The performance evaluation of PET scanners should follow the NEMA PET NU2‐2001 standard. This standard uses a polyethylene phantom of 700mm axial length with a line source to measure scatter fraction, count losses and randoms. The measurement of sensitivity is conducted with a line source surrounded by known absorbers, and the sensitivity with no absorbers can be found by extrapolation. The intent of the image quality measurement is to mimic a whole body scan using a torso phantom containing hot and cold spheres of various diameters (representing lesions) in a warm background. An updated standard that considers the intrinsic radiation in the scintillators has been drafted and will be discussed. Quality assurance of PET scanners must be performed on a regular basis to maintain and confirm proper scanner performance. These procedures should track system stability and be sensitive to changes in scanner operation. The quality control and calibration of a PET scanner includes detector and electronic characterizations such as adjustment of PMT gain, definition of crystal and energy maps and coincidence timing calibration. These characterizations are applied to the PET data during acquisition. A PET quality control regimen includes system corrections such as normalization, calibration and, in the case of non‐PET/CT systems, blank scans. The accuracy of the coregistration of the PET and CT images from a PET/CT scanner should also be monitored. This presentation will focus on the rationale and methodology of the NEMA NU2‐2001 performance standards. The presentation will also describe the calibrations and corrections required to maintain proper system performance. Educational Objectives: 1. Describe NEMA NU2‐2001 PET performance standards. 2. Describe the calibrations required to properly detect the location of a coincident event. 3. Describe the post acquisition corrections required to minimize image artifacts.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging