, 1, 1.25,
1.75, 2.5, 3.5, 4
2 to 4
1.25, 1.5, 1.75,
2.25, 2.5, 2.75, 3
180º LI, 360° & zfilter interpolation
180º, 360º, high
order non linear
filters
Adaptive axial
interpolator
180º, 360º,
Muscot
39 (300mA),
56 (250 mA),
Maximum number of rotations in
>60 (210mA)
one helical run at standard
[99 (300mA),
abdomen parameters
110 (270 mA),
120 (250mA)]
All 0.7s scan time
200
100 (100mA)
100 (150mA)
45 (200mA)
All 0.8s scan time
115
(190mA, 0.75s)
133
(160mA, 0.75s)
Maximum continuous scan time
(s)
120
100
100
100
Gantry tilt for helical scanning
(degrees)
±30
±30
±30
Recommended pitches for
optimal image quality
Helical interpolation algorithms
available
ImPACT Dual Slice CT Scanner Comparison v 7.12
17
Appendix 1: Extended specification comparison
Scan projection radiograph (SPR)
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
1000
1024
1024
1390
500 x 1000
width: 500
length: 100 - 1024
(1mm steps)
512 x 1024
width:
240, 400, 500,
length:
200 - 1,390
Any angle from
0 - 355 (5º steps)
0, 90, 180, 270
AP, PA, LAT
0, 90, 180, 270
(oblique in 5º
steps)
Yes
Available next
software release.
(Recon time
curently 2s)
Standard
Yes
Accuracy of slice prescription
from the scanogram (mm)
± 0.25
<±1
± 0.5
± 0.25
Accuracy of distance
measurements from SPR's taken
at isocentre (lateral and axial
directions) (mm)
± 0.25
± 0.25
± 0.5
< ± 0.5 mm
Maximum SPR length (mm)
SPR field dimensions (mm x mm)
Angular positions of x-ray tube
available for SPR (degrees)
Real time image
18
ImPACT Dual Slice CT Scanner Comparison v 7.12
Appendix 1: Extended specification comparison
Manufacturers’ performance data
GE NX/i Plus
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
15.5 lp @ 0%
MTF 130 kV,
60mA, 0.8sec,
1mm, U90S.
18 lp @ cut off,
14.5 lp @ 2%
MTF,
12.5 lp 10% MTF,
FC90
1 sec.
High contrast spatial
resolution
Resolution (lp/cm) for sharpest
clinical algorithm
15 lp @ 0% MTF
13 lp @ 10% MTF
8.5 lp @ 50%
24.0 lp/cm @ cut
MTF Performance off, Ultra-high
algorithm, 0.7 sec
mode
scan time, small
focus
Low contrast resolution
Smallest rod size (mm)
discernable at given parameters
in 20 cm CATPHAN
5.0mm @ 0.3%
5 mm @ 0.3%, 5 mm 3 HU 15.8
Directly
120 kVp, 250
mGy at 90 mAs,
comparable data
mAs, 2 x 10 mm 0.8 sec, 10 mm at
not available
slice
130 kv
Dose
CTDI100 for axial standard brain
scans at given parameters:
120 kVp, 2x5mm
Info. not available
slice, 1 sec scan
130 kV 140 mA
1.5 s scan time
Info. not available
8 mm slice
thickness
- centre of CTDI phantom
(mGy/100 mAs)
14.7
13.9
21.7
Info. not available
- periphery of CTDI phantom
(mGy/100 mAs)
14.2
15.4
23.3
Info. not available
CTDI100 for axial standard
abdomen scans
120 kVp, 8mm
Info. not available
slice, 1 sec scan
130 kV 100 mA
1 s scan time
Info. not available
8 mm slice
thickness
- centre of CTDI phantom
(mGy/100 mAs)
4.6
4.3
6.7
Info. not available
- periphery of CTDI phantom
(mGy/100 mAs)
7.4
8.8
12.8
Info. not available
Info. not available
5 : 4.9
4 : 3.9
2.5: 2.5
1.5: 1.4
1: 1.1
Info. not available
Dose profile FWHM (mm)
10: 10.3 (l)
7: 8.0 (l)
5: 6.2 (l)
3: 4.7 (l)
2: 3.1 (s)
1: 1.6 (s)
ImPACT Dual Slice CT Scanner Comparison v 7.12
19
Appendix 1: Extended specification comparison
Factors affecting image quality
Dose
Post-patient collimation for
narrow slices
Automatic mA adjustment
according to body dimensions or
density during examination
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
No
Yes
No
No
Smart mA
(standard)
N/A
Yes, mA
modulation
Yes
Advanced noise
reduction
Adaptive image
enhancement or
smoothing for up
to three density
ranges
Yes (automatic)
Yes (user
programmable)
Yes
Yes
Yes
Yes
No
Noise
Adaptive filtration for noise
reduction
Resolution
Quarter detector shift
Moving (dynamic/flying) focal
spot
No
Yes
Yes, for all scan
times
Number of imaging detectors per
row
789
672
672
896
1388 Hz
2,320 views (in
standard imaging
mode of 0.75s
rotation time)
1000 Hz
1200 Hz
Sampling frequency
Artefacts
Artefact reduction algorithms
20
Advanced artefact
reduction,
advanced noise
reduction,
interative bone
option (IBO),
motion correction
Iterative bone
correction
Beam hardening
Modified beam
correction, raster
hardening
artefact
(abdomen, pelvis,
suppression
shoulder), Motion
protocol (RASP),
correction
stack scanning,
(sequential
automatic patient
modes)
motion correction
ImPACT Dual Slice CT Scanner Comparison v 7.12
Appendix 1: Extended specification comparison
Operator’s console
Image monitor
Diagonal dimension of image
screen (inches)
Number of monitors at console
(functions of each if > 1)
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
21
20
21
21
1
1 standard ,
2 (patient set up
(acquisition/
and acquisition/
review and
image review,
processing). 2nd
recon and filming) optional (shared
database)
2 (acquisition/
review and
processing)
Image display
Image display matrix dimensions
Usual range of CT number
displayed (HU)
1024
1024
512, 512 x 1024,
1024
-1024 to +3071
-1000 to +3094
-1024 to +3071
(-10,240 to
30,710 if metal
implants)
-1024 to +8191
Yes
Yes
Yes
Yes
No
WIP
Yes
Info. not available
Not applicable
(>70% for all
collimations)
Not applicable
(>70% for all
collimations)
Not applicable
(>70% for all
collimations)
Info. not available
512, 768, 1024
Dose information
Weighted CTDI (CTDIw) diplayed
on console
Dose Length Product (DLP)
displayed on console
Geometric efficiency displayed
on console when <70%
Hardware interface
Control methods
Mouse, keyboard Mouse, keyboard Mouse, keyboard
ImPACT Dual Slice CT Scanner Comparison v 7.12
Mouse, cursor,
keyboard
21
Appendix 1: Extended specification comparison
Main computer
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
2 x Silicon
Graphics O2
Make and model
Silicon Graphics
O2
2 x Silicon
Graphics O2
Siemens PC with
array processor;
IRS - 2 x Pentium
IV, ICS - Pentium
IV, ( 2nd console
'Wizard' is option)
Operating system
IRIX
Unix
Windows NT
IRIX
RU5200, 300
MHz
2 x RISC
processor
300 MHz (one for
each console)
Pentium IV
1.7 GHz
R5000 (scan
console) R12000
(display console)
300 MHz
(i) supplied as standard
512
2 x 1024
Navigator: 1024,
Optional Wizard:
1536
2 x 1024
(ii) maximum
512
2 x 1024
Navigator: 1024,
optional Wizard:
1536
2 x 1024
Type and speed of CPU
Amount of computer RAM
(Mbytes):
22
ImPACT Dual Slice CT Scanner Comparison v 7.12
Appendix 1: Extended specification comparison
Image storage
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
Total standard hard disk capacity
(Gbytes) available for data
storage
36
72
18 GByte system
disk, 2 x 18
GByte data disk
45
Maximum hard disk capacity
(Gbytes) available for data
storage
36
72
36
90
Standard hard disk capacity for
image storage (Gbytes and
number of uncompressed
512x512 images)
18,
20,000 images
72,
54,000 images
9,
13,000 images
16,000 images
Standard hard disk capacity for
storage of raw data files (Gbytes
and no. of data files)
18,
6000 data files
72, approx. 1800
data files
18, 8,000 raw
data files
Data from 4,000
rotations
MOD (standard)
MOD (standard),
CD-R (standard)
MOD and CD-R
(standard)
Rewritable MOD
(standard)
Hard disk storage
Archive options
Archive options
MOD: 4.1Gb
2.3 (12,000 JPEG
(26,000 losslessly
losslessly
4.1 (15,650
compressed
2.6 (9600
Capacity of a single archive disk
compressed
512 x 512
images), CD-R: 512 x 512 images
(Gbytes and no. of images)
512 x 512 images images. Factor 2- 0.65Gb (4800
- slightly
or 600 raw data
3 compression)
compressed
compressed)
files)
images)
256 x 256 matrix
Time to mount an archive disk or
tape (s)
5 - 6 in
background
operation
Immediate (disk
continually
accessible)
approx 30 for full
disk
20 for full disk
Archive data transfer rate
(images/s)
1 (read), 0.7
(write)
>3
2-3
Approx. 1
ImPACT Dual Slice CT Scanner Comparison v 7.12
23
Appendix 1: Extended specification comparison
Image reconstruction
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
256, 512
340, 512, 768,
1024
256, 512
256, 512
0.1
0.1
0.1
0.1
60 (with IBO)
23
45
50 prospective,
65 retro.
(ii) axial spine scan
47
23
45
45 prospective,
60 retro.
(iii) helical abdomen scan
48
23
45
35 prospective,
50 retro.
Simultaneous scanning and
reconstruction
Yes
Yes
Yes
Yes
Any delay in either scanning or
reconstruction when performed
concurrently
No
No
No
No
Simultaneous scanning and
routine analysis
Yes
Yes
Yes
Yes
Simultaneous scanning and
archiving and/or hard copying
Yes
Yes
Yes
Yes
Simultaneous scanning and
transfer to second
console/workstation
Yes
Yes
Yes
Yes
24
ImPACT Dual Slice CT Scanner Comparison v 7.12
Reconstruction matrix
Minimum reconstruction interval
in helical scanning (mm)
Reconstruction times
Time (secs) from the start of data
acquisition to the appearance of
the 30th image of a series:
(i) standard axial brain scan
Parallel processing details
Appendix 1: Extended specification comparison
3D reconstruction
3D Reconstruction on main
console (MC) and
workstation (WS)
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
MIPs and MinIPs (maximum and
minimum intensity projections)
MC - standard,
WS - standard
(MIP & MinIP)
MC - standard,
WS - standard
(Angio MIP)
MC - standard,
WS - standard
MC - standard,
WS - standard
SSD (3D shaded surface display)
MC - optional,
WS - otandard
(3D)
MC - standard,
WS - standard
(3D SSD)
MC - standard,
WS - standard
MC - standard,
WS - standard
3D volume rendering software
MC - N/A,
WS - standard
(Volume
Rendering)
MC - standard,
WS - standard
(Vol Rend 4D
Angio)
MC - optional,
WS - standard
MC - standard,
WS - standard
3D virtual endoscopy
MC - optional,
WS - standard
(Navigator)
MC - option,
WS - option
(V-endo Voyager)
MC - optional
WS - optional
MC - optional,
WS - standard
MPR (multi-planar
reconstruction)
MC - standard,
WS - standard
(MPR & MPVR)
MC - standard,
WS - standard
(MPR)
MC - standard,
WS - standard
MC - standard,
WS - standard
Planes available in MPR
All planes as
defined by
operator in real
time. MPVR is
also std & real
time
Axial, sagittal,
All planes, any
coronal, oblique,
Axial, sagittal,
oblique (identical
coronal, oblique, curved with cross
on console and
cut through the
curvilinear
workstations)
curved reformat
ImPACT Dual Slice CT Scanner Comparison v 7.12
25
Appendix 1: Extended specification comparison
Optional features
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
Optional
Optional
Optional
Optional
Contrast media bolus tracking
Standard
(SmartPrep)
Standard
(BolusPro Ultra)
Standard
(CARE Bolus)
Standard
CT fluoroscopy software and
hardware
Optional
Optional
(Continuous CT
Imaging)
Optional (CARE
Vision)
Optional
Hard-copy imaging device
Optional
Optional
Optional
Optional
Optional (RT flat
pad and 'Exact'
couch top)
Optional (RTP)
Optional
Optional
Optional
Optional
Optional
N/A
Optional (Exact
couch E8505M)
Optional
Optional
Optional
MC - N/A,
WS - optional
(PC option)
BMD
MC - optional,
WS - optional
(Q BMAP II)
MC - optional,
(Osteo CT)
WS - optional
MC - optional,
WS - N/A
MC - standard,
WS - standard
(including MIP
MinIP Average)
MC - standard,
WS - standard
(Angio MIP)
MC - standard,
WS - standard
MC-standard,
WS-standard
MC - optional,
WS - optional
(Dentascan)
MC - optional,
WS - optional
(DENT -3)
MC - optional,
(Dental CT)
WS - optional
MC - optional,
WS - optional
Radiotherapy CT simulation
software
MC - N/A,
WS - standard for
CT Sim purchase,
otherwise optional
MC - optional,
WS - optional
(ACQSim)
Available from 3rd
party
MC - optional,
WS - N/A
Prospective ECG-triggered
cardiac software
N/A
MC - optional,
WS - N/A
MC - optional,
WS - N/A
MC - optional,
WS - N/A
Retrospective ECG-gated
cardiac software
MC - N/A,
WS - optional
MC - optional,
WS - N/A
N/A
MC - optional,
WS - N/A
Contrast injector
Radiotherapy planning
accessories
Radiotherapy planning table top
Carbon fibre breast board
Means for attaching patient
immobilisation devices and a
stereotactic frame to the end of
the couch
Software packages on main
console (MC) and
workstation (WS)
Bone mineral densitometry
CT angiography
Dental
26
ImPACT Dual Slice CT Scanner Comparison v 7.12
Appendix 1: Extended specification comparison
Installation requirements
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Environmental requirements
(max/min temperature, humidity)
in scanner room
20 - 28 ºC,
30 - 70% non
cond. humidity
15 - 30 °C,
relative humidity
40 - 60%
Environmental requirements
(max/min temperature, humidity)
in scanner control room
20 - 28 ºC,
30 - 70% non
cond. humidity
15 - 30 °C,
15-28 ºC,
16 - 28 ºC,
relative humidity
relative air
humidity 40 - 80%
40 - 60%
humidity 15-75 %
Peak heat output from system
during scanning (kW)
System cooling method
Air conditioning requirements for
scanner room of minimum floor
area
Minimum floor area required for
2
the system (m )
Siemens
Emotion Duo
Toshiba
Asteion Dual
18 - 30 ºC,
16 - 28 ºC,
relative humidity
humidity 40 - 80%
15 - 75%,
3.9 (120kV,
300mA, 1s scan
time, 280 scans
per hour)
13.5
4.7
10.6 max
Output to air
Water/water or
water/air
Output to air
Output to air
Recommended
Not required other
than for patient
comfort
None
Not necessary but
recommended
18
25
18, though 22
recommended
20
1850 x 1820 x
911 1190 kg
2050 x 2290 x
980 2100kg
1780 x 770 x
2300 1200kg
1760 x 1970 x
870 1300kg
Dimensions of:
(i) Gantry (H x W x D (mm)) and
weight
(ii) Couch (H xW x L (mm)) and
weight
995 x 650 x 2240 480 x 670 x 2550 890 x 680 x 2260 390 x 620 x 2390
295 kg
500kg
400kg
330kg
(iii) Supplementary units
(H x W x D (mm)) and weight
Power Cabinet:
Power
1800 x 900 x 750
Distribution Unit:
550kg,
820 x 550 x 700,
Cooling Unit:
157kg
1800 x 900 x 750,
500kg
Power supply requirements
3 phase 380480V, 100kVA
3 phase 380480V, 90kVA
ImPACT Dual Slice CT Scanner Comparison v 7.12
None
Transformer:
980 x 800 x 770,
550kg
3 phase 200480V, 48kVA
3 phase 380440V, 75kVA
27
Appendix 1: Extended specification comparison
Independent workstation
Is a workstation provided?
Computer make and model
Operating system
Type and speed of CPU
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
Standard
Standard
(MX VIEW)
Standard
(Leonardo)
Standard
(AlatoView)
Siemens Fujitsu
Pentium 4
Silicon Graphics
O2
NT
Unix
Sun UltraSPARC Silicon Graphics
O2
60
Solaris 2.7
Two 450 MHz
ultraSPARC II
Unix
RISC processor, Pentium (at least
R12000, 300 MHz
300MHz
1.7 GHz)
Amount of computer RAM
(Mbytes):
(i) supplied as standard
1024
1024
1024
1024
(ii) maximum
2048
1024
3072
1024
(i) supplied as standard
36
18
36
27
(ii) maximum
36
18
36
27
MOD or CD-R/W
(optional)
MOD Drive
(Option), CD-R
(Option)
CD-R (standard)
MOD (optional)
MOD (optional)
Total hard disk storage capacity
(Gbytes):
Archive options
MOD: 2.3 (9400
losslessly
Capacity of a single archive disk
compressed
(Gbytes)
512 x 512 images
or 700 raw data
files)
4.1 (15,650
losslessly
compressed
512 x 512
images)
MOD: 4.1Gb
(26,000 losslessly
2.6 (9600
compressed
images) CD-R: 512 x 512 images
- slightly
0.65Gb (4800
compressed)
compressed
images)
256 x 256 matrix
10 - 40 ºC,
Environmental requirements
20 - 80 % relative
(max/min temperature, humidity)
non-condensing
for workstation
humidity at 40 ºC
0 - 40° C
15 - 30 ºC,
16 - 28 ºC,
20 - 85% relative
humidity 40 - 80%
humidity
28
ImPACT Dual Slice CT Scanner Comparison v 7.12
Appendix 1: Extended specification comparison
Image transfer and connectivity
GE NX/i
[and NX/i Pro]
Philips
Mx8000D
Siemens
Emotion Duo
Toshiba
Asteion Dual
100
100
100
100
Optional
Optional EasyWeb
Optional
Optional
Storage SCU and
DICOM service classes provided
SCP,
by CT console (SCP and SCU)
query/retrieve
Storage SCU and
SCP,
query/retrieve,
print
Storage SCU and
SCP,
query/retrieve,
print, modality
worklist
Storage SCU and
print (standard),
storage SCP and
modality worklist
(optional)
DICOM service classes provided Storage SCU and
by Independent workstation
SCP,
(SCP and SCU)
query/retrieve
Storage SCU and Storage SCU and Storage SCU and
SCP,
SCP,
SCP, print,
query/retrieve,
query/retrieve,
query/retrieve
print
print
(standard)
Speed of scanner/workstation
connections to local area
networks (Mbits/s)
Remote PC access to images on
workstation
ImPACT Dual Slice CT Scanner Comparison v 7.12
29
Appendix 2: Image quality assessment and Q
Statistical noise, spatial resolution and slice sensitivity are fundamental parameters
describing the amount of object information retrievable from an image, or its image quality.
X-ray dose can be regarded as a 'cost' of this information. In general, it is meaningless to
quote any one of these measurements without reference to the others. The Q-value
incorporates the dose, noise, spatial resolution and slice width into one number. This figure
is derived from a relationship between image quality and dose received.
A dose efficiency factor has a fundamental meaning, in that a dose efficient scanner will
produce good resolution at minimum dose and noise. However, it can take a number of
forms depending on how the various parameters are measured and quoted.
The Q-value used in this comparison report, Q2, is the same one used in Comparison Report
12 (MDA/00/11), which was modified from the previous value used by ImPACT, Q1.
Q2 is defined as follows:
3
Q2 =
f av
2
σ z1CTDI w
where:
2
σ = image noise, expressed as a percentage for a 5cm region of interest at the centre of the
field of view in the standard ImPACT water phantoms.
fav = spatial resolution, given as (MTF50+ MTF10)/ 2
Where MTF50 and MTF10 are the spatial frequencies corresponding to the 50% and 10%
modulation transfer function values respectively (in line pairs per cm).
z1 = the full width at half maximum (FWHM) of the imaged slice profile (z-sensitivity).
This is measured using the inclined plates method for axial imaging, and using a 0.1mm
thickness, 6mm diameter tungsten disc for helical scanning
CTDIw = weighted CT dose index, as defined in EUR 16262
The Q-factor is in part empirical and it should be used with caution. It is not an absolute
figure, as its derivation relies on assumptions of the shape of convolution filter used.
Comparisons between scanners will be more reliable when comparing scans reconstructed
with similar convolution filters. It is of most importance when considering the standard
scans for head or body. The uncertainty in this value is up to about ±15%, with a
conservative estimate of ±10%.
30
ImPACT Dual Slice CT Scanner Comparison v 7.12
Appendix 3: Manufacturers’ comments
Responses are included from the following manufacturers :
GE Medical Systems
Philips Medical Systems
Siemens Medical Solutions
ImPACT Dual Slice CT Scanner Comparison v 7.12
31
Appendix 2: Manufacturers’ comments
Response from GE Medical Systems
2nd May 2001
ImPACT 2-Slice CT Comparison Reports
Dear Sue
Thank you, for the draft version of the report.
We were pleased with the results of the comparison, which confirm the high image quality
and low dose nature of these scanners.
We are happy that these measurements are representative of the NX/i CT Scanners.
Please note that the horizontal movement range is in fact 160cm, and not 162cm as stated.
The figure of 162cm has been taken from a service manual, as this range is possible in
service mode only
Kind regards
Yours sincerely
Paul Morgan
CT Clinical Scientist
32
ImPACT Dual Slice CT Scanner Comparison v 7.12
Appendix 2: Manufacturers’ comments
Response from Philips Medical Systems
Dear Sue,
Thank you and all the ImPACT team for all your work on producing a thorough Blue Cover
Report for the CT scanner comparison and assessment.
On behalf of Marconi Medical Systems we have no additional comments to make and look
forward to receiving a hardback copy and working with you all in the future.
Best Regards
Derek Tarrant
CT Product Manager
Marconi Medical Systems UK
28/05/01
ImPACT Dual Slice CT Scanner Comparison v 7.12
33
Appendix 2: Manufacturers’ comments
Response from Siemens Medical Solutions
10/05/01
ImPACT Comparison Reports; Manufacturer's Response
Dear Sue,
Thank you for your invitation to respond to the ImPACT Comparison report. Firstly, we
would like to acknowledge the work and effort that you and your team have put into these
reports. Tremendous efforts have been made by all involved to deal with this.
Of course specifications are changing as each CT system evolves. For example the Emotion
CT system is now delivered with a new filter which results in reduced dose. Thus, I realise
it is simply not possible to provide a continuous comprehensive report with the rate of
change taking place. So I think it is reasonable to recognise the work done and propose not
to comment on, for example, specifications that may have changed between original report
and this version of the publication in relation to each individual system.
However, whilst you do not wish for a detailed response from us, there is one general
aspect we would wish to highlight in some reasonable detail and I hope that you agree that
this is appropriate. I am referring to the 'Q' factor, which reduces a complex issue of image
quality to a single number combining spatial resolution, dose and noise level at the centre of
rotation. We note that you do point out the limitations of the 'Q' factor in the appendices,
however, it could be possible for some clinical teams to take this factor and regard it as a
categorical statement regarding dose efficiency. Perhaps I could focus on the Volume
Zoom, though this would affect any system. Since this 'Q' factor places the Volume Zoom
in a ranking amongst different manufacturers in a poor position, we believe that the
performance of this system in delivering outstanding clinical images is not properly
reflected in this ranking.
We look forward to continuing to work with you in the future.
Yours sincerely
David Forrest
Product Manager CT
34
ImPACT Dual Slice CT Scanner Comparison v 7.12
Appendix 4: ImPACT and the MDA
Background
One of the roles of the Medical Devices Agency (MDA) is to fund evaluation programmes
for medical devices and equipment. The programme includes evaluation of x-ray
Computed Tomography Equipment currently available on the UK market.
MDA aims to ensure that evaluation techniques keep abreast of improvements in CT
imaging performance and that MDA reports present evaluation information that is timely,
useful and readily understood.
ImPACT
ImPACT (Imaging Performance Assessment of Computed Tomography) is the MDA's CT
evaluation facility. It is based at St George's Hospital, London, part of St George's
Healthcare NHS Trust.
ImPACT have developed test objects and measurement procedures suitable for intercomparing CT scanner performance. For each CT evaluation hundreds of images are
obtained from the system under test and subsequently analysed using custom written
software. Dose measurements are made using ion chambers, and x-ray film is used to obtain
additional x-ray dose information.
Members of ImPACT contributing to and writing this report: N. Keat, A. L. Hill, M. A.
Lewis, J. F. Barrett and S. Edyvean (ImPACT Group Leader).
MDA support to purchasers and users
The ImPACT team is available to answer any queries with regard to the details of this
report, and also to offer general technical and user advice on CT purchasing, acceptance
testing and quality assurance.
ImPACT
Bence-Jones Offices
St. George's Hospital
London SW17 0QT
Tel: 020 8725 3366
Fax: 020 8725 3969
email: [email protected]
web site: http://www.impactscan.org
MDA contact point for general information on the CT evaluation programme:
Debbie Smith
Programme Manager
Room 1207, Hannibal House
Elephant and Castle
London SE1 6TQ
Tel: 020 7972 8155
Fax: 020 7972 8105
35
ImPACT Dual Slice CT Scanner Comparison v 7.12
MEDICAL DEVICES AGENCY
MDA Evaluation Reports
MDA evaluation reports are published by the Medical Devices Agency, an Executive Agency of the Department of
Health. They are available free of charge to the UK National Health Service (NHS), and are for sale to commercial
organisations and other interested parties. A free catalogue of available reports can be obtained from the Orders
Department, or downloaded from the MDA web site:
http://www.medical-devices.gov.uk
Ordering
Send your order to the address given below, stating the number, title and quantity of each report required. Your
reports will be despatched by second class post the following working day. If you are not a representative of the
NHS, you will be invoiced separately. Non-NHS customers are reminded that it is not possible to offer refunds for
reports ordered in error.
Orders Department
Room 1207
Medical Devices Agency
Hannibal House
Elephant and Castle
London
SE1 6TQ
Tel:
Fax:
E-mail:
020-7972 8181
020-7972 8105
[email protected]
Enquiries
General publication enquiries should be directed to the Orders Department:
Tel: 020-7972 8181
Fax: 020-7972 8105
E-mail: [email protected]
ISBN 1 84182 556 5
Smart number 36 27707 1