Contrast-to-noise ratio with different large volumes in a cone-beam computerized tomography machine: An in vitro study

ObjectivesThe objectives were to determine whether the images obtained from different cone-beam computerized tomography (CBCT) field of view (FOV) sizes with varying scan time and kilovolt peak using the Picasso Master 3D machine (Vatech, Hwasung, South Korea) differ in contrast-to-noise ratio (CNR).Study DesignA phantom was used. Scans were acquired using the same voxel size, 2 scan times (15 and 24 seconds) for 3 different FOV sizes and 5 different kilovolt peaks. The contrast and CNR were calculated for each FOV.ResultsThe CNRs were similar for the 2 scan times for all 3 FOV sizes. The CNR was lower in the 20 × 19 cm FOV compared with the other 2 FOVs for both scan times.ConclusionsThe CNR does not vary significantly with increasing scan times for all FOV sizes. Smaller FOVs result in enhanced CNR and contrast.