Lesson 3 - Isotopes and Radioactivity
Student Performance Objectives1. Define nuclear decay, nuclear stability and half-life.2. Draw the Bohr models for hydrogen, deuterium and tritium.3. Define biological half-life and background radiation.4. Explain the difference in ionizing radiation exposure when a simple x-ray, an angiogram or magnetic resonance imaging (MRI) is used in a medical imaging procedure.Lesson OutlineLesson OutlineA. Concept of ionizing radiation, sources and atomic nuclear stability. 1. Nuclear decay http://en.wikipedia.org/wiki/Radioactive_decay 2. Medical applications. See http://www.who.int/ionizing_radiation/en/ or http://www.who.int/ionizing_radiation/about/what_is_ir/en/B. Diagram hydrogen, deuterium and tritium. C. Radioisotopes and half-life. 1. Physical half-life - time for 50% of atoms to decay to more stable forms. 2. Biological half-life - time for half to disappear from the human body generally through excretion.D. Practical considerations 1. Background radiation from the sun and outer space. 2. Medical sources from dental and chest X-rays, CT scans. 3. Compare ionizing radiation to MRI's, sonograms, and thermograms. 4. Consider angiograms - one such motion picture X-ray procedure exposes one to the equivalent of thousands of chest X-rays.