Wiegel Spring Semester

huskerfansanfran49's version from 2015-05-13 23:02


Question Answer
When did Edison Invent Fluoroscopy?1896 (one year after Roetgen)
What are the parts of the Conventional Fluoroscopic Imaging Chain?II, Image Recording Device, Vidoe camera and monitor
The Image Intensifier is the same as theImage Receptor
Who invented the Electronic Image Intensifier tube?Russel H. Morgan in 1940s
How much mA is used during fluoroscopy exams?Between 1 and 5 mA
What activates "The Bucky Slot Shield?"Sliding the buck to the foot of the table

Image Intensifier

Question Answer
What are the parts of the Image Intensifier?Input Screen, Photocathode, Electrostatic Lenses
What is the purpose of the Image Intensifier tube?Increase Brightness
What are the various sizes (in inches) of the input phosphor?6,9,12, or 16
What is the Input phosphor made out ofCesium Iodide
What role does the Input Phosphor play in the II?Converts X-rays to Light
What is the Photocathode made out of?Antimony and Cesium compounds
What role does the Photocathode play in the II?Absorbs light and emits Electrons
The Photocathode screen multiples the amouenergy that is produced by ___ times (for every one x-ray photon)200
In the Input phosphor a single x-ray photon having 30 kV can be split into ______ light photons each having _________ volts10,000;3 volts
Combined efficiency of the input phosphor and Photocathode is that for each 60 kV x-ray about ___ electrons are produced200
What are the Electrostatic Focusing LensesSeries of charged metal rings that become narrower towards Anode
The concentration of these Electrons by the Electrostatic Focusing Lenses is calledMinification
The Accelerating Anode imparts _________ to _________ times the kinetic energy they start with50-75
A small ring of metal in the neck of the tube with _____ to____ volts of ___ charge applied to it is the AA25 thousand to 30
The Output Phosphor is made out ofCesium iodide
What role does the Output phosphor play in the IIConverts Kinetic energy of the Electrons to light

Brightness gain and shit

Question Answer
Typical Brightness gains range from _____ to _____5,000 to 20,000
Overall Brightness gains is the product of ______ x ______Minification Gain x Flux gain
What is Field of View?A specification of the active diameter of the input phosphor
How would one project a smaller region of the input phosphor onto the output phosphorBy moving the focal point of the electron beam closer to the Input phosphor
What allows us to magnify an image?Using a smaller FOV on the input screen
What allows different magnification levels to be selected at the push of a button?Dual Field or Tri Field intensifiers
Why is the image dimmer smaller field of viewMinification gain isn't as high
Magnification mode could improve spatial resolution, why?Tech factors are increased and we use a smaller area
What increases the mA to compensate for the loss of minification gain?Automatic Brightness Control
How doe we get the images on the camera?Images are gathered from light at the output phosphor and converted to electronic signal
The television camera tubes are made out of what material?Plumbicon and Vidicon
Automatic Brightness Control increases patient dose _________ to _________Times
What are 2 different ways of keeping brightness consistent?Automatic Brightness control and Automatic Gain Control
Does Automatic Gain control Change Tech factors? What does it Change?No;Brightness
What does Automatic Brightness Control Change?Changes the mAs and kVp to a consistent output give us better resolution and detail!

Viewing Systems

Question Answer
What are the TV tubes made out of ?Plumbicon and Vidicon
What is a Beam Splitter?A mirror that sends the info to the spot film camera
Instead of taking light to the monitor, the ____ _____ takes it to the camera to record the imageBeam Splitter
T or F the Beam Splitter is found in both Conventional and Flat panel FluoroF
The Photospot camera contains a ___ and ____ mm role of film/photopaper70 and 105 mm
In Cassette loaded Static films, Single cassettes may be used for multiple exposure T or FTrue

Development of Fluoroscopy

Question Answer
What are two ways of keeping brightness consistent on the monitor?Automatic Brightness Stabilizer and Automatic Gain Control
Which Brightness compensator just changes the brightness on the screen?Automatic Gain Control
Which Brightness compensator changes the kVp and mAs ?Automatic Brightness Control

Fluoroscopic Image Quality

Question Answer
What is Scintillation?Small, momentary defects in the distribution of Brightness (Twinkling)
What kind of Fluoro is Scintillation found?In dynamic images (similar to mottle)
Whats the best way to get rid of Scintillation?Increase mA
What is Contrast?Destructive to image Contrast
Image Intensifiers are generally poor at preserving ____ contrast in the transmitted imageHigh
What is Pincushion DistortionWhen we have good resolution in the center but it gets worse at the periphery
What is Veiling Glare?Scattered Random Light from the output phosphor
What causes Veiling Glare?Scattered x-rays and Electrons passing through the II
What is Vignetting?Loss of brightness toward the periphery of the image
How can this be tested for?by observing a flat field fluoroscoped image with no object

Digital Fluoroscopy

Question Answer
Pulsed progressive mode fluoro units operate at an mA anywhere from ___ to ___ mA100 to 200
What is the Frame rate of Pulsed-Progressive mode?30 Frames per second
What is an advantage of using Pulsed Progressive mode?Image Subraction Techniques
In Pulsed Progressive mode, what can the pulse width be adjusted to?3 to 10 milliseconds
Image Intensifying tubes are being replaced by whatDynamic Flat Panel detectors
What are the two types of Dynamic FPDsDirect and Indirect
Indirect Dynamic Flat Panel Detectors use what?Cesium Iodide phosphor and Active Matrix Array of Amorphous Silicon TFTs
Direct Dynamic Flat Panel Detectors use what?Amorphous Selenium TFT
Indirect Dynamic FPD convert what to whatX-rays to light
Direct Dynamic FPD convert what to whatX-rays to electricity

Digital Fluoroscopy Cont.

Question Answer
Compared to Static DR detectors, Dynamic FPDs haveLarger Dimensions, Larger Matrix sizes and Pixels
Static DR detectors pixels equal how many microns?100-150 microns
Dynamic FPD pixels equal how many microns?200-300 microns
These Flat Panel systems allow both Radiography and Fluoroscopy to be performedDual Use
The act of grouping 4 small pixels to with larger dimensionsBinned
Dynamic Flat Panel Detectors can operate in either _____ or ____ X-ray modeDynamic or Pulsed
What feature, on DFPDs is the same as magnification mode on II's?Zoom
What erases ghost images on DFPDs?LED
What are ghost images?A change in the sensitivity of the detector after exposure

Digital Subtraction Techniques

Question Answer
What is Temporal Subtraction?Uses the difference in time between exposures
What is Energy SubtractionUses the difference in x-ray absorption between tissues at different kVp levels
Which is easier to achieve both economically and technologically?Temporal
What is the K-edge?K-shell binding energy(what the computer uses to subtract the anatomy)
What is Hybrid subtractionDual energy Subtraction- both Temporal and Energy Subtraction used together


Question Answer
What does AEC stand for?Automatic Exposure Control
What did the first AEC's use?Phototimers (Detectors and Photomultiplier tube behind Cassette)
What do modern AEC's use?Ionization Chambers
Where is the AEC located?Between the Patient and the IR
How does the Photomultiplier work?Photomultiplier turns x-rays to light and turned of when there was a certain amount of light
AEC eliminates need for radiographer to select ____ and ____Time and mAs
What is the Intensity/Density Controls?Determines how much exposure is needed before AEC is shut off
A -1 in Density/Intensity controls would be a decrease of25%
What is something else that might cause the AEC to shut off early?Scatter (Watch Collimation)
AEC's should not be used to image what?Large metal artifacts, prosthetics
What is the shortest Exposure time necessary for the AEC to respond to the ionization and send a signal to terminate the exposure.0001 to .002 seconds
What is Back up time used for?Used to prevent EXTREME over exposure of the patient to radiation
What percentage of the expected time150%
Federal law requires automatic termination at ___ mAs when working above 50 kVp and 2000 mAs below 50 kVp600 mAs

Atomic Structure

Question Answer
These atomic particles have a negative chargeElectron
These atomic particles have a positive chargeProtons
These atomic particles have a no chargeNeutrons
This atomic Particle has the most massNeutron
This atomic Particle has the least massElectrons
Which two atomic particles have similar mass?Protons and Neutrons
the number of ____ and ____ is usually the sameTrue
What Row an element is on is determine byThe number of Electron Shells
What Column an element is in is determined byNumber of Electrons in the outer shell
When an atom can give, the valence isPositive
When an atom can take, the Valence isNegative
A negative Ion has more ____ than _____Electrons than Protons
A positive atom has more _____ than _____Protons than Electrons
Any number of Neutrons that is different from the normIsotope
Too few or too many NeutronsRadioisotope
A beta particle is what?An electron emitted from the nucleus
An alpha particle is what?2 protons and 2 neutrons emitted from the nucleus