Nuclear Chemistry Radiation technologists specialize in the use of imaging techniques to diagnose and treat medical problems. Patients may be given radioactive tracers that emit gamma radiation that is then detected by a scanner and used to develop an image of the desired area of the body. Elements with atomic numbers 20 and higher usually have one of more isotopes with unstable nuclei. An unstable nucleus is radioactive, emitting small particles of energy called radiation to become more stable. Radiation may take the form of: - Alpha particles - Beta particles - Positrons - Pure energy such as gamma rays An isotope of an element that emits radiation is called radioisotope . When radiation is emitted, a radioisotope - May undergo a change in the number of protons - May be converted to an atom of another element Atomic symbols for various isotopes are written two ways: - The mass number in the upper left corner and the atomic number in the lower left corner of the element symbol - The mass number after the element name An alpha particle (α) has two protons and two neutrons, and it is identical to He nucleus (2+ charge is omitted) A beta particle (β) is a high-energy electron, with a charge of -1, formed when a neutron is changed to a proton A positron , an example of antimatter, is a positive electron produced when a proton is transformed to a neutron and positron Gamma rays (γ) are the high-energy radiation released from a nucleus when it decays. They have no mass or charge. When radiation strikes molecules, it may - Knock away electrons, forming unstable ions - Interact with water molecules, removing electrons and producing H 2 O + , which can cause undesirable chemical reactions Cells most sensitive to radiation are those that undergo rapid cell division, such as those in bone marrow, skin, reproductive cells, and cancer cells Radiation protection requires
- Paper and clothing for alpha particles - A lab coat and gloves for beta particles - A lead shield or thick concrete wall for gamma rays - Limiting the amount of time spent near a radioactive source - Increasing distance from the source If you work in an environment where radioactive materials are present, try to keep the time you spend in a radioactive area to a minimum.