RT Journal Article SR Electronic T1 PET Performance Measurements Using the NEMA NU 2-2001 Standard JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1398 OP 1409 VO 43 IS 10 A1 Margaret E. Daube-Witherspoon A1 Joel S. Karp A1 Michael E. Casey A1 Frank P. DiFilippo A1 Horace Hines A1 Gerd Muehllehner A1 Vilim Simcic A1 Charles W. Stearns A1 Lars-Eric Adam A1 Steve Kohlmyer A1 Vesna Sossi YR 2002 UL http://jnm.snmjournals.org/content/43/10/1398.abstract AB 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. Methods: 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. Results: 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. Conclusion: 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.