Chapter 15 Test Flashcards
In radiographic image intensification, the ratio of the number of light photons at the output phosphor to the number of photons at the input phosphor describes:
a.) brightness gain
b.) flux gain
c.) minification gain
d.) conversion factor
b.) flux gain
mAs controls the ____________ of photons in the xray beam
a.) inertia
b.) penetrating power
c.) quality
d.) quantity
d.) quantity
__________ imaging is used to view the human body in real time, accomplished with fluoroscopy as opposed to radiography.
a.) static
b.) still
c.) dynamic
d.) colorized
c.) dynamic
The purpose of the 5 minute timer in fluoroscopy is to:
a.) inform the radiographer of equipment malfunction
b.) alert the radiographer
c.) open the circuit
d.) terminate exposure once the maximum time has been reached
b.) alert the radiographer
A fluoro system equipped with an ABC mechanism with the tube below the table, moving the I.I away from the patient will:
a.) increase the size of the radiation field at the table top
b.) reduce image size of an anatomic structure
c.) decrease patient dose
d.) increase patient dose
d.) increase patient dose
Magnification fluoroscopy is accomplised by:
1.) moving the image intensifier focal point further from the output phosphor
2.) selecting a smaller portion of the input phosphor
3.) decreasing the voltage to the electrostatic focusing lenses
a.) 1 only
b.) 1 and 2 only
c.) 2 and 3 only
d.) 1, 2 and 3
b.) 1 and 2 only
Which of the following will occur if voltage to the electrostatic focusing lenses is increases?
a.) magnification of the image
b.) inversion of the image
c.) reversal of the image
d.) minification of the image
a.) magnification of the image
How does an increase of 25 mAs to 50 mAs affect xray beam quality?
a.) it depends on the focal spot size
b.) decreases quality
c.) it has no effect
d.) increases quality
c.) it has no effect
Which of the following describes how fluoroscopic images are acquired that study human anatomy and function?
a.) real time acquisition
b.) exposures timed with the patients body position
c.) mobile c arm system
d.) single, static exposure using low mA
a.) real time acquisition
The commercial fluoroscope was developed by:
a.) rutherford
b.) edison
c.) newton
d.) einstein
b.) edison
How do modern fluoroscopic systems record images?
a.) digital capture technologies and processing
b.) television and cathode ray tube (CRT) technology
c.) mirror optics and lenses
d.) light tight film magazines
a.) digital capture technologies and processing
Fluoroscopic frame averaging is:
a.) identical to pulsed fluoro
b.) not impacted by fast moving patient anatomy
c.) designed to calculate absorbed dose
d.) a technique that combines video frames
d.) a technique that combines video frames
The photocathode is made of:
a.) cesium iodide
b.) glass substrate
c.) zinc and cadmium
d.) cesium and antimony
d.) cesium and antimony
Aluminim filtration has its greatest effect on:
a.) low energy xray photons
b.) high energy scattered photons
c.) low energy scattered photons
d.) high energy xray photons
a.) low energy xray photons
A loss of brightness around the edge of the fluoroscopic image caused by the curve of the photocathode is:
a.) noise
b.) pincushion appearance
c.) vignetting
d.) magnification
c.) vignetting
Unwanted IR exposure that creates fog is caused by:
Scatter secondary radiation
This part of the image intensifier absorbs light and produces electrons:
a.) input phosphor
b.) output phosphor
c.) photocathode
d.) electrostatic focusing lenses
c.) photocathode
In an indirect capture DR system, the electronic components that is configured in a network of detector elements is the:
a.) charge coupled device (CCD)
b.) photoconductor
c.) thin film transistor (TFT)
d.) scintillator
c.) thin film transistor (TFT)
Which device converts analogue signal into a digital signal?
a.) CCD
b.) ADC
c.) TFT
d.) CMOS
b.) ADC
The output phosphor is made of:
a.) cesium and antimony
b.) zinc and cadmium
c.) cesium iodide
d.) zinc and antimony
b.) zinc and cadmium
Federal law requires an audible ____________ minute timer in fluoroscopy.
a.) 3
b.) 5
c.) 9
d.) 10
b.) 5
The input phosphor is made of:
a.) cesium and antimony
b.) zinc and cadmium
c.) cesium iodide
d.) zinc and columnar crystals
c.) cesium iodide
An IR that has been exposed with insufficient mAs may exhibit what effect?
Noise, Quantam Mottle
The original fluoroscopic image was very:
a.) dim
b.) bright
c.) clear
d.) fuzzy
a.) dim
For a mobile fluoroscopic tube, the distance from the source (xray tube) to the tabletop shall be no more than:
a.) 12 inches
b.) 18 inches
c.) 24 inches
d.) 15 inches
a.) 12 inches
The greatest detail sharpness is obtained by using:
1.) a small focal spot
2.) the longest SID
3.) the smallest OID
4.) longer exposure times
a.) 1 only
b.) 1, 2 and 3
c.) 4 only
d.) 1, 2, 3 and 4
b.) 1, 2 and 3