Are superparamagnetic ferrite particles cleared from the liver

The purpose of this study has been to monitor the biologic breakdown of ferrite particles (5- 40μmol/kg) injected in 37 patients with liver cancer. Twelve patients were imaged at intervals from 24 hours to 3 months after ferrite injection. Images were evaluated quantitatively against baseline liver-muscle signal intensity ratios measured before and 1 hour after ferrite injection. Liver tissue specimens were available in five of these patients for microscopic evaluation (iron stain and electron microscopy). Ferrite particles homogeneously blacken normal liver. This effect is transient and disappears as early as 4 days after injection. These findings were confirmed with histologic evaluation where RE cells stained positively for iron immediately after ferrite injection but were not detected in specimens obtained 2 months after administration