Expression of Permeability-glycoprotein (P-gp) and Uptake of Technetium-99m-Hexakis-2-Methoxy-Isobutyl-Isonitrile (Tc-99m-MIBI) in Malignant Tumor of the Head and Neck

对于滞留指数(延迟摄取/早期摄取)，99m-Tc-MIBI显示恶性肿瘤的滞留指数小于1(平均值±标准差=0.853±0.067)，提示延迟摄取有下降的趋势。根据肿瘤的组织病理类型，201-TlCl显像的保留指数分为三组：良性肿瘤0.81±0.06，高分化恶性肿瘤1.01±0.10，中分化肿瘤1.09±0.13，低分化肿瘤1.24±0.14。因此，良性肿瘤的平均保留指数小于1，而恶性肿瘤的平均保留指数大于1。P-gp表达(评分0、1、2分)与肿瘤组织学类型的关系：良性肿瘤评分(Mean±SD)=0.75±0.19，高分化组为0.71±0.36，中分化组为0.83±0.40，低分化组为1.60±0.24。因此，P-gp在良性肿瘤或低度恶性肿瘤中的平均表达分数较小，而在高度恶性肿瘤中的平均表达分数较大。Na，K-ATPase表达(0、1、2分)与肿瘤组织学类型的比较，高分化组为0.82分，中分化组为1.44分，低分化组为1.50分。(结论)99m-TC-MIBI和201-TlCl显像显示不同的延迟摄取倾向，99m-TC-MIBI和201-TlCl显像均可对肿瘤作出准确诊断。P-gp和Na，K-ATPase的表达与99m-Tc-MIBI和201-TlCl核素显像结果一致。

(Clinical evaluation) As for the retention index (delayed uptake / early uptake), 99m-Tc-MIBI showed the retention index of under 1 (mean ± SD = 0.853 ± 0.067) in malignant tumor, indicating a tendency of decreasing in the delayed uptake. On the other hand, the retention indexes of 201-TlCl scintigraphy were classified into three groups according to histopathological types of tumor ; 0.81 ± 0.06 in benign tumors, 1.01 ± 0.10 in well differentiated malignant tumors, 1.09 ± 0.13 in moderately differentiated tumors, and 1.24 ± 0.14 in poorly differentiated tumors. Thus, the mean retention indexes were under 1 in benign tumor, but over 1 in malignant tumor. The higher the histopathological grade was, the larger the retention index became.(Accumulation mechanism) As for the relationship between P-gp expression (score 0, 1 and 2) and histopathological type of tumor, the scores (mean ± SD) = 0.75 ± 0.19 in benign tumors, 0.71 ± 0.36 in well differentiated tumor, 0.83 ± 0.40 in moderately differentiated tumor, and 1.60 ± 0.24 in poorly differentiated tumor. Thus, the mean score of P-gp expression was small in the benign or low-grade malignant tumor, but large in the high-grade malignant tumors. Comparing of Na, K-ATPase expression (score 0, 1 and 2) to the histopathological type of tumor, the scores (mean) = 0.82 in well differentiated tumor, 1.44 in moderately differentiated tumor, and 1.50 in poorly differentiated tumors respectively.(Conclusion) 99m-Tc-MIBI and 201-TlCl scintigraphy showed different tendency of delayed uptake, and accurate diagnosis of tumor could be obtained by using both 99m-Tc-MIBI and 201-TlCl scintigraphy. P-gp and Na, K-ATPase expression were observed in accordance with the results of 99m-Tc-MIBI and 201-TlCl scintigraphy.