48 terms

Ch 5 - X-ray Production

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Crookes
Roentgen discovered x-rays while working with a _______ tube
Space charge
An "electron cloud" surrounding the filament of the cathode is referred to as?
Filament
Free electrons for x-ray production come from the?
Thermionic emission
The creation of the space charge in the x-ray tube produces?
Bremsstrahlung interactions
The majority of photons in the x-ray beam are created by which process?
Heat
More than 99% of the energy of the electron stream is converted into?
Dissipation of heat
The high-speed rotation (10,000 rpm) of the anode enables what?
Size of the actual and effective focal spot
The degree of angulation of the x-ray tube target will determine what?
Two filaments and two focal spots
A dual-focus x-ray tube has:
Uneven distribution of radiation within the x-ray field
The anode heel effect is a phenomenon of x-ray production that results in:
kVp
The penetrating power of the x-ray beam is controlled by varying the:
milliamperes
The rate of current flow across the x-ray tube is measured in:
Increased patient dose; twice as many photon in the x-ray beam; increased radiographic density
Doubling the mA will result in:
milliampere-seconds
The unit used to indicate the total quantity of x-ray exposure is:
Filter
The device for removing the long-wavelenth radiation from the primary x-ray beam.
2.5 mm Al equiv.
X-ray equipment capabable of producing 70 kVp or more is required to have total filtration of at least:
Increase the heat capacity of the anode.
The purpose of rotating the anode of the x-ray tube is?
Size of the effective focal spot
Image sharpness is determined by:
Thermionic emission
The process that causes charged particles to be given off when heat is applied.
The x-ray beam contains a wide range of wavelengths.
Heterogeneous is a term that describes?
12 degrees
How much target angulation is needed in a general purpose tube?
Anode Heel Effect
Variation in radiation intensity across the length of the radiation field.
Electron Stream
The fast moving negatively charged electrons traveling toward the target.
Filtration
Process of removing long wavelengths from the x-ray beam.
Focal Spot
A very precise area on the target where the electrons are focused.
Focal Track
Tungsten focal area around the beveled edge of the rotating anode.
Positive
Anode is positive side/negative side)
Negative
Cathode is (positive side/negative side)
Voltage is measured at the peak of the electric cycle.
What is Kilovolts Peak
Penetrating power and contrast
What does kVp control
The size of the effective spot influences image sharpness
What is the Line Focus Principle
mAs
Measures the rate of current flow across the x-ray tube
Target
The positive end of the x-ray tube which attracts the negative charged electrons of the "space charge" which move rapidly across the tube forming an electron stream.
Target Angle
The slant of the anode surface.
W
What element symbol is tungsten?
74
How many electrons are there in a tungsten atom?
Exposure Time
The length of time that the x-rays are turned on.
Filament
A small coil of tungsten wire.
Negative
Is the filament the positive side or negative side of the x-ray tube?
Focusing cup
A hollow area in the cathode where the filament is situated.
heat distribution
What is the purpose of the Rotating Anode
T
T/F The voltage applied to the x-ray tube controls the speed and power of the electrons in the electron stream.
T
T/F When voltage is increased, the result is shorter wavelength & greater energy
kVp
What controls the penetrating power of the x-ray beam?
Decrease
Increasing the kVp will Increase/Decrease the contrast?
T
T/F The steeper the target angle, the greater the size difference between the actual and effective focal spot?
Electron Cloud
Another name for Space charge
Thermionic Emission
Process by which electrons are "boiled off" from the tungsten filament in the x-ray tube.
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