Guoming Wang

Application values of 99mTc‑methoxyisobutylisonitrile imaging for differentiating benign and malignant thymic masses

The aim of the present study was to investigate the application value of 99mTc-methoxyisobutylisonitrile (MIBI) imaging to differentiate between benign and malignant thymic masses. A total of 32 patients with space-occupying mediastinal masses were enrolled and early and delayed-phase images were collected following injection with the imaging agent. The tumor to background ratio (T/N) values at the different phases were also recorded. The sensitivity of the qualitative analysis to distinguish between benign and malignant thymic masses was 95.24%, with specificity as 90.91%. The T/N values in the early and delayed phases were not significantly different in the group with benign thymic masses, but demonstrated statistical significant differences in the groups with low- and intermediate-grade malignant thymic masses. The T/N values at the above early and delayed phase were significantly different between the benign and low-grade malignancy groups, as well as between low- and moderate-grade malignancy groups. Those between the benign and moderate-grade malignancy groups demonstrated no significant difference. 99mTc-MIBI imaging was able to differentiate between benign and malignant thymic masses, and the simultaneous semi-quantitative analysis of the T/N values of the tumors may be able to initially determine the degree of malignancy of thymoma.

99mTc-octreotide Receptor Scintigraphy in NCI-H446 Small Cell Lung Cancer Nude Mice Model

背景与目的 小细胞肺癌恶性程度高，早期诊断对其预后有重要价值，目前的检查方法比较局限，传统影像学方法特异性差，而PET/CT价格昂贵，难于推广应用。小细胞肺癌属神经内分泌肿瘤，高表达生长抑素受体，是其早期进行分子影像诊断的理论基石。本实验旨在观察99mTc-octreotide在正常裸鼠体内的分布、代谢及荷人NCI-H446小细胞肺癌裸鼠模型体内显像变化，为临床小细胞肺癌早期诊断奠定基础。 方法 建立人小细胞肺癌的裸鼠肿瘤模型，正常裸鼠及荷瘤鼠静脉注射99mTc-octreotide显像剂后行动态及延迟显像。运用感兴趣区（region of interest, ROI）技术勾画各时相裸鼠各脏器、肿瘤（T）及肿瘤对侧对应部位（N）放射性计数，计算相应T/N比值，并建立30 min内各ROI的时间-放射性（A-T）曲线。 结果 ① 正常裸鼠的肾脏、肝脏内99mTc-octreotide分布最多，肺部、心脏部位分布较低，头部放射性分布最少，99mTc-octreotide主要通过泌尿系统排泄；各脏器30 min内A-T曲线显示放射性分布随时间延迟呈逐渐下降趋势。②5例荷瘤裸鼠的肿瘤显像均呈阳性；静脉注射99mTc-octreotide后肿瘤部位在3 h显像最清楚，整个检查时间内肝脏放射性强度明显高于肿瘤组织，肺部放射性与肿瘤部位较相近。半定量分析结果显示，静脉注射99mTc-octreotide后肿瘤组织与对侧肢体肌肉的T/N比值在0.5 h、2 h、3 h、4 h分别为1.163±0.03、2.08±0.12、3.03±0.23、2.689±0.31；各时相T/N比值差异有统计学意义（F=51.69, P < 0.000, 1）；通过两两比较发现，静脉注射显像剂后3 h的T/N比值与其他各时相差异均有统计学意义（P < 0.05）；不同检查时间肝脏部位的放射性平均计数高于肿瘤部位，肺部的平均计数与肿瘤相近。肿瘤部位A-T曲线显示，注射99mTc-octreotide后2 min-3 min出现一过性放射性分布高峰。 结论 运用99mTc-octreotide作显像剂，人小细胞肺癌NCI-H446裸鼠模型具有极高的显像阳性率，且3 h肿瘤显像最清楚。BACKGROUND 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. 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 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. 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 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. CONCLUSIONS 99mTc-octreotide receptor imaging on nude mice bearing SCLC shares high positive rate, especially at 3 h postinjection.

The Value of 99mTc-MDP SPECT/CT Fusion Imaging in Evaluating the Extent of Mandibular Invasion by Squamous Cell Carcinoma of Oral Cavity

Objective: Comparing the Accuracy of computed tomography (CT) and 99mTc-methylene-diphosphonate (MDP) SPECT/CT fusion imaging in determining the extent of mandibular invasion by squamous cell carcinoma of the oral cavity, to study the clinical value of SPECT/CT fusion imaging in evaluating the extent of mandibular invasion by squamous cell carcinoma of oral cavity. Material and Methods: Fifty-one patients were revealed mandibular invasion by moderately differentiated squamous cell carcinoma of the oral cavity underwent CT and SPECT/CT. The patients were divided into two groups: A group (oral mucosal squamous cell carcinoma) and B group (primary intra-osseous carcinoma). Two radiologists assessed the CT images and two nuclear medicine physicians separately assessed the SPECT/CT images in consensus and without knowledge of the results of other imaging tests. The extent of bone involvement suggested with an imaging modality was compared with pathological findings in the surgical specimen. Results: The pathological findings as the reference standard ,group A:the extent of mandibular invasion by moderately differentiated squamous cell carcinoma underwent SPECT/CT was 1.02±0.20cm lager than the pathological examination identified, and the extent of mandibular invasion underwent CT was Advances in Cancer: Research & Treatment 2 1.42±0.35cm smaller than the pathological examination identified. There were statistically significant differences among the three methods, p<0.01. Group B: the extent of mandibular invasion by moderately differentiated squamous cell carcinoma underwent SPECT/CT was 1.3±0.39cm larger than that underwent pathological examination. The extent of mandibular invasion underwent CT was 2.55±1.44cm smaller than the pathological examination identified. There were statistically significant difference among the three methods (p<0.01), too. Conclusion: SPECT/CT fusion imaging in identifying the extent of squamous cell carcinoma of the oral cavity on mandibular invasion has important clinical value. The extent of mandibular invasion underwent SPECT/CT was the extent which surgeon to reach the clear margins to the limits of resection.