title: Twins in spirit part II: DOTATATE and high-affinity DOTATATE--the clinical experience.
abstract: OBJECTIVE
  Over recent decades interest in diagnosis and treatment of neuroendocrine tumours (NET) has steadily grown. The basis for diagnosis and therapy of NET with radiolabelled somatostatin (hsst) analogues is the variable overexpression of hsst receptors (hsst1-5 receptors). We hypothesized that radiometal derivatives of DOTA-iodo-Tyr(3)-octreotide analogues might be excellent candidates for somatostatin receptor imaging. We therefore explored the diagnostic potential of (68)Ga-DOTA-iodo-Tyr(3)-octreotate [(68)Ga-DOTA,3-iodo-Tyr(3),Thr(8)]octreotide ((68)Ga-HA-DOTATATE; HA, high-affinity) compared to the established (68)Ga-DOTA-Tyr(3)-octreotate ((68)Ga-DOTATATE) in vivo.
  
  
  METHODS
  The study included 23 patients with known somatostatin receptor-positive metastases from NETs, thyroid cancer or glomus tumours who were investigated with both (68)Ga-HA-DOTATATE and (68)Ga-DOTATATE. A patient-based and a lesion-based comparative analysis was carried out of normal tissue distribution and lesion detectability in a qualitative and a semiquantitative manner.
  
  
  RESULTS
  (68)Ga-HA-DOTATATE and (68)Ga-DOTATATE showed comparable uptake in the liver (SUVmean 8.9 ± 2.2 vs. 9.3 ± 2.5, n.s.), renal cortex (SUVmean 13.3 ± 3.9 vs. 14.5 ± 3.7, n.s.) and spleen (SUVmean 24.0 ± 6.7 vs. 22.9 ± 7.3, n.s.). A somewhat higher pituitary uptake was found with (68)Ga-HA-DOTATATE (SUVmean 6.3 ± 1.8 vs. 5.4 ± 2.1, p < 0.05). On a lesion-by-lesion basis a total of 344 lesions were detected. (68)Ga-HA-DOTATATE demonstrated 328 lesions (95.3% of total lesions seen), and (68)Ga-DOTATATE demonstrated 332 lesions (96.4%). The mean SUVmax of all lesions was not significantly different between (68)Ga-HA-DOTATATE and (68)Ga-DOTATATE (17.8 ± 11.4 vs. 16.7 ± 10.7, n.s.).
  
  
  CONCLUSIONS
  Our analysis demonstrated very good concordance between (68)Ga-HA-DOTATATE and (68)Ga-DOTATATE PET data. As the availability and use of (68)Ga-HA-DOTATATE is not governed by patent restrictions it may be an attractive alternative to other (68)Ga-labelled hsst analogues.
authors: Department of Nuclear Medicine, Technische Universität Dresden, Fetscherstr. 74, 01307, Dresden, Germany, claudia.brogsitter@uniklinikum-dresden.de.
authors: Claudia
authors: C
authors: Brogsitter
authors: Klaus
authors: K
authors: Zöphel
authors: Holger
authors: H
authors: Hartmann
authors: Margret
authors: M
authors: Schottelius
authors: Hans-Jürgen
authors: HJ
authors: Wester
authors: Jörg
authors: J
authors: Kotzerke
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000000981:diagnostic imaging*; D009942:Organometallic Compounds / Q000493:pharmacokinetics*; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging*; D014018:Tissue Distribution
chemical_list: C000594971:68Ga-DOTA-iodo-Tyr(3)-octreotate; D009942:Organometallic Compounds; D019275:Radiopharmaceuticals; C513399:gallium Ga 68 dotatate