Kappadath S Cheenu, Erwin William D, Wendt Richard E
The University of Texas M.D. Anderson Cancer Center, Department of Imaging Physics, Houston, Texas 77030, USA.
J Appl Clin Med Phys. 2006 Nov 28;7(4):74-80. doi: 10.1120/jacmp.v7i4.2376.
We conducted an evaluation of the intercamera (i.e., between cameras) variability in clinically relevant performance characteristics for Symbia gamma cameras (Siemens Medical Solutions, Malvern, PA) based on measurements made using nine separate systems. The significance of the observed intercamera variability was determined by comparing it to the intracamera (i.e., within a single camera) variability. Measurements of performance characteristics were based on the standards of the National Electrical Manufacturers Association and reports 6, 9, 22, and 52 from the American Association of Physicists in Medicine. All measurements were performed using 99mTc (except 57Co used for extrinsic resolution) and low-energy, high-resolution collimation. Of the nine cameras, four have crystals 3/8 in. thick and five have crystals 5/8 in. thick. We evaluated intrinsic energy resolution, intrinsic and extrinsic spatial resolution, intrinsic integral and differential flood uniformity over the useful field-of-view, count rate at 20% count loss, planar sensitivity, single-photon emission computed tomography (SPECT) resolution, and SPECT integral uniformity. The intracamera variability was estimated by repeated measurements of the performance characteristics on a single system. The significance of the observed intercamera variability was evaluated using the two-tailed F distribution. The planar sensitivity of the gamma cameras tested was found be variable at the 99.8% confidence level for both the 3/8-in. and 5/8-in. crystal systems. The integral uniformity and energy resolution were found to be variable only for the 5/8-in. crystal systems at the 98% and 90% confidence level, respectively. All other performance characteristics tested exhibited no significant variability between camera systems. The measured variability reported here could perhaps be used to define nominal performance values of Symbia gamma cameras for planar and SPECT imaging.
我们基于对九个独立系统的测量，对西门子医疗解决方案公司（位于宾夕法尼亚州马尔文）的Symbiaγ相机临床相关性能特征的相机间（即不同相机之间）变异性进行了评估。通过将观察到的相机间变异性与相机内（即单个相机内部）变异性进行比较，确定了其显著性。性能特征的测量基于美国国家电气制造商协会的标准以及美国医学物理学家协会的第6、9、22和52号报告。所有测量均使用99mTc（用于外部分辨率测量的57Co除外）以及低能、高分辨率准直器。在这九个相机中，四个相机的晶体厚度为3/8英寸，五个相机的晶体厚度为5/8英寸。我们评估了固有能量分辨率、固有和外部空间分辨率、在有效视野内的固有积分和微分泛源均匀性、20%计数损失时的计数率、平面灵敏度、单光子发射计算机断层扫描（SPECT）分辨率以及SPECT积分均匀性。相机内变异性通过在单个系统上对性能特征进行重复测量来估计。使用双尾F分布评估观察到的相机间变异性的显著性。对于3/8英寸和5/8英寸晶体系统，在99.8%的置信水平下，测试的γ相机的平面灵敏度存在差异。对于5/8英寸晶体系统，分别在98%和90%的置信水平下，积分均匀性和能量分辨率存在差异。测试的所有其他性能特征在相机系统之间均未表现出显著差异。此处报告的测量变异性或许可用于定义Symbiaγ相机用于平面和SPECT成像的标称性能值。
