Comparison between predicted and actual dose distribution in interstitial therapy of the oral cavity.

During the period 1985-1986, 10 patients with lesions of the floor of the mouth or of the mobile part of the tongue were treated by interstitial curietherapie with iridium-192. In the patients treated with the looping technique essential differences were found between the predicted source configuration and that actually achieved, resulting in a disagreement between precalculated and actual dose distribution. To avoid this undesirable situation, a simple oral cavity applicator was constructed which guarantees parallelism and equidistance between the implanted needles. It was found that the use of this applicator resulted in an almost complete agreement between forecast and actual dose distribution.