The Usefulness of Combined Diagnostic CT and 99m Tc-Octreotide Somatostatin Receptor SPECT/CT Imaging on Pulmonary Nodule Characterization in Patients

UNLABELLED: The objective of this study was to evaluate the clinical value of combination of diagnostic computed tomography (CT) and somatostatin receptor imaging with (99m)Tc-octreotide acetate SPECT/CT in differentiation of benign pulmonary nodules from cancers. METHODS: This was a retrospective study, 29 patients with suspected pulmonary neoplasm underwent diagnostic CT and (99m)Tc-octreotide SPECT/CT scans, and the tumor-to-normal tissue tracer value (T/N) for (99m)Tc-octreotide was measured. Diagnosis was confirmed by histological analysis. RESULTS: Eighteen of the 29 patients included in this study had lung cancer: 2 with small cell lung cancer and 16 with nonsmall cell lung cancer. The other 11 patients had benign lung lesions: 5 with tuberculosis, 4 with nontuberculosis infection, 1 with hematoma, and 1 with fibroma. (99m)Tc-octreotide uptake (expressed as mean T/N±SD) was significantly higher in lung cancers (2.58±0.91) than benign lesions (1.38±0.79) (p=0.002). Specificity for pulmonary malignant nodule diagnosis was 63.6% for diagnostic CT, 72.7% for somatostatin receptor SPECT/CT imaging, and 81.8% for the combined use of diagnostic CT and somatostatin receptor SPECT/CT imaging. CONCLUSION: Somatostatin receptor imaging with (99m)Tc-octreotide SPECT/CT is useful for the differentiation of benign pulmonary nodules from lung cancers, the combination of diagnostic CT and (99m)Tc-octreotide SPECT/CT further increases the specificity of malignant pulmonary nodule detection.