Optimization of image acquisition techniques for dual-energy imaging of the chest
Optimization of image acquisition techniques for dual-energy imaging of the chest
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DOI：
10.1118/1.2777278
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发表时间：
2007-10-01
期刊：
影响因子：
3.8
通讯作者：
Van Metter, R.
中科院分区：
文献类型：
--
作者：
Shkumat, N. A.;Siewerdsen, J. H.;Van Metter, R.
进行了实验和理论研究，以确定最佳的采集技术的原型双能量（DE）胸部成像系统。研究的技术因素包括选择增加的X射线过滤，kVp对，低能量和高能量投影之间的剂量分配，总剂量等于或小于传统胸片。计算Optima以最大化肺结节可检测性，其特征在于DE胸部图像中的信噪比（SDNR）。通过DE图像SDNR的级联系统分析确定最佳射束过滤，用于在周期表（Z（过滤器）= 1- 92）上选择过滤器，证明了低kVp投影和高kVp投影之间的差分过滤的重要性，并建议在Z（过滤器）=25-50范围内的最佳高kVp过滤器。例如，向高kVp射束添加类似于2.1 mm Cu、类似于1.2 mm Zr、类似于0.7 mm Mo和类似于0.6 mm Ag的过滤，提供了最佳（且几乎等同）的软组织SDNR。最佳kVp对和剂量分配进行了研究，使用胸部体模模拟肺结节和肋骨薄，平均和厚的身体体质。低能量和高能量技术的范围分别为60-90 kVp和120-150 kVp，对于所有患者厚度和所有成像剂量水平，在[60/120] kVp时达到峰值软组织SDNR。一个强烈的依赖于kVp的低能量投影进行了观察。低能量和高能量投影之间的剂量最佳分配是这样的，即总剂量的30%由低kVp投影提供，表现出对kVp对和剂量的相当弱的依赖性。这些结果指导了原型DE成像系统的实施，用于早期肺结节检测和诊断的成像试验。(C)2007年美国医学物理学家协会。
Experimental and theoretical studies were conducted to determine optimal acquisition techniques for a prototype dual-energy (DE) chest imaging system. Technique factors investigated included the selection of added x-ray filtration, kVp pair, and the allocation of dose between low- and highenergy projections, with total dose equal to or less than that of a conventional chest radiograph. Optima were computed to maximize lung nodule detectability as characterized by the signal-difference-to-noise ratio (SDNR) in DE chest images. Optimal beam filtration was determined by cascaded systems analysis of DE image SDNR for filter selections across the periodic table (Z(filter) = 1- 92), demonstrating the importance of differential filtration between low-and high-kVp projections and suggesting optimal high-kVp filters in the range Z(filter)=25-50. For example, added filtration of similar to 2.1 mm Cu, similar to 1.2 min Zr, similar to 0.7 mm Mo, and similar to 0.6 mm Ag to the high-kVp beam provided optimal (and nearly equivalent) soft-tissue SDNR. Optimal kVp pair and dose allocation were investigated using a chest phantom presenting simulated lung nodules and ribs for thin, average, and thick body habitus. Low- and high-energy techniques ranged from 60-90 kVp and 120-150 kVp, respectively, with peak soft-tissue SDNR achieved at [60/120] kVp for all patient thicknesses and all levels of imaging dose. A strong dependence on the kVp of the low-energy projection was observed. Optimal allocation of dose between low- and high-energy projections was such that similar to 30% of the total dose was delivered by the low-kVp projection, exhibiting a fairly weak dependence on kVp pair and dose. The results have guided the implementation of a prototype DE imaging system for imaging trials in early-stage lung nodule detection and diagnosis. (C) 2007 American Association of Physicists in Medicine.