Abstract:
The Nasopharyngeal carcinoma is the most common cancer in Sudan; unfortunately it becomes more common in young People in Sudan (9 to 25years). The side effects of nasopharyngeal irradiation are cataract, spinal cord necroses , temporal lope deviation, ect..
Such undesirable side effect could be due to manual planning with out consideration of different anatomy between the patients. Because so there are very sensitive regions (critical organs), And depends on experience of doctor. The main objective of this study was Evaluate the dose received by critical organs in order to reduce the radiation sickness.
The researcher studied and assessed the radiation dose received with critical organs (eye, temporal lope, brain stem and spine) The study consist of 50 patients planned by ( CT) and by using (TPS) that selected randomly .the collected data include the dose received by critical organs , ,tumor dose and the given Dose. The result showed that the dose received by critical organ was well correlated with given dose respectively And the dose received by spinal cord increased by 0.02 cGy for each 1cGy of the given dose ,Spine dose = 0.0172 * G.D + 48060 and dose received by temporal lope increased by 0 .5 cGy for each 1cGy of the given dose ,Temporal lobe dose = 0.4794 * G.D + 1287.7, Also for brain stem the dose increased by0 .4 cGy for each 1cGy of the given dose, Brain dose = 0.3287 * given dose + 2425, and same to eye 0.06 cGy for each 1cGy of given dose, Eye dose = 0.0554 * given dose – 190.67. All those equations explain the effect of given dose in the dose received by critical organs.