Electromagnetic Radiation & X-ray Production Flashcards
how does electromagnetic radiation travel?
in straight lines
what is the intensity of the x-ray beam
the total amount of energy passing through unit area in one second (also called energy fluence)
what is the inverse square law?
the intensity of the beam is inversely proportional to the square of the distance from the source, ie: further away, lower intensity of radiation, less dose of radiation received
What are the main electromagnetic radiation used in the radiology department?
X-rays and Gamma rays
How are x-rays produced?
They are produced by the interaction of high speed electrons with the target nucleus
Two ways that high speed electrons interact with the target nucelus
- Characteristic radiation
- Bremsstrahlung
What is Bremsstrahlung?
Electrons interact with the nucleus of the target material as they pass close to it
Causing the electron to slow down and deviate from its path
Kinetic energy is lost and this is converted to x-ray energy i.e., an x-ray photon is emitted by the electron
Bremsstrahlung produces a _____ X-Ray spectrum
Continous
One radiology division where bremsstrahlung is not relevant
Mammography
How does characteristic radiation work?
The incoming electron interacts with an inner shell electron (K shell) of the target nucleus
This electron is ejected from the inner shell, and an electron from an outer shell drops to fill the vacancy
This outer shell electron gives off energy as a photon to make this transition
Photon energy often depends on target material!
What factors determine the intensity of the x-ray beam emitted by the x-ray tube?
- mA or mAs
- kVp
- Constant potential
- Target material
- By reducing added filtration
- By reducing the distance to the X-ray tube
What are important in contributing tot he energy / quality of the x-ray beam?
- kVp
- Constant potential generator
