title: Four-dimensional (4D) motion detection to correct respiratory effects in treatment response assessment using molecular imaging biomarkers.
abstract: Observing early metabolic changes in positron emission tomography (PET) is an essential tool to assess treatment efficiency in radiotherapy. However, for thoracic regions, the use of three-dimensional (3D) PET imaging is unfeasible because the radiotracer activity is smeared by the respiratory motion and averaged during the imaging acquisition process. This motion-induced degradation is similar in magnitude with the treatment-induced changes, and the two occurrences become indiscernible. We present a customized temporal-spatial deformable registration method for quantifying respiratory motion in a four-dimensional (4D) PET dataset. Once the motion is quantified, a motion-corrected (MC) dataset is created by tracking voxels to eliminate breathing-induced changes in the 4D imaging scan. The 4D voxel-tracking data is then summed to yield a 3D MC-PET scan containing only treatment-induced changes. This proof of concept is exemplified on both phantom and clinical data, where the proposed algorithm tracked the trajectories of individual points through the 4D datasets reducing motion to less than 4 mm in all phases. This correction approach using deformable registration can discern motion blurring from treatment-induced changes in treatment response assessment using PET imaging.
authors.affiliation: Department of Radiation Oncology, Emory University School of Medicine and Winship Cancer Institute of Emory University, Atlanta, GA, USA. eschre2@emory.edu.
authors.forename: Eduard
authors.initials: E
authors.lastname: Schreibmann
authors.forename: Ian
authors.initials: I
authors.lastname: Crocker
authors.forename: David M
authors.initials: DM
authors.lastname: Schuster
authors.forename: Walter J
authors.initials: WJ
authors.lastname: Curran
authors.forename: Tim
authors.initials: T
authors.lastname: Fox
mesh_terms: D000465:Algorithms; D015415:Biomarkers; D002138:Calibration; D066264:Datasets as Topic; D019788:Fluorodeoxyglucose F18; D056973:Four-Dimensional Computed Tomography; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis / Q000473:pathology; D057054:Molecular Imaging; D009038:Motion; D009369:Neoplasms / Q000175:diagnosis* / Q000628:therapy; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography
chemical_list: D015415:Biomarkers; D019788:Fluorodeoxyglucose F18