Dosimetric study of adaptive radiotherapy for nasopharyngeal carcinoma / 安徽医科大学学报

ABSTRACT

Seven patients with nasopharyngeal carcinoma treated with ART were recruited . All patients were treated with SIB-IMRT regimen( named IMRT) . All patients had a second computed tomography scan after 10 fractions and a new plan based on this was initiated from fraction 11 ( ART1 ) . And a third CT scan after 21 fractions and a new plan based on this was initiated from fraction 22(ART2). When the treatment was finished,a fourth CT scan was made. Results revealed that the volumes of primary tumors and parotid glands regressed significantly after the teat-ment. The position of the parotid glands shifted medially an average of 4.5(1.6~9.2)mm during the plans. ART1 reduced mean dose to left parotid by 0. 42 Gy(1. 68%)(P=0.019) and right parotid by 0. 79 Gy (3.04%) (P=0. 013) over the IMRT alone. ART2 further reduced the mean left parotid dose by 0. 86 Gy or 3.5% ( P =0.001 ) and right parotid by 1 . 04 Gy or 4 . 13% ( P=0.035 ) .