The aim of this lecture is to present on Radiation Effects. here briefly focus on How much radiation does it take to cause a person’s risk for a health effect to increase? What are the health effects that can occur if there is enough exposure? There are many thoughts on the answers to these questions and suggested answers lie along a continuum, especially when the topic is low-level radiation. Risk from a radiation dose is typically based on calculations of the “real” effect of the radiation dose that is absorbed.