Performance evaluation of the Biograph mCT Flow PET/CT system according to the NEMA NU2-2012 standard.
Performance evaluation of the Biograph mCT Flow PET/CT system according to the NEMA NU2-2012 standard.
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DOI：
10.1186/s40658-015-0132-1
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发表时间：
2015-12
期刊：
影响因子：
4
通讯作者：
Minear G
中科院分区：
文献类型：
--
作者：
Rausch I;Cal-González J;Dapra D;Gallowitsch HJ;Lind P;Beyer T;Minear G
本研究的目的是评估 Biograph mCT Flow 64-4R PET/CT 系统（德国西门子医疗）的物理性能，并比较步进拍摄 (SS) 和连续工作台运动 (CTM) 采集中的临床图像质量。按照美国电气制造协会 (NEMA) NU2-2012 标准评估空间分辨率、灵敏度、计数率曲线和图像质量 (IQ) 参数。对于分辨率测量，使用玻璃毛细管内的 18F 点源。灵敏度测量基于填充了 4.5 MBq FDG 的 70 厘米长聚乙烯管。使用直径为 20 厘米的 70 厘米长聚乙烯圆柱体和以偏心 4.5 厘米轴向插入圆柱体的线源（1.04 GBq FDG）测量散射分数和计数率。使用包含六个球体（直径 10 至 37 毫米）的 NEMA IQ 体模来评估图像质量。首先，获取单床扫描（NEMA 标准），然后对 IQ 体模进行双床扫描（每次 4 分钟），图像平面包含以两个床位置重叠区域为中心的球体。此外，在 CTM 模式下对同一区域进行扫描，工作台速度为 0.6 毫米/秒。此外，在 CTM 和 SS 模式下进行了两次患者扫描。比较 SS 和 CTM 采集之间的图像对比度和患者图像。空间分辨率的半高全宽 (FWHM) 范围为 4.3 至 7.8 毫米（径向距离 1 至 20 厘米）。在 FOV 中心和偏离中心 10 cm 处测得的灵敏度均为 9.6 kcps/MBq。测得的噪声当量计数率 (NECR) 峰值为 185 kcps，浓度为 29.0 kBq/ml。分散率为 33.5%。图像对比度恢复值（球体与背景比例为 8:1）在 42%（10 毫米球体）至 79%（37 毫米球体）之间。背景变异性在 2.1 至 5.3% (SS) 之间以及 2.4 至 6.9% (CTM) 之间。 SS 和 CTM 模式之间没有观察到图像质量的显着差异。空间分辨率、灵敏度、散射分数和计数率与前身系统 Biograph mCT 的公布值一致。 SS 和 CTM 采集模式下获得的对比度恢复值和图像质量相似。
The purpose of the study is to evaluate the physical performance of a Biograph mCT Flow 64-4R PET/CT system (Siemens Healthcare, Germany) and to compare clinical image quality in step-and-shoot (SS) and continuous table motion (CTM) acquisitions. The spatial resolution, sensitivity, count rate curves, and Image Quality (IQ) parameters following the National Electrical Manufactures Association (NEMA) NU2-2012 standard were evaluated. For resolution measurements, an 18F point source inside a glass capillary tube was used. Sensitivity measurements were based on a 70-cm-long polyethylene tube, filled with 4.5 MBq of FDG. Scatter fraction and count rates were measured using a 70-cm-long polyethylene cylinder with a diameter of 20 cm and a line source (1.04 GBq of FDG) inserted axially into the cylinder 4.5 cm off-centered. A NEMA IQ phantom containing six spheres (10- to 37-mm diameter) was used for the evaluation of the image quality. First, a single-bed scan was acquired (NEMA standard), followed by a two-bed scan (4 min each) of the IQ phantom with the image plane containing the spheres centered in the overlap region of the two bed positions. In addition, a scan of the same region in CTM mode was performed with a table speed of 0.6 mm/s. Furthermore, two patient scans were performed in CTM and SS mode. Image contrasts and patient images were compared between SS and CTM acquisitions. Full Width Half Maximum (FWHM) of the spatial resolution ranged from 4.3 to 7.8 mm (radial distance 1 to 20 cm). The measured sensitivity was 9.6 kcps/MBq, both at the center of the FOV and 10 cm off-center. The measured noise equivalent count rate (NECR) peak was 185 kcps at 29.0 kBq/ml. The scatter fraction was 33.5 %. Image contrast recovery values (sphere-to-background of 8:1) were between 42 % (10-mm sphere) to 79 % (37-mm sphere). The background variability was between 2.1 and 5.3 % (SS) and between 2.4 and 6.9 % (CTM). No significant difference in image quality was observed between SS and CTM mode. The spatial resolution, sensitivity, scatter fraction, and count rates were in concordance with the published values for the predecessor system, the Biograph mCT. Contrast recovery values as well as image quality obtained in SS and CTM acquisition modes were similar.