Quality Control
Siemens MAMMOMAT NovationDR
Donald Jacobson, Ph.D.
Asst. Adjunct Professor, Radiology
Medical College of Wisconsin
Milwaukee, WI
drj@mcw,edu
414-805-3163
Siemens
Opdose
W or Mo target
Mo or Rh
(tilted) filter
Effective X-ray Energy
Target
Mo
Mo
Rh
Mo
Rh
W
Filter
Mo
Rh
Rh
Al
Al
Rh
kVp
22
14.1
24
14.6
15.4 14.7
26
14.9
15.8 15.7
17.6
17.8
28
15.4
16.2 16.2
17.8 18.5
18.4
30
15.7
16.5 16.6
18
32
16.9
18.9 18.6
18.1 19.1
on-off
on-off
Flex paddles are
optional, additional to
standard paddles
Cone or tapered
paddle for
MLO view
20 x 22 cm FOV
The measurement devices listed below must always display a valid calibration stamp to ensure
compliance with the described measurement and calibration intervals.
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Mammography line pair phantom (2-10 lp/mm)
3 x 20 mm plexi (PMMA) phantom (10x10 cm)
Test phantom (RMI model 156 or Nuclear Associates model 18-220)
One collimator mounted plexi (4 cm thick) absorber
Three plexi (PMMA) absorbers, each with a thickness of 20 mm
Lint free non-woven cotton or gauze (100% cotton)
Water or lukewarm diluted aqueous solution of household dishwashing liquid
Luminance/Illuminance meter
Densitometer
A non-invasive digital kV meter
Dose meter calibrated at the mammography X-ray beam energies
Film or CR cassette 24x30 cm or larger
Magnification table
Compression plate (set for a 1.5 magnification)
Compression plate simulator*
2 mm steel plate (FD object table size)
2 mm thick steel bars (approx. 3 x 10 cm)
Six sheets of 99.9% pure aluminum
Four coins
Four paper clips
Timer
Ruler with a mm scale
SMPTE pattern, AAPM TG18 test images
* Provided with every system. Testing device allows exposures to be performed without compression plate
attached. Detach compression plate and insert metal plug compression plate simulator.
4 cm acrylic attenuator
Compression plate
simulator
Grid
Quality Control Manual
MAMMOMAT NovationDR
Version 03, dated
10/05 or
Version 04 dated
01/06 or
Version 05, dated
04/07
Version 4 adds
SNR & CNR for
T weekly
Compression force
semi-annually
Repeat rate
quarterly
3. Start up and Login Procedure
CAUTION!
If the MAMMOMAT is started from being completely shut down (for details about complete shut down, see
Instructions for Use for MAMMOMAT NovationDR) the detector should be powered on at least 1 hour before intended use.
Otherwise, detector image quality can be affected.
The start-up time can be shortened to approximately 5 minutes if the MAMMOMAT is started from the standby mode
(for details about the standby mode, see Instructions for Use for MAMMOMAT NovationDR).
1.
Press the enable button ( ) on the control panel to enable the MAMMOMAT. Allow a warm up time of approximately 5 minutes.
The internal monitoring system automatically performs a functional check of the MAMMOMAT.
A “DR” is displayed on the density display on the control panel to indicate that the
MAMMOMAT NovationDR system is operational.
2.
Switch ON the acquisition workstation if it is off. Otherwise proceed to step # 3.
NOTE!
A message about warming-up of the detector might be displayed. If the detector has been ON for more than 60 minutes, dismiss.
Otherwise, wait for the detector to warm up. Every other week, a message about calibration of the detector is displayed.
If the detector has been calibrated within the intervals described in the chapter: “Calibrating the detector” in the
MAMMOMAT NovationDR Instructions for Use, dismiss. Otherwise, perform a calibration procedure according to the same chapter.
3.
Login to the acquisition workstation’s operating system as apps-level user.
4.
Sign in to the DirectRay FFDM Acquisition Station software, see chapter “Signing in to the DirectRay FFDM Acquisition Station
software” in the MAMMOMAT NovationDR Instructions for Use.
User name: mammo
Password: mammo
Patient menu
task
cards
Test 4.1 Detector calibration
4.2 Artifact detection (field flatness)
Test 4.1 Detector calibration
4.2 Artifact detection (field flatness)
Test 4.3 Acquisition workstation monitor check
SMPTE
test
pattern
5%, 95% squares
high contrast lines
visual evaluation
Test 4.4: Mechanical Inspection and Follow up
18 safety and operational checks
Test 4.5: Collimator Assessment
(from
the film)
(from
the digital
image)
Light field illuminance
> 160 lux
Test 5.2: Chest Wall Missed Tissue (Optional)
(Not optional)
Measure diameter and imaged portion of coin
this is called “α"
Test 4.6: Compression Plate Position
Make an image of
each paddle to
make sure it is not
visible at the chest
wall.
< 6.5 mm
this is called “α"
Test 4.7: Spatial Resolution
AEC, on 4 cm plexiglas
> 7 lp/mm
Test 4.8: Phantom Image Quality
RMI 156 phantom
Place flush
5
4
4
Test 4.9: Detector Uniformity
< 10%
deviation
from mean
of means.
Test 4.10
Radiation Output Rate > 800 mR/sec
Test 4.11: Tube Voltage Measurement & Reproducibility
Use non-invasive kVp meter
Place on the 2 mm steel plate
accy < 5%, CV < 2%
Test 4.12: Beam Quality (HVL)
Use spot compression plate (not mag. paddle)
to hold Al sheets (99.9% pure)
all anode-filter combinations
> 0.28 mm Al (at 28 kVp)
Test 4.13: Mean
glandular dose
< 3 mGy required
< 2 mGy desired
(for both H and
D modes)
Phantom should be centered L-R
Opdose
AEC mode
Use Program 2 for phantom imaging (W/Rh 27-28 kVp). H and D modes.
PMB 45 (2000)
3225-3240
Patient Radiation Dose
Average glandular dose
Dg (mrad) = exp x HVL x 1/T x 2.1
exp in mR
HVL in mm Al
Thickness (T) in cm
100 mrad = 1 mgrey (mG)
Jacobson, DR. Radiographic Exposure Calculator and Mammographic Dose
Calculator. Radiology, 1992; 182:578-580
Test 4.14: SNR and AEC reproducibility
Place flush, expose 5 times
AUTO mode
Sensor posn. 2
SNR =
meanb – 50
SDb
mAs
exp.
<pix>
SNR
Test 4.15: SNR and CNR Measurements
SNR > 40
SNR, CNR dev within + 15%
of baseline value
SNR = meanb – 50
SDb
CNR =
meanb – meanm
SDb
Test 4.16: AEC Thickness Tracking Test
2,4,6 cm (24,26,28 kVp)
SNR > 40
Deviation < 15% from mean of the means
Place flush
Test 4.17: Printer check
Follow Siemens or camera manufacturers instructions
Print SMPTE pattern, measure 11 optical densities
“If your values do not meet the values specified above, then please refer
to the printer manufacturer’s quality control procedure. You can create
your own baseline with the measured values that result from the initial
install of the printer that was installed according to the manufacturer’s
QC procedure.”
syngo
MammoReportPlus
syngo
MammoReportPlus
User name: mammo
Password: mammo
SCR Administration
Equipment needed:
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Ruler
Luminance meter
Illuminance meter
Magnification lens
Test images (installed on Mammotest Plus)
• Multi: TG18-QC
• glare: TG18-GQ, -GQB, -GQN
• lumin: TG18-LN12-01, -LN12-18, -UNL10, -UNL80
• noise: TG18-AFC
Mammo Report QC Tests
1. Reflection
2. Overall evaluation
3. Geometric distortion (CRT only
4. Luminance response
5. Luminance uniformity
6. Resolution
7. Noise
Acceptance and annual testing – MP – tests 1-7
Daily – RT/Rad. – tests 1-2
Technologist performs daily (pass/fail)
Test 3: Geometric distortion
Illuminance refers to light falling on the screen.
Lamb is ambient diffuse illuminance
Loff is reflected Lamb with monitor o
Luminance refers to light
emitted from the screen.
Must supply own light meter.
Test 4: Luminance response
Ambient light should be < 10 lux.
Lmin should be < 1.0 cd/m2 (TG18-LN-12-01)
Lmax should be > 250 cd/m2 (TG18-LN-12-18)
LR = Lmax / Lmin > 250
(Lmax, left –LLmax.right ) / Lmax. left. < 10%
Loff should be < 0.6 Lmin
Test 5: Luminance Uniformity
Maximum deviation: (Lmax – Lmin) / Lcenter should be < 30%.
TG18-UNL10
TG18-UNL80
Test 6: Resolution
Evaluate TG18-QC.
CX pattern.
x
x
Test 7: Noise
Evaluate TG18-AFC.
Visualization of all targets in 3 quadrants of the pattern
AFC (alternative forced choice)