Quality Control Testing GE Digital Mammography Systems

71 Pages·2007·1.25 MB·English

by  John Sandrik

Quality Control Testing
of
GE Digital Mammography
Systems
John M. Sandrik, Ph.D.
GE Healthcare
Milwaukee, WI
[email protected]
GE Healthcare 2007
Day 2: Overview
General considerations
•
The QC tests
•
Tests also done by Rad. Tech.
–
Flat Field and Phantom Image Quality
•
MTF and CNR
•
AOP and SNR
•
Tests that need no introduction
–
kVp Accuracy and Reproducibility
•
Beam Quality Assessment (HVL)
•
Radiation Output
•
Mammo. Unit Assembly Evaluation
•
GE Healthcare 2007
Day 2: Overview (cont’d.)
The QC tests
•
FFDM-specific, FFDM-modified tests
–
Collimation Assessment / “Film-less”
•
Evaluation of Focal Spot Performance
•
Sub-system MTF
•
Ent. Exposure, Avg. Glandular Dose
•
Artifact Eval., Flat Field Uniformity
•
View Conditions Check and Setting
•
Monitor Calibration
•
Image Quality–SMPTE Pattern
•
Display Screen Uniformity
•
GE Healthcare 2007
General Considerations
GE Healthcare 2007
Protecting the Detector
Repeated imaging of a stationary
•
object may lead to formation of
“ghost” image.
(2.5 mm thick)
E.g., HVL, kVp tests.
–
Cover detector with
•
steel & lead plate 235
mm
(provided) when
images not needed.
233 mm
GE Healthcare 2007
Order of Performing Tests
1. Flat Field test (RT Test, Chap. 1)
but not Phantom IQ tests.
–
2. Artifact Evaluation; Flat Field
Uniformity (MP Test, Chap. 2)
3. Remaining tests
including Phantom IQ tests, Chap. 1
–
Minimize artifacts caused by testing.
GE Healthcare 2007
Analyzing Images
Images displayed after acquisition
•
are in logarithmic format.
Labeled “Proces” in Browser.
–
Quantitative tests must be performed
•
on “Raw” images.
CNR Test
–
MTF Measurements
–
AOP Mode and SNR Check
–
Automatic image selection for RT
Tests on Seno DS and Essential
GE Healthcare 2007
Raw or Processed Image?
Annotation Level
“Full” or “Partial”
Processing Description
• “PROC_0,” “PROC_1,”
etc., then Processed
• None, then Raw
GE Healthcare 2007
Seno DS & Essential: FineView
From the QC Manual:
“… a physicist’s measurements (e.g. MTF and noise)
performed using methods other than those described in
this manual can be affected when FineView processing
is applied.”
• FineView compensates for the detector MTF.
• With FineView enabled, measurement
procedures differing from the QC Manual or
QAP Tool may give unexpected results.
• Disable Fine View for Sub-system MTF.
Check FineView before doing independent tests.
GE Healthcare 2007
The QC Tests
Tests also done by Rad. Tech.
GE Healthcare 2007