Secondary Calibration / Daily Qa; Secondary Calibration Overview; Starting The Daily Qa (Secondary Calibration) - GE Medical Systems PRODIGY Service Manual

2.17 Secondary Calibration / Daily QA

2.17.1 Secondary Calibration overview

2.17.2 Starting the Daily QA (secondary calibration)

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PRODIGY Service Manual (Rev C - 2000)
• Daily QA (Quality Assurance) tests the integrity of the scanner so
operator knows it is operating within specifications.
• Daily QA (Secondary Calibration) adjusts the calibration of the scanner to
offset any changes due to the tube aging, temperature varying, or when
certain components are changed.
• A third type of function, QC Phantom, is another method for testing
system performance. A QC phantom is scanned using standard software
and results are stored (aluminum spine in lucite).
• Daily QA ensures the system is operating properly by running 3 types of
tests:
• A peak test to adjust photon counting electronics.
• A functional test that checks the indicator lights, motion system,
shutter, tube output, and detector performance.
• A test that measures a secondary calibration object with different
bone chambers and tissue plugs which correct for system aging and
prevents long-term drifts.
• On many tests, the results must be calculated for all 16 detectors
separately. The display for the test will consist of the mean value.
• All tests are run all of the time. The tests are executed and test results
reported as each test completes. Test results include pass/fail and any
quantitative information when appropriate.
Operator presses [F5] to start [Daily QA] which presents a plot of the last used
parameter from the last Daily QA run. (Default display is the medium bone
chamber.) At this point operator can interactively manipulate the data in QA
database to create tables and graphs that can be printed.
Tech presses [Start] to start running Daily QA tests.
Software displays instructions to position calibration block on the table. Tech
places block on tabletop silk screen and click [OK] to start.
The UI locks out all other operations except Stop button.
Scan arm moves to the "Home" position. In this case, Home is always at head
of scanner for QA independent of user setting for Home.
System Overview 2-91