3.

• 1. ray production happens at the Anode side and does not hit the nucleus interaction; near the nucleus, the interaction changes spot and releases energy called x-ray
• Points to remember about x-rays:

  • X-ray beam is not a solid beam
  • Electrical energy is converted to x-ray energy (1%) and heat (99%)
  • Millions of high-speed electrons interact with an uncountable number of atoms at the target
  • The millions of x-rays produced are of different wavelengths and energy
• Two mechanisms that explain x-ray production at the atomic level are General radiation (or Bremstrahlung radiation) and Characteristic radiation
• General radiation (or Bremstrahlung radiation):

  • Nucleus pushes electrons from the Cathode out of the atom, changing their direction and producing x-rays
  • Incident photons from the Cathode do not hit the nucleus, but suddenly stop and change direction
  • Uses 60-90 kVp (60,000-90,000 V)
  • Can produce Heterogeneous radiation
• Three possibilities when an x-ray photon interacts with matter:

  1. No interaction

  2. Absorption of energy

  3. Scatter of energy
• Factors that affect the type and amount of absorption:

  1. Energy of the x-ray beam

  2. Composition of absorber material

  3. Atomic configuration of absorber material for aprons
• • Inelastic scattering of photons in matter results in a decrease in energy of an x-ray or gamma ray photon
  • Energy of the scattered radiation is different from the incident radiation
  • Involves medium to high form of energy – 62%
  • With Ionization – Absorption – Scatter
• Four interactions with matter:

  1. No interaction: No ionization – No scatter – No absorption

  2. Photoelectric effect:

  • Phenomenon where electrons are emitted from the matter due to absorption of energy from electromagnetic radiation
  • Energy stays within the atom and is absorbed
  • In radiographs, bone appears white due to high density and atomic number causing high absorption
  • Ionization – Absorption occurs – No scatter

  3. Coherent scattering:

  • Also known as Thomson effect or Unmodified scatter
  • Disperses low-energy x-rays without the incident photon losing its energy
  • Accounts for a negligible part of the total interaction between x-rays and matter
  • No ionization – No absorption – ONLY scatter

  4. Compton scattering:

  • Type of scatter that x-rays and gamma rays undergo in matter