Contrast-to-noise ratio with different large volumes in a cone-beam computerized tomography machine: an in vitro study.
OBJECTIVE
The 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).


METHODS
A 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.


RESULTS
The 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.


CONCLUSIONS
The CNR does not vary significantly with increasing scan times for all FOV sizes. Smaller FOVs result in enhanced CNR and contrast.
Department of Comprehensive Dentistry, University of Texas Health Science Center, San Antonio, Texas, USA. boulosbchara@hotmail.com
Boulos
B
Bechara
C Alex
CA
McMahan
William S
WS
Moore
Marcel
M
Noujeim
Hassem
H
Geha
D006801:Humans; D066298:In Vitro Techniques; D008437:Maxilla / Q000000981:diagnostic imaging; D019047:Phantoms, Imaging; D059629:Signal-To-Noise Ratio; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*