Cross-sectional imaging in dentomaxillofacial diagnostics:: Dose comparison of dental MSCT and NewTom® 9000 DVT

Purpose: For nonsuperimposed and three-dimensional imaging of jaws and teeth, multislice computer tomography (MSCT) can be performed, or alternatively digital volume tomography as a cone beam technique can be applied. The radiation dose of both procedures should be evaluated with different methods of dose assessment. Materials and Methods: A4-row MSCT (Volume Zoom Siemens(R)) and a cone beam CT (NewTom QR-DVT 9000(R)) were compared regarding the radiation exposure of the patient during a dental examination. Organ dose and effective dose were estimated by thermoluminescence dosimetry (TLD) using an Alderson-Rando phantom for both devices. In addition the effective dose of MSCT was calculated from the CTDIvol-value at scanner display and by CT-Expo(R) program. Results: The effective dose of MSCT was 0.33 mSv for women (w) and 0.32 mSv for men (m) measured with TLD in the Alderson-Rando phantom, 0.39/0.35 mSv (w/m) by CTDI calculation and 0.39/0.33 mSv by CT-Expo(R) program. The effective dose of NewTom(R) QR-DVT 9000 from TLD measurement was 0.095/0.093 mSv (w/m). Conclusion: The radiation exposure of a typical dental examination with a NewTom(R) cone beam DVT is about one third of the MSCT dose. Both techniques, however, moderate patient doses. Dosimetry methods as routinely used for MSCT cannot be applied to cone beam DVT.