The influence of antiscatter grids on soft-tissue detectability in cone-beam computed tomography with flat-panel detectors
The influence of antiscatter grids on soft-tissue detectability in cone-beam computed tomography with flat-panel detectors
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DOI：
10.1118/1.1819789
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发表时间：
2004-12-01
期刊：
影响因子：
3.8
通讯作者：
Jaffray, DA
中科院分区：
文献类型：
--
作者：
Siewerdsen, JH;Moseley, DJ;Jaffray, DA
本文通过广泛的实验研究，评价了抗散射X射线滤线栅对锥束CT图像质量的影响，包括不同的解剖部位（头部和身体）、散射条件（散射-一次比（SPR）从10%到150%）、患者剂量和三维重建的空间分辨率。研究涉及线性网格结合平板成像器的千伏锥束CT成像和放射治疗的指导系统。发现网格在减少X射线散射“杯状”伪影方面是有效的，较重的网格提供增加的图像均匀性。该系统是高度鲁棒性对环伪影，可能会出现在CT重建作为投影数据中的网格线阴影的结果。在16 cm“头部”和32 cm“身体”圆柱体的锥形束CT重建中，根据绝对对比度、体素噪声和对比度噪声比（CNR）定量评价网格对软组织可检测性的影响。在观察者偏好测试中，基于使用和不使用防散射滤线栅采集的患者图像（骨盆、腹部和头颈部位），对成像性能进行了定性研究。结果表明，虽然网格减少散射伪影和提高对比度的主题，有一点强烈的动机，在锥束CT中的CNR和整体图像质量在大多数情况下使用网格。结果突出了对比度和滤线栅噪声的权衡，显示仅在高X射线散射（SPR > 100%）、高成像剂量（D中心> 2 cGy）和低空间分辨率（体素尺寸大于或等于1 mm）的特定条件下滤线栅的图像质量得到改善。(C)2004年美国医学物理学家协会。
The influence of antiscatter x-ray grids on image quality in cone-beam computed tomography (CT) is evaluated through broad experimental investigation for various anatomical sites (head and body), scatter conditions (scatter-to-primary ratio (SPR) ranging from similar to10% to 150%), patient dose, and spatial resolution in three-dimensional reconstruct ions. Studies involved linear grids in combination with a flat-panel imager on a system for kilovoltage cone-beam CT imaging and guidance of radiation therapy. Grids were found to be effective in reducing x-ray scatter "cupping" artifacts, with heavier grids providing increased image uniformity. The system was highly robust against ring artifacts that might arise in CT reconstructions as a result of gridline shadows in the projection data. The influence of grids on soft-tissue detectability was evaluated quantitatively in terms of absolute contrast, voxel noise, and contrast-to-noise ratio (CNR) in cone-beam CT reconstructions of 16 cm "head" and 32 cm "body" cylindrical phantoms. Imaging performance was investigated qualitatively in observer preference tests based on patient images (pelvis, abdomen, and head-and-neck sites) acquired with and without antiscatter grids. The results suggest that although grids reduce scatter artifacts and improve subject contrast, there is little strong motivation for the use of grids in cone-beam CT in terms of CNR and overall image quality under most circumstances. The results highlight the tradeoffs in contrast and noise imparted by grids, showing improved image quality with grids only under specific conditions of high x-ray scatter (SPR > 100%), high imaging dose (D-center > 2 cGy), and low spatial resolution (voxel size greater than or equal to1 mm). (C) 2004 American Association of Physicists in Medicine.