Abstract
1650
Objectives: An initial performance evaluation of a resolution-recovery algorithm for PET, the Siemens TrueX iterative reconstruction, was made. TrueX incorporates a spatial point-spread correction in addition to scatter, attenuation, normalization, and randoms corrections in a 3D reconstruction.
Methods: Phantom and patient images were acquired on a Siemens Biograph 64 PET/CT system to compare the TrueX 3D OSEM reconstruction against 2D OSEM processing. The ACR PET phantom, the NEMA NU2 phantoms, and others were imaged. Image quality was visually assessed, and SUV measurements were compared against known phantom activity to determine the quantitation accuracy for different size lesions.
Results: Physician subjective assessment was that TrueX images showed lesions more conspicuously than 2D OSEM images. Quantitatively, improved spatial resolution across the transaxial field of view was demonstrated with a line source phantom. Visual evaluation of either cold or hot rods in a FOV-centered ACR phantom did not substantially change small lesion visability. However, the SUV results obtained with TrueX for small hot cylinders were more accurate, with the SUV(TrueX)/SUV(2D OSEM) ratio increasing with decreasing object size. For large objects (the whole 20 cm phantom), the reported SUVs were equal.
Conclusions: The TrueX resolution-recovery technique improved the accuracy of measured activity values for small hot lesions. The resolution improvement increases from center to periphery, and either large or off-centered phantoms are needed to quantify imaging performance with such systems.
- Society of Nuclear Medicine, Inc.