Novel Methods for Reducing Breast Dose During Computed Tomography Scans
Mathieu, Kelsey Boitnott
Mikos, Antonios G.
Doctor of Philosophy
Pediatric female and young adult female patients who undergo computed tomography (CT) scanning may be at higher risk for developing radiation-induced breast cancer later in life. Thus, the purpose of this thesis was to both accurately quantify dose and explore new strategies for CT breast dose reduction. In order to determine dose reduction, dose quantification was first assessed through the development and validation of an empirical model for describing attenuation in CT and second through evaluation of the precision of dosimetry-related measurements obtained using three different models of CT scanners. Breast dose-savings was evaluated using CT dose index phantoms, anthropomorphic phantoms, and Monte Carlo computer modeling. Modifications to current scanning procedures, such as proper patient centering and beginning data acquisition with the x-ray tube facing a patient's posterior, were shown to minimize breast dose. Novel techniques, including varying the x-ray tube voltage during scanning and incorporation of a dynamic x-ray beam filter over the breasts, were also found to successfully reduce breast dose.