title: Patient-dependent count-rate adaptive normalization for PET detector efficiency with delayed-window coincidence events.
abstract: Quantitative PET imaging is widely used in clinical diagnosis in oncology and neuroimaging. Accurate normalization correction for the efficiency of each line-of- response is essential for accurate quantitative PET image reconstruction. In this paper, we propose a normalization calibration method by using the delayed-window coincidence events from the scanning phantom or patient. The proposed method could dramatically reduce the 'ring' artifacts caused by mismatched system count-rates between the calibration and phantom/patient datasets. Moreover, a modified algorithm for mean detector efficiency estimation is proposed, which could generate crystal efficiency maps with more uniform variance. Both phantom and real patient datasets are used for evaluation. The results show that the proposed method could lead to better uniformity in reconstructed images by removing ring artifacts, and more uniform axial variance profiles, especially around the axial edge slices of the scanner. The proposed method also has the potential benefit to simplify the normalization calibration procedure, since the calibration can be performed using the on-the-fly acquired delayed-window dataset.
authors.affiliation: Toshiba Medical Research Institute, Vernon Hills, IL 60061 USA.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Niu
authors.forename: Hongwei
authors.initials: H
authors.lastname: Ye
authors.forename: Ting
authors.initials: T
authors.lastname: Xia
authors.forename: Evren
authors.initials: E
authors.lastname: Asma
authors.forename: Mark
authors.initials: M
authors.lastname: Winkler
authors.forename: Daniel
authors.initials: D
authors.lastname: Gagnon
authors.forename: Wenli
authors.initials: W
authors.lastname: Wang
mesh_terms: D000465:Algorithms; D002138:Calibration; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008099:Liver / Q000000981:diagnostic imaging*; D056888:Patient Positioning; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography / Q000295:instrumentation* / Q000379:methods*