Study on the impact of high-voltage generator setting time to CT dose measurement accuracy

With the increasing use of Computed Tomography (CT) in different clinical applications, people pay much more attention to CT dose. The accuracy of CT dose results is directly related to the vital interests of patients, health examination population, clinicians and also competent authority. This study evaluated the critical factors of CT dose measurement and explored the major impact from high-voltage generator setting time on the measurement accuracy. Repeated dose test were conducted at four CT scanners under the various scanning condition, such as dose at different holes, dose at different gantry rotation speed, tube voltage and tube current feedback analysis. Experiments show that the high-voltage generator setting time is the main factor affecting the accuracy of CT dose measurement, and its impact will increase with the higher gantry rotation speed. At 95% confidence level, the permissible errors between measured CTDIvol values and true values of two of the scanners are 8.4% and 12.6% respectively.