Endothelial repair of radiation damage following beta irradiation.

Lamellar keratectomy was performed in dogs to induce capillary endothelial proliferation at the limbus of the eye and the radiation response of endothelial cells was evaluated in terms of the dose required to prevent neovascularization in 50% of irradiated eyes (NVD50).Single- and split-dose experiments were carried out before and after induction of proliferation to determine the response of slowly and rapidly proliferating endothelial cells. the NVD-50-S prior to induction were about 400 rads greater than those following induction,indicating increased resistance of slowly proliferating cells. Split-dose studies indicatedthat the radiation repair capability was about 350 rads, either before or after induction.