Chapter 2 - 1

Question 1

1. The ______ is the portion of the x-ray tube that contains the filament.

a. cathode
b. anode
c. rotor
d. rotating disk

Answer 1

Solution: a. cathode

The filament, the source of electrons during x-ray production, is located in the cathode.
REF: p.16

Question 2

2. The cathode filament is made of:

a. tungsten
b. rhenium
c. molybdenum
d. lead
e. nickel

Answer 2

Solution: a. tungsten

The cathode filament is made of tungsten.
REF: p.16

Question 3

3. The focusing cup:

a. surrounds the anode.
b. has a positive charge.
c. has a negative charge.
d. focuses the x-ray beam.

Answer 3

Solution: c. has a negative charge

The focusing cup, surrounding the filament on three sides, has a negative charge, keeping the negatively charged electrons focused.
REF: p.16

Question 4

4. In a dual-focus tube, how many filaments are energized at any one time during x-ray production?

a. One
b. Two
c. Four
d. An infinite number

Answer 4

Solution: a. One

Only one filament is energized at any one time during x-ray production.
REF: p.16

Question 5

5. The focusing cup is made of:

a. tungsten
b. rhenium
c. molybdenum
d. lead
e. nickel

Answer 5

Solution: e. nickel

The focusing cup is made of nickel.
REF: p.16

Question 6

6. ______ is the phenomenon that occurs around the filament during thermionic emission and prevents the further escape of electrons from the filament.

a. Saturation current
b. Space charge effect
c. mA rectification
d. Line focus principle

Answer 6

Solution: b. Space charge effect

The space charge effect limits the number of electrons in the space charge by preventing additional electrons from being boiled off the filament.
REF: p.24

Question 7

7. The positive side of the x-ray tube is the:

a. anode
b. cathode
c. window
d. stream of electrons

Answer 7

Solution: a. anode

The anode is the positive side of the x-ray tube, and the cathode is the negative.
REF: p.17

Question 8

8. The maximum speed the rotating anode will typically achieve is ______ rpm.

a. 3200
b. 5000
c. 10,000
d. 20,000

Answer 8

Solution: c. 10,000

Rotating anodes rotate at a set speed ranging from 3000 to 10,000 revolutions per minute (rpm).
REF: p.17

Question 9

9. What is the base material of the anode disk?

a. Molybdenum
b. Tungsten
c. Rhenium
d. Graphite
e. A and B
f. A and D

Answer 9

Solution: f. A and D

The base of the rotating anode disk is made of molybdenum with a graphite layer.
REF: p.17

Question 10

10. What is the name of the fixed physical area on the anode target that is struck by the electron stream?

a. Focal spot
b. Focal point
c. Focal range
d. Any of the above

Answer 10

Solution: a. Focal spot

The focal spot is the fixed physical area on the focal track of the anode target where electrons strike.
REF: p.18

Question 11

11. What is the name of the device in a rotating anode x-ray tube that turns the rotor?

a. Stator
b. Rotor
c. Focusing cup
d. Rheostat

Answer 11

Solution: a. Stator

Located outside the envelope of the x-ray tube, the stator is an electric motor that turns the rotor.
REF: p.18

Question 12

12. Effective compensation for the anode heel effect would involve positioning:

a. the thinnest portion of the part under the anode.
b. the thickest portion of the part under the anode.
c. the thinnest portion of the part under the cathode.
d. B and C.

Answer 12

Solution: a. the thinnest portion of the part under the anode

The thinnest portion of a part should be placed under the anode, because the more intense X-rays are emitted toward the cathode end of the tube, where the thickest part should be placed.
REF: p.34

Question 13

13. What is an acceptable level of leakage from the tube housing?

a. 100 mR per hour, measured 6 feet away
b. 10 mR per hour, measured 1 foot away
c. 1000 R per hour, measured at a distance of 4 meters
d. 100 mR per hour, measured at a distance of 1 meter

Answer 13

Solution: d. 100 mR per hour, measured at a distance of 1 meter

The maximum amount of leakage radiation from an x-ray tube is 100 mR per hour when measured at a distance of 1 meter.
REF: p.20

Question 14

14. Which of the following could be defined as the production of an x-ray photon by the electrostatic attraction between the incident electron and the nucleus of the tungsten atom?

a. Photoelectric interaction
b. Bremsstrahlung interaction
c. Characteristic interaction
d. Pair production interaction

Answer 14

Solution: b. Bremsstrahlung interaction

Production of an x-ray photon as a result of a slowing down of the incoming electron due to the electrostatic force of the nucleus is due to a bremsstrahlung interaction.
REF: p.20

Question 15

15. Which of the following could be defined as the production of an x-ray photon by a collision between the incident electron and a K-shell electron of the tungsten atom?

a. Photoelectric interaction
b. Bremsstrahlung interaction
c. Characteristic interaction
d. Pair production interaction

Answer 15

Solution: c. Characteristic interaction

Characteristic interactions involve the incident electron colliding with a K-shell electron and ejecting it from orbit. X-rays are produced as a result.
REF: p.21

Question 16

16. ______ is the boiling off of electrons from the filament when current is applied.

a. Saturation emission
b. Thermionic emission
c. Filament transport
d. Proton emission

Answer 16

Solution: b. Thermionic emission

Thermionic emission is the emission of electrons (ion) as a result of heat (therm). The heating of the filament is due to the application of current.
REF: p.23

Question 17

17. The actual flow of electrons from cathode to anode within the x-ray tube is known as:

Answer 17

Solution: a. tube current

The tube current is the flow of electrons from cathode to anode within the tube.
REF: p.24

Question 18

18. mA is a measure of ______ that flows from cathode to anode.

a. filament current
b. tube current
c. space charge
d. thermionic emission

Answer 18

Solution: b. tube current

mA or milliampere, is the unit of measure for the amount of current flowing from cathode to anode within the x-ray tube.
REF: p.24

Question 19

19. Increasing the kVp will do which of the following?

a. Decrease the tube current.
b. Increase the speed of the electrons.
c. Increase the penetrability of the beam.
d. A and C.
e. B and C.

Answer 19

Solution: e. B and C

Increasing the kilovoltage (kVp) increases the speed of the electrons traveling between cathode and anode and results in an x-ray beam with greater penetrability.
REF: p.27

Question 20

20. The amount the voltage varies during an x-ray exposure is known as:

a. kVp
b. voltage ripple
c. mA
d. tube current

Answer 20

Solution: b. voltage ripple

The amount of variation of the voltage during an x-ray exposure is voltage ripple; it can vary from 100% to less than 1%, depending on the type of generator being used.
REF: p.28

Question 21

21. What focal spot size is measured directly under the anode target?

a. Actual focal spot
b. Target focal spot
c. Filament focal spot
d. Effective focal spot

Answer 21

Solution: d. Effective focal spot

Based on the line focus principle, the effective focal spot size refers to the measurement of the focal spot from a point directly below the target.
REF: p.32

Question 22

22. Filtration of the x-ray beam results in:

a. increased beam quality.
b. increased beam quantity.
c. lower average energy photons.
d. A and C.

Answer 22

Solution: a. increased beam quality

Beam filtration results in removing lower-energy x-ray photons, resulting in an x-ray beam with fewer photons but with a higher average energy.
REF: p.36

Question 23

23. Which of the following is not classified as inherent filtration?

a. The oil in the transformer
b. The collimator mirror
c. The tube envelope
d. The oil surrounding the tube

Answer 23

Solution: a. The oil in the transformer

The oil in the transformer is not in the path of the x-ray beam, so it has no role in filtering the beam.
REF: p.35

Question 24

24. The amount of filtration required to reduce the exposure of the beam to half of its original intensity is defined as:

a. wedge filtration.
b. HVL
c. mAs compensator.
d. TVL

Answer 24

Solution: b. HVL

HVL, or half value layer, is the amount of filtration needed to reduce the intensity of the x-ray beam to half of its original.
REF: p.36

Question 25

25. *Which* of the following types of filtration produce a more uniform exposure to the image receptor? a. Compensating b. Half-value c. Inherent d. Spatial

Answer 25

Solution: a. Compensating Compensating filters are added filters that alter the beam intensity so images of nonuniform anatomic structures have more uniform brightness/density. REF: p.36

Question 26

26. In order to produce x-rays, electrons must be: a. suddenly decelerated. b. accelerated. c. liberated from the cathode filament. d. all of the above.

Answer 26

Solution: d. all of the above Electrons must be liberated from the cathode filament (thermionic emission), accelerated, and then decelerated very suddenly in order to produce x-rays. REF: p.16

Question 27

27. The device that nearly surrounds the filament is the: a. rotor. b. focusing cup. c. stator. d. anode.

Answer 27

Solution: b. focusing cup The focusing cup surrounds the filament with the exception of the side open to the anode. REF: p.16

Question 28

28. A dual-focus tube has two: a. cathode filaments. b. anodes. c. tubes. d. none of the above.

Answer 28

Solution: a. cathode filaments A dual-focus x-ray tube has two cathode filaments: a large and a small one. REF: p.16

Question 29

29. The rotating target track is primarily made of: a. rhenium b. nickel c. tungsten d. copper

Answer 29

Solution: c. tungsten The target track of a rotating anode is made up primarily of tungsten. REF: p.17

Question 30

30. The target angle of rotating targets typically ranges from: a. 1° to 5° b. 5° to 20° c. 30° to 50° d. 50° to 70°

Answer 30

Solution: b. 5° to 20° Rotating anode target angles usually range from 5° to 20°. REF: p.17

Question 31

31. Tungsten has a ________ atomic number and a ________ melting point. a. low; low b. low; high c. high; low d. high; high

Answer 31

Solution: d. high; high Tungsten has a high atomic number and a high melting point. REF: p.17

Question 32

32. The part of the x-ray tube that is connected to the target and causes it to turn is the: a. filament b. rotor c. stator d. base

Answer 32

Solution: b. rotor The rotor is physically connected to the target and causes it to turn. REF: p.18