Physics of Radiography Vicki@sciencewow.co.uk

Physics of Radiography

Vicki@sciencewow.co.uk www.sciencewow.co.uk

Physics of Radiography• Structure of an atom• Wave theory• Quantum theory of electromagnetic radiation• Physical properties of X-rays• X-ray spectra (continuous and emission line)• X-ray tube• Types of X-ray tube and power supplies• Compton scattering• Absorption process – matter & materials• Dosimetry

Physics of Radiography• Structure of an atom

Properties of sub-atomic particles Structure of atom Energy levels Electron configuration

Physics of Radiography• Wave theory

Wave terminology Wave equation to calculate frequency and

wavelength

Physics of Radiography• Quantum theory of electromagnetic radiation

Quantisation of energy The photon Wave particle duality

Physics of Radiography• Physical properties of X-rays

X-ray photon energies Frequency & wavelength of X-rays

Physics of Radiography• X-ray spectra (continuous and emission line)

Electronic transitions Line and continuous spectra Effect on spectra of varying accelerating voltage Maximum photon energy

Physics of Radiography• X-ray tube

Diagram of the x-ray tube Calculate electron kinetic energy (J) Convert J to eV

Physics of Radiography• Types of X-ray tube and power supplies

Power supply for electron tube High anode-cathode voltage Effect of high cathode current

Physics of Radiography• Compton scattering

Simple scattering Compton scattering Photoelectric effect Pair production

Physics of Radiography• Absorption process – matter & materials

Material thickness Different materials Attenuation Photographic image Image quality Image intensifiers

Physics of Radiography• Dosimetry

Absorbed dose, dose equivalent, effective dose Units ALARA principle