Measurement of the Adsorbed Radiation Dose to Eyelens During CT Scan and Radiotherapy of Nasopharynx Cancer

  Introduction: The study of the cause of death during the last few decades has shown that death due to infectious diseases has been declining and has been rising due to noninvasive diseases, especially cancers and accidents. Cancer is considered as one of the fatal diseases, and every year, more than 10.9 million people worldwide are diagnosed with the disease. Materials and Methods: This is an empirical study in which the ocular absorption of dose is measured due to the CT scan and radiotherapy in nasopharyngeal cancer treatments to measure the chance of cataract in nasopharyngeal cancer radiotherapy using dosimeter TLD, Gafchromic film and treatment design software on human phantom according to previous studies, and further studied with the aid of the 3-D treatment design system. This study was conducted with a medical linear accelerator in the Oncology Center of Roshana, using Varian iX linear accelerator. Results: The value of radiation dose absorption, outside the radiation field, the average dose rate of radiation in the left eye lens is 5.76% of the total, and the average dose rate of radiation in the right eye lens is 5.68% of the total. The absorption dose of radiation by the eye, inside the radiation field, the average dose rate of radiation in the left eye lens is 10.04% of the total. The average dose rate of radiation in the right eye lens is 10.02% of the total. Conclusion: The eye is one of the most sensitive of the body's organs versus the radiation. One of the most sensitive parts of it is the lens that can be damaged in low doses and have cataract. In this study, due to the sensitivity of the lens to ionizing radiation, we are looking for a way to prevent the excessive doses from reaching the eye, which will be measured and designed to reduce the absorption dose of the eye lens.