X-Ray Production Flashcards
Four essential requirements for the production of X-Rays:
Vacuuum,A Source of Electrons,Target,and High Potential Difference
Formation of the basic structures of the X-Ray tube :
Pyrex Glass Envelope
The source of electrons:
FIlament
The filament consist of a small coil of:
Tungsten wire
The electron cloud is called:
Space charge
Electrons in the outermost orbital shell move so far from the nucleus that they are no longer held in orbit but are flung out of the atom,forming:
An Electron Cloud
Electrons in the outermost orbital shell move so far from the nucleus that they are no longer held in orbit but are flung out of the atom,forming an electron cloud around the filament,This process is called:
Thermionic Emission
A large Step-Up Transformer supplies:
The Voltage
The filament end of the target is:
Negative
The target end is ______ during an exposure:
Positive
The high positive electric potential at the target attracts the negatively charged electrons of the space charge,which move rapidly across the tube,forming:
An Electron Stream
Great majority of kinetic energy is converted into:
Heat
Created when an incoming electron is suddenly slowed down,changes directions ,and leaves the tungsten atom.This kinetic energy of the electron is converted into an X-Ray photon:
Bremsstrahlung Radiation
Created when an incoming electron interacts with the K-Shell electron and knocks it out of orbit.When the electron void is filled with an outer shell electron,an x-ray photon is created
Characteristic Radiation
Bremsstrahlung is a German word that means:
Braking or slowing
The wave length and energy of the X-Ray beam is said to be:
Heterogenous
Each filament is situated in a hollow area in the cathode called:
A Focusing Cup
The shape of the focusing cup and its negative electric charge cause the electrons to be repelled in the direction of a very precise area on the target called:
The Focal Spot
Focal Spot size ACTUAL
Affects tube heat capacity
Bigger is better
Measure of FS on target surface
Focal Spot size EFFECTIVE
Affects image resolution
Smaller is better
Measurement of vertical projection of actual focal spot
The small filament and focal spot provide much better
Spatial Resolution
The small focal spot should be used for most body parts on small-to-average-size patients to obtain:
The best resolution
Small focal spot exposure factors:
kVp,mA, and Exposure Time will be low to moderate
Large filament provides more _____ and strikes a larger _____:
Electrons,Target area
An electromagnetic induction motor is used to :
Rotate the anode
The tungsten focal area all around the beveled edge of the rotating anode is called:
A Focal Track
The slant of the anode surface is called:
A target angle
X-Ray tube target angles are between _______,with ____ being most common
7 to 17,and 12
The target angle affects the tubes:
Heat Capacity,the sharpness of the radiographic image and the maximum side of X-ray beam
The area on the target surface that is struck by the electron stream
Actual Focal Spot
Refers to the vertical projection of the actual spot onto the patient and image receptor
Effective Focal Spot
Size of the effective focal spot influences resolution in the image:
Line Focus Principle
Effective focal spot is always _____ than Actual focal spot:
Smaller
The size of the effective focal spot determines:
Image resolution
The relative size of the effective focal spot is determined by:
Target Angle
Greater radiation intensity toward the cathode end of the field and place thinner portion of the body part toward anode end of tube:
Anode Heel Effect
Increasing mA,
Increases FIlament heat
Decreasing mA,
Decreases FIlament heat
High mA produce,:
More X-rays
Low mA produce,:
Fewer X-ray
Refers to the length time that the X-rays are turned on:
Exposure Time
Process of removing the long wavelength photons from the x-ray beam:
FIltration
The primary purpose of filtration:
To reduced patient dose
The material commonly used to filter the X-ray beam is aluminum:
Added Filtration
The filtration provided by the glass of the tube and the surrounding oil is called:
Inherent Filtration (Built In)
Inherited Filtration + Added Filtration=
Total FIltration
