Ch. 25.5Applications 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)