RETROSPEVT？VE STUDY OF TARGET VOLUME AND CR？T？CAL ORGAN DOSES US？NG THREE VOLUMETR？C ARC THERAPY (VMAT) TECN？QUES ？N HEAD AND NECK CANCER (H&N) RAD？OTHERAPY

The aim of this study is the target volüme dose and critical organ doses in three different radiotherapy plans reported with the volumetric arc therapy (VMAT) teqniques in head and neck cancer (H&N) radiotherapy In radiotherapy plans, with 8 H&N patients; the form of double rotation 1 arc (sVMAT), double ark (dVMAT) and 150 collimator angles (cVMAT) plans have been prepared. In three methods, the prescribed dose of the target volüme could be given in the desired way. No significant difference was abserved in the values of the left and right parotid Dmean, however, the sVMAT tecnique for the right parotid was found lower dose value. In three different plans, sVAMT dose was provided in the desired way and organ doses could be kept within the desired limits. However the low dose value obtanied from the parotid gland and the brain stem has made sVMAT tecnique superior to other tecniques