Performance of an automatic dose control system for CT: specifications and basic phantom tests.

PURPOSE

To assess the performance and to provide more detailed insight into the characteristics and limitations of devices for automatic dose control (ADC) in CT.

MATERIALS AND METHODS

A comprehensive study on DoseRight 2.0, the ADC system provided by Philips for its Brilliance CT scanners, was conducted. Phantom tests were carried out on a 64-slice scanner (Brilliance 64) using assorted quality control (QC) phantoms that allowed verification of the basic specifications. If feasible, the findings were verified by model calculations based on known specifications.

RESULTS

For all tests, the dose reductions and modulation characteristics fully met the values expected from the specifications. Adverse effects due to increased image noise were only moderate as a result of the "adequate noise system" design that employs comparatively gentle modulation, and the additional use of adaptive filtration.

CONCLUSION

Simple tests with QC phantoms allow evaluation of the most relevant characteristics of devices for ADC in CT.