Week 1 Homework Flashcards
What is the minification gain for an image intensification tube with an input screen diameter of 9 inches and an output screen diameter of 1 inch?
a. 9
b. 81
c. 27
d. 18
b. 81
What is the Brightness Gain for an image intensifier with a 9” input phosphor, 1” output phosphor, and a flux gain of 80?
a. 720
b. 81
c. 6,480
d. 11,520
c. 6,480
With image intensified fluoroscopy, there is a reduction of brightness seen at the periphery of the image because objects positioned furthest from the center of the input phosphor are inherently unfocused. This type of distortion is called:
a. lens coupling
b. vignetting (pincusion distortion)
c. modution transfer function (MTF)
d. last image hold
b. vignetting (pincusion distortion)
Internal scatter radiation in the form of x-rays, electrons, and light, can reduce the contrast of image intensifiers through a process called:
a. vignetting (pincusion distortion)
b. modulation transfer function (MTF)
c. veiling glare
d. last image hold
c. veiling glare
Electrons hit the _______________ after passing through the anode.
a. Photocathode
b. Focusing lens
c. Output phosphor
d. Tube housing
c. Output phosphor
The photocathode responds to the light produced at the input phosphor by emitting electrons through a process called:
a. photoemission
b. veling glare
c. brightness gain
d. thermionic emission
a. photoemission
Fluoroscopy allows for continuous imaging of a patient’s internal structures. If the radiologist observes something during a fluoroscopic exam and would like to preserve that image for further study, what type of image can be taken?
a. Flat Plate
b. Topogram
c. Spot Film
d. KUB
c. Spot Film
The photocathode is a thin metal layer bonded directly to the input phosphor and is composed of a photoemissive material called:
a. Zinc-Cadmium Sulfide
b. Calcium Tungstate
c. Barium Strontium Sulfate
d. Cesium and Antimony
d. Cesium and Antimony
The ____________________ in the image intensifier emits electrons when it is stimulated by light photons.
a. Electron gun
b. Output phosphor
c. Photocathode
d. Input phosphor
c. Photocathode
Regardless of part thickness, part composition, and collimation, Automatic Brightness Control (ABC) maintains brightness of the image by varying:
a. Monitor settings
b. Anode voltage
c. Collimation
d. kVp and/or mA
d. kVp and/or mA
Electrostatic lenses are used to accelerate and focus:
a. Electrons
b. Light photons
c. Scatter photons
d. X-ray photons
a. Electrons
Depending on patient size, part thickness, or pathologies present inside the patient, image brightness during a fluoroscopic exam is maintained by automatically varying the kVp and/or mA by this feature:
a. automatic brightness control (ABC)
b. minification gain
c. flux gain
d. photoemission
a. automatic brightness control (ABC)
The biggest disadvantage of using magnification during image intensified fluoroscopic imaging is:
a. Increased patient dose
b. Decreased spatial resolution
c. Decreased contrast resolution
d. Increased quantum mottle
a. Increased patient dose
The output phosphor of the image intensifier is composed of _________________.
a. Graphite
b. Crystallized Silicon
c. Silver-Activated Zinc Cadmium Sulfide
d. Cesium iodide
c. Silver-Activated Zinc Cadmium Sulfide
Most image intensifiers are of the multifield type which allow for image magnification (example a common trifield tube is 25/17/12 cm). The numeric dimensions refer to the _____________ of the image intensifier (II).
a. electrostatic lenses
b. output phosphor
c. input phosphor
d. photocathode
c. input phosphor
During Fluoroscopy, the SOD on a fixed unit cannot be less than ______________ inches.
a. 20 in (50 cm)
b. 40 in (100 cm)
c. 15 in (38 cm)
d. 12 in (30 cm)
c. 15 in (38 cm)
The number of light photons emitted within the image intensifier is _______________ to the amount of x-ray photons exiting the patient.
a. Directly proportional
b. Unrelated
c. Inversely proportional
d. Unequal
a. Directly proportional
X-rays that exit the patient and enter the image intensifier first interact with the:
a. Photocathode
b. Anode
c. Input Phosphor
d. Output phosphor
c. Input Phosphor
The input phosphor on an image intensifier is made of:
a. Sodium-Activated Cesium Iodide
b. Barium Strontium-Sulfate
c. Zinc Cadmium Sulfide
d. Molybdenum
a. Sodium-Activated Cesium Iodide
What is the magnification factor for an image viewed with an image intensification tube with an input screen diameter of 9 inches that is using a 3-inch diameter area during magnification?
a. 6.0
b. 27
c. 3.0
d. 4.1
c. 3.0
The input phosphor of the image intensifier converts _______________ to _______________.
a. Light, electrons
b. X-rays, light
c. X-rays, electrons
d. Electrons, light
b. X-rays, light
With the image intensifier, viewing the fluoroscopic image in magnification mode increases __________________.
a. Contrast resolution
b. Spatial resolution
c. Patient Dose
d. All of the above
d. All of the above
In order to magnify an image during a fluoroscopic exam, the voltage to the _______________ must be increased.
a. Input Phosphor
b. Output Phosphor
c. Anode
d. Electrostatic Lens
d. Electrostatic Lens
The output phosphor absorbs ______________ and emits ______________.
a. X-ray photons, light photons
b. Light photons, x-ray photons
c. Electrons, light photons
d. Light photons, electrons
c. Electrons, light photons
