title: Intraindividual comparison of 68Ga-DOTA-TATE and 18F-DOPA PET in patients with well-differentiated metastatic neuroendocrine tumours.
abstract: OBJECTIVE
  To compare the diagnostic impact of (68)Ga-DOTA-TATE and (18)F-DOPA PET in the diagnosis of well-differentiated metastatic neuroendocrine tumours (NET).
  
  
  METHODS
  PET/CT using both (68)Ga-DOTA-TATE and (18)F-DOPA was performed in 25 patients with histologically proven metastatic NET (nine gut, five pancreas, six lung, one paranasal sinus, four with unknown primary). Analyses of PET examinations were patient-based (pathological uptake: yes/no), and based on tumour regions (primary tumour if present and metastases of liver, lung, bones and lymph nodes). The results were compared with the results of contrast enhanced CT, and with plasma serotonin levels, which were available in 24 of the 25 patients.
  
  
  RESULTS
  Patient-based sensitivities were 96% for (68)Ga-DOTA-TATE PET and 56% for (18)F-DOPA PET. (68)Ga-DOTA-TATE PET delineated metastases in 54 of 55 positive metastatic tumour regions in contrast to 29 of 55 delineated by (18)F-DOPA PET. Overall, (68)Ga-DOTA-TATE was superior to (18)F-DOPA in 13 patients (two patients showed fewer positive tumour regions with (18)F-DOPA PET). The results were comparable in 12 patients. In 13 of 24 patients, plasma serotonin levels were elevated, and 11 of these 13 patients showed pathological uptake of (18)F-DOPA. Of the 11 patients with normal levels of serotonin, 3 also showed positive (18)F-DOPA uptake. In patients positive for (18)F-DOPA uptake the maximum tumour SUVs were correlated with the levels of serotonin (r=0.66, p=0.01).
  
  
  CONCLUSIONS
  In this study (68)Ga-DOTA-TATE PET proved clearly superior to (18)F-DOPA PET for detection and staging of NET. (18)F-DOPA uptake tended to be increased in those patients with elevated plasma serotonin. We conclude that (18)F-DOPA PET should be employed in patients with NET with negative (68)Ga-DOTA-TATE PET and elevated plasma serotonin.
authors.affiliation: Department of Nuclear Medicine, Ludwig Maximilians University, Munich, Germany. Alexander.Haug@med.uni-muenchen.de
authors.forename: Alexander
authors.initials: A
authors.lastname: Haug
authors.forename: Christoph J
authors.initials: CJ
authors.lastname: Auernhammer
authors.forename: Björn
authors.initials: B
authors.lastname: Wängler
authors.forename: Reinhold
authors.initials: R
authors.lastname: Tiling
authors.forename: Gerwin
authors.initials: G
authors.lastname: Schmidt
authors.forename: Burkhard
authors.initials: B
authors.lastname: Göke
authors.forename: Peter
authors.initials: P
authors.lastname: Bartenstein
authors.forename: Gabriele
authors.initials: G
authors.lastname: Pöpperl
mesh_terms: D000328:Adult; D000368:Aged; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives*; D005260:Female; D005710:Gallium Radioisotopes; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D018358:Neuroendocrine Tumors / Q000175:diagnosis* / Q000473:pathology; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D017481:Receptors, Somatostatin / Q000378:metabolism; D012680:Sensitivity and Specificity; D012701:Serotonin / Q000097:blood
chemical_list: D005710:Gallium Radioisotopes; D019275:Radiopharmaceuticals; D017481:Receptors, Somatostatin; C043437:fluorodopa F 18; D012701:Serotonin; D004295:Dihydroxyphenylalanine