Author:
Kämpfer I.,Seese A.,Dannenberg C.,Kluge R.,Burchert W.,Knapp W. H.,Barthel H.
Abstract
Summary
Aim: 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. Methods: 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 (QS), 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. Results: 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-H M PAO (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. Conclusions: 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.
Subject
Radiology, Nuclear Medicine and imaging,General Medicine
Cited by
12 articles.
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