Performance assessment of four 64-slice computed tomographic devices for a typical clinical protocol.

Objective: To compare the performances of four 64-slice CT devices, as regards radiation dose and image quality.

Methods: Effective dose was measured with thermoluminescent dosimeters in an Alderson Rando phantom (Alderson Research Laboratories, New York, NY). Quantitative image quality was evaluated in a Catphan 600 phantom (The Phantom Laboratory, New York, NY) using 3 parameters (modulation transfer function, contrast-to-noise ratio, and figure of merit).

Quality assurance in diagnostic radiology: practical outcomes.

Over the last four years, our Health Physics Department has implemented a quality control programme focusing on the performance of the diagnostic X-ray machines in use at our hospital. The results of the tests performed (X-ray and light field alignment, tube voltage reproducibility and accuracy, ) were used to compare the 1999 and 2002 findings by means of the chi squared and Fischer statistical tests. The comparison has demonstrated that the decrease in the number of non-conformities, also emerging from a simple comparative analysis on the experimental data, was statistically significant with a p<0.