采用过采样方法评估口腔锥形束 CT 的调制传递函数。
Modulation transfer function evaluation of cone beam computed tomography for dental use with the oversampling method.
机构信息
Oral and Maxillofacial Radiology, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, 5-45 Yushima 1-chome, Bunkyo-ku, Tokyo 1138549, Japan.
出版信息
Dentomaxillofac Radiol. 2010 Jan;39(1):28-32. doi: 10.1259/dmfr/27069629.
OBJECTIVES
The aim was to investigate the possibility of evaluating the modulation transfer function (MTF) of cone beam CT (CBCT) for dental use using the oversampling method.
METHODS
The CBCT apparatus (3D Accuitomo) with an image intensifier was used with a 100 mum tungsten wire placed inside the scanner at a slight angle to the plane perpendicular to the plane of interest and scanned. 200 contiguous reconstructed images were used to obtain the oversampling line-spread function (LSF). The MTF curve was obtained by computing the Fourier transformation from the oversampled LSF. Line pair tests were also performed using Catphan(R).
RESULTS
The oversampling method provided smooth and reproducible MTF curves. The MTF curves revealed that the spatial resolution in the z-axis direction was significantly higher than that in the axial direction. This result was also confirmed by the line pair test.
CONCLUSIONS
MTF analysis was performed successfully using the oversampling method. In addition, this study clarified that the 3D Accuitomo had high spatial resolution, especially in the z-axis direction.
目的
旨在探讨利用过采样方法评估口腔锥形束 CT（CBCT）调制传递函数（MTF）的可能性。
方法
使用带有图像增强器的 CBCT 设备（3D Accuitomo），以轻微角度将 100 微米钨丝放置在垂直于感兴趣平面的平面内的扫描仪中进行扫描。使用 200 个连续重建的图像获得过采样线扩散函数（LSF）。通过从过采样 LSF 计算傅里叶变换来获得 MTF 曲线。还使用 Catphan（R）进行线对测试。
结果
过采样方法提供了平滑且可重复的 MTF 曲线。MTF 曲线表明，在 z 轴方向上的空间分辨率明显高于轴向方向。线对测试也证实了这一结果。
结论
成功地使用过采样方法进行了 MTF 分析。此外，本研究还阐明了 3D Accuitomo 具有很高的空间分辨率，特别是在 z 轴方向上。
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