Week 1 :Concepts of Radiologic Science

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# Week 1 :Concepts of Radiologic Science - PowerPoint PPT Presentation

##### Week 1 :Concepts of Radiologic Science

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1. Welcome to the field of medical imaging • Objectives: • Matter, energy, the electromagnetic spectrum – ionizing radiation • Relative intensity of ionizing radiation • Discovery of x-radiation • Basic concepts of radiation protection

2. Matter and Energy • Matter = anything that has mass and occupies space. • Energy = the ability to do work

3. Matter • A primary characteristic of matter is “mass”. • Mass = the quantity of matter contained in any physical object.

4. Mass vs Weight • For our purposes mass and weight can be considered the same. • In the strictest sense they are not the same. • Mass = energy equivalence • Weight = the force exerted on a body under the influence of gravity

5. Mass • Mass is measured in kilograms (kg). • How many grams are in a kilogram? • Kilogram is the scientific unit of mass and is unrelated to gravitational effects.

6. kilo • Kilo stands for 1000 • Kilogram = 1000 grams

7. Atom Molecules Elements Compounds Building blocks of matter

8. Energy • Define Energy? • Energy can exist in several forms • Energy can be measured in varied units of measurement. The International System (SI) = joules (J). In Radiology = electron volt (eV) (ex: e- energy vs. kVp)

9. Several forms of Energy

10. Potential energy • Ability to do work by virtue of position. • Ex: roller coaster or stretch spring.

11. Kinetic energy • Energy of Motion • Work because of motion • Ex: moving car, moving river

12. Chemical energy • Energy released by chemical reaction • Ex: energy from the food we eat.

13. Electrical energy • Electrons moving through an electrical potential difference • Ex: household electricity – 110 volts

14. Thermal energy (heat) • Energy of motion at the atomic and molecular level. The kinetic energy of molecules vibrating • Ex: Heat from an X-ray tube

15. Nuclear energy • Energy contained in the nucleus of an atom • Ex: nuclear electric power plants

16. Electromagnetic energy • Not as familiar to us as other forms of energy … but very important to radiographers • Results from electric and magnetic disturbances in space • This energy is produced by the acceleration of a charge

17. Radio waves, microwaves, ultraviolet, infrared, visible light… what else?

18. Electromagnetic energy • Is often referred to Electromagnetic radiation when it is traveling through space. • Radiation is the transfer of energy (usually through space) • When a guitar string vibrates it is said to radiate sound.

19. Exposed or Irradiated • Matter that intercepts radiation and absorbs part or all of it is exposed or irradiated

21. X-rays • You will learn to expose or irradiate patients for medical treatments or diagnosis

22. X-Rays are Ionizing radiation X-rays are a special type of radiation. X-rays are capable of removing an orbital electron from the atom with which it interacts.

23. Ionization • Ionization occurs when an x-ray passes close to an orbital electron of an atom and transfers sufficient energy to the electron to remove it from the atom.

24. Ion pair • The orbital electron and the atom from which it was separated are called an ion pair. • The electron is a negative ion and the atom is a positive ion.

25. What is Ionization?

26. Examples of Ionizing Radiation • X-rays, gamma rays, and ultraviolet light

27. Ionization • Some particles with high kinetic energy can cause ionization • Ex: Alpha & Beta particles

30. MEDICAL IMAGING • Diagnostic Imaging • Medical xrays • Dental xrays • GREATEST SOURCE OF MAN-MADE RADIATION

31. Diagnostic x-rays • 1990 the National Council on Radiation Protection and Measurements (NCRP) • 39 mrem/yr OR 0.39 mSv/yr • More recent NCRP estimates indicate nearly 320 mrem/yr OR 3.2 mSv/yr. Due to increasing use of multslice spiral CT and high-level fluoroscopy

32. What does this information mean?How does this affect us?

33. Is this a safe profession ? • Natural radiation = 300 mrem/yr • Average medical exposure = 50 mrem/yr 39 – 320 mrem/yr • Technologists?

34. How Medical X-Ray Began

35. Crookes Tubes • Were the beginning of the modern fluorescent lamps and x-ray tubes.

36. Historical Perspectives

37. Collaborative Events