RTE 1401 Final Exam – Questions With Accurate
Solutions
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Terms in this set (345)
Fixed mAs/ variable kVp chart adjust kVp by multiplying by 2 (+/-) for every
increment of ONE centimeter or inch of size
difference
Fixed KVP/ variable mAs chart adjust mAs by multiplying (+) by 2 for every 4-5
centimeter or inch size difference
digital image quality factors brightness, contrast resolution, spatial resolution,
distortion exposure indicator, noise
brightness intensity of light coming through monitor
contrast resolution how well a system can display varying shades of
gray
-affected by dynamic range
,pixel depth determines the number of shades of gray that can
be displayed: 2 to the 14th power= 16,384 shades of
gray
spatial resolution measured in Lp/ mm
-2.5- 5 Lp/mm in digital imaging
distortion size & shape
effected by SID, OID, and alignment
exposure indicator number displayed on the processed image to
indicate the level of x-ray exposure received to the
digital image receptor.
-red, yellow or green
noise random disturbance that reduces of obscures image
clarity
-SNR and quantum noise
Signal to Noise Ratio (SNR) The ratio of the speech signal (intended signal) to
that of the background noise
-HIGH is ALWAYS best
quantum noise lack of sufficient data (photons) - results in blotchy
or mottled image. Increase mAs to fix
algorithms complex math equations used to maintain image
quality
Dynamic range range of shades a digital system is capable of
displaying as seen by the human eye
exposure latitude the range of exposures that can be used and still
result in the capture of a diagnostic-quality image
-DR has more than film-screen imaging
,scotopic vision night vision; uses rods of retina which are
peripherally located
photopic vision daylight vision; uses cones, centrally located
Image Intensifier an electronic vacuum tube that converts beam of
light to electrons, then back to light, increasing the
light intensity in the process
-brightens image up to 5,000 times brighter than
conventional floural
-5 principal parts
5 principal parts of Image Intensifier input phosphor screen, photocathode, electrostatic
focusing lenses, accelerating anode*, output
phosphor screen
Dead man's switch apply positive pressure to switch (not constant
power)
input phosphor screen a 6"- 23" screen bonded to the curved surface of
the flourscopy tube
-made of cesium iodide which acts as a scintillator
-converts XR to light
-curved to maintain distance to focal point
photocathode emits e- when stimulated by light in a process called
photoemission due to it being made of cesium and
antimony compounds
-bonded directly to input phospher
electrostatic focusing lenses negatively charged plates that repel the e- to
accelerate and focus them
-gradient in operation
output phosphor screen 2.5 cm screen located at the opposite end of the
image intensifier that converts e- to intensified light
-made of zinc cadmium sulfide
, accelerating anode* located at the neck of the intensifier near output
phospher, it sets the e- stream in motion at a
constant velocity
Multifield Image Intensifier multiple sizes of input screen; may be used to
magnify the image
Flux Gain Ratio of the number of light photons at the output
phosphor to the number of x-rays at the input
phosphor
Minification Gain Ratio of the square of the diameter of the input
phosphor to the square of the diameter of the
output phosphor.
Total Brightness Gain is equal to the product of Minification Gain and Flux
Gain.
MG x FG
Tube failure reasons 1. Single high-heat exposure on cold anode
2. Tungsten vaporizing
3. Consecutive high heat exposures or long
exposure times
Heat Units (HU) kVp × ma × sec. × rectification constant (RC)
Solutions
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Play your way to mastery with fun games
Match Blocks Charms NEW
Terms in this set (345)
Fixed mAs/ variable kVp chart adjust kVp by multiplying by 2 (+/-) for every
increment of ONE centimeter or inch of size
difference
Fixed KVP/ variable mAs chart adjust mAs by multiplying (+) by 2 for every 4-5
centimeter or inch size difference
digital image quality factors brightness, contrast resolution, spatial resolution,
distortion exposure indicator, noise
brightness intensity of light coming through monitor
contrast resolution how well a system can display varying shades of
gray
-affected by dynamic range
,pixel depth determines the number of shades of gray that can
be displayed: 2 to the 14th power= 16,384 shades of
gray
spatial resolution measured in Lp/ mm
-2.5- 5 Lp/mm in digital imaging
distortion size & shape
effected by SID, OID, and alignment
exposure indicator number displayed on the processed image to
indicate the level of x-ray exposure received to the
digital image receptor.
-red, yellow or green
noise random disturbance that reduces of obscures image
clarity
-SNR and quantum noise
Signal to Noise Ratio (SNR) The ratio of the speech signal (intended signal) to
that of the background noise
-HIGH is ALWAYS best
quantum noise lack of sufficient data (photons) - results in blotchy
or mottled image. Increase mAs to fix
algorithms complex math equations used to maintain image
quality
Dynamic range range of shades a digital system is capable of
displaying as seen by the human eye
exposure latitude the range of exposures that can be used and still
result in the capture of a diagnostic-quality image
-DR has more than film-screen imaging
,scotopic vision night vision; uses rods of retina which are
peripherally located
photopic vision daylight vision; uses cones, centrally located
Image Intensifier an electronic vacuum tube that converts beam of
light to electrons, then back to light, increasing the
light intensity in the process
-brightens image up to 5,000 times brighter than
conventional floural
-5 principal parts
5 principal parts of Image Intensifier input phosphor screen, photocathode, electrostatic
focusing lenses, accelerating anode*, output
phosphor screen
Dead man's switch apply positive pressure to switch (not constant
power)
input phosphor screen a 6"- 23" screen bonded to the curved surface of
the flourscopy tube
-made of cesium iodide which acts as a scintillator
-converts XR to light
-curved to maintain distance to focal point
photocathode emits e- when stimulated by light in a process called
photoemission due to it being made of cesium and
antimony compounds
-bonded directly to input phospher
electrostatic focusing lenses negatively charged plates that repel the e- to
accelerate and focus them
-gradient in operation
output phosphor screen 2.5 cm screen located at the opposite end of the
image intensifier that converts e- to intensified light
-made of zinc cadmium sulfide
, accelerating anode* located at the neck of the intensifier near output
phospher, it sets the e- stream in motion at a
constant velocity
Multifield Image Intensifier multiple sizes of input screen; may be used to
magnify the image
Flux Gain Ratio of the number of light photons at the output
phosphor to the number of x-rays at the input
phosphor
Minification Gain Ratio of the square of the diameter of the input
phosphor to the square of the diameter of the
output phosphor.
Total Brightness Gain is equal to the product of Minification Gain and Flux
Gain.
MG x FG
Tube failure reasons 1. Single high-heat exposure on cold anode
2. Tungsten vaporizing
3. Consecutive high heat exposures or long
exposure times
Heat Units (HU) kVp × ma × sec. × rectification constant (RC)
