ann review Flashcards
what measures tube current?
mA meter
what is surrounded by the negatively charged focusing cup?
filament
Which device reduces voltage and provides current to produce an electron cloud or space charge at the filament?
step down transformer
What type of x-ray machine uses a continually decreasing mA for the shortest times possible?
falling load generator
The speed of x-rays is based on:
The fact that they are a form of electromagnetic radiation
The test that measures the accuracy of adjacent mA stations is:
it must be accurate to within:
exposure linearity
10%
The test that measures the accuracy of successive exposures is:
it must be accurate to within:
Exposure reproducibility
5%
What device always delivers the shortest exposure time possible?
Falling load generator
What is the most commonly used AEC?
ionization chamber
The primary type of grid used in diagnostic imaging is:
focused
The primary purpose of filtration is:
RADIATION PROTECTION MOTHER F-ER!!!
The electricity provided to the radiology department operates at:
120 pulses per second
Resolution of the television system may be measured using the following tool(s):
Resolution test pattern
Fluoroscopy exposure rate may not exceed:
100 mGya per minute
what is electrostatics?
Electrostatics is the study of electric charges at rest
Electrostatic charges concentrate on a conductor in the ares of greatest curvature
____________________ is done during preprocessing to correct for an irregular pattern over the image.
flat fielding
__________________ is corrected by the application of an offset voltage.
image lag
The two principal characteristics of a medical image are __________.
spatial resolution and contrast resolution
The portion of useful image-forming x-rays is referred to as the ____________>
signal
The number of gray shades that an imaging system can reproduce is called its ______________.
dynamic range
The laser is one of the features of the computed radiography reader.
optical
The human visual system can distinguish _______ shades of gray.
30
The four steps of creating an image with computed radiography are .
metastable state, stimulate, read, and erase
The following computer component temporarily stores data for processing.
hard disk drive
he dynamic range determines the degree of in the image.
contrast resolution
The computed radiography image has:
narrow exposure latitude
improved contrast resolution
The ______________ digital imaging system uses the highest dynamic range.
mammography
patial frequency is used to describe the quality of spatial resolution in terms of _____________.
line pairs
Spatial resolutuion is determined by the ratio of ____ to ____
FOV
matrix size
In digital imaging, spatial resolution is ultimately limited by ______________.
pixel size
If there were such thing as a perfect imaging system, the MTF would be equal to __________.
1
If digital radiography imaging system has a spatial resolution of 10 lp/mm, what is the pixel size of that system?
.05mm
Europium is the of the photostimulable phosphor.
activator
Histogram selection is done __________________.
by the radiographer before each exam