A quality assurance program for the on-board imager®
A quality assurance program for the on-board imager®
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DOI：
10.1118/1.2362872
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发表时间：
2006-11-01
期刊：
影响因子：
3.8
通讯作者：
Munro, Peter
中科院分区：
文献类型：
--
作者：
Yoo, Sua;Kim, Gwe-Ya;Munro, Peter
为机载成像仪（OBI）系统制定质量保证（QA）计划，并总结多个机构在较长时间内的QA测试结果。影像学和锥形束计算机断层扫描（CBCT）的操作模式进行了评价。来自四个机构的QA程序已经结合起来，生成一系列测试，用于评估车载成像仪的性能。组合QA计划包括三个部分：（1）安全性和功能性，（2）几何结构和（3）图像质量。安全性和功能性测试评价了插管预热期间整个系统的安全功能和临床操作。几何QA验证OBI/CBCT硬件/软件的几何精度和稳定性。图像质量QA监测射线照相图像的空间分辨率和对比灵敏度。CBCT的图像质量QA还包括Hounsfield单位（HU）线性、HU均匀性、空间线性和扫描切片几何形状的测试。每天通过所有安全和功能测试。OBI等中心的平均准确度优于1.5 mm，8个月内的变化范围小于1 mm。机械几何QA中手臂位置的平均准确度优于1 mm，8个月内的变化范围小于1 mm。其他几何结构QA测试的测量结果显示，在整个测试期间，结果稳定在公差范围内。放射学对比敏感度范围为2.2%至3.2%，空间分辨率范围为1.25至1.6 lp/mm。4个月后，CBCT图像显示稳定的空间线性、扫描切片几何形状、对比度分辨率（1%; < 7 mm磁盘）和空间分辨率（> 6 lp/cm）。所有测量的HU线性均在40 HU范围内。通过结合多个机构的测试方法，我们为OBI系统开发了一套全面而实用的QA测试。经长期使用表明，OBI系统机械精度可靠，图像质量稳定。然而，这些测试在检测需要重新校准的OBI系统中的性能缺陷方面很有用。重要的是，所有的测试都要定期进行。(c)2006年美国医学物理学家协会。
To develop a quality assurance (QA) program for the On-Board Imager (OBI) system and to summarize the results of these QA tests over extended periods from multiple institutions. Both the radiographic and cone-beam computed tomography (CBCT) mode of operation have been evaluated. The QA programs from four institutions have been combined to generate a series of tests for evaluating the performance of the On-Board Imager. The combined QA program consists of three parts: (1) safety and functionality, (2) geometry, and (3) image quality. Safety and functionality tests evaluate the functionality of safety features and the clinical operation of the entire system during the tube warm-up. Geometry QA verifies the geometric accuracy and stability of the OBI/CBCT hardware/software. Image quality QA monitors spatial resolution and contrast sensitivity of the radiographic images. Image quality QA for CBCT includes tests for Hounsfield Unit (HU) linearity, HU uniformity, spatial linearity, and scan slice geometry, in addition. All safety and functionality tests passed on a daily basis. The average accuracy of the OBI isocenter was better than 1.5 mm with a range of variation of less than 1 mm over 8 months. The average accuracy of arm positions in the mechanical geometry QA was better than 1 mm, with a range of variation of less than 1 mm over 8 months. Measurements of other geometry QA tests showed stable results within tolerance throughout the test periods. Radiographic contrast sensitivity ranged between 2.2% and 3.2% and spatial resolution ranged between 1.25 and 1.6 lp/mm. Over four months the CBCT images showed stable spatial linearity, scan slice geometry, contrast resolution (1%; < 7 mm disk) and spatial resolution (> 6 lp/cm). The HU linearity was within 40 HU for all measurements. By combining test methods from multiple institutions, we have developed a comprehensive, yet practical, set of QA tests for the OBI system. Use of the tests over extended periods show that the OBI system has reliable mechanical accuracy and stable image quality. Nevertheless, the tests have been useful in detecting performance deficits in the OBI system that needed recalibration. It is important that all tests are performed on a regular basis. (c) 2006 American Association of Physicists in Medicine.