1. MEDICAL IMAGING Dr. Hugh Blanton ENTC 4390

2. Lecture 1 EM Introduction

3. Dr. Blanton - ENTC 4337 - Lab 2 3 Mass Mass  Measure of the resistance of a body to acceleration. eg. Newton’s 2 nd Law

4. Dr. Blanton - ENTC 4337 - Lab 2 4 Mass kg (kilograms) is a lot of mass in the nuclear physics world. Define 1 atomic mass unit (amu) = 1/12 mass of 1 atom of Carbon 12

5. Dr. Blanton - ENTC 4337 - Lab 2 5 Energy Energy  The ability to do work. For electrical forces:

6. Dr. Blanton - ENTC 4337 - Lab 2 6 Electron-Volt For 1 electron moving in a 1V potential difference, Define this as 1 electron-Volt (eV)

7. Dr. Blanton - ENTC 4337 - Lab 2 7 Conservation of Mass c is the speed of light

8. Dr. Blanton - ENTC 4337 - Lab 2 8

9. EM Radiation

10. Dr. Blanton - ENTC 4337 - Lab 2 10 Two ways to transfer energy from one body to another: particle—kinetic energy wave—propagation of a disturbance. EM radiation has properties of both of these—the wave/particle duality.

11. Dr. Blanton - ENTC 4337 - Lab 2 11 Waves Longitudinal waves—disturbance in the direction of propagation. eg. sound Animation courtesy of Dr. Dan Russell, Kettering University

12. Dr. Blanton - ENTC 4337 - Lab 2 12 Transverse waves—disturbance perpendicular to direction of propagation. eg. waves in the ocean Animation courtesy of Dr. Dan Russell, Kettering University

13. Dr. Blanton - ENTC 4337 - Lab 2 13 Regardless of the type of wave, they can be characterized by: wavelength  frequency (f) phase  velocity  amplitude

14. Dr. Blanton - ENTC 4337 - Lab 2 14 Wave characteristics of EM radiation: EM radiation can be seen to be a transverse wave of particular oscillations of electric and magnetic fields. wavelength oscillatory electric field (force) perpendicular magnetic field (force)

15. Dr. Blanton - ENTC 4337 - Lab 2 15 EM radiation has wave characteristics such as: reflection refraction interference

16. Dr. Blanton - ENTC 4337 - Lab 2 16

17. Dr. Blanton - ENTC 4337 - Lab 2 17 Particle characteristics of EM radiation: Particles of EM radiation are called quanta or photons. Photons can be thought of as wave packets of electric and magnetic fields wavelength oscillatory electric field (force) perpendicular magnetic field (force)

18. Dr. Blanton - ENTC 4337 - Lab 2 18 h is Planck’s constant

19. Example What is the frequency and for 100 keV photons? Dr. Blanton - ENTC 4337 - Lab 2 19

20. What is the frequency and for 100 keV photons? Dr. Blanton - ENTC 4337 - Lab 2 20

21. Dr. Blanton - ENTC 4337 - Lab 2 21 EM Radiation Low E, long —Acts like wave. High E, short —Acts like particles.

22. Dr. Blanton - ENTC 4337 - Lab 2 22 Scientists have observed that electromagnetic radiation has a dual "personality." Besides acting like waves. It acts like a stream of particles (called "photons") that have no mass. The photons with the highest energy correspond to the shortest wavelengths.

23. Dr. Blanton - ENTC 4337 - Lab 2 23 Electromagnetic waves are produced by the motion of electrically charged particles. These waves are also called "electromagnetic radiation" because they radiate from the electrically charged particles. They travel through empty space as well as through air and other substances.