QUALITY CONTROL Flashcards
(20 cards)
Center of beam to SID tolerance
1%
Actual SID to indicated SID tolerance
+/- 2%
Collimation to SID tolerance
+/- 2%
Actual exposure time to indicated exposure time
+/- 5%
Actual kVp to assigned kVp
+/- 5%
Exposure reproducibility
+/- 5%
Exposure linearity
+/- 10%
Tested using a digital dosimeter; half-value layer measurement is required
Filtration-beam quality
Effective focal-spot size: Should be within ___ of the size stated in equipment specifications
50%
Viewing of the digital image normally takes place on this type of computer monitor
flat panel LCD screen
accuracy of the AEC is tested using a variety of exposures to ensure they are consistent; should be accurate within:
± 5%
ensures the observer’s view of image contrast is consistent throughout the pixel value range of a displayed image
Grayscale standard display function
Decreased density along the periphery of the image caused by absorption of image-forming rays
Grid cutoff
Result is image-forming rays absorbed all across the radiographic field, with cutoff (decreased density) visible over the entire radiograph
Off-level
range of exposure techniques that will result in an acceptable image
exposure latitude
computer keeps the images at uniform brightness and contrast regardless of exposure used
Rescaling
also known as low-pass filtering; removes high-frequency noise
Smoothing
As window level increases;
image brightness increases
As window width narrows;
contrast increases
histogram of pixel values from image acquisition that can be used to correct or enhance luminance values
Look-up table (LUT)
