Tumours in Mice after Pulmonary Deposition of Radioactive Particles

Summary

The intratracheal administration to BAF₁ or CAF₁ mice of plutonium and ruthenium particles suspended in Tween-80 or Pluronics caused an increased incidence of pulmonary adenomas compared with controls at levels of 0·1 μc ²³⁹PuO₂ and 3·0 µc ¹⁰⁶RuO₂. Decreased incidence of adenomas was obtained at 0·16 µc ²³⁹PuO₂ and 24·0 µc ¹⁰⁶RuO². Intravenous administration of similar particles caused an increased incidence at a level of 0·16 µc ²³⁹Pu(OH)₄ and a decrease at 0·37 µc ²³⁹PuO₂. Certain inconsistencies in the incidence values were noted.

Histological lesions resulting from deposition of plutonium particles included fibrosis with bronchiolar proliferation and squamous metaplasia. Ruthenium particles caused the presence of numerous bizarre cells in fibrotic lesions. Plutonium particles were considered responsible for the development of two squamous-cell carcinomas and a bronchiolar carcinoma. Two bronchiolar carcinomas occurred in ruthenium-treated animals.