Ch. 25.5 Applications and Effects of Nuclear Reactions CHM Hon.

Last class…we talked about nuclear fission:

Today… We will discuss another application of nuclear chemistry: MEDICINE

Detecting Radioactivity Ionizing radiation = radiation energetic enough to ionize matter with which it collides Geiger Counter makes use of ionizing radiation

Detecting Radioactivity Geiger counter: radiation detection device

Detecting Radioactivity Scintillation counter Uses phosphor-coated surface to detect radiation Scintillations = bright flashes of light produced when ionizing radiation excites the electrons in certain types of atoms (phosphors) The number and brightness is detected / recorded, determines the amount of ionizing radiation present

Uses of radiation Neutron activation analysis Detects trace amounts of elements in a sample Used in computer chip technology (analysis of composition) Bombardment with stream of neutrons Type of radiation emitted determines the types / quantities of elements present

Uses of Radiation Used to follow the course of an element through a chemical reaction Helps Scientists understand processes Radiotracer = radioisotope that emits non-ionizing radiation and is used to signal the presence of an element or specific substance. Iodine-131

Uses of Radiation Positron emission transaxial tomograpgy (PET)

Uses of Radiation Radiation therapy Used to treat cancer by destroying unhealthy cells, fast-growing cells Down side: also kills good cells!

Biological Effects of Radiation Can be very harmful Damaged produced depends on: energy of radiation type of tissue Distance Gamma rays easily penetrate human skin

Biological Effects of Radiation Ionizing radiation damage to living systems SOMATIC: affects non-reproductive body tissue GENETIC: damages reproductive tissue

Biological Effects of Radiation Dose – the amount of radiation your body absorbs from a radioactive source Rad (Radiation absorbed dose) Rem (roentgen equivalent for man)