1. Tracers and Effects of Radiation

2. Medical Applications of Radioactivity Radiotracers- radioactive nuclides that can be introduced into organisms in food or drugs and subsequently traced by monitoring their radioactivity

3. Medical Applications of Radioactivity Examples: Iodine-131 for the diagnosis and treatment of thyroid illness Thallium-201 damage to heart muscle

4. Medical Applications of Radioactivity Provide sensitive and nonsurgical methods for learning about biological systems, for detecting disease, and for monitoring the action and effectiveness of drugs Nuclides used as radiotracers have short half-lives so that they disappear rapidly from the body

5. Effects of Radiation Somatic damage – damage to the organism resulting in sickness or death Genetic damage – damage to the genetic machinery of reproductive cells creating problems affecting offspring.

6. Factors Determining Biological Damage 1. Energy of the radiation 2. Penetrating ability of the radiation 3. Ionizing ability of the radiation 4. Chemical properties of the radiation source

7. Factors determining biological damage 1.The E of the radiation: higher energy, more damage 2.The penetrating ability: gamma- highly beta- 1cm alpha- stopped by skin

8. Factors determining biological damage 3.The ionizing ability –  vs.   is very effective at ionizing (more damaging)  is neutral and doesn’t ionize as readily 4.Chemical properties Toxic, accumulate in body, inert... Rem indicates the danger the radiation poses for humans.

9. Effects of Short-Term Exposures to Radiation Dose (rem) 0-25 25-50 100-200 500 Clinical Effect Nondetectable Temporary decrease in white blood cell counts Strong decrease in white blood cell counts Death of half the exposed population w/in 30 days

10. Effects of Radiation Typical Radiation for a person in the US per year About 200 rems