Dose and image quality for a cone-beam C-arm CT system
Dose and image quality for a cone-beam C-arm CT system
复制标题
DOI：
10.1118/1.2370508
复制
发表时间：
2006-12-01
期刊：
影响因子：
3.8
通讯作者：
Strobel, Norbert
中科院分区：
文献类型：
--
作者：
Fahrig, Rebecca;Dixon, Robert;Strobel, Norbert
我们评估了最先进的血管造影C臂系统(Axiom Artis DTA，西门子医疗解决方案，德国Forchheim)在不同剂量水平和管电压下用于三维神经成像的剂量和图像质量以及相关的测量方法。与传统CT不同，束长度覆盖整个体模，因此，计算机断层扫描剂量指数(CTDI)的概念不是可选的度量，人们可以通过使用小电离室直接测量不同点的剂量来恢复到传统的剂量测量方法。这种方法允许我们定义和计算一种新的剂量度量，该度量适合于与常见的传统CT的CTDIW进行直接比较。一项涉及CATPHAN 600的感知研究表明，当使用从70kVp到125kvp的管子电压时，在推荐的头部扫描剂量(60 MGY)下，人们可以预期看到至少9 mm的嵌片，标称对比度为0.5%。在分析固定剂量下管电压对图像质量的影响时，我们发现较低的管电压可以改善小直径物体的低对比度检测能力。讨论了KVP、图像噪声、剂量和对比度知觉之间的关系。(C)2006年美国医学物理学家协会。
We assess dose and image quality of a state-of-the-art angiographic C-arm system (Axiom Artis dTA, Siemens Medical Solutions, Forchheim, Germany) for three-dimensional neuro-imaging at various dose levels and tube voltages and an associated measurement method. Unlike conventional CT, the beam length covers the entire phantom, hence, the concept of computed tomography dose index (CTDI) is not the metric of choice, and one can revert to conventional dosimetry methods by directly measuring the dose at various points using a small ion chamber. This method allows us to define and compute a new dose metric that is appropriate for a direct comparison with the familiar CTDIW of conventional CT. A perception study involving the CATPHAN 600 indicates that one can expect to see at least the 9 mm inset with 0.5% nominal contrast at the recommended head-scan dose (60 mGy) when using tube voltages ranging from 70 kVp to 125 kVp. When analyzing the impact of tube voltage on image quality at a fixed dose, we found that lower tube voltages gave improved low contrast detectability for small-diameter objects. The relationships between kVp, image noise, dose, and contrast perception are discussed. (c) 2006 American Association of Physicists in Medicine.