TY - JOUR
T1 - Contrast-to-noise ratio difference in small field of view cone beam computed tomography machines.
AU - Bechara, Boulos
AU - McMahan, Clyde A.
AU - Moore, William S.
AU - Noujeim, Marcel
AU - Geha, Hassem
AU - Teixeira, Fabricio B.
PY - 2012
Y1 - 2012
N2 - Each of three cone beam computed tomography (CBCT) machines offer a small field of view (FOV); Promax, Accuitomo 3D, and Kodak 9000. The objectives were to determine, when using a small FOV, the difference in contrast-to-noise ratios (CNR) of images obtained from different machines and different scan settings within each machine. A phantom made of a dry mandible with an epoxy resin based substitute (ERBS) block was used. The ERBS block was fixed to the lingual cortex in the posterior left mandible. Water was used to simulate soft tissue. Twenty scans were acquired. CNR was calculated as the difference in density of the ERBS block and a control area divided by the standard deviation of the difference. The CNR obtained from images acquired with the Promax machine (voxel size of 0.2 mm) was higher than the other machines (voxel sizes 0.076, 0.08, or 0.125 mm) when using a small FOV. The Accuitomo 360° scan had higher CNR than the Accuitomo 180° scan due to the doubling of the number of basis images acquired. Smaller voxel size does not necessarily lead to enhanced CNR. Increasing the number of basis images did increase the CNR.
AB - Each of three cone beam computed tomography (CBCT) machines offer a small field of view (FOV); Promax, Accuitomo 3D, and Kodak 9000. The objectives were to determine, when using a small FOV, the difference in contrast-to-noise ratios (CNR) of images obtained from different machines and different scan settings within each machine. A phantom made of a dry mandible with an epoxy resin based substitute (ERBS) block was used. The ERBS block was fixed to the lingual cortex in the posterior left mandible. Water was used to simulate soft tissue. Twenty scans were acquired. CNR was calculated as the difference in density of the ERBS block and a control area divided by the standard deviation of the difference. The CNR obtained from images acquired with the Promax machine (voxel size of 0.2 mm) was higher than the other machines (voxel sizes 0.076, 0.08, or 0.125 mm) when using a small FOV. The Accuitomo 360° scan had higher CNR than the Accuitomo 180° scan due to the doubling of the number of basis images acquired. Smaller voxel size does not necessarily lead to enhanced CNR. Increasing the number of basis images did increase the CNR.
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U2 - 10.2334/josnusd.54.227
DO - 10.2334/josnusd.54.227
M3 - Article
C2 - 23047033
AN - SCOPUS:84880855162
SN - 1343-4934
VL - 54
SP - 227
EP - 232
JO - Journal of oral science
JF - Journal of oral science
IS - 3
ER -