Meetings » 11th CTUG Meeting » Abstracts

Effective Dose from Cone Beam CT Examinations in Dentistry

J Roberts

Radiation Protection Service,
Velindre Hospital,


Cone beam CT (CBCT) is becoming an increasingly utilized imaging modality for dental examinations in the UK. Previous studies have presented little information on patient dose for the range of fields of view (FOVs) that can be utilised. The purpose of the study was therefore to calculate the effective dose delivered to the patient during a selection of CBCT examinations performed in dentistry. In particular, the i-CAT CBCT scanner was investigated for several imaging protocols commonly used in clinical practice. A Rando phantom containing thermoluminescent dosemeters was scanned. Using both the 1990 and recently approved 2007 International Commission on Radiological Protection recommended tissue weighting factors, effective doses were calculated.

Despite calculated doses being an order of magnitude less than a conventional CT head scan it was demonstrated that on average a full FOV CBCT scan delivers significantly greater radiation dose to the patient than traditional dental imaging techniques. This finding served to highlight the importance of proper justification by the clinician when considering patients for CBCT examinations. The effects of using the new tissue weighting factors were also noted.

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