Megavoltage CT imaging quality improvement on TomoTherapy via tensor framelet
Megavoltage CT imaging quality improvement on TomoTherapy via tensor framelet
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DOI：
10.1118/1.4816303
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发表时间：
2013-08-01
期刊：
影响因子：
3.8
通讯作者：
Low, Daniel A.
中科院分区：
文献类型：
--
作者：
Gao, Hao;Qi, X. Sharon;Low, Daniel A.
目的：研究一种新的基于张量框架的重建技术改善断层放射治疗图像质量的可行性。方法：将重建问题描述为一个最小二乘的L1型优化问题，利用张量框架进行图像正则化，张量框架是L1、全变差和小波的推广。图像的高阶导数同时在x、y和z方向上以L1范数在多层上正则化。利用Split Bregman方法有效地求解了这个凸方程。此外，还开发了一种基于GPU的并行算法来加速图像重建。结果：基于张量框架的方法改善了基于滤波反投影和基于全变差的图像质量。当只使用25%的投影视图时，新方法是稳健的。基于GPU的求解器重建一幅40层1 mm分辨率350x350三维图像所需时间与2min相当，每层200个投影视图，每个视图528个检测像素。结论：作者提出了一种基于GPU的张量帧重建方法，该方法可提高CT图像质量，适用于全采样和欠采样投影图像。特别是，体模和患者研究表明，通过张量帧方法增强的成像质量对于TomoTreatment的低剂量成像来说是显著的，投影视图减少了75%。(C)2013年美国医学物理学家协会。
Purpose: This work is to investigate the feasibility of improving megavoltage imaging quality for TomoTherapy using a novel reconstruction technique based on tensor framelet, with either full-view or partial-view data.Methods: The reconstruction problem is formulated as a least-square L1-type optimization problem, with the tensor framelet for the image regularization, which is a generalization of L1, total variation, and wavelet. The high-order derivatives of the image are simultaneously regularized in L1 norm at multilevel along the x, y, and z directions. This convex formulation is efficiently solved using the Split Bregman method. In addition, a GPU-based parallel algorithm was developed to accelerate image reconstruction. The new method was compared with the filtered backprojection and the total variation based method in both phantom and patient studies with full or partial projection views.Results: The tensor framelet based method improved the image quality from the filtered backprojection and the total variation based method. The new method was robust when only 25% of the projection views were used. It required similar to 2 min for the GPU-based solver to reconstruct a 40-slice 1 mm-resolution 350 x 350 3D image with 200 projection views per slice and 528 detection pixels per view.Conclusions: The authors have developed a GPU-based tensor framelet reconstruction method with improved image quality for the megavoltage CT imaging on TomoTherapy with full or undersampled projection views. In particular, the phantom and patient studies suggest that the imaging quality enhancement via tensor framelet method is prominent for the low-dose imaging on TomoTherapy with up to a 75% projection view reduction. (C) 2013 American Association of Physicists in Medicine.