Medical Procedures – Ionizing –X-Ray –CT Scan (Computed Tomography) –Nuclear Medicine Medical Procedures – Non-Ionizing –Ultrasound –MRI (Magnetic Resonance Imaging) 1 Beneficial Uses of Radiation

- Because the element iodine accumulates in the thyroid, the radioisotope Iodine-131 can be used to diagnose thyroid problems. - As Iodine-131 atoms are absorbed by the thyroid, their nuclei decay, emitting beta particles and gamma rays. - The beta particles are absorbed by the surrounding tissues, but the gamma rays penetrate the skin. - The emitted gamma rays can be detected and used to determine whether the thyroid is healthy. 2 Beneficial Uses of Radiation

Question: –What is required in order for a radioisotope to be useful as tracers in nuclear medicine? 3 Beneficial Uses of Radiation

Answer: A radioisotope must be important in body processes and accumulate in the organism being studied. 4 Beneficial Uses of Radiation

5 Museums and archeologists rely on radiation detection to verify the authenticity or age of art objects or archeological finds Radiocarbon decays at a known rate. Paleontologists are able to determine the age of a fossil by measuring the amount of C-14 it contains. Fossil A small piece of the fossil is burned and converted to carbon dioxide gas. Unstable C-14 Stable C-12 Nitrogen Electron Living organisms absorb C-14 (radiocarbon) during their lifetimes A radiation counter records the number of electrons emitted C-14 decays into N-14 emitting an electron Beneficial Uses of Radiation

Radioactive Half-Life & Radioactive Dating: –Half-lives vary widely among the radioactive isotopes. –The half-lives of some radioactive elements are listed in the table. –The ages of rocks and fossils can be determined using radioactive isotopes and their half-lives. 6 Beneficial Uses of Radiation

7 Radioactive Half-Life: Some radioisotopes decay to stable atoms in less than a second. A measure of the time required by the nuclei of an isotope to decay is called the half-life. Beneficial Uses of Radiation