title: 4D-PET data sorting into different number of phases: a NEMA IQ phantom study.
abstract: This study aims at evaluating the dependence of 4D-PET data sorting on the number of phases in which the respiratory cycle can be divided. The issue is to find the best compromise to reduce the conflicting effects induced by increasing the number of phases: lesion motion on each set of images decreases, but on the other hand image noise increases. The IQ NEMA 2001 IEC body phantom was used to simulate the movement of neoplastic lesions in the thorax and abdomen, investigating the effect of target size (10-37 mm), lesion to background activity concentrations ratio (4-to-1 and 8-to-1), total acquisition time (3, 6, 12, 20 min) and number of phase partition (1, 2, 4, 6, 8, 10, 13). The phantom was moved in a cranial-caudal direction with an excursion of 25 mm and with a period of 4.0 s. Five parameters associated to lesion volume and activity concentration were considered to assess the capability of the 4D-PET technique to "freeze" the phantom motion. The results for all the parameters showed the capability of the 4D-PET acquisition technique to "freeze" the lesion motion. The division into 6 phases was found to be the best compromise between temporal resolution and image noise for the phase where the "lesions" move faster, whereas the partition into 4 phases could be used if a stable breathing phase is considered.
authors.affiliation: Radiotherapy Department, IRCCS Istituto Clinico Humanitas, Rozzano (Mi), Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Mancosu
authors.affiliation: Medical Physics Department, Arcispedale S. Maria Nuova, Reggio, Emilia, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Sghedoni
authors.affiliation: Nuclear Medicine Department, Scientifc Institute H San Raffaele, Milan, Italy.
authors.forename: Valentino
authors.initials: V
authors.lastname: Bettinardi
authors.affiliation: Medical Physics Department, Arcispedale S. Maria Nuova, Reggio, Emilia, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Fioroni
authors.affiliation: Nuclear Medicine Department, Scientifc Institute H San Raffaele, Milan, Italy.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Aquilina
authors.affiliation: Medical Physics Department, Arcispedale S. Maria Nuova, Reggio, Emilia, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Grassi
authors.affiliation: Nuclear Medicine Department, Scientifc Institute H San Raffaele, Milan, Italy.|Faculty of Medicine, University of Milano-Bicocca, Milan, Italy.
authors.forename: Ferruccio
authors.initials: F
authors.lastname: Fazio
authors.affiliation: Medical Physics Department, Arcispedale S. Maria Nuova, Reggio, Emilia, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Borasi
authors.affiliation: Nuclear Medicine Department, Scientifc Institute H San Raffaele, Milan, Italy.|Faculty of Medicine, University of Milano-Bicocca, Milan, Italy.|IBFM-CNR, Institute for Molecular Bioimaging and Physiology, Milan, Italy.
authors.forename: Maria C
authors.initials: MC
authors.lastname: Gilardi
mesh_terms: D000465:Algorithms; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography / Q000295:instrumentation* / Q000379:methods*; D015656:Respiratory Mechanics / Q000502:physiology / Q000528:radiation effects*; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods