Abstract
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Objectives We success to acquire SPECT brain image of technetium-99m-ethylcysteinate dimer (Tc-99m -ECD) on rodent stroke animal model. Experiments were designed to compare images between Tc-99m -ECD and Tc-99m-HMAPO (Tc-99m-Hexa- methylpropyleneamine Oxime), a well-known blood flow agent by multi-pinhole SPECT.
Methods Male C57BL/6J mice and SD rat were used in this study. Permanent focal ischemia was induced by occlusion of the right middle cerebral artery (MCA). We prepared Tc-99m -ECD and Tc-99m-HMPAO using a two-vial kit, and injected 10 mCi via tail vein. The multi-pinhole collimator we used is five pinholes, 1.0 mm aperture. After the onset of SPECT imaging, the brain was sliced and stained with TTC to define the infracted area. The ex vivo autoradiography was also performed to acquire radioactivity distribution
Results Tc-99m-ECD SPECT imaging demonstrated that higher radioactivity was detected on the same side of ischemia. Besides, ex vivo autoradiography also detected the similar result identically to SPECT live imaging. However, Tc-99m-HMAPO SPECT image showed that right brain had lower radioactivity than the left side.In addition, control brain without ischemia had equal radioactivity distribution of both radio pharmaceuticals in right and left hemisphere.
Conclusions Our results showed that higher Tc-99m-ECD radioactivity could be detected in occlusive side but the radioactivity of Tc-99m-HMAPO was accumulated in non-occluded side, indicated the retention of these two blood flow agent in brain might result from different mechanisms in our stroke animal model
Research Support This study was supported by grant awarded by the department of industrial technology, Ministry of Economic Affairs, R.O.C