人小细胞肺癌NCI-H446裸鼠模型的(99m)Tc-octreotide受体显像研究

BACKGROUND AND OBJECTIVE: For highly aggressive small cell lung cancer (SCLC), early diagnosis is important for its prognosis, but the current inspection methods are more limited, with poor specificity of the traditional imaging methods, and the high cost of PET/CT, difficult to popularization and application. SCLC is kind of neuroendocrine tumors, high expression of somatostatin receptors, which is the cornerstone of its early molecular imaging diagnosis. The aim of this study is to observe the biodistribution and metabolism of (99m)Tc-octreotide in normal and the human SCLC bearing nude mice. METHODS: Dynamic and static scintigraphy at 0.5 h, 2 h, 3 h, 4 h were performed in both normal and tumor bearing nude mice after intravenous injection of (99m)Tc-octreotide. The technique of drawing region of interest (ROI) was used to obtain the averaged pixel counts and the activity-time (A-T) curve of brain, heart, lung, liver, kidney, tumor, respectively. RESULTS: ① The biodistribution study in normal nude mice showed highest uptake in kidney and liver, lower in lung and heart, lowest in brain. Most (99m)Tc-octreotide was excreted via kidney. ② All tumors were displayed clearly at 3 h postinjection of (99m)Tc-octreotide. The averaged T/N ratio at 0.5 h, 2 h, 3 h, 4 h postinjection of (99m)Tc-octreotide was 1.163±0.03, 2.08±0.12, 3.03±0.23, 2.689±0.31, respectively (F=51.69, P < 0.000, 1). The radioactivity of tumor was lower than liver, and similar with the lung. The curve of tumor showed a radioactivity peak at 2 min-3 min postinjection. CONCLUSION: (99m)Tc-octreotide receptor imaging on nude mice bearing SCLC shares high positive rate, especially at 3 h postinjection.