Abstracts Health Sciences

Effect of Scanning Conditions on Cone Beam ComputedTomography Gray Value

by Gregory Miles England

Cone beam computed tomography (CBCT) produces a three-dimensional image that allows for precise diagnosis and better treatment planning of various dental complications. However, reliability of CBCT to measure bone mineral density (BMD) measurement has not fully evaluated. Thus, the objective of the current study was to examine whether the CBCT can produce the gray value distribution parameters (mean, variability, and 5 percentile low and high) and their magnitudes are influenced by different scanning conditions and scanners. ATOM Max dental and diagnostic artificial head (model 711-HN, CIRS, Norfolk, VA) was scanned by two CBCT scanners (Planmeca ProMax® 3D Mid and iCAT). Planmeca and iCAT scanners used full field of view with normal dose and ultra-low dose (ULD) sub-options for 3 scanning resolutions (200, 400, and 600 micron voxel sizes) and 4 scanning resolutions (200, 250, 300 and 400 micron voxel sizes), respectively. After 9 weeks, the artificial head was scanned again by the Planmeca scanner with the same scanning conditions. In addition, 2 hydroxyapatite phantoms (1220, and 1540 mg/cm3) were adhered on the artificial head and scanned using the normal and ULD scanning conditions of 400 micron voxel size with both scanners. The gray value histograms of each region were utilized to determine mean value (Mean), standard deviation (SD), 5th percentiles low and high (Low5 and High5) of gray values. The gray value parameters were successfully measured by the CBCT images. The different scanning conditions and the bilateral locations of the artificial head did not have significant effects on measurements of the gray value parameters (p>0.436) with excellent repeatability. However, the iCAT scanner produced significantly different gray values from the Planmeca scanner (p<0.001). These results suggested that the CBCT can measure a material density while calibration of absolute measures is necessary to obtain comparable values between different scanners. Advisors/Committee Members: Kim, Do-Gyoon (Advisor).