A Preliminary Study of Radiation Dose of 64-row Spiral CT in Temporal Bone

Objective To study the relation between the radiation dose and kv/mA,and the low-dose scanning protocol of 64-row spiral CT in temporal bone. Materials and Methods With 120kV/100kV/80kV,0.5s/rot and HP41,one adult and one child cranium specimen were scanned with gradient declining mA from 200mA in Toshiba Aquilion 64-row spiral CT. The CT dose index volume (CTDIvol) and the quality of images were compared among the different groups. Results The relation between CTDIvol and mA was the linear correlation. The CTDIvol was significantly reduced,the average standard difference (SD) was 120-150 with 30mA,and the structure of the images still could show clearly. The relation between the CTDIvol and kV is exponential correlation. The CTDIvol could be significantly reduced,as declining kV slightly when mA large.Keeping the same SD,the scanning kV and mA could be used lower in children than in adults. Conclusion The CT low-does scanning protocol could be used by low mA or low kV in the temporal bone scanning with Toshiba Aquilion 64-row spiral CT.