Clinical application of low-dose spiral CT for orthodontics

Objective To determine the effect of reducing the value of mA or kV on the image quality and the radiation dose of the patients undergoing low-dose spiral CT for orthodontics.Methods Thirty patients were divided into three groups,each group has 10 patients.They were group 1(80 kV and 200 mA),group 2 (120 kV and 80 mA),group 3(120 kV and 200 mA)The volume CT dose index(CTDI)was recorded and the average dose-length produce(DLP)was calculated in three groups,respectively.Image quality of three groups were compared and scored by two radiologists,and the results were statistically analysed.Results The CTDI among three groups in diagnostic image quality.Conclusions Low-dose spiral CT for orthodontics,especially the low-kV scan,may decrease the radiation exposure and guarantee the image quality. Key words: Orthodontics; Tomography; X-ray computed; Image processing; Radiation dosage