Accurate determination of CT point-spread-function with high precision.
Accurate determination of CT point-spread-function with high precision.
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DOI：
10.1120/jacmp.v14i4.3905
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发表时间：
2013-07-08
影响因子：
2.1
通讯作者：
Wada S
中科院分区：
文献类型：
--
作者：
Kayugawa A;Ohkubo M;Wada S
计算机断层扫描（CT）中调制传递函数（MTF）的测量通常通过扫描点源体模（如细线或微珠）来执行。在这些方法中，通常将感兴趣区域（ROI）放置在扫描图像上以裁剪点源响应。本研究的目的是检查的影响，感兴趣区域的大小上的MTF测量，并优化ROI的大小。使用4个多探测器行CT，通过线和珠方法测量三种类型的重建内核的MTF，这些内核被指定为“平滑”、“标准”和“边缘增强”内核。方形ROI的尺寸从30像素变更为50像素（约2.9 mm至4.9 mm）。使用验证方法对MTF的精度进行了评估。通过线和珠方法测量的MTF取决于ROI大小，特别是在“边缘增强”内核的MTF测量中。通过验证方法评估的MTF精度随ROI大小而变化，我们能够确定每种方法（线/珠）和每种内核的最佳ROI大小。使用这些最佳的ROI尺寸，在每个内核中，通过线方法获得的MTF与通过珠方法获得的MTF非常一致。我们的数据表明，通过将验证方法结合到线和珠方法中，可以克服获得某些内核（如边缘增强）的准确MTF的困难，从而优化ROI大小以准确确定MTF。PACS编号：87.57. -s，87.57.cf，87.57.Q-
The measurement of modulation transfer functions (MTFs) in computed tomography (CT) is often performed by scanning a point source phantom such as a thin wire or a microbead. In these methods the region of interest (ROI) is generally placed on the scanned image to crop the point source response. The aim of the present study was to examine the effect of ROI size on MTF measurement, and to optimize the ROI size. Using a 4 multidetector‐row CT, MTFs were measured by the wire and bead methods for three types of reconstruction kernels designated as ‘smooth', ‘standard', and ‘edge‐enhancement’ kernels. The size of a square ROI was changed from 30 to 50 pixels (approximately 2.9 to 4.9 mm). The accuracies of the MTFs were evaluated using the verification method. The MTFs measured by the wire and bead methods were dependent on ROI size, particularly in MTF measurement for the ‘edge‐enhancement’ kernel. MTF accuracy evaluated by the verification method changed with ROI size, and we were able to determine the optimum ROI size for each method (wire/bead) and for each kernel. Using these optimal ROI sizes, the MTF obtained by the wire method was in strong agreement with the MTF obtained by the bead method in each kernel. Our data demonstrate that the difficulties in obtaining accurate MTFs for some kernels such as edge‐enhancement can be overcome by incorporating the verification method into the wire and bead methods, allowing optimization of the ROI size to accurately determine the MTF. PACS numbers: 87.57.‐s, 87.57.cf, 87.57.Q‐
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影响因子：
3.8
作者：
Xu, J.;Reh, D. D.;Siewerdsen, J. H.
通讯作者：
Siewerdsen, J. H.
影响因子：
3.8
作者：
Kwan, Alexander L. C.;Boone, John M.;Huang, Shih-Ying
通讯作者：
Huang, Shih-Ying
影响因子：
3.8
作者：
Flohr, TG;Stierstorfer, K;McCollough, CH
通讯作者：
McCollough, CH
影响因子：
3.8
作者：
Kachelriess, M;Kalender, WA
通讯作者：
Kalender, WA
影响因子：
3.2
作者：
Ohkubo, Masaki;Wada, Shinichi;Nishizawa, Kanae
通讯作者：
Nishizawa, Kanae