Utility of ^99mTc HYNIC-TOC SPECT/CT in neuroendocrine tumors

The objective of this study was to evaluate the use of ^99mTc HYNIC-TOC SPECT/CT in the diagnosis staging and management of gastroenteropancreatic neuroendocrine tumors (GPNETs). 40 patients (median age, 55 years)with histologically proven GPNETs underwent ^99mTc HYNIC TOC whole body scintigraphy and regional SPECT/CT as indicated. 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. 10 patients had pancreatic tumor with liver metastasis, 15 patients with liver and bone metastasis, 8 patients had lung metastasis and other 7 patients with nodal metastasis.^99mTc HYNIC-TPC showed sensitivity and specificity of 92.5% and 90.7%, respectively, for primary tumor and 98% and 89% for metastasis.It showed better results than conventional imaging modalities for the detection of both primary tumor (P<0.001) and supported management decisions in 10 patients (25%) ^99mTc HYNIC TOC SPECT/CT appears to be a highly sensitive and specific modality for the detection 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. (author)