Spring semester Test 5 Ch 14-22 Flashcards
Exposure artifacts are
Improper pt preparation
Double exposure
Blur
Grid cutoff
In handling artifacts; light fog is caused by
The temp or humidity is too high
The safelight is too bright
Film has been left in X-ray room
Acceptance testing
Routine performance monitoring
Maintenance
An acceptable QC program consists of these 3 steps
The Ten Step monitoring system and eval process is promoted by the
The joint commission JTC
The most important part of patient protection is ?
What is the minimum total required?
Filtration -2.5 mm aluminum
To measure proper filtration, what is used and how frequently should this be done ?
Half value layer
Annually or when there has been a change to tube housing
Misalignment of collimator should not exceed _____
2% of the SID
Most systems use _____ collimators which can not be larger than the receptor size
PBL
Spatial resolution is principally determined by
Focal spot size
3 tools used for measurement of focal spot size
The pinhole camera
The star pattern
Th slit camera
How long can a Cr sit before it needs to be erased?
24hrs
The process of assigning a value to a dead pixel based on the recorded values of adjacent pixels
Interpolation
A software correction that is performed to equalize the response of each pixel to a inform X-ray beam
Flat-shielding
A graph of frequency of occurrence versus digital value intervals
Has discrete plots
Histogram
IR artifacts for digital
Dust, dirt, scratches
Pixel malfunction
Ghost images
Software artifacts for digital
Histograms
Range/scaling
Image compression
Object artifacts in digital
Pt positioning
Collimation/partitioning
Backscatter
2 artifacts in pre processing are
Interpolation
Flatshielding
Artifacts that occur bcuz of dead pixels or dead rows/columns
Pre -processing
Things that associate with image compression
Lossless compression
CAD systems require uncompressed images for processing
Compressed images may cause ____ whole using CAD systems
Lesions or lack of data
Multiple images on a single IP results in a proper separation and collimation of each image
Partitioning
Dust on the CR optical path (mirrors and lenses) can’t be cleaned by _______
Rad techs, they must have professional service
The backup timer terminates after how long ??
6sec or 600ma
In flouro, Entrance skin exposure (ESE) should not exceed _____
10R/min
Any combo of mA and S should produce same mAs value 10%
Make 3 exposures the same
Exposure linearity
Exposure reproducibility
Kvp calibration uses a _____
Ion chamber and is +-10%
A line pair test is used to measure
Resolution
Background light is also called
Ambient light
ROI
Region of interst -bring sharpness of interest
LCD
CRT
Flat, active matrix
Curved, light emitting, scanned electron
Image inversion
Window and level
Black to white, white to black
Makes all shades of grey visible
Materials that emit light
Light during stimulation
Glows after stimulation
Luminescence
Fluorescence
Phosphorescence
The property of the source of light
Basic Photometric unit
Candela aka nit
Lumen
LED
Light emitting diode
Photostimuable phosphor is used in:
TFT and CCD is used in
CR
DR
A property of luminescence transmitted by fiber optic bundles
A scintillator
Spatial resolution is the ability to
See small objects
Soft tissue = low spatial frequency
Bone,breast=high spatial frequenc
Binary system uses
2 digits (0,1)
Bit
Byte
(0,1)
Group of 8 bits
CPU
Motherboard
Control unit
Ram, Rom
PACS
DICOM
Picture archiving and communications system
(Radiologist can access anywhere)
Digital imaging and communications in medicine (image storage)
RIS
Earliest calculating tools
Radiology information system
Abacus
1st general purpose computer
1st operational computer
ENIAC
Colossus
Parallax effect =
Image characteristics
Penumbra
Spatial res, contrast res, noise, artifacts
Test device for Filtration
Test device for Collimation
HVL-2.5 mm Aluminum
PBL-spatial resolution [not exceed 2%]
How to test protective apparel?
Radiograph to check for cracks or tears
2 type of luminance meters
Near range
Telescopic
(0.05 to 1000 cd/m)
Test device for Kvp calliboration and criteria needed?
Ion chambers
W/in 10% of selected kvp !!
Th frequency for all testing is Annually!!!!! But which is done semi annually??
Collimation
Test device used for geometric, reflection, resolution, display noise???
TG-18-
Luminance response should be less than 30% _____
Nonuniformity
Protective apparel lead aprons for Diagnostic imaging should at least be
.25mm lead
And .50 for Flouro!!!
For best digital viewing, we should view __________
Photometry is the ________
Straight on!!
Science of measuring light
4 components of any medical image
Spatial resolution
Contrast resolution
Artifacts
Noise
To have quantum mottle is to have
Contrast resolution is limited by
Not enough mAs
Noise or SNR (signal to noise ratio)
The principle source of noise is
DR is a ____bit range
Scatter radiation
14Bit
Direct DR uses which capture element ??
Indirect Dr uses with capturing elements??
A-se
Amorphous selenium
CSI or a-Si
Amorphous silicon
Spatial resolution is limited by
Pixel size !! And MTF!!(modulated transfer system)
Contrast resolution is more important
A measure of X-ray absorption efficiency
DQE
Detective quantum efficiency
Photopic
Scotopic
Bright light with cones of eye
Dim light with rods of eye
QC deals with what
QA deals with
Instrument and equipment
People
Exposure timer and exposure reproductiblity is within
5%
The SMPTE
The society motion picture and television engineers
Described format for contrast and display resolutions
DICOM presented a document to allow medical images to be transferred referred to as
GSDF
Gray scale display function
Measurements and observations should be instituted for all display devices
AAPM TG 18
Best digital viewing is done
Straight on!
The TG 18-QC
Should be viewed
Regularly
Done by technologists!!!
