Award Date


Degree Type


Degree Name

Master of Science (MS)


Health Sciences

First Committee Member

Phillip Patton

Number of Pages



The rapid technological advances in CT over the past 30 years have resulted in a steady increase in the number of CT scans being performed annually, making it the major source of exposure to the population via diagnostic x-rays. With this increased utilization, the concerns over patient radiation doses from CT have also grown. Although CT studies only amount to about 5% of all X-ray examinations, it contributes approximately 40% of the collective dose from diagnostic radiology to the population. This fact has made CT dosimetry an important topic in diagnostic radiology today. The introduction of multislice scanners has focused further attention on this issue; and it is generally believed multi slice scanners can lead to higher patient doses. This is due to the increased abilities of the multi-slice scanners, i.e. increased volume coverage at higher tube currents, which could lead to an increase in patient dose; This study will provide a comparison of three multi-slice CT scanners. All three scanners are the same make and model and only vary in their slice capabilities. Six protocols are performed, two axial protocols, consisting of one head and one abdomen scan, and four helical protocols, consisting of two head and two abdomen scans. The acquisition parameters was kept consistent for each set of scans with the goal of providing comparative data to substantiate or refute the concern that multi-slice scanners will increase patient dose; Doses for all three CT scanners were compared for each protocol. The results showed that the 4-slice CT generated a larger dose than both the 16-slice and the 64-slice scanners. In the axial protocols, the dose decreased as the slice capabilities if the scanners increased. In the helical protocols, the 64-slice scanner produced a larger dose in comparison to the 16-slice scanner.


Comparison; Computed; Dose; Scanners; Slice; Tomography

Controlled Subject

Diagnostic imaging; Biophysics

File Format


File Size

2068.48 KB

Degree Grantor

University of Nevada, Las Vegas




If you are the rightful copyright holder of this dissertation or thesis and wish to have the full text removed from Digital Scholarship@UNLV, please submit a request to and include clear identification of the work, preferably with URL.


IN COPYRIGHT. For more information about this rights statement, please visit