Abstract
Changes of vascular density and drug distribution after 25 Gy single local irradiation were studied in two different mouse tumor systems. Histologically, squamous cell carcinoma (SCC) and fibrosarcoma (Fib) were used. Squamous cell carcinoma was much more radiosensitive than fibrosarcoma. In SCC, the vascular density and the distribution were remarkably decreased from 3 to 7 days after irradiation. These changes were observed earlier than tumor regression. Fourteen days after irradiation when tumor regrowth was evident, vascular density and drug distribution had recovered significantly. In Fib, in which no regression was observed after irradiation, the vascular density and drug distribution decreased as the tumor grew. The vascular density 3 days after irradiation could not be evaluated in Fib due to homogeneous stain of the whole tumor.
