The influence of bowtie filtration on cone-beam CT image quality
The influence of bowtie filtration on cone-beam CT image quality
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DOI：
10.1118/1.3017470
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发表时间：
2009-01-01
期刊：
影响因子：
3.8
通讯作者：
Jaffray, D. A.
中科院分区：
文献类型：
--
作者：
Mail, N.;Moseley, D. J.;Jaffray, D. A.
锥形束CT（CBCT）中探测器处的X射线能量密度的大变化对探测器有限的动态范围提出了重大挑战，导致皮肤线的损失以及CT数量精度、对比度噪声比和图像均匀性的降低。作者研究了在图像引导放射治疗系统（Elekta肿瘤系统，XVI）中实现的蝴蝶结滤波器的性能，该滤波器作为补偿器，通过通量调制、减少X射线散射和减少患者剂量来改善图像质量。在CTDI剂量体模上进行了带和不带蝴蝶结滤波器的剂量测量，并进行了经验拟合，以计算距体模中心轴任何径向距离的剂量。无论患者的体型、形状、解剖部位和视野如何，蝴蝶结滤波器都能全面提高CT数准确度、图像均匀性、低对比度可检测性和成像剂量。所实现的蝴蝶结滤波器提供了成像性能的显著改善，并且与当前用于图像引导放射治疗的临床系统兼容。(C)2009年美国医学物理学家协会。[DOI 10.1118/1.3017470]
The large variation of x-ray fluence at the detector in cone-beam CT (CBCT) poses a significant challenge to detectors' limited dynamic range, resulting in the loss of skinline as well as reduction of CT number accuracy, contrast-to-noise ratio, and image uniformity. The authors investigate the performance of a bowtie filter implemented in a system for image-guided radiation therapy (Elekta oncology system, XVI) as a compensator for improved image quality through fluence modulation, reduction in x-ray scatter, and reduction in patient dose. Dose measurements with and without the bowtie filter were performed on a CTDI Dose phantom and an empirical fit was made to calculate dose for any radial distance from the central axis of the phantom. Regardless of patient size, shape, anatomical site, and field of view, the bowtie filter results in an overall improvement in CT number accuracy, image uniformity, low-contrast detectability, and imaging dose. The implemented bowtie filter offers a significant improvement in imaging performance and is compatible with the current clinical system for image-guided radiation therapy. (C) 2009 American Association of Physicists in Medicine. [DOI: 10.1118/1.3017470]