An efficient Monte Carlo-based algorithm for scatter correction in keV cone-beam CT
An efficient Monte Carlo-based algorithm for scatter correction in keV cone-beam CT
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DOI：
10.1088/0031-9155/54/12/016
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发表时间：
2009-06-21
影响因子：
3.5
通讯作者：
Webb, S.
中科院分区：
文献类型：
--
作者：
Poludniowski, G.;Evans, P. M.;Webb, S.
提出了一种锥束CT图像散射校正的新方法。在初始迭代步骤中使用粗略重建。该算法中包括X射线管光谱和探测器响应的建模。使用蒙特卡罗方法计算成像对象内部的光子扩散。使用对固定节点集的强制检测来计算检测器处的光子得分。然后通过线性插值获得散射轮廓。该算法被称为粗重建和固定检测（CRFD）技术。散射预测定量验证对广泛使用的通用蒙特卡罗代码：BEAMnrc/EGSnrc（NRCC，加拿大）。协议是极好的。将CRFD算法应用于使用Synergy XVI CBCT装置（Elekta Limited，Crawley，UK），使用RANDO和Catphan体模（The Phantom Laboratory，Salem NY，USA）采集的投影数据。该算法被证明是有效的CBCT图像中消除散射引起的伪影，并在台式PC上只需2分钟。图像的均匀性得到了很大的改善，重建中的CT值准确性也得到了很大的改善。当材料的预期CT值与其嵌入的背景材料非常不同时，后者的改善不太明显。
A new method is proposed for scatter-correction of cone-beam CT images. A coarse reconstruction is used in initial iteration steps. Modelling of the x-ray tube spectra and detector response are included in the algorithm. Photon diffusion inside the imaging subject is calculated using the Monte Carlo method. Photon scoring at the detector is calculated using forced detection to a fixed set of node points. The scatter profiles are then obtained by linear interpolation. The algorithm is referred to as the coarse reconstruction and fixed detection (CRFD) technique. Scatter predictions are quantitatively validated against a widely used general-purpose Monte Carlo code: BEAMnrc/EGSnrc (NRCC, Canada). Agreement is excellent. The CRFD algorithm was applied to projection data acquired with a Synergy XVI CBCT unit (Elekta Limited, Crawley, UK), using RANDO and Catphan phantoms (The Phantom Laboratory, Salem NY, USA). The algorithm was shown to be effective in removing scatter-induced artefacts from CBCT images, and took as little as 2 min on a desktop PC. Image uniformity was greatly improved as was CT-number accuracy in reconstructions. This latter improvement was less marked where the expected CT-number of a material was very different to the background material in which it was embedded.