Barthel H, Kämpfer I, Seese A, Dannenberg C, Kluge R, Burchert W, Knapp W H
Nuklearmedizin. 1999 Apr;38(3):80-4.
This present study was carried out to investigate whether stabilization of Tc-99m-HMPAO with methylene blue (MB) or cobalt chloride (CC) causes a sensible improvement in image quality and how cerebral to noncerebral activity ratios compare with those of Tc-99m-ECD.
30 minutes after preparation 400-600 MBq unstabilized Tc-99m-HMPAO (N = 35 patients), Tc-99m-HMPAO added with MB (N = 24 patients), added with CC (N = 30 patients) or Tc-99m-ECD (N = 28 patients) were injected. Radiochemical stability was measured in vitro with three chromatographical methods. Image quality was assessed quantitatively using two ratios, one of them determined by count densities of brain/scalp (Os), the other one by count densities of brain/nose (QN). In addition, image quality (0 = bad, 3 = excellent) and background activity (0 = high, 3 = no) were visually assessed by three independent observers.
In contrast to unstabilized Tc-99m-HMPAO the integrity of the complexes of MB-Tc-99m-HMPAO, CC-Tc-99m-HMPAO and Tc-99m-ECD decreased only by a few percent during a period of 2 hours after reconstitution (66.8 +/- 9.9 vs. 93.0 +/- 2.5, 91.8 +/- 1.9 and 96.9 +/- 1.4%, p < 0.001). Qs and Qn (m.v. +/- SD) differed significantly between studies using unstabilized Tc-99m-HMPAO (3.0 +/- 0.4 and 2.1 +/- 0.3), MB-Tc-99m-HMPAO (3.4 +/- 0.4 and 2.3 +/- 0.3), CC-Tc-99m-HMPAO (3.6 +/- 0.6 and 2.6 +/- 0.4) and those using Tc-99m-ECD (4.3 +/- 0.7 and 4.8 +/- 1.4, p < 0.05 and < 0.001). Stabilization with CC or MB resulted in significant higher scoring of image quality and lower scoring of background activity in comparison to that of unstabilized Tc-99m-HMPAO, without reaching the scores obtained with Tc-99m-ECD.
It is concluded that stabilization of Tc-99m-HMPAO with MB or CC definitely improves image quality in rCBF-SPECT, without reaching that of Tc-99m-ECD. Improvement of image quality results from the reduction of the amount of decomposition products that contribute to considerable extracerebral activity.
本研究旨在调查用亚甲蓝（MB）或氯化钴（CC）稳定锝-99m-六甲基丙烯胺肟（Tc-99m-HMPAO）是否能显著改善图像质量，以及脑与非脑活性比值与锝-99m-双半胱乙酯（Tc-99m-ECD）的比值相比情况如何。
在制备后30分钟，注射未稳定化的Tc-99m-HMPAO（400 - 600MBq，N = 35例患者）、添加MB的Tc-99m-HMPAO（N = 24例患者）、添加CC的Tc-99m-HMPAO（N = 30例患者）或Tc-99m-ECD（N = 28例患者）。用三种色谱方法在体外测量放射化学稳定性。使用两个比值定量评估图像质量，其中一个由脑/头皮计数密度（Os）确定，另一个由脑/鼻计数密度（QN）确定。此外，由三名独立观察者对图像质量（0 = 差，3 = 优）和背景活性（0 = 高，3 = 无）进行视觉评估。
与未稳定化的Tc-99m-HMPAO相比，在重构后2小时内，MB-Tc-99m-HMPAO、CC-Tc-99m-HMPAO和Tc-99m-ECD复合物的完整性仅下降了几个百分点（66.8±9.9对93.0±2.5、91.8±1.9和96.9±1.4%，p < 0.001）。在使用未稳定化的Tc-99m-HMPAO（3.0±0.4和2.1±0.3）、MB-Tc-99m-HMPAO（3.4±0.4和2.3±0.3）、CC-Tc-99m-HMPAO（3.6±0.6和2.6±0.4）的研究与使用Tc-99m-ECD（4.3±0.7和4.8±1.4）的研究之间，Qs和Qn（平均值±标准差）存在显著差异（p < 0.05和< 0.001）。与未稳定化的Tc-99m-HMPAO相比，用CC或MB稳定化导致图像质量评分显著更高，背景活性评分更低，但未达到用Tc-99m-ECD获得的分数。
得出结论，用MB或CC稳定化Tc-99m-HMPAO确实能改善rCBF-SPECT中的图像质量，但未达到Tc-99m-ECD的图像质量。图像质量的改善源于减少了导致大量脑外活性的分解产物的量。
