Xray Interactions

negative tube end

cathode

positive tube end

anode

Target angle of rotating targets range from

5-20 degrees

2 interactions that occur in the tube

characteristic and brems

Incoming electron kicks out k shell electron, creating an empty hole and causes a cascade effect. kVp must be AT LEAST 69.5 to occur

Characteristic Interaction

Incoming electron bends around nucleus and changes direction, creating a primary xray photon

Brems Interaction

Loss of some energy from beam as it passes through tissue being imaged 

attenuation

Higher kvp results in

fewer photon interactions and more photon transmission

K Shell =

69.5

L Shell =

12.1

M Shell =

2.82

What does filtration do?

gets rid of low energy x ray photons

2 types of filtration are:

 Inherent and added (Total filtration is 2.5 mm aluminum)

Makes nonuniform images appear uniform

compensating filter

The advantage of having a focal track is

higher exposure factors can be used

Filament current range

3 to 5 A

mA x sec x kvp x generator factor

Heat units equation

• Single phase = 1.0

• 3 phase = 1.35 

• High frequency = 1.40 (most efficient)

Generator factor

Compton scatter; the interaction of a photon with a free electron, resulting in energy transfer that ejects the electron and modifies the photon's wavelength.

Compton:

occurs when an x-ray interacts with an electron in the matter. The photo is completely absorbed and its energy is transferred to an electron that is removed from the electron cloud.; results in production of secondary photon

photoeletric

Total photon absorption depends on the

energy of the incoming photon and atomic number of tissue 

interaction that is non diagnostic; no ionization occurs

Classical (Coherent):