1. Gamma Camera Quality Control
Without adequate quality control, the functional reliability of a nuclear medicine facility is in doubt.
Frank P. Dawry
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2. Quality Control: A Crucial Component In Ensuring Quality Patient Care
Routine conduction of equipment quality control is a necessity for ensuring quality patient care by establishing quality imaging.
All instrumentation specific to the operations of a nuclear medicine facility must undergo quality control testing on a regular basis to assure reliability and safety.
Quality patient care can only be achieved if optimal diagnostic accuracy is demonstrated through appropriate quality control procedures.
According to published guidelines written by
the American Society of Nuclear Cardiology (ASNC),
the Joint Commission on the Accreditation of Healthcare Organizations (JCAHO),
the Society of Nuclear Medicine (SNM),
as well as radiation safety guidelines issued by the Nuclear Regulatory Commission (NRC), agreement states and other radiology societies,
quality control of equipment must be performed routinely and documented.
Frank P. Dawry
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3. Quality Control testing The routine assessment of an instrument in order to confirm acceptable system performance
Part of an overall nuclear medicine quality assurance program
Survey meter calibration
Dose calibrator QC testing
Scintillation (thyroid) probe testing
Scintillation camera QC testing
Computer software testing
Monitor performance testing
Staff performance
‘Outcomes’ testing
Frank P. Dawry
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4. Standards NEMA – National Electrical Manufacturers Association
Establishes definitions, quantitative measurements of performance characteristics and reporting techniques for the specification of scintillation camera parameters
Spatial linearity
Energy resolution
Flood field uniformity
Spatial resolution (intrinsic and extrinsic)
System alignment
SPECT reconstructed spatial resolution
Whole body spatial resolution
Multiple window spatial registration
Count rate performance
System sensitivity
Detector shielding
Detector sensitivity
System volume sensitivity
Performed during acceptance testing prior to first use
Verified during total system evaluation annually
Frank P. Dawry
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5. Routine Camera Quality Control procedures
Daily
Visual checking the energy spectrum – “peaking”
Evaluating the system performance with flood sources – “daily floods”
Weekly
Checking the spatial resolution with a bar phantom
Checking the system linearity with a bar phantom
Correcting for system and collimator non-uniformities
Performing camera uniformity analysis
Monthly
Checking the center of rotation for tomographic scans
System sensitivity
Frank P. Dawry
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6. Scintillation Camera Performance
Extrinsic, or System measurements – with the collimator attached
Give the best indication of clinical performance
Intrinsic measurements– with the collimator off
Useful for comparing the performance of different cameras because they uncouple the camera performance from the collimator performance
Frank P. Dawry
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7. Camera operation James R Halama, PhD Loyola UniversityMedical Center
Frank P. Dawry
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8. Camera operation James R Halama, PhD Loyola UniversityMedical Center
Frank P. Dawry
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9. Camera operation James R Halama, PhD Loyola UniversityMedical Center
Frank P. Dawry
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10. Camera operation James R Halama, PhD Loyola UniversityMedical Center
Frank P. Dawry
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11. Camera operation James R Halama, PhD Loyola UniversityMedical Center
Frank P. Dawry
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12. Frank P. Dawry
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13. Uniformity
The measure of a camera’s response to a uniform irradiation of the camera surface.
Intrinsic uniformity is measured using a radionuclide point source (~150 uCi Tc-99m) placed approximately 5 crystal diameters away from an uncollimated camera
System or Extrinsic uniformity is measured using a sheet source placed directly on the surface of a collimated camera
5 to 10 millicuries (mCi) of Co-57 or
25 mCi Tc-99m in fillable-water tank.
Frank P. Dawry
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14. Sheet Sources 57Co Sheet Source T1/2 = 270 days 122 keV
10-15 mCi at time of purchase.
99mTc Sheet Source (water filled)
T1/2 = 6 hrs.
140 keV
10-15 mCi at time of filling.
Frank P. Dawry
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15. Daily Flood 5 million counts 256 x 256 acquisition matrix
Resulting image should show a uniform distribution across the entire field of view
Frank P. Dawry
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16. Uniformity parameters
UFOV – useful field of view
CFOV – center field of view
Integral uniformity
The difference between the maximum and the minimum pixel value divided by the sum of these two values X 100
= +/- 100 X (Max – Min)/(Max + Min)
Differential uniformity
The largest difference between any two pixels within a set of 5 contiguous pixels in a row or column (rate of change)
= +/- 100 X (Hi – Low)/(Hi + Low)
Frank P. Dawry
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17. Frank P. Dawry
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18. Spatial Resolution / System Linearity “BARS”
Resolution - the ability of a camera to separately image two objects.
If the two objects are seen as a single blurred spot in the image until they are 5mm apart, the resolution is said to be 5mm.
Linearity - the ability of a camera to reproduce a straight line.
3 million counts, 256 x 256 matrix for extrinsic
30 million counts 512 x 512 matrix for intrinsic
Frank P. Dawry
Physx.home.comcast.net

19. Spatial Resolution James R Halama, PhD Loyola UniversityMedical Center
Frank P. Dawry
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20. Spatial Resolution James R Halama, PhD Loyola UniversityMedical Center
Frank P. Dawry
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21. Spatial Linearity Deviation from straight line of less than 1
Spatial Linearity Deviation from straight line of less than 1.0 mm for UFOV
PLES Phantom
Quadrant Bar Phantom
James R Halama, PhD
Loyola UniversityMedical Center
Frank P. Dawry
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22. Intrinsic Uniformity James R Halama, PhD
Loyola UniversityMedical Center
Frank P. Dawry
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23. Extrinsic Uniformity James R Halama, PhD
Loyola UniversityMedical Center
Frank P. Dawry
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24. Resolution phantoms
Moire effect
Frank P. Dawry
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25. UB gamma camera test pattern
One image per detector head is all that's needed to equally and effectively test all quadrants of the gamma camera.
Frank P. Dawry
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26. Uniformity corrections
Correcting for system and collimator non-uniformities due to small variations in sensitivity.
Applied to tomographic (SPECT) reconstructed images
Acquired for each collimator that is used for SPECT imaging
30 to 120 million count acquisition
256 or 512 matrix size
Frank P. Dawry
Physx.home.comcast.net

27. Uniformity corrections
James R Halama, PhD
Loyola UniversityMedical Center
Frank P. Dawry
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28. Camera uniformity analysis
Similar to a daily flood except greater number of counts acquired
≥30 million counts
256 x 256 matrix
Useful for tracking of uniformity trends
Frank P. Dawry
Physx.home.comcast.net

29. Center of rotation - COR
Used to verify the integrity of the motion of the gantry during tomographic imaging
COR value is the difference between the measured COR and the theoretical COR
Tc-99m point source either centered in the field of view or off centered
Acceptable limits < ±2 mm
Frank P. Dawry
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30. Frank P. Dawry
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31. Center of rotation - COR
James R Halama, PhD
Loyola UniversityMedical Center
Frank P. Dawry
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32. SPECT Phantoms – system performance testing
Jaszczak
Frank P. Dawry
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33. SPECT Phantoms – tomographic system performance testing
Frank P. Dawry
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34. SPECT Phantoms – tomographic system performance testing
James R Halama, PhD
Loyola UniversityMedical Center
Frank P. Dawry
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35. SPECT Phantoms – planar system performance testing
James R Halama, PhD
Loyola UniversityMedical Center
Frank P. Dawry
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36. Society of Nuclear Medicine ‘simulator’ phantom program
Lumbar Spine
Cardiac
Frank P. Dawry
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37. SPECT phantom
Frank P. Dawry
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38. ICANL INTERSOCIETAL COMMISSION FOR THE ACCREDITATION OF NUCLEAR LABORATORIES
Frank P. Dawry
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39. PET/CT
TEST (PET ONLY)
Blank scan
Normalization
Absolute activity calibration
Preventive maintenance
FREQUENCY
Daily
After a hardware change or per manufacturer recommendations*
Every 6 months, or per manufacturer recommendations*
plus consideration for the CT portion and the merging of the two imaging modalities.
Frank P. Dawry
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40. SPECT/CT in review
Similar to SPECT with consideration for CT portion and the merging of the two imaging modalities.
Frank P. Dawry
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