Effect of FOV and mA on Metal Artifacts on CBCT

Cone Beam Computed Tomography (CBCT) is considered an important valuable imaging technique in the diagnosis and treatment planning in oral and maxillofacial surgery as well as implant dentistry by means of three dimensional images which provide extra information about the buccolingual dimension of the alveolar bone with more details for bone anatomy and inclination.

To make an accurate diagnosis and treatment planning, we have to obtain images with more details and good resolution and quality which could be achieved by CBCT. However, there are some issues in scanned areas that can affect their quality such as presence of metals (metallic restorations, orthodontic appliances, dental implants, crowns) which result in artifacts which can be considered as an important cause of poor image quality which will lead to poor diagnosis.

There are many types of artifacts which can be observed on CBCT images. Beam hardening artifact is considered a common one which occurs when an x-ray beam comprised of polychromatic energies passes through an object, resulting in selective attenuation of lower energy photons. The effect is conceptually similar to a high-pass filter, in that only higher energy photons are left to contribute to the beam and thus the mean beam energy is increased ("hardened").