64Cu-TETA-octreotide as a PET imaging agent for patients with neuroendocrine tumors

J Nucl Med. 2001 Feb;42(2):213-21.

Abstract

64Cu (half-life, 12.7 h; beta+, 0.653 MeV [17.4%]; beta-, 0.579 MeV [39%]) has shown potential as a radioisotope for PET imaging and radiotherapy. (111)In-diethylenetriaminepentaacetic acid (DTPA)-D-Phe1-octreotide (OC) was developed for imaging somatostatin-receptor-positive tumors using conventional scintigraphy. With the advantages of PET over conventional scintigraphy, an agent for PET imaging of these tumors is desirable. Here, we show that 64Cu-TETA-OC (where TETA is 1,4,8,11-tetraazacyclotetradecane-N,N',N'',N'''-tetraacetic acid) and PET can be used to detect somatostatin-receptor-positive tumors in humans.

Methods: Eight patients with a history of neuroendocrine tumors (five patients with carcinoid tumors and three patients with islet cell tumors) were imaged by conventional scintigraphy with (111)In-DTPA-OC (204-233 MBq [5.5-6.3 mCi]) and by PET imaging with 64Cu-TETA-OC (111 MBq [3 mCi]). Blood and urine samples were collected for pharmacokinetic analysis. PET images were collected at times ranging from 0 to 36 h after injection, and the absorbed doses to normal organs were determined.

Results: In six of the eight patients, cancerous lesions were visible by both (111)In-DTPA-OC SPECT and 64Cu-TETA-OC PET. In one patient, (111)In-DTPA-OC showed mild uptake in a lung lesion that was not detected by 64Cu-TETA-OC PET. In one patient, no tumors were detected by either agent; however, pathologic follow-up indicated that the patient had no tumors. In two patients whose tumors were visualized with (111)In-DTPA-OC and 64Cu-TETA-OC, 64Cu-TETA-OC and PET showed more lesions than (111)In-DTPA-OC. Pharmacokinetic studies showed that 64Cu-TETA-OC was rapidly cleared from the blood and that 59.2% +/- 17.6% of the injected dose was excreted in the urine. Absorbed dose measurements indicated that the bladder wall was the dose-limiting organ.

Conclusion: The high rate of lesion detection, sensitivity, and favorable dosimetry and pharmacokinetics of 64Cu-TETA-OC indicate that it is a promising radiopharmaceutical for PET imaging of patients with neuroendocrine tumors.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenoma, Islet Cell / diagnostic imaging
  • Aged
  • Animals
  • Carcinoid Tumor / diagnostic imaging
  • Female
  • Gastrointestinal Neoplasms / diagnostic imaging
  • Humans
  • Indium Radioisotopes
  • Male
  • Middle Aged
  • Neuroendocrine Tumors / chemistry
  • Neuroendocrine Tumors / diagnostic imaging*
  • Octreotide / analogs & derivatives*
  • Octreotide / pharmacokinetics
  • Organometallic Compounds* / pharmacokinetics
  • Pancreatic Neoplasms / diagnostic imaging
  • Papio
  • Pentetic Acid / analogs & derivatives*
  • Radiation Dosage
  • Radiopharmaceuticals*
  • Receptors, Somatostatin / analysis
  • Sensitivity and Specificity
  • Tomography, Emission-Computed*

Substances

  • Indium Radioisotopes
  • Organometallic Compounds
  • Radiopharmaceuticals
  • Receptors, Somatostatin
  • copper 1,4,8,11--tetraazacyclotetradecane-N,N',N'',N'''-tetraacetic acid-octreotide
  • SDZ 215-811
  • Pentetic Acid
  • Octreotide