QC Digital Flashcards
(21 cards)
Half-value measurement for testing filtration/quality of beam
Minimum amount at 70kvp is 2.5 mm of aluminum equivalent
Light field to radiation field alignment - accuracy of collimator
Must be accurate to +- 2% of SID
Positive beam limitation (testing collimation)
Primary beam should not be allowed to be larger than the IR when activated
Central ray alignment
centering mark should be +- 1% of the light field central ray
Focal spot size
size should be within +- 50% of equipment specifications
kVp accuracy
should be within +- 3-5 kVp on control panel OR +- 10% of kVp indicated
Timer accuracy
should be within +- 5% for exposure longer than 10 milliseconds
OR +- 20% for exposures less than 10 milliseconds
mA linearity
should be within +- 10%
mA reproducability
should be within +- 5%
mA reciprocity
should be within +- 10%
AEC Ion chamber sensitivity
should be w/in +- 10%
IR Exposure Variation (density adjustment)
vary per unit
AEC response capabilities
should be w/in +- 10%
backup timer verification
backup timer should terminate exposure after prolonged on time (tested by placing lead on the detector and waiting for the backup timer to kick in)
Fluoroscopy exposure rate
No more than 100 mgy/min and no more than 10 R/min
Automatic Brightness Control
Checked to make sure the radiation dose hitting the input phosphor is constant. Use phantoms to measure if dose is adjusted.
Plate uniformity
Numbers on plate should be similar in value. Less than 20 value difference should be seen amongst the measured areas.
Spacial resolution line pairs of digital imaging systems
2.5 lp/mm
Grayscale standard display function
Should not vary more than 10% as recommended by American Association of Physicists in Medicine task group 18
Average luminance of primary display monitors
300-500 cd/m2
How often should aprons be checked?
Visually every 6 mths
Checked fluoroscopically annually
