Performance Evaluation Of A Fourth-Generation Computed Tomography (CT) Scanner

One of the first American Science and Engineering Co. (AS&E) CT scanners installed in a clinical environment is operational at the University of Colorado Medical Center. The performance characteristics of several aspects of this stationary detector array scanner have been measured. Included in these characteristics are the resolution capabilities of the scanner in terms of MTF for high contrast objects, and the perceptability capabilities for objects of lower contrast. Other characteristics include patient dose, beam profiles, CT number linearity, noise, algorithm dependences, and the performance of selected electromechanical features such as patient bed incrementing and light beam/radiation field coincidence. Equipment and techniques for measuring these quantities are described. Although data are presented solely for the CT scanner, the procedures for evaluation of performance and periodic quality control may be generalized to other CT scanners. A summary of quality assurance tests being performed and a brief description of these tests in tabular form are presented.