Newly added content of the NEMA standard (NU-1 2001)for scintillation camera

This paper is concerning on the NEMA Standard Publication NU 1-2001 of Performance Measurements of Scintillation Cameras. Two sections, the system alignment of section 2.5 and the detector-detector sensitivity variation of section 3.10, are newly added, and the system planar sensitivity and penetration of section 3.8 and detector shielding of section 3.9 have been modified, which comparing to the last edition of the NEMA Standard Publication NU-1 1994.