Haematoporphyrin Derivative Photosensitization and γ-radiation Damage Interaction in Chinese Hamster Ovary Fibroblasts

Abstract

The interaction of haematoporphyrin derivative (HPD) photosensitization and γ-irradiation was studied with regard to clonogenicity of Chinese hamster ovary (CHO) fibroblasts. Exposure to either treatment alone resulted in shouldered response curves. Exposure to 4·2 Gy γ-radiation immediately before graded doses of visible light had no effect on the shape of the visible-light survival curve; similarly, exposure to 8·75 kJ/m² light immediately before graded doses of γ-radiation had no effect on the shape of the γ-radiation response curve. These data indicate that damage due to γ-radiation and HPD photosensitization did not interact, suggesting that the mechanisms of cell killing are different.