Intensity-Modulated Radiation Therapy (IMRT) for head and neck region

Intensity-modulated radiation therapy (IMRT) can produce highly conformal dose distributions. In head and neck region, IMRT has been used for the purpose of reduction parotid glands dose. Generally accepted, more precise set-up and careful observation are needed for IMRT than those of conventional RT, because it takes longer treatment time for IMRT and its dose gradient spreads within field. Our institute has developed real-time tumor-tracking (RTRT) systems and it realizes precise set-up and observation during treatment. We have used IMRT with RTRT system for head and neck region for 9 patients with 3-mm as the planning target volume margin. Salivary glands function was evaluated by subjective symptoms using visual analogue scale (VAS). After median follow-up of 17 months, all patients were alive without local relapse and distant metastasis. The mean VAS score of each periods were 9.6, 51.4, 55.1, 39.7and 47.9 mm at pre-treatment, 1-4 months, 5-8 months, 9-12 months, and 13 months or more after the radiotherapy respectively. IMRT with RTRT set-up system was shown to be feasible.