title: Performance evaluation of a high resolution dedicated breast PET scanner.
abstract: OBJECTIVE
  Early stage breast cancers may not be visible on a whole-body PET scan. To overcome whole-body PET limitations, several dedicated breast positron emission tomography (DbPET) systems have emerged nowadays aiming to improve spatial resolution. In this work the authors evaluate the performance of a high resolution dedicated breast PET scanner (Mammi-PET, Oncovision).
  
  
  METHODS
  Global status, uniformity, sensitivity, energy, and spatial resolution were measured. Spheres of different sizes (2.5, 4, 5, and 6 mm diameter) and various 18 fluorodeoxyglucose ((18)F-FDG) activity concentrations were randomly inserted in a gelatine breast phantom developed at our institution. Several lesion-to-background ratios (LBR) were simulated, 5:1, 10:1, 20:1, 30:1, and 50:1. Images were reconstructed using different voxel sizes. The ability of experienced reporters to detect spheres was tested as a function of acquisition time, LBR, sphere size, and matrix reconstruction voxel size. For comparison, phantoms were scanned in the DbPET camera and in a whole body PET (WB-PET). Two patients who just underwent WB-PET/CT exams were imaged with the DbPET system and the images were compared.
  
  
  RESULTS
  The measured absolute peak sensitivity was 2.0%. The energy resolution was 24.0% ± 1%. The integral and differential uniformity were 10% and 6% in the total field of view (FOV) and 9% and 5% in the central FOV, respectively. The measured spatial resolution was 2.0, 1.9, and 1.7 mm in the radial, tangential, and axial directions. The system exhibited very good detectability for spheres ≥4 mm and LBR ≥10 with a sphere detection of 100% when acquisition time was set >3 min/bed. For LBR = 5 and acquisition time of 7 min the detectability was 100% for spheres of 6 mm and 75% for spheres of 5, 4, and 2.5 mm. Lesion WB-PET detectability was only comparable to the DbPET camera for lesion sizes ≥5 mm when acquisition time was >3 min and LBR > 10.
  
  
  CONCLUSIONS
  The DbPET has a good performance for its clinical use and shows an improved resolution and lesion detectability of small lesions compared to WB-PET.
authors.affiliation: Department of Medical Physics, ERESA, Hospital General Universitario, Valencia 46014, Spain.
authors.forename: Trinitat
authors.initials: T
authors.lastname: García Hernández
authors.affiliation: Department of Medical Physics, ERESA, Hospital General Universitario, Valencia 46014, Spain.
authors.forename: Aurora
authors.initials: A
authors.lastname: Vicedo González
authors.affiliation: Department of Nuclear Medicine, ERESA, Hospital General Universitario, Valencia 46014, Spain.
authors.forename: Jose
authors.initials: J
authors.lastname: Ferrer Rebolleda
authors.affiliation: Department of Nuclear Medicine, ERESA, Hospital General Universitario, Valencia 46014, Spain.
authors.forename: Raúl
authors.initials: R
authors.lastname: Sánchez Jurado
authors.affiliation: Department of Medical Physics, ERESA, Hospital General Universitario, Valencia 46014, Spain and Department of Physiology, University of Valencia, Valencia 46010, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Roselló Ferrando
authors.affiliation: Department of Medical Physics, ERESA, Hospital General Universitario, Valencia 46014, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Brualla González
authors.affiliation: Department of Medical Physics, ERESA, Hospital General Universitario, Valencia 46014, Spain.
authors.forename: Domingo
authors.initials: D
authors.lastname: Granero Cabañero
authors.affiliation: Department of Nuclear Medicine, ERESA, Hospital General Universitario, Valencia 46014, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Del Puig Cozar Santiago
mesh_terms: D001940:Breast / Q000000981:diagnostic imaging*; D001941:Breast Diseases / Q000000981:diagnostic imaging; D019788:Fluorodeoxyglucose F18; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation / Q000379:methods; D008953:Models, Anatomic; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography / Q000295:instrumentation* / Q000379:methods; D016684:Prone Position; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18