title: The role of baseline Ga-68 DOTATATE positron emission tomography/computed tomography in the prediction of response to fixed-dose peptide receptor radionuclide therapy with Lu-177 DOTATATE.
abstract: OBJECTIVE
  To describe the role of baseline gallium (Ga)-68 DOTATATE positron emission tomography (PET)/computed tomography (CT) in the prediction of the response to peptide receptor radionuclide therapy (PRRT) using lutetium (Lu)-177 DOTATATE.
  
  
  METHODS
  Analysis was made of baseline Ga-68 DOTATATE PET/CT images of 29 patients (17 females and 12 males; mean age: 50.7 ± 14.6 years) with metastatic neuroendocrine tumors who received PRRT with Lu-177 DOTATATE. Maximum standardized uptake values (SUVmax) of reference lesions and their ratios to physiological uptake organs were calculated. The relationship between these values and the radiological response was analyzed.
  
  
  RESULTS
  Partial response was observed in 8 (28%) patients, stable disease in 18 (62%) patients, and progressive disease in 3 (10%) patients. Mean SUVmax of reference lesions was calculated as 23.8 ± 20.5 (min-max: 5.1-87.3). There was no significant correlation between radiological responses and SUVmax of reference lesions and their ratios to other organs.
  
  
  CONCLUSIONS
  Baseline Ga-68 DOTATATE PET/CT helps to show somatostatin receptor expression status and disease stage in patients who are candidates for PRRT. However, SUVs do not have a role in the prediction of treatment response.
authors: Department of Nuclear Medicine, Faculty of Medicine, Ankara University, Ankara, Turkey.
authors: Çiğdem
authors: Ç
authors: Soydal
authors: Department of Radiology, Faculty of Medicine, Ankara University, Ankara, Turkey.
authors: Ahmet
authors: A
authors: Peker
authors: Department of Nuclear Medicine, Faculty of Medicine, Ankara University, Ankara, Turkey.
authors: Elgin
authors: E
authors: Özkan
authors: Department of Nuclear Medicine, Faculty of Medicine, Ankara University, Ankara, Turkey.
authors: Özlem Nuriye
authors: ÖN
authors: Küçük
authors: Department of Nuclear Medicine, Faculty of Medicine, Ankara University, Ankara, Turkey.
authors: Metin Kemal
authors: MK
authors: Kir
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005710:Gallium Radioisotopes; D006801:Humans; D008187:Lutetium; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D000072078:Positron Emission Tomography Computed Tomography; D049268:Positron-Emission Tomography; D011868:Radioisotopes; D019275:Radiopharmaceuticals; D018000:Receptors, Peptide; D014057:Tomography, X-Ray Computed
chemical_list: D005710:Gallium Radioisotopes; D011868:Radioisotopes; D019275:Radiopharmaceuticals; D018000:Receptors, Peptide; D008187:Lutetium; C000615430:Gallium-68; C000615061:Lutetium-177
keywords: Ga-68 DOTATATE positron emission tomography/computed tomography; Peptide receptor radionuclide therapy; treatment response