Assessment of Somatostatin Receptor Expression in Neuroendocrine Tumors by 99mTc-Hynic-Toc Scan and Its Correlation to Tumor Grading and Analysis of Their Significance in The Overall Treatment Response to PRRT

Harilal. P; Arun B; Matthew James Vivek

doi:10.51168/4cfgq766

Autori

Harilal. P Associate Professor, Department of Nuclear Medicine, Government Medical College, Thiruvananthapuram, India.
Arun B Assistant Professor, Department of Nuclear Medicine, Government Medical College, Thiruvananthapuram, India
Matthew James Vivek Assistant Professor, Department of Nuclear Medicine, Government Medical College, Thiruvananthapuram, India

DOI:

https://doi.org/10.51168/4cfgq766

Cuvinte cheie:

Neuroendocrine tumors, Somatostatin receptors, 99mTc-HYNIC-TOC, Peptide receptor radionuclide therapy, Ki-67

Rezumat

Background: Neuroendocrine tumors (NETs) are a heterogeneous group of neoplasms characterized by variable biological behaviour and overexpression of somatostatin receptors (SSTRs), particularly subtype 2. Assessment of SSTR expression is essential for disease characterization, staging, and identifying patients suitable for receptor-targeted management. Among the available imaging modalities, 99mTc-HYNIC-TOC scintigraphy offers a cost-effective and widely accessible method for evaluating receptor expression.

Objective: To evaluate somatostatin receptor expression using qualitative and quantitative 99mTc-HYNIC-TOC scintigraphy in patients with histologically confirmed neuroendocrine tumors and to correlate imaging findings with histopathological tumor grading and proliferation index.

Methods: This prospective observational study included 50 patients with histopathologically confirmed metastatic, recurrent, or inoperable neuroendocrine tumors referred for somatostatin receptor imaging. All patients underwent whole-body 99mTc-HYNIC-TOC scintigraphy. Qualitative assessment of receptor expression was complemented by quantitative analysis using the HYNIC-TOC Lesion Index, calculated from tumor and mediastinal blood pool regions of interest after background correction. Imaging findings were correlated with tumor grade and Ki-67 proliferation index.

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