RESUMO
Objective: To observe the effect of superior technology using three dimension radiation treatment plans (3D-RTPS) in the reduction of postradiation xerostomia in patients with head and neck cancer. Methods: 3D-RTPS of conventional radiation and new superior technique were applied in the patients of 3 kinds of head and neck cancer (tumor in middle, lateral, between middle and lateral area of head and neck). Superior technology including superior ray entrance, multi fields, conformal irradiation and application of wedges. Analysis of 3D dose distributions and dose volume histograms (DVH) was used to evaluate the dose and volume in tumor, parotids and spinal cord in the patients. Tumor dose of 55.6～68.6 Gy (average 58.8 Gy) was given to the patients in conventional radiation group in 8 patients, 53.5～68.5 Gy (average 58.3 Gy) to new radiation technique group in 12 patients. Whole saliva flow rate and subjective xerostomia scores were assessed in patients during radiation course and follow-up. Results: The dose in contralateral parotids in patients with tumor in lateral area, between lateral and middle area in conventional radiation and new radiation technique groups were 51.8～64.3 Gy and 0.4～1.4 Gy, respectively. The dose in parotids in patients with tumor in middle area in conventional radiation and new radiation technique groups were 51.8 and 24.7 Gy respectively. The rate of xerostomia at the end of radiotherapy and in 4～6 months follow-up after radiotherapy in patients of new radiation technique group were 8.3 % (1/12) and 0 respectively. Those in patients in conventional radiation group were 87.5 % (7/8) and 50 % (4/8) respectively. Conclusion: Superior technology using 3D-RTPS can reduce the rate of postradiation xerostomia in patients with head and neck cancer.