University of Texas Health Science Center at San Antonio (UTHSCSA), Dental Diagnostic Science, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA.
Dentomaxillofac Radiol. 2010 Sep;39(6):323-35. doi: 10.1259/dmfr/19603304.
an in vitro study was performed to investigate the relationship between grey levels in dental cone beam CT (CBCT) and Hounsfield units (HU) in CBCT scanners.
a phantom containing 8 different materials of known composition and density was imaged with 11 different dental CBCT scanners and 2 medical CT scanners. The phantom was scanned under three conditions: phantom alone and phantom in a small and large water container. The reconstructed data were exported as Digital Imaging and Communications in Medicine (DICOM) and analysed with On Demand 3D(R) by Cybermed, Seoul, Korea. The relationship between grey levels and linear attenuation coefficients was investigated.
it was demonstrated that a linear relationship between the grey levels and the attenuation coefficients of each of the materials exists at some "effective" energy. From the linear regression equation of the reference materials, attenuation coefficients were obtained for each of the materials and CT numbers in HU were derived using the standard equation.
HU can be derived from the grey levels in dental CBCT scanners using linear attenuation coefficients as an intermediate step.
本体外研究旨在探讨牙科锥形束 CT（CBCT）中灰度值与 CBCT 扫描仪中亨氏单位（HU）之间的关系。
使用 11 台不同的牙科 CBCT 扫描仪和 2 台医用 CT 扫描仪对包含 8 种不同成分和密度的物质的体模进行成像。体模在三种条件下进行扫描：体模单独扫描、体模置于小和大的水容器中扫描。重建数据以数字成像和通信在医学（DICOM）格式导出，并使用韩国首尔 Cybermed 的 On Demand 3D(R) 进行分析。研究了灰度值与线性衰减系数之间的关系。
证明了在某些“有效”能量下，灰度值与每种材料的衰减系数之间存在线性关系。从参考材料的线性回归方程中，获得了每种材料的衰减系数，并使用标准方程推导出 HU 中的 CT 值。
可以使用线性衰减系数作为中间步骤，从牙科 CBCT 扫描仪的灰度值中得出 HU。
