Fluoroscopy Test Questions and Answers Graded A+
What does the automatic brightness control (ABC) do - Answer- allows the radiologist to select an image brightness level that is subsequently maintained automatically by varying the kVp, the mA, or sometimes both.
Principal advantage of image-int...
Fluoroscopy Test Questions and
Answers Graded A+
What does the automatic brightness control (ABC) do - Answer- allows the radiologist to
select an image brightness level that is subsequently maintained automatically by
varying the kVp, the mA, or sometimes both.
Principal advantage of image-intensified fluoroscopy over earlier types of fluoroscopy is
- Answer- increased image brightness
The structures in the eye that are responsible for the sensation of vision are called -
Answer- rods and cones
Located between cornea and lens- behaves like a diaphragm to allow more or less light
- Answer- Iris
Fluoroscopic technique = - Answer- max image detail is desired, high levels of image
brightness
The brightness of the fluoroscopic image depends primarily on - Answer- the anatomy
that is being examined, the kVp, and the mA.
In fluoroscopy, ____kVp and ____mA are preferred - Answer- high kVp and low mA
The image-intensifier (II) tube is - Answer- a device that converts the pattern of the x-ray
beam into a bright visible-light image of high intensity
input phosphor = - Answer- cesium iodide
active element of the image-intensifier tube is the - Answer- photocathode
the Photocathode is bonded - Answer- directly to the input phosphor with a thin,
transparent adhesive layer.
The photocathode emits electrons when - Answer- illuminated by the input phosphor in
a process known as photoemission.
Photoemission is - Answer- emission that follows light stimulation.
The number of electrons emitted by the photocathode is ____________ proportional to
the intensity of light that reaches it. - Answer- directly
, electron optics means - Answer- Maintaining proper electron travel - the pattern of
electrons emitted from the large cathode end of the image-intensifier tube must be
reduced to the small output phosphor.
electrostatic focusing lenses are responsible for - Answer- maintaining electron optics
Each photoelectron that arrives at the output phosphor produces _____ to ______ times
as many light photons as were necessary to create it. - Answer- 50 - 75
the flux gain - Answer- the number of light photons at the output phosphor over the
number of x-rays at the input phosphor
The ability of the image intensifier to increase the illumination level of the image is
called its - Answer- brightness gain
The brightness gain is simply the product of the - Answer- minification gain and the flux
gain
Flux Gain = - Answer- # of output light photons/(divided by)
# of input x-ray photons
Minification Gain = - Answer- Diameter of input phosphor ^2/(divided by)
Diameter of output phosphor ^2
Brightness Gain = - Answer- Minification X Flux Gain
As an image intensifier ages, patient dose - Answer- increases as a consequence of
maintaining image brightness.
Image intensifiers have conversion factors of - Answer- 50 to 300
veiling glare is a - Answer- process where internal scatter radiation in the form of x-rays,
electrons, and light can reduce the contrast of image-intensifier tubes
Tri-field tubes come in various sizes, but perhaps the most popular is - Answer-
25/17/12 cm.
vignetting is - Answer- a reduction in brightness at the periphery of the image.
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