Analysis of Radiation Dose Distribution in Nasopharyngeal and Organ Cancer Cases at Risk with Linear Accelerator Radiotherapy 6 MV Photon Energy Using the IMRT Technique at Prof. Hospital. Dr. I. G. N. G. Ngoerah

This study aims to determine the distribution of radiation doses on PTV and OAR radioteraphy planning in RSUP. Prof. Dr. I.G.N.G Ngoerah, Bali, Indonesia does no exceed a predetermined limit. The research metode used is the value of Homogenity Index (H), Conformity Index (CI), and the maximum value of radiation ose to the Organ At Risk (OAR), amely the right eye lens, left eye lens, brainstem, optic chiasma, and spinal cord. These data are compared with the provisions of ICRU report 83 and the maximum dose reference value for OAR. Using data from 30 nasopharyngeal cancer patients with a total radiation dose of 7000 cGy. Obtained a value for HI of 0.1214 with a t-test result of 0.459> 0.05 which means it is not significant. While the value for CI is 0.9850 with nonparametric statistical test results of 0.285> 0.05 which means it is not significant. The maximum dose value for the right eye lens is 772.7 cGy with a t-test result of 0.779> 0.05 which means it is not significant. For the maximum value of the dose in the lens of the left eye of 771.0 cGy with a t test result of 0.791> 0.05 which means it is not significant. For the maximum value of the dose in the brain stem of 5178.1 cGy with nonparametric test results of 0.686> 0.05 which means not significant. The maximum dose value at the optic chiasma is 4,837.2 cGy with a nonparametric test result of 0.225>0.05 which means it is not significant. For the maximum value of the dose in the spinal cord of 4,663.3 cGy with a t test result of 0.958> 0.05 which means it is not significant.