Presentation is loading. Please wait.

Presentation is loading. Please wait.

Frank P. Dawry Physx.home.comcast.net Gamma Camera Quality Control Without adequate quality control, the functional reliability of a nuclear medicine facility.

Similar presentations


Presentation on theme: "Frank P. Dawry Physx.home.comcast.net Gamma Camera Quality Control Without adequate quality control, the functional reliability of a nuclear medicine facility."— Presentation transcript:

1 Frank P. Dawry Physx.home.comcast.net Gamma Camera Quality Control Without adequate quality control, the functional reliability of a nuclear medicine facility is in doubt.

2 Frank P. Dawry Physx.home.comcast.net 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 American Society of Nuclear Cardiology (ASNC), the Joint Commission on the Accreditation of Healthcare Organizations (JCAHO), the Joint Commission on the Accreditation of Healthcare Organizations (JCAHO), the Society of Nuclear Medicine (SNM), 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, 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.

3 Frank P. Dawry Physx.home.comcast.net 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 Survey meter calibration Dose calibrator QC testing Dose calibrator QC testing Scintillation (thyroid) probe testing Scintillation (thyroid) probe testing Scintillation camera QC testing Scintillation camera QC testing Computer software testing Computer software testing Monitor performance testing Monitor performance testing Staff performance Staff performance ‘Outcomes’ testing ‘Outcomes’ testing

4 Frank P. Dawry Physx.home.comcast.net Standards 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 NEMA – National Electrical Manufacturers Association Establishes definitions, quantitative measurements of performance characteristics and reporting techniques for the specification of scintillation camera parameters Performed during acceptance testing prior to first use Verified during total system evaluation annually

5 Frank P. Dawry Physx.home.comcast.net Routine Camera Quality Control procedures Daily Visual checking the energy spectrum – “peaking” Visual checking the energy spectrum – “peaking” Evaluating the system performance with flood sources – “daily floods” Evaluating the system performance with flood sources – “daily floods”Weekly Checking the spatial resolution with a bar phantom Checking the spatial resolution with a bar phantom Checking the system linearity with a bar phantom Checking the system linearity with a bar phantom Correcting for system and collimator non-uniformities Correcting for system and collimator non-uniformities Performing camera uniformity analysis Performing camera uniformity analysisMonthly Checking the center of rotation for tomographic scans Checking the center of rotation for tomographic scans System sensitivity System sensitivity

6 Frank P. Dawry Physx.home.comcast.net Scintillation Camera Performance Extrinsic, or System measurements – with the collimator attached Give the best indication of clinical performance 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 Useful for comparing the performance of different cameras because they uncouple the camera performance from the collimator performance

7 Camera operation Frank P. Dawry Physx.home.comcast.net James R Halama, PhD Loyola UniversityMedical Center

8 Camera operation Frank P. Dawry Physx.home.comcast.net James R Halama, PhD Loyola UniversityMedical Center

9 Camera operation Frank P. Dawry Physx.home.comcast.net James R Halama, PhD Loyola UniversityMedical Center

10 Camera operation Frank P. Dawry Physx.home.comcast.net James R Halama, PhD Loyola UniversityMedical Center

11 Camera operation Frank P. Dawry Physx.home.comcast.net James R Halama, PhD Loyola UniversityMedical Center

12 Frank P. Dawry Physx.home.comcast.net

13 Frank P. Dawry Physx.home.comcast.net 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 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 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.

14 Sheet Sources 57Co Sheet Source T1/2 = 270 days 122 keV mCi at time of purchase. 99mTc Sheet Source (water filled) T1/2 = 6 hrs. 140 keV mCi at time of filling. Frank P. Dawry Physx.home.comcast.net

15 Frank P. Dawry Physx.home.comcast.net Daily Flood 5 million counts 256 x 256 acquisition matrix Resulting image should show a uniform distribution across the entire field of view

16 Frank P. Dawry Physx.home.comcast.net 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 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) 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)

17 Frank P. Dawry Physx.home.comcast.net

18 Frank P. Dawry Physx.home.comcast.net 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

19 Spatial Resolution Frank P. Dawry Physx.home.comcast.net James R Halama, PhD Loyola UniversityMedical Center

20 Spatial Resolution Frank P. Dawry Physx.home.comcast.net James R Halama, PhD Loyola UniversityMedical Center

21 Spatial Linearity Deviation from straight line of less than 1.0 mm for UFOV PLES Phantom Quadrant Bar Phantom Frank P. Dawry Physx.home.comcast.net James R Halama, PhD Loyola UniversityMedical Center

22 Intrinsic Uniformity Frank P. Dawry Physx.home.comcast.net James R Halama, PhD Loyola UniversityMedical Center

23 Extrinsic Uniformity Frank P. Dawry Physx.home.comcast.net James R Halama, PhD Loyola UniversityMedical Center

24 Frank P. Dawry Physx.home.comcast.net Resolution phantoms Moire effect

25 Frank P. Dawry Physx.home.comcast.net 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.

26 Frank P. Dawry Physx.home.comcast.net 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 30 to 120 million count acquisition 256 or 512 matrix size 256 or 512 matrix size

27 Frank P. Dawry Physx.home.comcast.net Uniformity corrections James R Halama, PhD Loyola UniversityMedical Center

28 Frank P. Dawry Physx.home.comcast.net 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

29 Frank P. Dawry Physx.home.comcast.net 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

30 Frank P. Dawry Physx.home.comcast.net

31 Frank P. Dawry Physx.home.comcast.net Center of rotation - COR James R Halama, PhD Loyola UniversityMedical Center

32 Frank P. Dawry Physx.home.comcast.net SPECT Phantoms – system performance testing Jaszczak

33 Frank P. Dawry Physx.home.comcast.net SPECT Phantoms – tomographic system performance testing

34 Frank P. Dawry Physx.home.comcast.net James R Halama, PhD Loyola UniversityMedical Center

35 SPECT Phantoms – planar system performance testing Frank P. Dawry Physx.home.comcast.net James R Halama, PhD Loyola UniversityMedical Center

36 Frank P. Dawry Physx.home.comcast.net Society of Nuclear Medicine ‘simulator’ phantom program Lumbar Spine Cardiac

37 Frank P. Dawry Physx.home.comcast.net SPECT phantom

38 Frank P. Dawry Physx.home.comcast.net ICANL INTERSOCIETAL COMMISSION FOR THE ACCREDITATION OF NUCLEAR LABORATORIES

39 Frank P. Dawry Physx.home.comcast.net 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* PET/CT plus consideration for the CT portion and the merging of the two imaging modalities.

40 Frank P. Dawry Physx.home.comcast.net SPECT/CT in review Similar to SPECT with consideration for CT portion and the merging of the two imaging modalities. Similar to SPECT with consideration for CT portion and the merging of the two imaging modalities.


Download ppt "Frank P. Dawry Physx.home.comcast.net Gamma Camera Quality Control Without adequate quality control, the functional reliability of a nuclear medicine facility."

Similar presentations


Ads by Google