Bushong: Radiologic Science for Technologists: 8th Edition
Chapter 24: Fluoroscopy Q& A
1. Fluoroscopy was developed so that radiologists could view _______ images.
a. static
b. dynamic
c. magnified
d. darkened
ANS: B -Fluoroscopy was developed so that radiologists could view dynamic images.
2. What is the milliamperage used during fluoroscopy?
a.
100 mA
b.
50 mA
c.
5 mA
d.
1 mA
ANS: C -During fluoroscopy, the x-ray tube is operated at less than 5 mA.
3. The image intensifier improved fluoroscopy by increasing image __________.
a. brightness
b. resolution
c. magnification
d. contrast
ANS: A - The image intensifier improved fluoroscopy by increasing image brightness.
4. Image intensified fluoroscopy is performed at illumination levels similar to
a. star gazing.
b. darkened theaters.
c. night driving.
d. radiograph viewing.
ANS: D
Image intensified fluoroscopy is performed at illumination levels similar to radiograph viewing.
5. Visual acuity in the eye is greatest at the ___________, where ________ are
concentrated.
a. retinal periphery, cones
b. fovea centralis, cones
c. retinal periphery, rods
d. fovea centralis, rods
ANS: B
Visual acuity in the eye is greatest at the fovea centralis, where cones are concentrated.
6. The ability of the eye to detect differences in brightness levels is termed
a. visual acuity.
b. scotopic vision.
c. photopic vision.
d. contrast perception.
ANS: D
The ability of the eye to detect differences in brightness levels is termed contrast perception.
7. The _____ in the retina are stimulated by _____ light; the ______ are stimulated by
______ light.
a. rods, bright; cones, low
b. rods, low; cones, low
c. rods, low; cones, bright
d. rods, bright; cones, bright
ANS: C -The rods in the retina are stimulated by low light; the cones are stimulated by bright light.
8. With image intensification the light level is raised to _______ vision.
a. photopic
b. scotopic
c. night
d. twilight
ANS: A -With image intensification the light level is raised to photopic vision.
9. X-rays that exit the patient and enter the image intensifier first interact with the
a. output phosphor.
b. input phosphor.
c. photocathode.
d. anode.
ANS: B - X-rays that exit the patient during fluoroscopy first interact with the input phosphor.
10. The output phosphor of the image intensifier is composed of __________.
a. cesium iodide
b. antimony
c. zinc cadmium sulfide
d. graphite
ANS: A - The output phosphor of the image intensifier is composed of cesium iodide.
11. The input phosphor converts _________ to _________.
a. x-rays, electrons
b. light, electrons
c. electrons, light
d. x-rays, light
ANS: D - The input phosphor converts x-rays to light.
12. The ____________ in the image intensifier emits electrons when it is stimulated by
light photons.
a. input phosphor
b. output phosphor
c. photocathode
d. electron gun
ANS: C -The photocathode in the image intensifier emits electrons when it is stimulated by light photons.
13. The number of light photons emitted within the image intensifier is _____________ to the amount of x-ray
photons exiting the patient.
a. equal
b. unrelated
c. inversely proportional
d. directly proportional
ANS: D
The number of light photons emitted within the image intensifier is directly proportional to the amount of x-ray
photons exiting the patient.
14. The kinetic energy of photoelectrons in the image intensifier is greatly increased by the
a. mAs of the exposure.
b. potential difference across the tube.
c. cesium iodide at the input phosphor.
d. zinc cadmium sulfide at the output phosphor.
ANS: B
The kinetic energy of photoelectrons in the image intensifier is greatly increased by the potential difference
across the tube.
15. Light produced at the output phosphor of the image intensifier has been increased ____ times in intensity.
a. 5–10
b. 20–35
c. 50–75
d. 100–300
ANS: C -Light produced at the output phosphor has been increased 50–75 times in intensity.
16. Electrons hit the ________________ after exiting the anode.
a. output phosphor
b. tube housing
c. photocathode
d. focusing lenses
ANS: A - Electrons hit the output phosphor after exiting the anode.
17. The __________________________ is the product of the minification gain and the flux gain.
a. horizontal resolution
b. brightness gain
c. contrast resolution
d. flux gain
ANS: B - The brightness gain is the product of the minification gain and the flux gain.
18. The ratio of x-rays incident on the input phosphor to light photons exiting the output phosphor is called
___________ gain.
a. magnification
b. minification
c. brightness
d. flux
ANS: D - The ratio of x-rays incident on the input phosphor to light photons exiting the output phosphor is
called flux gain.
19. The capability of an image intensifier to increase the illumination level of the image is called its
a. flux gain.
b. conversion factor.
c. brightness gain.
d. veiling glare.
ANS: C
The ability of the image intensifier to increase the illumination level of the image is called its brightness gain.
20. An image intensifier tube is identified by the diameter of its
a. input phosphor.
b. glass housing.
c. output phosphor.
d. focusing lenses.
ANS: A - An image intensifier tube is identified by the diameter of its input phosphor.
21. Brightness gain is typically in the range of ____________.
a. 50–75
b. 100–1,000
c. 3,000–4,000
d. 5,000–30,000
ANS: D - Brightness gain is typically in the range of 5,000–30,000.
22. Fluoroscopy for an air contrast barium enema is generally done at ____ kVp.
a. 65–75
b. 70–80
c. 80–90
d. 100–110
ANS: C - Fluoroscopy for an air contrast barium enema is generally done at 80–90 kVp.
23. Viewing the fluoroscopic image in magnification mode increases
a. contrast resolution.
b. spatial resolution.
c. patient dose.
d. All of the above.
ANS: D
Viewing the fluoroscopic image in magnification mode increases contrast resolution, spatial resolution, and
patient dose.
24. Television monitoring allows ___________ to be controlled electronically.
a. brightness
b. contrast
c. bandwidth
d. Both a and b.
ANS: D
Television monitoring allows brightness and contrast to be controlled electronically.
25. Automatic brightness control (ABC) maintains the brightness of the image by
varying
a. monitor settings.
b. kVp and mA.
c. monitor bandwidth.
d. All of the above.
ANS: B
Automatic brightness control (ABC) maintains the brightness of the image by varying kVp and mA.