Radiation dose measurement and prediction for linear slit scanning radiography

 

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dc.contributor.advisor Douglas, Tania S en_ZA
dc.contributor.advisor Hering, Egbert en_ZA
dc.contributor.advisor Maree, Gert en_ZA
dc.contributor.author Irving, Benjamin en_ZA
dc.date.accessioned 2014-07-28T18:16:51Z
dc.date.available 2014-07-28T18:16:51Z
dc.date.issued 2008 en_ZA
dc.identifier.citation Irving, B. 2008. Radiation dose measurement and prediction for linear slit scanning radiography. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/3251
dc.description Includes abstract.
dc.description Includes bibliographical references (leaves 112-117).
dc.description.abstract This study describes dose measurements made for linear slit scanning radiography (LSSR) and a dose prediction model that was developed for LSSR. The measurement and calculation methods used for determining entrance dose and effective dose (E) in conventional X-ray imaging systems were verified for use with LSSR. Entrance dose and E were obtained for LSSR and compared to dose measurements on conventional radiography units. Entrance dose measurements were made using an ionisation chamber and dosemeter; E was calculated from these entrance dose measurements using a Monte Carlo simulator. Comparisons with data from around the world showed that for most examinations the doses obtained for LSSR were considerably lower than those of conventional radiography units for the same image quality. Reasons for the low dose obtained with LSSR include scatter reduction and the beam geometry of LSSR. These results have been published as two papers in international peer reviewed journals. A new method to calculate entrance dose and effective dose for LSSR is described in the second part of this report. This method generates the energy spectrum for a particular set of technique factors, simulates a filter through which the beam is attenuated and then calculates entrance dose directly from this energy spectrum. The energy spectrum is then combined with previously generated organ energy absorption data for a standard sized patient to calculate effective dose to a standard sized patient.Energy imparted for different patient thicknesses can then be used to adjust the effective dose to a patient of any size. This method is performed for a large number of slit beams moving across the body in order to more effectively simulate LSSR. This also allows examinations with technique factors that vary for different parts of the anatomy to be simulated. This method was tested against measured data and Monte Carlo simulations. This model was shown to be accurate, while being specifically suited to LSSR and being considerably faster than Monte Carlo simulations. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Biomedical Engineering en_ZA
dc.title Radiation dose measurement and prediction for linear slit scanning radiography en_ZA
dc.type Thesis / Dissertation en_ZA
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Health Sciences en_ZA
dc.publisher.department Division of Biomedical Engineering en_ZA
dc.type.qualificationlevel Masters en_ZA
dc.type.qualificationname MSc en_ZA
uct.type.filetype Text
uct.type.filetype Image


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