Absorbed and effective doses from cone beam volumetric imaging for implant planning

Objectives: Volumetric CT using a cone beam has been developed by several manufacturers for dentomaxillofacial imaging. The purpose of this study was to measure doses for implant planning with cone beam volumetric imaging (CBVI) in comparison with conventional multidetector CT (MDCT). Methods: The two CBVI systems Used were a 3D Accuitomo (R) (J. Morita), including an image-intensifier type (II) and a flat-panel type (FPD), and a CB MercuRay (R) (Hitachi). The 3D Accuitomo (R) operated at 80 kV, 5 mA and 18 s. The CB MercuRay (R) operated at 120 kV, 15 mA, 9.8 s. The MDCT used was a HiSpeed QX/i (R) (GE). operated at 120 kV, 100 mA and 0.7 s, and its scan length was 77 mm for both jaws. Measurement of the absorbed tissue and organ doses was performed with tin Alderson phantom, embedding the radiophotoluminescence glass dosemeter into the organs/tissues. The values obtained were converted into the absorbed (lose. The effective dose as defined by the International Commission on Radiological Protection was then calculated. Results: The absorbed doses of the 31) Accuitomo (R) of the organs in the primary beam ranged from 1-5 mGy, and were several to ten times lower than other (loses. The effective dose of the 3D Accuitomo (R) ranged from 18 mu Sv to 66 mu Sv, and was an order of magnitude smaller than the others. In conclusion, these results show that the dose in the 31) Accuitomo (R) is lower than the CB MercuRay (R) and much less than MDCT.