title: Early and delayed evaluation of solid tumours with 64Cu-ATSM PET/CT: a pilot study on semiquantitative and computer-aided fractal geometry analysis.
abstract: OBJECTIVE
  The aim of this study was to analyse early and delayed acquisition on copper-64 diacetyl-bisN4-methylthiosemicarbazone (Cu-ATSM) PET/CT in a small cohort of patients by comparing semiquantitative and computer-aided fractal geometry analyses.
  
  
  METHODS
  Five cancer patients, including non-small-cell lung cancer and head and neck cancer, were investigated with Cu-ATSM PET/CT. Participants received an intravenous injection of Cu-ATSM according to body size and were imaged 60 min (early) and 16 h (delayed) later on hybrid PET/CT. Reconstructed images were visualized on advanced workstations for the definition of semiquantitative parameters: standardized uptake value (SUV)max, SUVratio-to-muscle, SUVmean, hypoxic volume (HV) and hypoxic burden (HB=HV×SUVmean). DICOM data retrieved from both scans were analysed using an ad-hoc computer program to determine the mean intensity value, SD, relative dispersion, three-dimensional histogram fractal dimension and three-dimensional fractal dimension.
  
  
  RESULTS
  All tumour lesions showed increased uptake of Cu-ATSM at early evaluation, with a median SUVratio-to-muscle of 4.42 (range: 1.58-5.62), a median SUVmax of 5.3 (range: 1.9-7.3), a median SUVmean of 2.8 (range: 1.5-3.9), a median HV of 41.6 cm (range: 2.8-453.7) and a median HB of 161.5 cm (range: 4.4-1112.5). All semiquantitative data obtained at 1 h were consistent with the parameters obtained on delayed imaging (P>0.05). A borderline statistically significant difference was found only for SUVmax of the muscle (P=0.045). Fractal geometry analysis on DICOM images showed that all parameters at early imaging showed no statistically significant difference with late acquisition (P>0.05).
  
  
  CONCLUSIONS
  Our findings support the consistency of Cu-ATSM PET/CT images obtained at early and delayed acquisition for the assessment of tumour lesions.
authors.affiliation: aResearch Doctorate Course in Specialized Medical Sciences, Alma Mater Studiorum - University of Bologna bPET Unit cDivision of Thoracic Surgery, University Hospital S. Orsola-Malpighi, Bologna dDepartment of Nuclear Medicine eDepartment of Inflammation and Immunology fDepartment of Medical Oncology, Humanitas Clinical and Research Hospital, Rozzano gMichele Rodriguez Foundation, Milan, Italy.
authors.forename: Egesta
authors.initials: E
authors.lastname: Lopci
authors.forename: Fabio
authors.initials: F
authors.lastname: Grizzi
authors.forename: Carlo
authors.initials: C
authors.lastname: Russo
authors.forename: Luca
authors.initials: L
authors.lastname: Toschi
authors.forename: Ilaria
authors.initials: I
authors.lastname: Grassi
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Cicoria
authors.forename: Filippo
authors.initials: F
authors.lastname: Lodi
authors.forename: Sandro
authors.initials: S
authors.lastname: Mattioli
authors.forename: Stefano
authors.initials: S
authors.lastname: Fanti
mesh_terms: D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging*; D056831:Coordination Complexes; D003301:Copper Radioisotopes; D005260:Female; D017709:Fractals; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D009942:Organometallic Compounds; D010865:Pilot Projects; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods* / Q000706:statistics & numerical data; D019275:Radiopharmaceuticals; D013882:Thiosemicarbazones
chemical_list: D056831:Coordination Complexes; D003301:Copper Radioisotopes; D009942:Organometallic Compounds; D019275:Radiopharmaceuticals; D013882:Thiosemicarbazones; C089548:copper (II) diacetyl-di(N(4)-methylthiosemicarbazone)