Optimization of exposure parameters in dental cone-beam computed tomography using a three-step approach

Publication date: Available online 20 August 2018

Source: Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology

Author(s): Soontra Panmekiate, Peera Rungwittayathon, Wijuck Suptaweeponboon, Nattarus Tangtraitham, Ruben Pauwels

Abstract

Objective

to find the optimal balance between tube voltage (kV), tube current (mA) and exposure time (s) in cone-beam computed tomography (CBCT).

Study Design

three human hemimandibles were scanned using the 3D Accuitomo 170. First, three combinations of kV and mA were used at a constant radiation dose. Seven observers evaluated the images; the kV of the highest-scoring scan was considered as optimal. Second, the lowest acceptable mA for visualizing different anatomical structures was determined. Finally, the samples were scanned using 3 combinations of tube current and exposure time; observers determined the combination with the highest image quality.

Results

at a constant radiation dose, the highest available voltage (i.e. 90 kV) resulted in the highest image quality in terms of general impression, sharpness, noise and artefacts. Depending on the anatomical structure, mA reductions of 20-40% compared with the default setting were possible. Fast-scan protocols showed equal or slightly better image quality compared with the standard scan mode.

Conclusion

For the CBCT model used in this study, optimization implies the use of the highest kV along with the shortest exposure time and a task-specific mA. The proposed step-wise optimization approach could be applied to any CBCT unit, preferably during commissioning.

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