title: Two peptide receptor ligands (99m)Tc-EDDA/HYNIC-Tyr(3)-octreotide and (99m)Tc-EDDA/HYNIC-(D)Glu-octagastrin for scintigraphy of medullary thyroid carcinoma.
abstract: Somatostatin and gastrin receptors are overexpressed in medullary thyroid carcinoma (MTC) cells; hence, both of them are potential targets for peptide receptor scintigraphy and radiotherapy. Therefore, the aim of our study was to assess the clinical value of two technetium-99m-labeled peptides, a new gastrin analog, the EDDA/HYNIC-(D)Glu-octagastrin and a somatostatin analog, EDDA/HYNIC-Tyr(3)-octreotide (EDDA/HYNIC-TOC) for scintigraphy in patients with MTC to detect recurrences and metastases and select patients for peptide receptor radiotherapy.
  
  
  METHODS
  Thirty (30) patients, 20 females and 10 males, 22-83 years of age (mean, 52.7) with the diagnosis of MTC in different stages of the disease (preoperative, postsurgery, remission, recurrence, or metastatic disease) were included in this study. Before surgery, in all patients serum calcitonin concentrations were elevated. The diagnosis of MTC was confirmed in all cases by histopathology of the removed tumor and immunohistochemical staining giving positive reactions for calcitonin and chromogranin A. Imaging studies using (99m)Tc-EDDA/HYNIC-TOC and a new minigastrin analog, (99m)Tc-EDDA/HYNIC-(D)Glu-octagastrin, were performed in each patient and the results compared with each other and with other imaging methods. Scans of the whole body, head, neck, and chest were performed 2 and 4 hours after injections of the tracer, 500-600 MBq in each case, using a double-head Varicam (Elscint, Israel) gamma camera.
  
  
  RESULTS
  (99m)Tc-EDDA/HYNIC-TOC detected somatostatin receptor-positive lesions in 20 patients with MTC, whereas (99m)Tc-EDDA/HYNIC-(D)Glu-octagastrin displayed gastrin receptors in 11 patients. In 9 cases, the scans were positive in both methods, although in 2 cases different pathologic foci were visualized. In 12 cases, only (99m)Tc-EDDA/HYNIC-TOC scintigraphy was positive, whereas in 3 other cases only (99m)Tc-EDDA/HYNIC-(D)Glu-octagastrin revealed pathologic lesions.
  
  
  CONCLUSIONS
  Scintigraphy using (99m)Tc-HYNIC-TOC permits the visualization of somatostatin receptor-positive MTC in the majority of cases. The new gastrin analog, (99m)Tc-HYNIC-(D)Glu-octagastrin, is well tolerated, shows no renal retention, and in some cases of MTC, provides additional information on the expression of gastrin receptors. However, inferior quality of octagastrin scans indicates the need for further improvement of this radiopeptide.
authors.affiliation: Department of Endocrinology, Metabolism and Internal Diseases, Poznań University of Medical Sciences, Poznań, Poland. jkosowicz@poczta.fm
authors.forename: Jerzy
authors.initials: J
authors.lastname: Kosowicz
authors.forename: Renata
authors.initials: R
authors.lastname: Mikołajczak
authors.forename: Rafał
authors.initials: R
authors.lastname: Czepczyński
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Ziemnicka
authors.forename: Maria
authors.initials: M
authors.lastname: Gryczyńska
authors.forename: Jerzy
authors.initials: J
authors.lastname: Sowiński
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D018276:Carcinoma, Medullary / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000532:radiotherapy; D004492:Edetic Acid / Q000031:analogs & derivatives / Q000737:chemistry; D005260:Female; D005755:Gastrins / Q000737:chemistry / Q000493:pharmacokinetics; D006801:Humans; D006834:Hydrazines / Q000737:chemistry; D007205:Indium Radioisotopes / Q000737:chemistry; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000517:prevention & control; D009539:Nicotinic Acids / Q000737:chemistry; D015609:Organotechnetium Compounds / Q000138:chemical synthesis / Q000493:pharmacokinetics; D011877:Radionuclide Imaging / Q000379:methods; D012680:Sensitivity and Specificity; D013961:Thyroid Gland / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000532:radiotherapy
chemical_list: C120392:6-hydrazinopyridine-3-carboxylic acid; D005755:Gastrins; C518250:Glu-Octagastrin; D006834:Hydrazines; D007205:Indium Radioisotopes; D009539:Nicotinic Acids; D015609:Organotechnetium Compounds; C487389:technetium 99m EDDA-HYNIC-Tyr(3)-octreotide; C026058:EDDA; D004492:Edetic Acid