Exposure Indicators
What does an EI indicate?
Amount of radiation reaching the IR
Name two of the 2 criteria which are essential in the production of a quality image.
Pixel Brightness
Image Contrast
Sufficient kVp
Spatial Resolution
Artifacts
Shape Distortion
Size Distortion
Where is the primary workstation?
Radiologist reading room
(Official interpretation)
What does RIS stand for?
Radiology Information System
What does PACS stand for?
Picture Archiving and Communication System
The Carestream system uses Logarithmic scale and has a 2,000 EIt. What does it mean when an image had a 2,300 EI?
2x the ideal exposure
Where does electronic noise come from?
Movement of electrons through the system.
What is the minimum frame-rate the human eye requires so there is no appearance of flicker?
20 frames per second
What are the 2 key functions of PACS
Transmit and Store
The measure of dose to the amount of area exposed.
Dose Area Product
Detective Quantum Efficiency
Logarithmic
Proportional
Inversely Proportional
(Must have all 3)
What type of monitor consists of a vacuum tube, electron gun, and a deflecting coil?
Cathode Ray Tube
What is the universally accepted standard for exchanging medical images among the modality, workstation, and archive?
DICOM
What is a compression ratio of Lossly compression?
10:1 - 50:1
SNR2 Output / SNR2 Input = ?
DQE
Using 60Hz will produce ...
____ Frames per second
____ Fields per second
30 Frames
60 Fields
Which part of the CRT controls the brightness?
Control Grids
What is a compression ratio of Lossless compression?
2:1 or 3:1
In an LCD monitor, what is formed where the vertical and horizontal electrodes meet?
Pixel
Which phosphor has the highest DQE?
Amorphous Selenium (a-Se)
What is the Nyquist frequency?
Sampling frequency at which the CR plate is scanned with the Lazer.
What is the most common crystal used in LCD monitors?
Hydrogenated Amorphous Selenium
What is a communication standard for information systems where PACS, RIS, HIS, and EMR can exchange information?
Health Level 7
Linearly shaped and electrically charged crystals are called ____
Nematic