whats the difference between quality assurance and quality control
QA- the plan for the systemic assessment of equuipemnt
QC- set of activities that help monitor and maintain equip
why do we do QC
to produce trhe best quality img while following ALARA
acceptence testing
routine maintenance
error maintenance
A- done when equipemtn is first installed
R- done periodically to ensure equip is preforming well (done annually and compared to initial test)
E- done when equip malfunctions and needs repairing
continuous quality improvement
total quality management
focused to improve process that people follow as a team to complete work
evaluates overall effectiveness of img sys. encompasses maintanence of equip, img aquisition, and processing standards
what is PACS evaluated for
img display quality (monitor and film)
processing speed
network (img) transfer speed
integrity of compressed data called back
how often is the preformace of all display devices (monitors) checked? what are the 2 test patterns called? how is this done?
monthly
SMPTE and AAPM. patterns are stored and then recalled to see how it looks on monitor each time. colours and sharpness should stay same and should have optimal luminance and minimal noise
what is a photometer used for
measure luminance (brightness), reflection, noise, and glare
how to evasluate processing speed
-chose a study for the test (always use same one)
-note time takes to open and download imgs
-note time to perfprm a processing function such as edge enhancement
-if time takes to do these increases then upgrafdes are req
how to eval img tranfser speed
-set study to be used (same everytime)
-check speed from modality to PACS and from the archive to workstation.
-retrieve the stdu y and note the time takes for entire study to arrive at workstation
how to test compression of PACS
have the org img and the lossless comp version and lossy com version. recall these and compare to org img of test pattern
what is DR systems evaluated for
uniformity
contrast
spatial accuracy
noise
erasure
relative sensitivity test
ensures the CR reader sys sensitivity calibration or DR sys sensitivity are consisten w baseline (org test when it was installed)
sensitivity affected pat dose and generator input/output consistancey
uniformity test
evaluates uniformity of img brightness across a CR or DR plate
also confirms CXR reader sys light positioing and optics
uniformity test steps
-180 cm SID, 80 kVP, and enough mAs to prod 10mR rad
-process IR and examine for unformity
-use region of interest to check brightnedd st various ponits on img
-readings should be within 10% of each other
what is flat fielding
a software corerction that can equalize each pixel to make more uniform (fixes dead/malfuncting pix)
spatial accuracy
img noise test
erasure test
SA- measure spat res capability of DR plate or CR reader optics
INT- eval the img for noise/artifacts
ET- conforms the CR plate has been completely erased or that all prev img have been removed from DR
erasure test steps
-use knee phantom to take img.w CR plate using extreme expo
-erase plate
-if not eraswed there is ghosting artifact which is when part of prev anatomy is still on plate
(in DR use lead block instead of knee)
what tests are done annually
response function
exposure index
dynamic range
uniformity
spat res
contrast detectability
digital detecter residual imgs
phantom dose measurements
what is the responsibilitys of trhe MRT
-daily,weekly,monthly, and annual QC tests
-cleaning and erasing plates(daily)
-monitor test pattern(d)
-inspect cr plate for damage (weekly)
-clean monitor,mouse, keyboard (w)
daily and weekly MRT responsibility
-cleaning and erasing plates(daily)
-monitor test pattern(d)
-inspect cr plate for damage (weekly)
-clean monitor,mouse, keyboard (w)
monthly and annually MRT responsibity
-repeat analysis
-clean img plates
-prob reporting
-light field congruence
-AEC test
who establishes standards for all DI departments for QA
MANQAP - manitoba quality assurance program
investigates and inspects DI facilities for safety and monitors complience w standards
