Abstract
The authors have already reported that perforation or restenosis might occur when the irradiation to normal dog's trachea was applied on a half circle of more than 4 rings in the direction of major axis with 40w×3 seconds until the mucosa turned to white. In this series, a comparative study of irradiation to a half circle and a whole circle of tracheal ring is discussed. Irradiation was applied on less than three rings in the direction of major axis and totally 24 places for 13 dogs were subjected. The average dose was 1,350 joules per cm2. Irradiation was performed to the submucosal layer in 19 places out of 24, however the deformity of the cartilage ring was observed in one place out of 6 (17%) with a whole circle irradiation and 4 places out of 18 (22%) with a half circle irradiation. The tracheal lumen was not deformed in 11 places which were irradiated on less than two rings in the direction of major axis with under 1,600 joules per cm2, wheather it would be irradiated to a whole circle or a half circle.
