The utility of Tc-99m-EDDA/HYNIC-TOC scintigraphy for assessment of lung lesions in patients with neuroendocrine tumors

Our aim was to assess clinical utility of Tc-99m-EDDA/HYNIC-TOC scintigraphy for evaluation of lung lesions in patients with neuroendocrine tumors (NETs). Single photon emission computed tomography (SPECT) of the thorax and whole body scintigraphy were performed in 34 patients using Tc-99m-EDDA/HYNIC-TOC. Visual assessment was complemented by semiquantitative evaluation based on tumor to non-tumor (TINT) ratio. Clinical, laboratory, and histological findings served as the standard for comparison. Enhanced tracer uptake was observed on both SPECT and whole body scintigraphy in 29 of 34 patients (88% sensitivity). TINT ratios were significantly higher on SPECT than whole body images (2.96 +/- 1.07 vs. 1.70 +/- 0.43, p LT 0.01) and did not correlate with NET proliferation index Ki-67 (r= - 0.36, p=0.27). Conclusion: Tc-99m-EDDA/HYNIC-TOC scintigraphy is useful for evaluation of NET tissue in the lungs. SPECT provides better visualization of lung lesions than whole body scintigraphy. The intensity of tracer uptake, however, does not relate to the proliferation rate of NETs. Tc-99m-EDDA/HYNIC-TOC scintigraphy may be helpful for selecting and monitoring treatment options, particularly when radiolabeled somatostatin analogue therapy becomes available