Related Experiment Video
Updated: Apr 28, 2026
A Practical Guide for the Production and PET/CT Imaging of 68Ga-DOTATATE for Neuroendocrine Tumors in Daily Clinical Practice
Published on: April 17, 2019
Evaluation of cobalt-labeled octreotide analogs for molecular imaging and auger electron-based radionuclide therapy
Helge Thisgaard1, Birgitte Brinkmann Olsen2, Johan Hygum Dam2
1PET & Cyclotron Unit, Department of Nuclear Medicine, Odense University Hospital, Odense, Denmark Institute of Clinical Research, University of Southern Denmark, Odense, Denmark Helge.Thisgaard@rsyd.dk.
Unlabelled:
The somatostatin receptor, which is overexpressed by many neuroendocrine tumors, is a well-known target for molecular imaging and peptide receptor radionuclide therapy. Recently, (57)Co-labeled DOTATOC, an octreotide analog, was shown to have the highest affinity yet found for somatostatin receptor subtype 2. The aim of this study was to evaluate the biologic effects of novel cobalt-labeled octreotide analogs targeting the somatostatin receptor to identify promising candidates for molecular imaging and Auger electron-based radionuclide therapy.
Methods:
Cobalt-labeled DOTATATE, DOTATOC, and DOTANOC were prepared with (57)Co or (58m)Co for SPECT or Auger electron-based therapy, respectively. The cellular uptake and intracellular distribution of the radioligands were characterized with the pancreatic tumor cell line AR42J in vitro, including assessment of the therapeutic effects of (58m)Co-DOTATATE via DNA double-strand break and proliferation assays. Comparisons with the therapeutic effects of (111)In- and (177)Lu-DOTATATE were also performed. Tumor uptake and normal tissue uptake were characterized in a subcutaneous pancreatic tumor mouse model.
Results:
All 3 cobalt-conjugated peptides resulted in time-dependent and receptor-specific uptake, with a high level (≥88%) of cellular internalization in vitro of the total cell-associated radioactivity. The DNA double-strand break yield showed a dose-dependent increase with activity, whereas cell survival showed a dose-dependent decrease. (58m)Co-DOTATATE was significantly more efficient in cell killing per cumulated decay than (111)In- and (177)Lu-DOTATATE. The in vivo pharmacokinetic studies showed a high level of receptor-specific tumor uptake.
Conclusion:
All cobalt-labeled radioligands showed a high level of receptor-specific uptake both in vitro and in vivo in tumor-bearing mice. Furthermore, (58m)Co-DOTATATE showed considerable therapeutic effects in vitro and, thus, could be an effective agent for eradicating disseminated tumor cells and micrometastases.
Insights
Novel cobalt-labeled octreotide analogs demonstrate high somatostatin receptor uptake for targeted neuroendocrine tumor therapy. (58m)Co-DOTATATE shows significant therapeutic potential for eradicating micrometastases.
Area of Science:
- Nuclear medicine
- Radiopharmaceutical chemistry
- Oncology
Background:
- Somatostatin receptors are overexpressed in neuroendocrine tumors, making them targets for imaging and therapy.
- Cobalt-labeled DOTATOC exhibits high affinity for somatostatin receptor subtype 2.
Purpose of the Study:
- To evaluate biologic effects of novel cobalt-labeled octreotide analogs targeting somatostatin receptors.
- To identify candidates for molecular imaging and Auger electron-based radionuclide therapy.
Main Methods:
- Preparation of (57)Co or (58m)Co labeled DOTATATE, DOTATOC, and DOTANOC.
- In vitro characterization of cellular uptake and distribution in AR42J cells.
- In vitro assessment of (58m)Co-DOTATATE therapeutic effects (DNA breaks, proliferation) and in vivo tumor uptake in mice.
Main Results:
- All cobalt-labeled peptides showed time-dependent, receptor-specific uptake and high cellular internalization (≥88%).
- (58m)Co-DOTATATE significantly increased DNA double-strand breaks and decreased cell survival dose-dependently.
- (58m)Co-DOTATATE demonstrated superior cell killing efficiency compared to (111)In- and (177)Lu-DOTATATE.
Conclusions:
- Cobalt-labeled radioligands exhibit high receptor-specific uptake in vitro and in vivo.
- (58m)Co-DOTATATE shows significant therapeutic potential for eradicating disseminated tumor cells and micrometastases.
More Related Videos
07:26Synthesis of 68Ga Core-doped Iron Oxide Nanoparticles for Dual Positron Emission Tomography /T1Magnetic Resonance Imaging
Published on: November 20, 2018
10:47Harnessing the Bioorthogonal Inverse Electron Demand Diels-Alder Cycloaddition for Pretargeted PET Imaging
Published on: February 3, 2015
Related Concept Videos
01:25Imaging Studies II: Positron Emission Tomography and Scintigraphy
Fundamental Principles of PET
01:29Positron Emission Tomography
One of the main requirements of a PET scan is a positron-emitting radioisotope, which is produced in a cyclotron and then attached to a substance used by the part of the body...