1. History and Introduction (Lfrances@hunter.cuny.edu) Why Radiochemistry IGERT program at Hunter College

2. Why Radiochemistry and Why Should I Care About Radiation? Medical applications Molecular Imaging of disease Single Photon Emission Computed Tomography (SPECT) Positron Emission Tomography (PET) Radiotherapy to treat disease Energy applications Environmental applications National Security

3. Radioactivity Radioactivity is emitted by atoms which are unstable and undergo radioactive decay Many elements in the periodic table are naturally radioactive other radioactive elements can be produced Doing chemistry with radioactive elements is called “radiochemistry”

4. In 1895, Röntgen discovered X-rays when he worked with electrons in a cathode ray tube— they penetrated black paper. Röntgen won the Nobel Prize in physics in 1901 for this discovery. Brief history of radiochemistry

5. In 1896, Becquerel discovered radioactivity working with uranium compounds. Images were seen on photographic plates on exposure to the uranium compounds, even in the absence of any light. Brief history of radiochemistry

6. Radiation emitted by the uranium was different from X- rays. It could be deflected by a magnetic field and therefore must consist of charged particles. Becquerel was awarded the1903 Nobel Prize in physics for his discovery of radioactivity. Brief history of radiochemistry

7. The term radioactivity was coined by Marie Curie. Working with uranium ore, she and Pierre Curie discovered the radioactive elements polonium (Po) and radium (Ra). The Curies were awarded the 1903 Nobel Prize in physics for their work on radioactivity. 1898 – Marie and Pierre Curie

8. 1912 — George de Hevesy Father of the “radiotracer” experiment. 1923: 212 Pb to study the absorption and translocation of Pb(NO 3 ) 2 in bean plants. Received the Nobel Prize in chemistry in 1943 for his concept of “radiotracers”

9. atomic radius ~ 100 pm = 1 x 10 -10 m nuclear radius ~ 5 x 10 -3 pm = 5 x 10 -15 m Rutherford’s Model of the Atom Radioactivity: reactions of the nucleus of the atom

10. Reactions of the nucleus of the atom: Subatomic Particles mass p = mass n = 1840 x mass e - mass alpha particle = mass 2 p + mass 2 n mass alpha particle = 7360 x mass e - (beta particle)

11. Radioactivity: reactions of the nucleus of the atom Nuclear decay often results in a transmutation reaction which is the process of an atom changing atomic number and becoming a different element Example: Parent nuclide Daughter nuclide Radiation

12. Radioactivity: reactions of the nucleus of the atom Half-lives (t ½ ):— time required for ½ of the material to decay Radioactive Decay

13. Ionizing Radiation * Radioactive decay emits ionizing radiation * Ionizing radiation consists of particles or waves with enough energy to remove electrons from surrounding atoms or molecules Ionizing Radiation Non-Ionizing Radiation Electromagnetic Spectrum We try to “harness” ionizing radiation for useful purposes, specifically diagnosis of disease (imaging) and therapy of disease

14.  - alpha particle—He 2+ nucleus  - --beta particle—e - ejected by nucleus  + --positron—e + ejected by nucleus –Undergoes annihilation to emit two 0.511 MeV photons at 180 o  --gamma ray—photon emitted by nucleus Types of Ionizing Radiation

15. Ionizing Radiation Fact Book, 2007. U.S. Environmental Protection Agency. http://www.epa.gov/radiation/docs/ 402 -f- 06 - 061.pdf (accessed Jun 7, 2011 ). Types of Ionizing Radiation Beta β + or positron β - or electron Gamma x-ray or photon Alpha or

16. Applications of Radiation Ionization Technology. U.S. Environmental Protection Agency. http://www.epa.gov/rpdweb00/sources/smoke_ion.html (accessed Jun 8, 2011 ). Smoke Alarm Current Disrupted Nuclear Power Nuclear Medicine Nuclear Forensics Drug design Smoke Detectors