T Radiologic examination are absolute important in the diagnosis of diseases of the nose and paranasal sinuses. Unfortunately, the eyes are always in the direct path of x-rays. In the last years the normal conventional CT is more and more replaced by the cone beam ct. Our purpose is to evaluate the differences in exposure rates between these radiologic methods also in comparison to the so called natural and environmental factors.To assess there great significance we rank natural and environmental factors due to their importance. Then we compare the exposure rates of the standard ct with those of the cbct. We also discuss the role of so called „low dose- protocols“ and the influence of scattered radiation in radiology. The great advantage from the radiological point of view is the extremely low dose of radiation of the CBCT in comparison to the standard medical CT and substantial less scattered radiation. In comparison to natural or environmental factors the exposure rates are negligible. In our belief the cone-beam computed tomography (CBCT) is a very useful tool in the diagnosis of sinusitis, especially concerning the exposure of radiation referring to the eyes.