title: Recovery coefficients determination for partial volume effect correction in oncological PET/CT images considering the effect of activity outside the field of view.
abstract: OBJECTIVE
  The partial volume effect (PVE) has a great impact in quantitative PET/CT imaging. Correction methods have been recently proposed by many authors to make the image quantification more accurate. This work presents a methodology for determining the recovery coefficients (RCs) for PVE correction in PET/CT images. It was taken into account the radioactivity outside the field of view (FOV), which is expected in a patient image acquisition.
  
  
  METHODS
  The NEMA image quality phantom and the NEMA scatter phantom were used. The phantoms were filled with (18)F-FDG for different sphere-to-background ratios. The RCs have been determined from image acquisitions in a Siemens Biograph 16 Hi-Rez PET/CT scanner with and without the scatter phantom.
  
  
  RESULTS
  The RC values that ranged from 0.38 to 1.00 without the scatter phantom exhibited a wider variation when this latter was taken into account (from 0.27 to 1.02). This more realistic estimation must be considered if one takes into account that an incorrect SUV measure in tumors leads to errors in the evaluation of the response to therapy based on PET/CT images.
  
  
  CONCLUSIONS
  The activity outside the FOV should be considered in RCs determination to improve the RC-based PVE correction method.
authors.affiliation: Biomedical Engineering Program, Federal University of Rio de Janeiro (COPPE, UFRJ), Avenida Horácio Macedo, 2030, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ, 21941-914, Brazil, krempser@peb.ufrj.br.
authors.forename: Alexandre R
authors.initials: AR
authors.lastname: Krempser
authors.forename: Roberto M
authors.initials: RM
authors.lastname: Ichinose
authors.forename: Antonio M F L
authors.initials: AM
authors.lastname: Miranda de Sá
authors.forename: Silvia M
authors.initials: SM
authors.lastname: Velasques de Oliveira
authors.forename: Michel P
authors.initials: MP
authors.lastname: Carneiro
mesh_terms: D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D064847:Multimodal Imaging; D009369:Neoplasms / Q000000981:diagnostic imaging*; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography; D012542:Scattering, Radiation; D014057:Tomography, X-Ray Computed