Gagne, Matthew P.2015-08-042015-08-0420132013https://hdl.handle.net/2144/12103Thesis (M.A.)--Boston UniversityThe purpose of our study was to determine if it is possible to acquire CTA images of small vessels using lower concentrations of iodinated contrast material without substantially diminishing image quality. A custom designed multi-purpose phantom was used to test multiple concentrations of iodinated contrast material using low x-ray tube voltage experimental CTA protocols. A single scan using 120 kVp and Noise Index at a setting of 23 was compared to scans using 100 kVp and 80 kVp tube voltages and Noise Index settings of 23, 21, and 19. Lower tube voltages did produce increased attenuation in contrast material regions of interest, however, increased image noise caused the CNR and FOM for the currently established imaging protocol to be superior to the experimental protocols tested. Despite minor decreases in image quality, the experimental imaging protocols were able to produce images utilizing significantly decrease levels of radiation dose. Given minor changes in imaging quality, the ability to substantially reduce dose while maintaining a satisfactory level of image quality was positive. Further experimentation with low kVp CTA imaging utilizing additional NI settings is warranted to measure possible further improvements in image quality while still maintaining low radiation dose.en-USThesis/Dissertation