The x-ray intensity is lower on the anode side of the tube because of the:
Line Focus Principle
Heel Effect
Focusing Cup
Filament Length
Which of the following is (are) true regarding the protective housing of the x-ray tube?
Provides mechanical support for the x-ray tube.
Protects the tube from damage.
Aids in absorbing low energy radiation created within the x-ray tube.
All of the above
The negative side of the x-ray tube holds the:
Filament
Anode
Target
Rotor
Tube arcing is caused by:
A small focal spot
The angle of the anode
Tungsten collecting on the envelope of the tube
Not warming up the tube
A dual focus tube has two:
Anodes
Filaments
Rotors
Stators
An x-ray tube has a tube rating chart to show:
Housing cooling times
Anode cooling times
Maximum exposure times
Maximum patient doses
This device is located outside the glass envelope:
Stator
Focal Spot
Which of the following is needed to produce an x-ray?
A source of electrons
A vacuum
A large potential difference
All the above
The tube current is changed by changing the:
Filament Current
Anode Voltage
Focal Spot Size
Exposure Time
A function of the cathode is to:
Be a focal spot
Produce an electrical connection to the rectifier
Produce a thermionic cloud
Rotate the anode
The function of the rotor & the stator assembly is to:
Create a vacuum
Insulate the anode
Each of the following is a part of the cathode assembly except the:
Associated Wiring
Each of the following is a material of choice for the filament except:
Copper
Tungsten
Rhenium
Molybdenum
Filament materials are chosen for their: 1)High Melting Point 2)Low Melting Point 3)Ability to Vaporize Easily 4)High Atomic Number
Numbers 1 & 3 only
Numbers 2 & 3 only
Numbers 1 & 4 only
Numbers 2 & 4 only
Numbers 1, 3, & 4 only
The focusing cup has a _______ charge.
Negative
Positive
The purpose of the focusing cup is to:
Alter the filament size
Group the electrons for their passage to the anode
Regulate anode rotation speed
Increase the heat capacity
X-ray production occurs at the:
Cathode
To extend the x-ray tube life, the technologist should: 1)Perform warm up exposures at the beginning of each day 2)Extend the time that the boost current (prep) button is held down 3)Avoid repeated exposures at or near the tube's capacity
1 & 2 Only
1 & 3 Only
2 & 3 Only
1, 2, & 3
When the anode angle is less than 45 degrees:
Effective focal spot is smaller than the actual focal spot
The actual focal spot of smaller than the effective focal spot
The angle has no effect on focal spot
The exact point in the x-ray unit where x-ray photons are created in:
To cover a 14x17 inch field at 40 inch SID, a ________ target angle is required.
3 Degrees
5 Degrees
7 Degrees
12 Degrees
The use of line focus principle causes a problem known as the ________.
Anode Heel Effect
Space Charge Effect
Quantum Mottle
Vacuum
The disadvantage of a small target angle is:
Increased heat distribution & capacity
Greater field coverage
A greater anode heel effect
A more uniform radiographic density
Warming the x-ray tube: 1)Is never necessary 2)Prevents cracking of the anode 3)Helps maintain the vacuum within the tube
Pitting of the anode commonly occurs:
Consistent low but very long exposures
Consistent single, high exposures
Failure to warm up the tube
All the Above
Anode melt might occur in a specific area on the anode due to:
The unit not being warmed up properly
Extended use
When the kVp is too high
When the stator fails & the rotor ceases to turn
The anode heel effect:
Exists because some x-rays are absorbed by the surface of the anode
Is caused by the charge difference between the anode & cathode
Depends on the mA & kVp
Is reduced by dual focal spot
The line focus principle:
Makes use of an angled cathode structure
Produces x-ray lines
Spreads the heat over a larger part if the anode
To best apply the anode heel effect, the anode should be placed towards which end of the body when performing an AP projection?
Towards the Knee
Towards the Hip
The vacuum created within the x-ray tube increase the efficiency of the tube's operation.
The cathode is the positive side of the x-ray tube.
The faster the anode rotation, the better the heat dissipation.
Many x-ray tubes have two filaments:
Because the second filament can be used as a spare part when the first is burned out
Provide two focal spots
To allow cooling of the filament by alternating exposures
To improve tube cooling by sharing the hear between two filaments
Modern general purpose radiographic equipment uses a stationary anode.
The most common diagnostic radiography target angle is 12 degrees.
The anode disk is composed of several different materials.
Changing the angle of the anode will change the effective focal spot.
One way to extend tube life is by using high mA stations when possible.
