Siemens SOMATOM Sensation 16 User guide

SOMATOM Sensation 16
Application Guide
Routine Protocols
Software Version A50

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The information presented in this application guide
is for illustration only and is not intended to be relied
upon by the reader for instruction as to the practice
of medicine Any health care practitioner reading this
information is reminded that they must use their own
learning, training and expertise in dealing with their
individual patients
This material does not substitute for that duty and is
not intended by Siemens Medical Solutions Inc , to
be used for any purpose in that regard The drugs and
doses mentioned herein were specified to the best
of our knowledge We assume no responsibility whats-
over for the correctness of this information
Variations may prove necessary for individual patients
The treating physician bears the sole responsibility
for all of the parameters selected The pertaining oper-
ating instructions must always be strictly followed
when operating the SOMATOM Sensation 16 The
statutory source for the technical data are the corres-
ponding data sheets
To improve future versions of this application guide,
we would highly appreciate your questions, suggestions
and comments
Please contact us:
CT Application Hotline:
Tel no [phone] (outside Germany)
0130-18 53 91 (in Germany)
Fax no [phone]
email: somatom examinationprotocol@siemens com
We express our sincere gratitude to the many customers
who contributed valuable input In addition I would like
to stress at this point that the SOMATOM Sensation 16
Application Guide is based very much on the other
SOMATOM Application Guides which have been written
by Dr Xiao-Yan Chen and Loke-Gie Haw
Special thanks to Dr med Martin Heuschmid,
Universitätsklinikum Tübingen
Editor: Bettina Klingemann

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3
Overview
General 8
Children 24
Head 70
Neck 86
Shoulder 94
Thorax 98
Abdomen 112
Pelvis 126
Spine 132
Extremities 138

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Content
General 8
· Concept 8
· Scan Set Up 9
· Scan and Reconstruction 9
– Slice Collimation and Slice Width 9
– Pitch 11
– Recon Job 11
– Kernel 12
– Image Filter 12
· Effective mAs 13
· Dose Information 14
– CARE Dose 17
– How Does It Work 17
· Workflow 19
– Auto Load in 3D and
Postprocessing Presets 19
· Contrast Medium IV Injection 20
· How to Create your own Scan Protocols 21
Children 24
· Overview 24
· Hints in General 26
· Head Spi 30
· HeadSeq 32
· SinusRoutine 34
· SinusMPR 36
· InnerEarSeq 38
· InnerEarSpi 40
· HeadAngio 42
· NeckRoutine 44
· CarotidCTA 46
· NeonateBody 48
· ChestRoutine 50
· ChestCombi 52
· ThoraxSeqHR 54
· AbdPelRoutine 56
· AbdCTA 58
· SpineSpiral 60
· SpineMPR 62
· ExtremitySpiral 64
· ExtremityUHRSeq 66
· ExtremityUHRSpi 68

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Content
Head 70
· Overview 70
· Hints in General 71
· AngioHead 72
· AngioThinSlice 74
· HeadSeq 76
· HeadSpi 78
· InnerEarSeq 80
· InnerEarSpi 82
· OrbiSinusSpi 84
Neck 86
· Overview 86
· Hints in General 87
· AngioCarotid 88
· NeckRoutine 90
· ThinSliceSpi 92
Shoulder 94
· Overview 94
· Hints in General 95
· ShoulderSpi 96
Thorax 98
· Overview 98
· Hints in General 99
· LungLowDose 100
· PulmonaryEmboli 102
· ThoraxCombi 104
· ThoraxRoutine 106
· ThoraxHiRes 108
· ThoraxSeqHiRes 110
Abdomen 112
· Overview 112
· Hints in General 113
· AbdRoutine 116
· AbdThinSlice 118
· AbdMultiPhase 120
· AngioFast 122
· AngioRoutine 124

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Content
Pelvis 126
· Overview 126
· Hints in General 127
· HipSpi 128
· PelvisRoutine 130
Spine 132
· Overview 132
· Hints in General 133
· RoutineSeq 134
· ObeseSeq 135
· SpineSpi 136
· ThinSliceSpi 137
Extremities 138
· Overview 138
· Hints in General 139
· AngioRunOff 140
· CombiSpi 142
· ExtrUHRSeq 144
· ExtrUHRSpi 146

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Content

8
General
Concept
The scan protocols for adult are defined according
to body regions – Head, Neck, Shoulder, Thorax,
Abdo en, Spine, Pelvis, Extre ities.
The pediatric scan protocols are defined under the
folder “Children“.
The protocols for special applications are defined
under “Special“ (please refer to the Application Guide
for Special applications)
The general concept is as follows:
“Fast“: uses 1 5 mm slice collimation and a higher
pitch for fast acquisition for CT Angios or trauma
cases
“Routine“: uses either 0 75 mm or 1 5 mm slice colli-
mation depending on the region of interest for routine
studies
“ThinSlice“: uses 0 75 mm slice collimation for thin
slice studies
“HiRes“: uses 0,75 mm slice collimation and rotation
time of 0 75 s for High-resolution studies
“UHR“: uses a 0 75 mm slice collimation in Spiral mode
and a 0 6 mm slice collimation in Sequence mode,
a rotation time of 0 75 s and a scan FOV of 250 mm for
ultra-high resolution studies
“Co bi“: uses 0 75 mm as slice collimation and
reconstruct images as both thinner slice width for HiRes
or CTA and thicker slice width for soft tissue studies
“Seq“: stands for Sequence E g “HeadSeq“ means the
sequence mode for the head; “Spi“ stands for “Spiral“
E g “HeadSpi“ means the spiral mode for the head

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General
Scan Set Up
Scans can be simply set up by selecting a predefined
examination protocol To repeat any mode, just click
the chronicle with the right mouse button for “repeat”.
To delete it, select “cut“. Each chronicle is rewriteable
before “load“.
Multiple ranges can be run either automatically with
“auto range“, or separately with a “pause” in between
Scan and Reconstruction
Slice Colli ation and Slice Width
Slice collimation is the slice thickness collimated by the
tube collimator, which determines the Z-coverage per
rotation In multislice CT, this is divided by the number
of active detector channels (e g 16 x 0 75 mm)
Slice width is the true thickness of the reconstructed
image
With the SOMATOM Sensation 16, you select the slice
collimation together with the slice width desired, the
slice width is independent of pitch and algorithm, i e
what you select is always what you get Actually, you
do not need to care about the algorithm any more; the
software does it for you
On the SOMATOM Sensation 16 some slice widths
are marked as “fast” (blue background) These images
will be reconstructed with highest performance (up
to 6-10 images per second) All others will be recon-
structed with up to 3 images per second
The reconstruction time depends on slice collimation
and the reconstructed slice width To get the fast
performance, slice width has to be at least 3 times the
slice collimation

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General
During scanning the user normally will get “Real time”
reconstructed images in full image quality, if the “fast”
slice has been selected
In some cases – this depends also on Scan range, Feed/
Rotation and Reconstruction increment – the Recon
icon on the chronicle will be labeled with “RT” This indi-
cates the Real time display of images during scanning
The Real time displayed image series has to be recon-
structed afterwards
The following tables show you the possibilities of image
reconstruction in spiral and sequential scanning
Slice Colli ation and Slice Width for Spiral Mode
12*/16** x 0 75 mm 0 75, 1, 1 5, 2, 3, 4, 5, 6, 7,
8, 10 mm
12*/16** x 1 5 mm 2, 3, 4, 5, 6, 7, 8, 10 mm
Cardio Spiral Modes
12 x 0 75 mm 0 75, 1 0, 1 5, 2,3 mm
12 x 1 5 mm 2, 3, 4, 5 mm
Slice Colli ation and Slice Width for
Sequence Mode
12 x 0 75 mm 0 75, 1 5, 3, 4 5, 9 mm
12 x 1 5 mm 1 5, 3, 4 5, 6, 9 mm
2 x 5 mm 5, 10 mm
Perfusion Modes
12 x 1 5 mm 6, 9, 18 mm
16 x 1 5 mm 12mm
ECG triggered Modes
12 x 0 75 mm 0 75, 1 5, 3 mm
12 x 1 5 mm 1 5, 3, 6 mm
UHR Modes
2 x 0 6 mm 0 6 mm
2 x 1 mm 1, 2 mm
* For all Spiral Modes using 0.42 sec or 0.75 sec
Rotation Time.
** For all Spiral Modes using a 0.5, .0 or .5 sec
Rotation Time (exception : Cardio Protocols).

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General
Pitch
In single slice CT:
Pitch = table movement per rotation/slice collimation
E g : slice collimation = 5 mm, table moves 5 mm
per rotation, then pitch = 1
With the SOMATOM Sensation 16, in Siemens multi-
slice CT, we differentiate between:
Feed/Rotation, the table movement per rotation
Volu e Pitch, the table movement per rotation/single
slice collimation
E g : single slice collimation = 1 5 mm, table moves
24 mm per rotation, then the Volume Pitch = 16
Pitch Factor, the table movement per rotation/
collimation
E g : slice collimation = 16 x 1 5 mm, table moves
24 mm per rotation, then the Pitch Factor = 1
With the SOMATOM Sensation 16, you do not need to
select pitch Once the scan range, scan time, slice colli-
mation, and rotation time is defined, the software will
adapt the table feed per rotation accordingly The Pitch
Factor can be freely adapted from 0 5 to 1 5
Recon Job
In the Recon card, you can define up to 3 reconstruction
jobs with different parameters either before or after
you acquire the data When you click on “Recon“, they
will all be done automatically In case you want to add
another recon job, simply click the little icon on the
chronicle with the right mouse button and select “delete
recon job“ to delete the one which has been completed,
and then one more recon job will be available in the
Recon card
(Note: what you delete is just the job from the display,
not the images that have been reconstructed)
You can also reconstruct images for all scan modes
completed at once – do not select any chronicle before
you click “Recon“

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General
Kernels
There are 5 different types of kernels: “H“ stands for
Head, “B“ stands for Body, “U“ stands for Ultra High
Resolution, “C“ stands for ChildHead, and “S“ stands
for Special Application, e g , Osteo CT
The image sharpness are defined by the numbers –
the higher the number, the sharper the image; the
lower the number, the smoother the image
Note: Do not use different kernels for other body parts
than designed for
I age Filter
There are 4 different filters available:
PFO: To reduce beam-hardening artifacts in head
images, particularly in the base of the skull, use the
Posterior Fossa Optimization (PFO) filter
ASA: The Advanced Smoothing Algorithm (ASA) filter
reduces noise in soft tissue while edges with high con-
trast are preserved
LCE: The Low-contrast enhancement (LCE) filter
enhances low-contrast detectability It reduces the
image noise
HCE: The High-contrast enhancement (HCE) filter
enhances high-contrast detectability It increases the
image sharpness

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General
Effective mAs
In sequential scanning, the dose (Dseq) applied to the
patient is the product of the tube current-time (mAs)
and the CTDIwper mAs:
Dseq = DCTDIwx mAs
In spiral scanning, however, the applied dose (Dspiral)
is influenced by the mAs (mA x Rot Time) and in addi-
tion by the Pitch Factor For example, if a Multislice CT
scanner is used, the actual dose applied to the patient
in spiral scanning will be decreased when the Pitch
Factor is larger than 1, and increased when the Pitch
Factor is smaller than 1 Therefore, the dose in spiral
scanning has to be corrected by the Pitch Factor:
Dspiral = (DCTDIwx mA x Rot Time)/Pitch Factor
To make it easier for the users, the concept of the
effective mAs was introduced with the SOMATOM
Multislice scanners
The effective mAs takes into account the influence of
pitch on both the image quality and dose:
Effective mAs = mAs/Pitch Factor
To calculate the dose on the SOMATOM Sensation 16,
you simply have to multiply the CTDIwper mAs with the
effective mAs of the scan:
Dspiral = DCTDIwx effective mAs
For spiral scan protocols, the indicated mAs is the effec-
tive mAs per image The correlation between tube
current mA and effective mAs of spiral scans on a Multi-
slice CT scanner is given by the following formula:
Effective mAs = mA x RotTime/Pitch Factor
Pitch Factor = Feed/Rot
nrow x Slice collimation
mA = effective mAs x Pitch Factor
RotTime
where collimated Slice refers to the collimation of one
detector row, and nrow is the number of used detector
rows

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General
Dose Information
The dose as described by CTDIwis displayed on the user
interface for the selected scan parameters The CTDIw
is measured in the dedicated plastic phantoms – 16 cm
diameter for head and 32 cm diameter for body (as
defined in IEC 60601 – 2 – 44) This dose number gives
a good estimate for the average dose applied in the
scanned volume as long as the patient size is similar to
the size of the respective dose phantoms
Since the body size can be smaller or larger than
32 cm, the CTDI value displayed can deviate from the
dose in the scanned volume
The CTDIwvalue does not provide the entire information
of the radiation risk associated with CT examination
For the purpose, the concept of the “Effective Dose“ was
introduced by ICRP (International Commission on
Radiation Protection) The effective dose is expressed
as a weighted sum of the dose applied not only to the
organs in the scanned range, but also to the rest of the
body It could be measured in whole body phantoms
(Alderson phantom) or simulated with Monte Carlo
techniques
The calculation of the effective dose is rather compli-
cated and has to be done by sophisticated programs
These have to take into account the scan parameters,
the system design of individual scanner, such as x-ray
filtration and gantry geometry, the scan range, the
organs involved in the scanned range and the organs
affected by scattered radiation For each organ, the
respective dose delivered during the CT scanning has
to be calculated and then multiplied by its radiation
risk factor Finally the weighted organ dose numbers
are added up to get the effective dose

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The concept of effective dose would allow the com-
parison of radiation risk associated with different CT or
x-ray exams, i e different exams associated with the
same effective dose would have the same radiation risk
for the patient It also allows comparing the applied
x-ray exposure to the natural background radiation,
e g 2 – 3 mSv per year in Germany
For most of our scan protocols, we calculated the
effective dose numbers for standard male* and female*
and listed the result in the description of each scan
protocol
The calculation was done by the commercially available
program “WinDose“ (Wellhoefer Dosimetry) – as shown
in figure 1 – 3
For pediatric protocols, we used the WinDose calcula-
tion and the correction factors published in “Radiation
Exposure in Computed Topography“**, in which there
only the conversion factors for the age of 8 weeks and
7 years old are available
General
Fig. : User interface of the PC program WinDose.
All parameters necessary for the effective dose calcu-
lation have to be specified.

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General
Fig. 2: A graphic interface of WinDose allows to
specify the anatomical scan range.
Fig.3: Results as output of WinDose with the organ
dose readings and the effective dose according
to I RP26 (previous version) and I RP60 (currently
valid).
* The alculation of Dose from External Photon
Exposures Using Reference Human Phantoms and
Monte arlo Methods. M. Zankl et al. GSF report
30/91
** Radiation Exposure in omputed Topography,
edited by Hans Dieter Nagel, published by O IR
c/o ZVEI, Stresemannallee 19, D-60596, Frankfurt,
Germany.
Please note: Effective dose values were calculated with
the WinDose™Software Version 2.1, which was opti ized
for SOMATOM Volu e Zoo scanners. SOMATOM
Sensation 16 has odified shaped filters which ight
cause slightly different effective dose nu bers (differ-
ence not expected to be ore than 5%).
An update of WinDose for the SOMATOM Sensation 16
is currently developed.

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General
CARE Dose
CARE Dose is a clinical application package that pro-
vides real-time tube current modulation for Spiral and
Sequential Scanning
CARE Dose reduces patient dose significantly, espe-
cially in the regions of shoulder and pelvis It decreases
tube load, which extends the capacity for volume scan-
ning with thinner slices, larger volumes or Multi-phase
studies
It can also improve image quality by increasing mA
and thus reducing image noise on the lateral views
How Does it Work
It reduces the mA for low attenuation views up to 90%
and keeps the nominal higher mA for high attenuation
views, e g in the lateral projection (Fig 4) This is done
“on-the-fly”, i e the scanner adapts the mA in real-time,
according to the patient’s attenuation profile (Fig 5)
Fig. 4: Example of scanning in the region of shoulder.
High
attenuation,
high A
Low attenuation,
low A

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General
Fig. 5: Principle of CARE Dose tube current adaptation.
• CARE Dose is pre-selected by default for all standard
protocols It can be switched on/off in the scan card
• The application of CARE Dose does not require any
changes in the scan parameters The mean value
of the mAs applied will be lower than what you have
selected
• The mean value of the effective mAs applied is shown
in the image text

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General
Workflow
Auto Load in 3D and Postprocessing Presets
If there are examinations, where you always do some
3D evaluation after the scanning, you can activate on
the Examination Card/Auto Tasking for this recon job
the Auto load in 3D Choose from the pull down menu
the Postprocessing type When this reconstruction job
is done, the images will be automatically loaded into
the 3D Card on the Navigator with the corresponding
Postprocessing type
On the 3D Card you have the possibility to create for
MPR and MIPthin Range Parallel protocols which can
be linked to a special series
For example, if you always do some sagittal Multiplanar
Reconstructions for a Spine examination, you load once
a Spine examination into the 3D Card Select the image
type (MPR, MIPthin), select the orientation and open
the Range Parallel function Adapt the range settings
(Image thickness, Distance between the images etc )
and hit the link button From now on, you have a pre-
defined Postprocessing protocol, linked to the series
description of a Spine examination
Exactly the same can be done for VRT presets In the
main menu, under Type/VRT Definition, you can link
VRT presets with a series description

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General
Some of the Scan protocols, mainly for Angio exami-
nations, are already delivered with Auto load in 3D
If you do not like, please deselect the Auto load in 3D
and save your scan protocol
Some of the Scan protocols are delivered with links
to a Postprocessing protocol If you do not like our
suggestions, please delete the Range Parallel preset or
overwrite them with your own settings
Contrast Medium IV Injection*
The administration of a contrast medium depends on
the indication and on the delay times to be used during
the examination The patients weight and circulatory
situation also play a role In general, no more than
3 ml per kg of body weight for adults and 2 ml per kg
of body weight for children should be applied
As a rule of thumb, the contrast medium injection
should be stopped when the scan (or acquisition)
is finished Keep this in mind, you may save contrast
medium in your routine study since the multislice
spiral scan can be up to 32 times faster than a 1 second,
single slice spiral scan
For CTA study (arterial phase), the principle is to keep
contrast injection for the whole scan Thus, the total
amount of contrast medium needed should be calcu-
lated with the following formula:
CM = (start delay time + scan time) x flow rate
CARE Bolus or Test Bolus may be used for optimal
contrast bolus timing Please refer to the Application
Guide for special protocols
* For more information regarding the general use
of drugs and doses mentioned in this guide, please
refer to page 2.