Which factors influence the choice of CBCT field of view to optimize dose?

• A. Diagnostic needs, area of interest, and required resolution; select the smallest FOV that adequately addresses clinical questions.
• B. Patient age only.
• C. Manufacturer's default setting only.
• D. A random field size.

Answer: (C)

Choosing the CBCT field of view is about balancing the clinical question with radiation exposure. The primary driver is what you need to diagnose: clearly defining the area of interest and the specific structures or pathology you must evaluate. If only a small area, such as a few teeth or a localized bone region, is in question, selecting a small FOV that covers exactly that region provides adequate image quality while minimizing exposure to surrounding tissues.

Resolution requirements matter too. Higher spatial resolution may require smaller voxels, which can influence the choice of FOV, but the goal remains to image only the region necessary to answer the clinical question. Dose optimization comes from limiting irradiated tissue, so the smallest FOV that still yields diagnostically acceptable images is preferred. While patient factors like age or size can influence dose considerations, they should not dictate imaging the wrong region or using a larger FOV than needed. Relying on manufacturer defaults or selecting a field size at random does not tailor the exam to the clinical question and usually results in unnecessary radiation.

In short, pick the smallest FOV that adequately addresses the clinical question with the needed image quality, tailoring to the region of interest and dose considerations.