Clinical utility of indigenously formulated single-vial lyophilized HYNIC-TOC kit in evaluating Gastro-entero Pancreatic neuro endocrine tumours

Objective(s): The objective of this study was to evaluate the performance and utility of 99mTc HYNIC-TOC planar scintigraphy and SPECT/CT in the diagnosis, staging and management of gastroenteropancreatic neuroendocrine tumors (GPNETs). Methods: 22 patients (median age, 46 years) with histologically proven gastroentero-pancreatic NETs underwent 99mTc HYNIC-TOC whole body scintigraphy and regional SPECT/CT as indicated. Scanning was performed after injection of 370-550 MBq (10-15 mCi) of 99mTc HYNIC-TOC intravenously. Images were evaluated by two experienced nuclear medicine physicians both qualitatively as well as semi quantitatively (tumor to background and tumor to normal liver ratios on SPECT -CT images). Results of SPECT/CT were compared with the results of conventional imaging. Histopathology results and follow-up somatostatin receptor scintigraphy with 99mTc HYNIC TOC or conventional imaging with biochemical markers were considered to be the reference standards. Results: 99mTc HYNIC TOC showed sensitivity and specificity of 87.5% and 85.7%, respectively, for primary tumor and 100% and 86% for metastases. It was better than conventional imaging modalities for the detection of both primary tumor (P < 0.001) and metastases (P < 0.0001). It changed the management strategy in 6 patients (31.8%) and supported management decisions in 8 patients (36.3%). Conclusion: 99mTc HYNIC TOC SPECT/CT appears to be a highly sensitive and specific modality for the detection and staging of GPNETs. It is better than conventional imaging for the evaluation of GPNETs and can have a significant impact on patient management and planning further therapeutic options.