RT Journal Article
SR Electronic
T1 Rigid vs. non-rigid motion correction for respiratory gated PET
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 410P
OP 410P
VO 48
IS supplement 2
A1 Nicole Detorie
A1 Magnus Dahlbom
YR 2007
UL http://jnm.snmjournals.org/content/48/supplement_2/410P.1.abstract
AB 1717 Objectives: The aim of this study was to investigate the feasibility of a rigid motion correction method for respiratory gated positron emission tomography (PET). Methods: The NCAT phantom was used and simulated to have three spherical lung lesions at different locations (upper, middle, and lower) in the right lung. All lesions had a source to background ratio of 5:1 and were 1 cm in diameter. Data were binned into 16, 8, 4, and 2 gates in addition to a non-gated data set. Poisson noise was added to the data before being reconstructed with OSEM, 4 iterations and 8 subsets. Two motion corrected methods were applied to the data. One method used a non-rigid registration algorithm, which was part of a commercially available image registration software package, to deform the gated images into the peak inhale gate. The other method rigidly aligned the gated images to the peak inhale gate based on the three dimensional displacements of the lesion centroids within each gate. This resulted in the motion corrected images, which were then summed for analysis. Regions of interest were placed in the lung background, soft tissue, and the center of each lesion. The mean lesion signal, contrast to noise ratio (CNR), and spatial resolution were evaluated. Results: Compared to the non-rigid motion correction method, the rigid motion correction method resulted in comparable or improved lesion signal recovery, lesion CNR recovery, and spatial resolution recovery. The upper lung lesion benefited the most from the rigid motion correction method, where signal recovery and CNR recovery improved an average of 4% and 15%, respectively, compared to the non-rigid motion corrected images. For the middle and lower lung lesions, signal recovery was comparable and CNR recovery improved an average of 5% within the rigid motion corrected images compared to the non-rigid motion corrected images. With respect to the data binned into 16 gates, spatial resolution recovery also improved an average of 20% in the axial direction within the rigid motion corrected images compared to the non-rigid motion corrected images. Conclusions: These results show that a simple, rigid motion correction method can be applied to respiratory gated PET images for lesion detection, and has comparable or improved lesion quantitation as a non-rigid motion correction method. Research Support (if any): DOE grant DE-FC02-02ER63420