Deck 5: The X-Ray Tube

Question 1

The stationary anode includes an area of tungsten embedded in:

A) a copper rod
B) a tungsten rod
C) a molybdenum disc
D) a copper disc

Answer 1

a copper rod

Question 2

The protective tube housing helps to:

A) keep the tube cool
B) prevent electrical shocks to the radiographer
C) limit leakage radiation
D) all of the above

Answer 2

all of the above

Question 3

The primary purpose of the glass or metal enclosure is to:

A) insulate against electrical shock
B) maintain a vacuum
C) allow the heat to dissipate
D) none of the above

Answer 3

maintain a vacuum

Question 4

The target window is usually approximately:

A) 1 mm²
B) 5 mm²
C) 1 cm²
D) 5 cm²

Question 5

After lengthy exposures,the x-ray tube on a mobile fluoroscopic unit may:

A) be very hot
B) produce large electric shocks
C) exceed leakage radiation limits
D) none of the above

Question 6

Arcing:

A) is a problem associated with glass envelopes
B) is a problem associated with metal envelopes
C) is another name for the flow of electrons from cathode to anode
D) is another name for the flow of electrons from anode to cathode

Question 7

To allow x-rays to leave the tube,the glass or metal enclosure in the area of the target window is:

A) removed
B) made thicker
C) made thinner
D) hinged to allow the window to open

Question 8

The anode includes the:

A) target
B) induction motor
C) envelope
D) A and B

Question 9

By regulation,x-ray tube leakage radiation can be no more than:

A) 100 R per hour
B) 100 R per minute
C) 100 mR per hour
D) 100 mR per minute

Question 10

The negative end of the x-ray tube is the:

A) anode
B) cathode
C) target
D) envelope

Question 11

The cathode includes the:

A) envelope
B) filaments
C) focusing cup
D) B and C

Question 12

The area of the envelope where x-rays should exit the tube is the:

A) door
B) window
C) trap
D) gate

Question 13

An issue with using glass envelopes is that they:

A) lose their resistance to heat over time
B) are very expensive to purchase
C) break into small pieces of glass when they break
D) allow vaporized tungsten to coat the inside of the glass

Question 14

The anode serves as a(n):

A) target to stop the electrons traveling from the cathode
B) electrical conductor
C) heat conductor
D) all of the above

Question 15

Glass enclosures are typically made of borosilicate glass (Pyrex)because:

A) it is an inexpensive material
B) it is an expensive material
C) it is very heat-resistant
D) none of the above

Question 16

The two types of anode designs are stationary and:

A) traveling
B) rotating
C) dynamic
D) all of the above

Question 17

The protective tube housing is lined with:

A) aluminum
B) copper
C) lead
D) glass

Question 18

Electrons from the cathode that do not produce x-rays will:

A) be absorbed in the envelope
B) return to the cathode filament
C) be absorbed in the air in the tube
D) continue on through the circuit

Question 19

In terms of the x-ray tube,envelope is another name for the:

A) anode
B) cathode
C) glass or metal enclosure
D) induction motor

Question 20

The positive end of the x-ray tube is the:

A) anode
B) cathode
C) filament
D) envelope

Question 21

The stationary anode includes an area of ___________ embedded in a copper rod:

A) copper
B) molybdenum
C) tungsten
D) glass

Question 22

For the covering of the rotating anode disc,_____________ may be added to tungsten to increase thermal capacity.

A) molybdenum
B) rhenium
C) copper
D) none of the above

Question 23

X-ray tubes with a stationary anode design may be found today:

A) in small x-ray departments
B) in small x-ray tubes
C) in medical areas that only need small x-ray exposures
D) in medical areas that only image the head and teeth

Question 24

The portion of the induction motor that is outside the tube enclosure is the:

A) rotor
B) stator
C) disc
D) bearings

Question 25

Tungsten is used to coat the anode disc because it:

A) has a low atomic number
B) has a low melting point
C) conducts heat well
D) does not conduct heat well

Question 26

Tungsten is used to coat the anode disc because it:

A) has a high melting point
B) has a low melting point
C) has a low atomic number
D) does not conduct heat well

Question 27

The motor that turns the anode operates through:

A) the use of a transformer
B) the physical connection between rotor and stator
C) self-induction
D) mutual induction

Question 28

The induction motor turns the rotor of a standard x-ray tube ___________ revolutions per minute.

A) 1400
B) 3400
C) 6000
D) 10,000

Question 29

Molybdenum is found in the _______________ of the rotating anode.

A) shaft
B) disc
C) target area
D) A and B

Question 30

One of the reasons that molybdenum is used in rotating anodes is because it is:

A) light
B) heavy
C) dense
D) an excellent conductor

Question 31

The primary disadvantage to the stationary anode is that it:

A) is too expensive
B) heats up too quickly during x-ray production
C) uses tungsten
D) all of the above

Question 32

Copper can be found __________________ of the rotating anode.

A) in the shaft
B) in the target area
C) surrounding the tungsten
D) in the base

Question 33

The melting point of tungsten is:

A) 400° C
B) 1400° C
C) 2400° C
D) 3400° C

Question 34

Molybdenum:

A) is an excellent conductor of electricity
B) is a poor conductor of electricity
C) is an excellent thermal conductor
D) is a poor thermal conductor

Question 35

The rotor is found:

A) near the tube window
B) outside the envelope
C) inside the envelope
D) towards the cathode end of the tube

Question 36

Copper is used in the rotating anode because:

A) it is an excellent conductor
B) it is an excellent insulator
C) it has a high atomic number
D) it has a low atomic number

Question 37

The induction motor turns the rotor of a specialty x-ray tube ___________ revolutions per minute.

A) 1400
B) 3400
C) 6000
D) 10,000

Question 38

Tungsten is used to coat the anode disc because it:

A) has a low melting point
B) has a low atomic number
C) has a high atomic number
D) does not conduct heat well

Question 39

The atomic number of tungsten is:

A) 14
B) 34
C) 74
D) 104

Question 40

The rotating anode design uses a disc whose core is made of:

A) copper
B) tungsten
C) aluminum
D) molybdenum

Question 41

The primary advantage of a rotating anode is that it allows:

A) greater heat capacity at the anode
B) less heat capacity at the anode
C) greater heat capacity at the cathode
D) less heat capacity at the cathode

Question 42

The smaller the anode angle:

A) the smaller the actual focal spot
B) the larger the actual focal spot
C) the smaller the effective focal spot
D) the larger the effective focal spot

Question 43

The advantage to using a small effective focal spot is:

A) the image is sharper
B) the image is less sharp
C) less exposure can be used
D) it is safer for the patient

Question 44

Most x-ray tube target angles range between:

A) 2-5 degrees
B) 7-18 degrees
C) 20-28 degrees
D) 35-45 degrees

Question 45

Based on the anode heel effect,an image taken at 40 inches SID.may demonstrate:

A) decreased exposure toward the anode end of the beam
B) decreased exposure toward the cathode end of the beam
C) decreased exposure toward the left side of the beam
D) decreased exposure toward the right side of the beam

Question 46

The size of the actual focal spot depends on:

A) the size of the anode
B) the size of the cathode filament being used
C) the size of the effective focal spot
D) the size of the tube

Question 47

If the anode angle becomes too small,which of the following may result?

A) x-ray beam size may start to be limited
B) the intensity of the beam near the anode may be reduced
C) the anode heel effect may be seen
D) all of the above

Question 48

The effective focal spot is the:

A) same as the actual focal spot
B) actual area where the electrons hit the target
C) actual size of the origin of the x-ray beam
D) size of origin of the x-ray beam as seen from below the tube

Question 49

The focusing cup is part of the:

A) filament circuit
B) primary circuit
C) secondary circuit
D) none of the above

Question 50

The relationship between the actual focal spot size,effective focal spot size,and anode target angle is called:

A) the anode heel effect
B) the line-focus principle
C) Roentgen's principle
D) all of the above

Question 51

The most common x-ray tube target angle is:

A) 2 degrees
B) 8 degrees
C) 12 degrees
D) 18 degrees

Question 52

The filaments are part of the:

A) filament circuit
B) primary circuit
C) secondary circuit
D) none of the above

Question 53

The rotor is made of:

A) an iron core
B) a molybdenum core
C) tungsten
D) rhenium

Question 54

The advantage to using a larger actual focal spot is:

A) the image is sharper
B) there is less wear and tear on the tube
C) the image is less sharp
D) higher exposures can be used

Question 55

The best situation is to have a _______________ actual focal spot and a ______________ effective focal spot.

A) large;large
B) small;small
C) large;small
D) small;large

Question 56

Each cathode filament is approximately:

A) 1-3 mm long
B) 5-6 mm long
C) 7-15 mm long
D) 20-35 mm long

Question 57

The cathode:

A) includes a focusing cup
B) provides electrons for x-ray production
C) includes filaments
D) all of the above

Question 58

Part of the useful x-ray beam gets absorbed in the anode when:

A) the anode angle is too large
B) the anode angle is too small
C) the actual focal spot is too large
D) the actual focal spot is too small

Question 59

With a rotating anode,the focal spot becomes a focal:

A) path
B) stripe
C) track
D) circle

Question 60

An x-ray tube with two filaments is called a:

A) two-focus tube
B) dual-focus tube
C) trifocal tube
D) highly specialized tube

Question 61

To keep the electrons together,the focusing cup:

A) has a negative charge
B) has a positive charge
C) physically surrounds the electron cloud
D) A and C

Question 62

Heat from x-ray production is removed through convection by the heat traveling from:

A) the tube to the room by cooling fans
B) the tube to heat tolerant materials
C) the tube to the oil bath
D) none of the above

Question 63

Thermionic emission is:

A) heating the filament
B) heating the filament until electrons are boiled off
C) using the focusing cup to create a space charge
D) the space charge that travels from cathode to anode

Question 64

The filament is primarily made of:

A) rhenium
B) copper
C) molybdenum
D) tungsten

Question 65

Which of the following occurs first during x-ray production?

A) thermionic emission
B) voltage is transformed to kilovoltage
C) current passes through the rheostat
D) kilovoltage is applied to anode and cathode

Question 66

The cloud of electrons produced through thermionic emission is more accurately called a(n):

A) space cloud
B) electron cloud
C) electron charge
D) space charge

Question 67

The electrons in the tube current travel:

A) at the speed of light
B) approximately half the speed of light
C) approximately one-fourth the speed of light
D) none of the above

Question 68

The focusing cup is able to keep the electrons together because:

A) opposite charges repel
B) opposite charges attract
C) like charges repel
D) like charges attract

Question 69

Tube rating charts:

A) are no longer used to select safe exposures
B) have been replaced by protective circuits
C) are useful today as quality control tools
D) all of the above

Question 70

Which of the following occurs last during x-ray production?

A) kilovoltage is applied to anode and cathode
B) thermionic emission
C) AC.is converted to DC
D) the rotor starts turning

Question 71

There is a small amount of ______________ added to the filament to increase thermionic emission.

A) thorium
B) rhenium
C) tungsten
D) copper

Question 72

Of all the energy involved in x-ray production,99% is converted to:

A) x-rays
B) electrons
C) heat
D) none of the above

Question 73

The focusing cup is made of:

A) tungsten
B) nickel
C) thorium
D) molybdenum

Question 74

Heat from x-ray production is removed through conduction by the heat traveling from:

A) the tube to the room by cooling fans
B) the tube to heat tolerant materials
C) the tube to the oil bath
D) none of the above

Question 75

Of all the energy involved in x-ray production,_________ is converted to x-ray energy.

A) 1%
B) 10%
C) 50%
D) 99%

Question 76

The purpose of the focusing cup is to:

A) produce thermionic emission from the filament
B) prevent thermionic emission from the filament
C) allow the electrons to spread out
D) keep the electrons together

Question 77

Which of the following occurs first during x-ray production?

A) voltage is transformed to kilovoltage
B) kilovoltage is applied to anode and cathode
C) alternating current is changed to direct current
D) voltage level is adjusted at autotransformer

Question 78

When the exposure switch at the operating console is first depressed:

A) high voltage creates a large potential difference between the anode and cathode
B) the anode starts rotating
C) thermionic emission is achieved
D) B and C

Question 79

Heat from x-ray production is removed through radiation by the heat traveling from:

A) the tube to the room by cooling fans
B) the tube to heat-tolerant materials
C) the tube to the oil bath
D) none of the above

Question 80

The space charge effect describes:

A) how the space charge is created
B) the effect the cloud of electrons has on the voltage across the tube
C) the effect the cloud of electrons has on limiting additional electrons being emitted
D) the effect of the heat of the filament on the size of the space charge