SyllabusThe subject will cover the following topics:
X Ray Production
Bremsstrahlung (B) and characteristic X radiation using electron (e) bombardment of X ray tube target, collisional/radiative ratio and relation to e-e interactions and e-nuclear interactions in X ray tube target, critical absorption and principal emission energies of target material, Duane Hunt Law, B intensity from a thin target, Kramers Law, B intensity from a thick target, efficiency of X ray production, squared voltage law for generated B intensity, total intensity and n(E) versus E spectra, Power voltage law for attenuated B intensity, relationship of the exit intensity power law to the scatter/primary ratio, angular distribution of X ray generation.
The Characterisation of Diagnostic X Ray Beams.
Single vs multi energy photon beams, spectrum representations and dependencies (on voltage V, current I, attenuation, and the V/i waveform), average photon energy, effective photon energy. The relationships between intensity, energy fluence, photon fluence kerma and exposure. Spectral distribution comparison, thin beam and broad beam measurement geometries. Analysis of the scatter/primary radiation ratio and its dependencies.
The Physical Basis of X Ray Image Production.
Analysis of Primary Radiographic Image Generation. Attenuation of the diagnostic X beam within the body, differential attenuation in tissue components and the image with reference to visualisation, spectral modification with differential attenuation. Dependencies and parameters of the primary radiographic image: energy fluence, unsharpness, spatial resolution, contrast, quantum noise and its Poissonate basis. Geometric dependencies of image formation, sharpness parameters.
Analysis of Transformation to the Secondary Radiographic Image: X photon interaction in the fluorescent screen, visible photon yield, efficiency. Radiographic film: X photon and visible photon response energy dependency , optical density Electronic detector response and photon energy dependency. Physical basis and analysis of the Hurter and Driffield film curve for visible and X photon irradiation. Quantitative relationship between contrast, film gamma, latitude, sensitivity. Intensification factor and dependency on effective beam energy. Physical basis of the approximation of linear attenuation coefficients for computerised tomographic images.
The Physical Basis of X Ray Technique Exposure Manipulation.
Basis of power voltage laws for exit energy fluence and exposure level, power voltage laws for film average optical density and average electronic signal magnitude. Theoretical basis and validity of the ?15% rule? in diagnostic radiography for constant part thicknesses.
Analysis of X ray exposure control for variable part thicknesses and theoretical basis of the 'fixed kVp' and 'variable kVp' approaches.
The Modulation Transfer Function.
The precise description of image quality. Elementary concepts of Fourier analysis, obtaining a valid definition of the MTF. MTF functional dependency upon spatial frequency and the physical interpretation, relationship of the MTF to contrast frequency response. Combining MTF values in a system.
Analytical Methods Used (integral in the above topics).
Simple dimensional analysis, elementary probabilistic analysis, elementary differential equations: analytical and also Euler solutions, (the latter utilising spreadsheet software), graphical analysis including curve fitting and logarithmic scaling using computer software where appropriate.
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