5.1 - Natural Radioactivity

• Radioactive isotopes are characterized as unstable nucles (decay), alpha (a), beta (b), positron (b+), gamma (g) radiation spontaneous radiation

• Radiation can damage the cells in the body and it is important to use the right protection: shielding, exposure time limit and distance.

5.2 - Nuclear Reactions

• The changes in the nuclei of reactants and products are represented by a balanced nuclear equation

• A number of symbols that display the mass and nuclear number of the isotopes in the nuclear equation can help determine the new isotopes and the type of radiation emitted.

• When a small particle bombards a non-radioactive isotope, a radioisotope is produced artificially.

5.3 - Radiation Measurement

• Radiation produces charged particles in the gas in a tube that generates an electric current in a Geiger counter.

• The curie (Ci) and the becquerel (Bq) measure the number of nuclear transformations per second. the activity is measured.

• A radical or gray measure of the amount of radiation absorbed by a substance (Gy).

• The rem and sievert (Sv) are units for the determination of the different radiation types of biological damage.

5.4 - Half-Life of a Radioisotope

• Each radioisotope has its own emission rate.

  • It's called half-life the time it takes for half of a radioactive sample to decline.

• Half-life is short for many medical radioisotopes, including Tc-99m and TC-1,

  • Half-lives are extremely long for other isotopes, typically occurring naturally, like C-14, Ra-226, and U-238.

5.5 - Medical Applications Using Radioactivity

• Radioisotopes that visit certain sites within the body are administered to the patient in nuclear medicine.

• By detecting the radiation that they emit, the size and scope of an injury, disease, tumor, or function level of a certain organ can be assessed.

  • Higher radiation levels are used for tumor treatment or destruction.

5.6 - Nuclear Fission and Fusion

• In fission, the bombing of a large nucleus divides into smaller nuclei and releases a large amount of energy and one or more types of radiation.

  • Infusion, small nuclei form larger nuclei and release large amounts of energy.