Some applications of filtered bremsstrahlung spectra in radiology

The use of energy spectral information in radiologic measurements was investigated. The energy spectral characteristics of bremsstrahlung radiations filtered by the K-edge absorption of an element were studied by developing suitable models of the filtered spectra. Using the models, the measurement errors caused by the polyenergetic nonlinearity, when such radiations were used as pseudomonoenergetic sources, were investigated. The measurement errors were found to be minimal and simple correction methods were available. A performance criterion was established to determine the optimal energies for measurements. The measurement errors caused by noise from electronic systems and also from limited data accuracies were studied. The noise effects from different types of noise were compared, the effects were shown to be similar and energy values could be chosen so that they were optimal to all types of noise discussed. The optimal energies were also found to be obtainable from a wide variety of filter materials. After the efficacy of the filtered radiations and the determination of the optimal energies were investigated, the rest of this dissertation dealt with the implementation of the measurements. Since radiographic films are the normal recording device in the clinic, their use as detectors and recorders in our measurements was studied