title: Impact of Region-of-Interest Delineation Methods, Reconstruction Algorithms, and Intra- and Inter-Operator Variability on Internal Dosimetry Estimates Using PET.
abstract: Human dosimetry studies play a central role in radioligand development for positron emission tomography (PET). Drawing regions of interest (ROIs) on the PET images is used to measure the dose in each organ. In the study aspects related to ROI delineation methods were evaluated for two radioligands of different biodistribution (intestinal vs urinary).
  
  
  
  PET images were simulated from a human voxel-based phantom. Several ROI delineation methods were tested: antero-posterior projections (AP), 3D sub-samples of the organs (S), and a 3D volume covering the whole-organ (W). Inter- and intra-operator variability ROI drawing was evaluated by using human data.
  
  
  
  The effective dose estimates using S and W methods were comparable to the true values. AP methods overestimated (49 %) the dose for the radioligand with intestinal biodistribution. Moreover, the AP method showed the highest inter-operator variability: 11 ± 1 %.
  
  
  
  The sub-sampled organ method showed the best balance between quantitative accuracy and inter- and intra-operator variability.
authors.affiliation: Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona, Spain. nl.vilanova@gmail.com.|Institut de Tècniques Energètiques (INTE), Universitat Politècnica de Catalunya (UPC), Barcelona, Spain. nl.vilanova@gmail.com.
authors.forename: N
authors.initials: N
authors.lastname: López-Vilanova
authors.affiliation: Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona, Spain.|Nuclear Medicine Department, Hospital Clínic i Provincial de Barcelona, Barcelona, Spain.|Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Pavía
authors.affiliation: Institut de Tècniques Energètiques (INTE), Universitat Politècnica de Catalunya (UPC), Barcelona, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Duch
authors.affiliation: Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.|Barcelona Imaging Group (BIG), Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Catafau
authors.affiliation: Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona, Spain.|Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.|Unitat de Biofísica i Bioenginyeria, Universitat de Barcelona, Barcelona, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Ros
authors.affiliation: Molecular Imaging Centre (CRC-CIM), Barcelona Biomedical Research Park, Barcelona, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Bullich
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015588:Observer Variation; D049268:Positron-Emission Tomography; D011874:Radiometry; D014018:Tissue Distribution
keywords: Dosimetry; PET; [11C]GSK931145; [11C]raclopride