3/28 Quiz Flashcards
kVp and mA determine the _________ level of the fluoroscopic image.
Brightness
What is above the table in nondigital fluoroscopy?
Spot imaging device and image intensifier
In nondigital fluoroscopy, the x-ray tube and IR are connected with a ____ to keep them the appropriate distance apart regardless of ________
C-arm
Movement of the equipment
The X-ray tube for fluoroscopy is operated at ___ to ___ mA
3 to 5
Regulation of kVp and mA for fluoroscopy depends on
The part being examined
kVp and mA are automatically adjusted during fluoroscopy by a process known as
Automatic brightness control (ABC)
-AKA automatic brightness stabilization Or automatic gain control
Visible image on the monitor is a result of
Image intensification
The image intensifier tube converts ______ energy into _____
X-ray
Visible light
Once X-ray energy is turned it visible light it is turned into an
Electronic signal (that is displayed on the monitor)
Receives exit rays from the patient and converts them into visible light
Input phosphor
Visible light from the input phosphor strikes the
Photocathode
The photocathode releases electrons in amounts ________ proportional to the visible light striking it
Directly
The electrons coming from the photocathode are concentrated and directed towards the other end of the image intensifier tube by a series of _________ and by ____ kVp applied through the tube.
Electrostatic lenses
25
Once electrons reach the other end of the image intensifier, they will strike the
Output phosphor
The energy of the electrons is converted by the phosphors to visible light in amounts ___ to ____ times greater than at the photocathode.
50 to 75
The increase in brightness caused by acceleration of the electrons is called
Flux gain
Is the output phosphor larger of smaller than the input phosphor?
Smaller
the output phosphor is smaller than the input phosphor, resulting in an increase in brightness called
Minification gain
The product of minification gain and flux gain is
Total brightness gain
Total brightness gain ranges from ______ to ______ and decreases as the tube ages.
5,000 to 20,000
_______ is possible only with dual focus or tri focus tubes, which results in increase patient dose
Magnification
In Digital fluoroscopy, what is added?
Operating console and computer work station
In Digital fluoroscopy, the image intensifier may be replaced by a
Flat panel IR
A flat panel image intensifier provides better resolution of
Smaller anatomy
In Digital fluoroscopy, the x-ray beam is _____ to keep the patient dose and heat units at a minimum
Pulsed
In Digital fluoroscopy, the analog signal is sent through an ______ to convert information into numerical digital date
Analog-to-digital converter
Viewing of digital fluoroscopy should take place on a
High resolution flat panel monitor
An image intensifier tube consists of
Input phosphor
Photocathode,
electrostatic lenses,
Output phosphor
The input phosphor coverts x-ray energy to
Light energy
Keeps electron beam narrowed as it travels toward output phosphor
Electrostatic lenses
The photocathode converts light energy to
Electron energy
The output phosphor converts electron energy to
Light energy for viewing
The analog to digital converter enables images to be
Manipulate and post processed
Mobile fluoroscopic units are usually called
C-arms
Complete program in a radiology department that addresses all aspects of quality, including customer service, image interpretation, accuracy of diagnosis, and distribution of radiologist reports
Quality assurance
Program that specifically addresses the safe and reliable operation of equipment
Quality control
Tested using a digital dosimeter; half-valve layer measurement required
Filtration-beam quality
Collimator/light field to radiation field alignment must be accurate to within ___ of the SID
2%
Effective focal spot size should be within ___ of the size stated in equipment specifications
50%
kVp must be accurate to within ____ of the kVp indicated
+/- 5%
Timer should be within_____ of the time chosen for exposures over 10ms
5%
Adjacent mA stations should be within ___ of one another
10%
Radiation intensity of sequential exposures should not vary more than ____
5%
AEC is tested to verify the reproductibility of exposure using _____ to simulate variations in patient thickness
Phantoms
Fluoroscopy exposure rate is tested with a digital dosimeter; dose should not be more than ____ per minute
100 mGy
ABC on image intensifier is checked to ensure that radiation dose hitting the _______ is constant
Input phosphor
