Abstract

Background: Neuroendocrine tumors (NETs) are often well-differentiated and express somatostatin receptors (SSTRs), making functional imaging essential for accurate localization and staging. While [68Ga]Ga-DOTANOC PET/CT is preferred for its superior sensitivity, [99mTc]Tc-HYNIC-TATE SPECT/CT offers a viable alternative in settings with limited positron emission tomography (PET) access.
Case Description: We report a case of a 44-year-old patient diagnosed with a Grade 1 NET on tru-cut biopsy from retroperitoneal mass. To evaluate disease extent and SSTR expression, [⁶⁸Ga]Ga-DOTANOC PET/CT and [99mTc]Tc-HYNIC-TATE SPECT/CT were performed. Both imaging modalities demonstrated concordant findings with significant tracer uptake in a subhepatic lesion, retroperitoneal lymph nodes, and a hepatic lesion in segment V of the liver. These results confirmed the presence of both primary and metastatic disease, as well as high SSTR expression, indicating suitability for somatostatin analog therapy and possibly peptide receptor radionuclide therapy (PRRT).
Conclusion: This case illustrates that while [68Ga]Ga-DOTANOC PET/CT remains the gold standard of imaging, [99mTc]Tc-HYNICTATE SPECT/CT is a reliable alternative, particularly when PET is not available. The concordance between both modalities reinforces the diagnostic utility of [99mTc]Tc-HYNIC-TATE SPECT/CT in clinical practice.

Key words: SSRT, [⁶⁸Ga]Ga-DOTANOC PET/CT, [⁹⁹ᵐTc]Tc-HYNIC-TATE SPECT/CT, PRRT Peptide Receptor Radionuclide Therapy (PRRT).