title: Technical Note: A new zeolite PET phantom to test segmentation algorithms on heterogeneous activity distributions featured with ground-truth contours.
abstract: OBJECTIVE
  Design, realization, scan, and characterization of a phantom for PET Automatic Segmentation (PET-AS) assessment are presented. Radioactive zeolites immersed in a radioactive heterogeneous background simulate realistic wall-less lesions with known irregular shape and known homogeneous or heterogeneous internal activity.
  
  
  METHODS
  Three different zeolite families were evaluated in terms of radioactive uptake homogeneity, necessary to define activity and contour ground truth. Heterogeneous lesions were simulated by the perfect matching of two portions of a broken zeolite, soaked in two different18F-FDG radioactive solutions. Heterogeneous backgrounds were obtained with tissue paper balls and sponge pieces immersed into radioactive solutions.
  
  
  RESULTS
  Natural clinoptilolite proved to be the most suitable zeolite for the construction of artificial objects mimicking homogeneous and heterogeneous uptakes in18F-FDG PET lesions. Heterogeneous backgrounds showed a coefficient of variation equal to 269% and 443% of a uniform radioactive solution. Assembled phantom included eight lesions with volumes ranging from 1.86 to 7.24 ml and lesion to background contrasts ranging from 4.8:1 to 21.7:1.
  
  
  CONCLUSIONS
  A novel phantom for the evaluation of PET-AS algorithms was developed. It is provided with both reference contours and activity ground truth, and it covers a wide range of volumes and lesion to background contrasts. The dataset is open to the community of PET-AS developers and utilizers.
authors.affiliation: DEIB, Department of Electronics, Information and Bioengineering, Politecnico di Milano, piazza Leonardo da Vinci 32, 20133 Milan, Italy.
authors.forename: Chiara D
authors.initials: CD
authors.lastname: Soffientini
authors.affiliation: Department of Medicine and Surgery and Tecnomed Foundation, University of Milano - Bicocca, 20900 Monza, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: De Bernardi
authors.affiliation: Nuclear Medicine Department, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, via Francesco Sforza 35, 20122 Milan, Italy.
authors.forename: Rosangela
authors.initials: R
authors.lastname: Casati
authors.affiliation: DEIB, Department of Electronics, Information and Bioengineering, Politecnico di Milano, piazza Leonardo da Vinci 32, 20133 Milan, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Baselli
authors.affiliation: Nuclear Medicine Department, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, via Francesco Sforza 35, 20122 Milan, Italy.|Health Physics Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico via Francesco Sforza 35, 20122 Milan, Italy.
authors.forename: Felicia
authors.initials: F
authors.lastname: Zito
mesh_terms: D000465:Algorithms; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography / Q000295:instrumentation*; D017641:Zeolites
chemical_list: D017641:Zeolites
keywords: 18F-FDG PET; experimental phantoms; segmentation; zeolites