Lecture #2 Flashcards
(21 cards)
High E Bremsstrahlung
e- directly collide with nucleus
Med E Bremsstrahlung
e- pass close to nucleus
Low E Bremsstrahlung
e- pass a far distance from nucleus
Characteristic Radiation… What is it?
high speed e- hits another e- and knocks it out of orbit
What is found at the Cathode?
- charge
Tungsten filament
focusing cup
What is found at the Anode?
+ charge
Tungsten target
Copper stem
What does placing a target at an angle provide?
Smaller effective focal spot for a sharp image
Low V tube current
Heats the tube filament and makes an e- cloud
High tube V
accelerates the e- stream
Step-Down Filament Transformer
Used to reduce voltage and heat the filament
Step-Up Transformer
Increase V to speed up electrical force
Auto - Transformer
controls the Step-Up transformer to get the desired kVp
What is the most frequent source of malfunction in X-ray tubes?
Filament burnout
What is directly proportional to the tube current?
Quantity of radiation
when tube current (ma) increases then….
More e- are released to the target
increase in kVp causes
and increase in x-ray penetration of matter
Why are aluminum filters used?
to absorb low E phtons
What is a Collimator?
a metal tube used to reduce the size of the x-ray
Define Coherent Scattering
low E photons are deflected by out ring e-
Causes “foggy film”
Define Compton Scattering
Occurs when a photon hits an e- and it is shot off
Causes darken images
What is Beam Attenuation?
Low E photons are more readily absorbed compared to High E photons
