Abstract: Objective: To investigate the value of low dose muti-slice computed tomography (MSCT) in preoperative evaluation of location for oral implantation procedure. Methods: A total of 80 patients planned to receive oral implantation procedure were enrolled, and were divided into 4 groups, with 20 patients in each group. SIEMENS Definition AS40 CT was used for MSCT scanning with the low dose of 40 mA, 50 mA, 60 mA and the conventional dose of 90 mA in the 4 groups, respectively. Volume CT dose index (CTDIv) and dose length product (DLP) were calculated, and image quality was compared between the 4 groups. Results: Except that there was no significant difference in CTDIv, DLP between 60 mA and 90 mA groups, significant difference was found in CTDIv, DLP between any of the other 2 groups. Image quality between the 4 groups were similar. Conclusions: For MSCT, low dose of 40 mA not only can guarantee the image quality but also can meet the needs of preoperative evaluation of location for oral implantation procedure and may sharply decrease the radiation dose（35.0%）.

Key words: Low dose, muti-slice computed tomography, Oral planting, radiation dose