List-mode-based reconstruction for respiratory motion correction in PET using non-rigid body transformations
Phys. Med. Biol.. 2007-08-09; 52(17): 5187-5204
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1. Phys Med Biol. 2007 Sep 7;52(17):5187-204. Epub 2007 Aug 9.
List-mode-based reconstruction for respiratory motion correction in PET using
non-rigid body transformations.
Lamare F(1), Ledesma Carbayo MJ, Cresson T, Kontaxakis G, Santos A, Le Rest CC,
Reader AJ, Visvikis D.
(1)INSERM, U650, Laboratoire du Traitement de l’Information Médicale, Brest,
Respiratory motion in emission tomography leads to reduced image quality.
Developed correction methodology has been concentrating on the use of respiratory
synchronized acquisitions leading to gated frames. Such frames, however, are of
low signal-to-noise ratio as a result of containing reduced statistics. In this
work, we describe the implementation of an elastic transformation within a
list-mode-based reconstruction for the correction of respiratory motion over the
thorax, allowing the use of all data available throughout a respiratory motion
average acquisition. The developed algorithm was evaluated using datasets of the
NCAT phantom generated at different points throughout the respiratory cycle.
List-mode-data-based PET-simulated frames were subsequently produced by combining
the NCAT datasets with Monte Carlo simulation. A non-rigid registration algorithm
based on B-spline basis functions was employed to derive transformation
parameters accounting for the respiratory motion using the NCAT dynamic CT
images. The displacement matrices derived were subsequently applied during the
image reconstruction of the original emission list mode data. Two different
implementations for the incorporation of the elastic transformations within the
one-pass list mode EM (OPL-EM) algorithm were developed and evaluated. The
corrected images were compared with those produced using an affine transformation
of list mode data prior to reconstruction, as well as with uncorrected
respiratory motion average images. Results demonstrate that although both
correction techniques considered lead to significant improvements in accounting
for respiratory motion artefacts in the lung fields, the
elastic-transformation-based correction leads to a more uniform improvement
across the lungs for different lesion sizes and locations.
PMID: 17762080 [Indexed for MEDLINE]