Dose and dose rate in 192Ir interstitial irradiation for carcinoma of the tongue.

Seventy-three patients with carcinoma of the tongue were treated with 192Ir implantation. The total dose for control of the primary lesion without late radiation injury could be fixed to about 70 Gy with a variation of the dose rate between 0.25 and 1 Gy per hour. Additional external irradiation, without reduction of the dose from the interstitial irradiation, involves a high risk of local necrosis.