title: Dynamic 68Ga-DOTATOC PET/CT and static image in NET patients. Correlation of parameters during PRRT.
abstract: OBJECTIVE
  To investigate the relationship between the dynamic parameters (Ki) and static image-derived parameters of 68Ga-DOTATOC-PET, to determine which static parameter best reflects underlying somatostatin-receptor-expression (SSR) levels on neuroendocrine tumours (NETs).
  
  
  METHODS
  20 patients with metastasized NETs underwent a dynamic and static 68Ga-DOTATOC-PET before PRRT and at 7 and 40 weeks after the first administration of 90Y-DOTATOC (in total 4 cycles were planned); 175 lesions were defined and analyzed on the dynamic as well as static scans. Quantitative analysis was performed using the software PMOD. One to five target lesions per patient were chosen and delineated manually on the baseline dynamic scan and further, on the corresponding static 68Ga-DOTATOC-PET and the dynamic and static 68Ga-DOTATOC-PET at the other time-points; SUVmax and SUVmean of the lesions was assessed on the other six scans. The input function was retrieved from the abdominal aorta on the images. Further on, Ki was calculated using the Patlak-Plot. At last, 5 reference regions for normalization of SUVtumour were delineated on the static scans resulting in 5 ratios (SUVratio).
  
  
  RESULTS
  SUVmax and SUVmean of the tumoural lesions on the dynamic 68Ga-DOTATOC-PET had a very strong correlation with the corresponding parameters in the static scan (R²: 0.94 and 0.95 respectively). SUVmax, SUVmean and Ki of the lesions showed a good linear correlation; the SUVratios correlated poorly with Ki. A significantly better correlation was noticed between Ki and SUVtumour(max and mean) (p < 0.0001).
  
  
  CONCLUSIONS
  As the dynamic parameter Ki correlates best with the absolute SUVtumour, SUVtumour best reflects underlying SSR-levels in NETs.
authors.forename: Sofie
authors.initials: S
authors.lastname: Van Binnebeek
authors.forename: Michel
authors.initials: M
authors.lastname: Koole
authors.forename: Christelle
authors.initials: C
authors.lastname: Terwinghe
authors.forename: Kristof
authors.initials: K
authors.lastname: Baete
authors.forename: Bert
authors.initials: B
authors.lastname: Vanbilloen
authors.forename: Karine
authors.initials: K
authors.lastname: Haustermans
authors.forename: Paul M
authors.initials: PM
authors.lastname: Clement
authors.forename: Kris
authors.initials: K
authors.lastname: Bogaerts
authors.forename: Alfons
authors.initials: A
authors.lastname: Verbruggen
authors.forename: Kris
authors.initials: K
authors.lastname: Nackaerts
authors.forename: Eric
authors.initials: E
authors.lastname: Van Cutsem
authors.forename: Chris
authors.initials: C
authors.lastname: Verslype
authors.forename: Felix M
authors.initials: FM
authors.lastname: Mottaghy
authors.affiliation: Christophe Deroose, MD, PhD, Nuclear Medicine, University Hospitals Leuven and Department of Imaging & Pathology, KU Leuven, christophe.deroose@uzleuven.be, Tel. +32/(0)16/34 37 15; Fax +32/(0)16/34 37 59.
authors.forename: Christophe M
authors.initials: CM
authors.lastname: Deroose
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D057054:Molecular Imaging / Q000379:methods; D018358:Neuroendocrine Tumors / Q000000981:diagnostic imaging* / Q000378:metabolism*; D009942:Organometallic Compounds / Q000493:pharmacokinetics*; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D017481:Receptors, Somatostatin / Q000378:metabolism*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D014408:Biomarkers, Tumor; D009942:Organometallic Compounds; D019275:Radiopharmaceuticals; D017481:Receptors, Somatostatin; C513399:gallium Ga 68 dotatate
keywords: 68Ga-DOTATOC PET; Ki; PRRT; neuroendocrine tumour; somatostatin receptor expression