Circlet Sign: Urinary Contamination on 177 Lu-DOTATATE Posttherapy Imaging

Area of Science:

• Nuclear Medicine
• Oncology
• Radiochemistry

Background:

• Peptide receptor radionuclide therapy (PRRT) is a key treatment for somatostatin receptor-positive metastatic neuroendocrine tumors.
• Physicians must manage radiation hazards from radioactive contamination during PRRT.
• Contamination can cause imaging fallacies on posttherapy scans, potentially leading to incorrect disease staging.

Purpose of the Study:

• To demonstrate image fallacies caused by radioactive urinary contamination.
• To highlight the importance of recognizing contamination in posttherapy imaging.
• To emphasize the potential for misstaging disease due to imaging artifacts.

Main Methods:

• Utilized 177Lu-DOTATATE for peptide receptor radionuclide therapy.
• Performed posttherapy planar imaging to assess treatment response and identify contamination.
• Analyzed imaging findings specifically for artifacts caused by radioactive urinary contamination.

Main Results:

• Radioactive urinary contamination was observed on posttherapy planar imaging.
• This contamination created image fallacies that could be misinterpreted.
• The potential for upstaging disease due to these fallacies was demonstrated.

Conclusions:

• Radioactive urinary contamination is a significant issue in 177Lu-DOTATATE therapy.
• Nuclear medicine physicians must be vigilant for these imaging fallacies.
• Proper identification of contamination is crucial to avoid inaccurate disease assessment in neuroendocrine tumor patients.