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Background and Purpose-We hypothesized that technetium-99m-ethylene dicysteine-metronidazole ( 99m Tc-EC-MN) localizes to brain tissue that is hypoxic but viable. This study prospectively evaluated the relationship between neurological outcome and uptake of 99m Tc-EC-MN in peri-infarcted regions of the brain. Methods-Eight patients with acute ischemic stroke in the territory of the left middle cerebral artery underwent 99m Tc-EC-MN and 99m Tc-ethyl cysteinate dimer (ECD) brain SPECTs on the same day during the subacute stage (10.3Ϯ2.5 days). The infarct volumes from 99m Tc-ECD images (IV ECD ), infarct volumes from diffusion-weighted MRI images (IV DW ), and hypoxic volume (HV) from 99m Tc-EC-MN images were calculated. The net infarct volume (NIV ECD ) was defined as IV ECD minus HV. The National Institutes of Health Stroke Scale scores were measured on admission and days 1, 3, 7, and 30. Results-IV ECD was greater than IV DW . The lesion-to-normal count-density ratios of 99m Tc-EC-MN ranged from 1.80 to 5.96. HV was 60.2Ϯ65.2 cm 3 , and the mean percent HV was 24.5Ϯ28.1% of IV ECD . NIV ECD was 162.6Ϯ133.4 cm 3 and was significantly smaller than IV ECD . NIV ECD was significantly correlated with National Institutes of Health Stroke Scale score at 1 month and was a significant predictor of neurological deficit at 1 month. Conclusions-99m Tc-EC-MN brain SPECT can detect hypoxic tissue after acute ischemic stroke and, in combination with 99m Tc-ECD brain SPECT, is useful in predicting neurological outcome in ischemic stroke patients.

Purpose: The aim of this study was to evaluate 99m Tc-ethylenedicysteine-glucosamine (EC-DG)

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188Re(Rhenium) is easily obtained from an in-house 188W/188Re generator that is similar to the current 99Mo/99mTc generator, making it very convenient for clinical use. This characteristic makes this radionuclide a promising candidate as a therapeutic agent. Polyethylenimine (PEI) is a cationic polymer and has been used as a gene delivery vector. Positively charged materials interact with cellular blood components, vascular endothelium, and plasma proteins. In this study, the authors investigated whether intratumoral injection of 188Re labeled transferrin (Tf)-PEI conjugates exert the effect of radionuclide therapy against the tumor cells. When the diameters of the Ramos lymphoma (human Burkitt's lymphoma) xenografted tumors reached approximately 1 cm, 3 kinds of 188Re bound compounds (HYNIC-PEI-Tf, HYNIC-PEI, 188Re perrhenate) were injected directly into the tumors. There were increases in the retention of 188Re inside the tumor when PEI was incorporated with 188Re compared to the use of free 188Re. The 188Re HYNIC-Tf-PEI showed the most retention inside the tumor (retention rate=approximately 97%). H&E stain of isolated tumor tissues showed that 188Re labeled HYNIC-PEI-Tf caused extensive tumor necrosis. These results support 188Re HYNIC-PEI-Tf as being a useful radiopharmaceutical agent to treat tumors when delievered by intratumoral injection.