Daube-Witherspoon Margaret E, Karp Joel S, Casey Michael E, DiFilippo Frank P, Hines Horace, Muehllehner Gerd, Simcic Vilim, Stearns Charles W, Adam Lars-Eric, Kohlmyer Steve, Sossi Vesna
Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
J Nucl Med. 2002 Oct;43(10):1398-409.
The NU 2-1994 standard document for PET performance measurements has recently been updated. The updated document, NU 2-2001, includes revised measurements for spatial resolution, intrinsic scatter fraction, sensitivity, counting rate performance, and accuracy of count loss and randoms corrections. The revised measurements are designed to allow testing of dedicated PET systems in both 2-dimensional and 3-dimensional modes as well as coincidence gamma cameras, conditions not considered in the original NU 2-1994 standard. In addition, the updated measurements strive toward being more representative of clinical studies, in particular, whole-body imaging.
Performance measurements following the NU 2-1994 and NU 2-2001 standards were performed on several different PET scanners. Differences between the procedures and resulting performance characteristics, as well as the rationale for these changes, were noted.
Spatial resolution is measured with a point source in all 3 directions, rather than a line source, as specified previously. For the measurements of intrinsic scatter fraction, sensitivity, and counting rate performance, a 70-cm line source is now specified, instead of a 19-cm-long cylindric phantom. The longer configuration permits measurement of these performance characteristics over the entire axial field of view of all current PET scanners and incorporates the effects of activity outside the scanner. A measurement of image quality has been added in an effort to measure overall image quality under clinically realistic conditions. This measurement replaces the individual measurements of uniformity and of the accuracy of corrections for attenuation and scatter.
The changes from the NU 2-1994 standard to the NU 2-2001 standard strive toward establishing relevance with clinical studies. The tests in the updated standard also are, in general, simpler and less time-consuming to perform than those in the NU 2-1994 standard.
用于正电子发射断层显像（PET）性能测量的NU 2 - 1994标准文件最近已更新。更新后的文件NU 2 - 2001包括了对空间分辨率、固有散射分数、灵敏度、计数率性能以及计数损失和随机符合校正准确性的修订测量方法。修订后的测量方法旨在允许对二维和三维模式下的专用PET系统以及符合伽马相机进行测试，这是原始NU 2 - 1994标准未考虑的情况。此外，更新后的测量方法力求更能代表临床研究，特别是全身成像。
按照NU 2 - 1994和NU 2 - 2001标准对几种不同的PET扫描仪进行性能测量。记录了程序之间的差异以及由此产生的性能特征，以及这些变化的基本原理。
空间分辨率是在所有三个方向上用点源测量，而不是像之前规定的那样用线源。对于固有散射分数、灵敏度和计数率性能的测量，现在规定使用70厘米长的线源，而不是19厘米长的圆柱形体模。更长的配置允许在所有当前PET扫描仪的整个轴向视野范围内测量这些性能特征，并纳入了扫描仪外部活性的影响。增加了图像质量测量，以努力在临床实际条件下测量整体图像质量。该测量取代了均匀性以及衰减和散射校正准确性的单独测量。
从NU 2 - 1994标准到NU 2 - 2001标准的变化力求与临床研究建立相关性。更新标准中的测试通常也比NU 2 - 1994标准中的测试更简单、耗时更少。
