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Fluoro. WB Questions
Question | Answer |
---|---|
In a modern fluoroscope, the fluoroscopic x-ray tube: | can be under or over the table |
the fluoroscope was invented by: | Thomas Edison |
Compared with a radiographic examination, the primary purpose of a flouroscopic examination is to visualize: | dynamic images |
fluoroscopy normally requires a tube current of: | 1 to 5mA |
Compared with radiography, the x-ray technique required for fluoroscopy calls for which of the following? | lower mA |
ABS is designed to compensate for changes in which of the ?following? | patient composition |
where are rods located in the eye? | cornea |
which of the following units of measurement is used to express fluoroscopic image brightness? | cd/m^2 |
which of the following structure is most sensitive to color? | cones |
what is the function of the iris? | control the light level |
the cones are used for ______ vision | photopic |
The frovea centralis is part of the.... | retina |
visual acuity is the ability to do what? | perceive fine detail |
The rods are used principally for .... | dim vision |
what is a major difference between fluoro and radiography in terms of technique?. | The mA is lower |
what is used in fluoro to maintain constant image intensity? | ABS (Automatic Brightness Stabilization) |
what is responsible for the vision of dim objects? | Rod |
What ocular structures immediately precedes the vitreous humor along the path of incident light? | lens |
what is the function of the iris? | controls brightness |
vertical television resolution is limited principally by which of the following? | lines per frame |
the electron beam in a television camera tube is produced by? | thermionic emission |
what is the camera tube most used in television fluoroscopy ? | vidicon |
what is the photoemissive component of image intensified fluoroscopy? | cesium iodine |
what is photoconductive?electron gun ,target or signal plate | signal plate |
what is the principle disadvantage of coupling the television camera to the image intensifier with the use of fiber optics? | photospot camera cannot be used |
which of the following refers to the image intensifier input phosphor?cesium iodine,electrons from light, or vidicon | cesium iodine |
what is a critical component in optically coupling an image intensifier with a photospot camera? | objective lens |
what is the most important component of a television monitor? | cathode ray tube |
In an optical coupling arrangement what is the nearest to the television camera? | camera lens |
what is the component of the television monitor in which the video signal is transformed into an image? | phosphor screen |
what is the electron beam of the television camera tube? | modulated |
one television frame is equivalent to what? | two television fields |
fluoroscopic television operates at a frame rate of | 30 f/s |
horizontal television resolution is limited principally by which of the following?bandpass, field rate, or frame rate | bandpass |
what is normally the weakest imaging link in television fluoroscopy? | television monitor |
common frame rates during cinefluorography are 15,30, and 60 f/s because: | of the frequency of the power supply |
when the electron beam of the cathode ray tube is blanked it is: | in a vertical retrace |
what is the television camera tube component of image-intensified fluoroscopy? | vidicon |
What is the emission of electrons from an illuminated surface? | photoelectric emission |
at what stage of image-intensified fluoroscopy is the number of image forming photons lowest? | entering the input phosphor |
image-intensifier brightness gain increases with increasing: | flux gain |
when an image intensifier receives x-rays at the input phosphor, what is emitted at the output phosphor? | visible light |
which of the following is the input phosphor of image intensifier?cadmium tungstate, cesium iodine, or sodium iodine | cesium iodine |
what is the output phosphor made of? | zinc cadmium sulfide |
the photocathode converts: | visible light into electrons |
what is the component of the image intensifier responsible for focusing the electron beam? | electrostatic lens |
the ability of an image intensifier to enhance image illumination is called? | brightness gain |
the minification gain of an image intensifier increases with increasing: | input phosphor size |
which of the following is a representative brightness gain for an image intensifier? 200, 2,000, or 20,000 | 20,000 |
if an image intensifier is described as a 25/12 tube, 25/12 refers to what? | diameter of the input phosphor in cm |
when a multifocus image intensifier is operated in magnification mode: | the electron focal point is closer to the input phosphor |
an image that displays vignetting is: | dim around the periphery |
with a multifocus image intensifier in the magnification mode what is improved? | spatial resolution |
In a 10/7/5 image intensifier the field of view is largest in the | 10 mode |
an image intensifier has a 5cm output phosphor and a 45cm input phosphor . The brightness gain is 10,000. flux gain is approximately: | 120 |
what is the proper sequence for image-intensified fluoroscopy? | 1- x-ray to light 2- light to electrons 3- electrons to light 4- light to electric signal 5- electric signal to light |
which of the following applies to the output phosphor? a- electrons emitted b- light absorbed c- light emitted d- x-rays absorbed e- x-rays emitted | C- Light emitted |