Li Chao, Zuo Shuyao, Wang Xufu, Liu Xinfeng, Wang Guoming, Wu Fengyu
Department of Nuclear Medicine, the Affiliated Hospital of Medical College, Qingdao University, Qingdao 266003, China.
Zhongguo Fei Ai Za Zhi. 2015 Jan;18(1):1-7. doi: 10.3779/j.issn.1009-3419.2015.01.01.
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 99mTc-octreotide in normal and the human SCLC bearing nude mice.
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 99mTc-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.
① The biodistribution study in normal nude mice showed highest uptake in kidney and liver, lower in lung and heart, lowest in brain. Most 99mTc-octreotide was excreted via kidney. ② All tumors were displayed clearly at 3 h postinjection of 99mTc-octreotide. The averaged T/N ratio at 0.5 h, 2 h, 3 h, 4 h postinjection of 99mTc-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.
99mTc-octreotide receptor imaging on nude mice bearing SCLC shares high positive rate, especially at 3 h postinjection.
对于侵袭性很强的小细胞肺癌（SCLC），早期诊断对其预后很重要，但目前的检查方法较为有限，传统成像方法特异性较差，而PET/CT成本高，难以推广应用。SCLC是一种神经内分泌肿瘤，生长抑素受体高表达，这是其早期分子成像诊断的基石。本研究旨在观察99mTc-奥曲肽在正常裸鼠和人SCLC荷瘤裸鼠体内的生物分布及代谢情况。
给正常裸鼠和荷瘤裸鼠静脉注射99mTc-奥曲肽后，分别于0.5小时、2小时、3小时、4小时进行动态和静态闪烁扫描。采用绘制感兴趣区（ROI）技术，分别获取脑、心、肺、肝、肾、肿瘤的平均像素计数及活度-时间（A-T）曲线。
①正常裸鼠生物分布研究显示，肾脏和肝脏摄取最高，肺和心脏较低，脑最低。大部分99mTc-奥曲肽经肾脏排泄。②注射99mTc-奥曲肽后3小时，所有肿瘤均清晰显示。注射99mTc-奥曲肽后0.5小时、2小时、3小时、4小时的平均T/N比值分别为1.163±0.03、2.08±0.12、3.03±0.23、2.689±0.31（F=51.69，P<0.0001）。肿瘤放射性低于肝脏，与肺相似。肿瘤曲线在注射后2分钟至3分钟出现放射性峰值。
99mTc-奥曲肽受体显像对SCLC荷瘤裸鼠有较高的阳性率，尤其是在注射后3小时。
