X-ray Production Flashcards
Describe sinusoidal waves
The strength of electric or magnetic fields varies in an alternating manner with distance
What are the four interactions that occur at the target of an X-ray tube?
Deflection- repulsive force of electrons in the target
Ionisation- complete removal of outer shell electrons in the target
Excitation- elevation of shell electrons in the target to higher energy levels
Interactions- between filament electrons and nuclei in the target
What is intensity?
The total energy per second flowing past a unit area
What factors affect intensity?
Tube current
Tube voltage
Filtration
Distance from focus
What is exposure?
The measure of the quantity of -radiation in a beam
What is ‘quality’ of radiation?
The penetrating power of that beam
How do you maximise quality of radiation?
Having a constant potential
Inserting a filter into the primary beam to selectively remove low energy photons
Increase kVp so the maximum photon energy gives greater penetrating power to the beam
What factors can affect quality?
The tube voltage
Filtration
Rectification
Describe characteristic X-ray production
Produced when filament electrons interact with one of the orbital electrons
May excite of ionise the electron= vacancy
Vacancy is filled by an outer electron
Specific electromagnetic radiation energy is emitted (X-ray) at specific energies
Describe Bremsstrahlung X-ray production
The positive charge of the nucleus attracts accelerating electron
Filament electron slowed down by the oath around the nucleus
X-ray photon emitted
Energy values will vary (a direct hit will have max photon energy, whilst no interaction will have no photon energy)
Explain kVp and keV
kVp= X-ray tube electrical potential
keV= energy of the filament electron and consequently the energy of the resultant X-ray beam
Explain filtration
Low energy photons are absorbed
Quality improved due to more effective energies
Intensity reduced
What will distance from the target affect?
Affects intensity
EG- at 2m the same intensity of radiation passing through 1m will be spread over a bigger area, therefore intensity is reduced with increased distance
Intensity= 1/distance squared
