RAD 354 – Chapter 1

1. RAD 354 – Chapter 1 • This class will be a FAST review of RAD 350 and will be TECHNIQUE oriented. • Techniques, technique charts and cooling charts as well as effects of all items on radiation outputs/patient-matter interactions will be stressed.

2. Comments by Joe –”Hey Dr. P! Good News! I passed my boards! On the morning of the test, I got up at 5 am and took out my notebook where I had listed all of your and Chad’s ‘bang on the desk/board’ items and read them ALL and no B.S. like 20-25 questions were right off of your notes as you both said! When you see the 1st and 2nd year students be sure to tell them this is no shi*!!!. Star and study those itmes.

3. Matter – anything that occupies space -consists of atoms and molecules -primary characteristic is mass Class discussion – Weight and mass differences

4. 7 Forms of Energy • Potential – capacity to work by virtue of position • Kinetic – energy of motion • Chemical – energy releases in Chem reactions • Electrical – Electron movement • Thermal – molecular level movement • Nuclear – energy in the nucleus of an atom • Electromagnetic – x-ray and magnetic energy

5. Ionizing Radiation • Capable of removing an orbital electron from an atom = an ION PAIR: ejected electron (called a negative ion) and the “upset” atom minus an electron (destabled atom called a “positive ion”)

6. Natural Radiation • Cosmic rays – particles emitted by the sun and stars • Terrestrial – emitted from deposits of uranium, thorium and other radioactive earthly substances (like radon gas) • Internally deposited – mainly potassium 40 (natural metabolites)

7. Man Made Radiation • Medical/dental x-rays • Nuclear power plants • Industrial plants • Screening (TSA, etc), airport surveillance • Smoke detectors

8. Key Dates • November 8, 1895 – X-rays discovered by Wilhelm C. Roentgen (was using a Crook’s Tube) • 1886 – Fluoroscope invented by Thomas Edison

9. Radiation Protection • ALARA – As low as reasonably achievable • Time, Distance, Shielding Early radiation exposure effects: blood changes, lowered sperm count Latent effects: genetic effects, cancer

10. Protection Items to Consider • Filtration – kVp driven (2.0 mm al. added at the 70-80 kVp range + .5 mm al equiv. inher. • Collimation – single most important thing a tech can do! • Intensifying screens – receptor/film-speed combination – as fast as possible (and still get a good image) • Protective barriers: shielding, gonadal shielding and PATIENT shielding!

11. Scientific notation makes it easy to write large positive or negative numbers • “milli” = 1/1000 (milliamp) • Kilo = 1,000 (kilovolts – kVp)

12. Radiation Units • Roentgen – couloumb/kilogram (radiation in air) that will create 2.08 X 109 ion pairs in a cubic centimeter of air • RAD/Gray = radiation ABSORBED dose • 1 X 10-2Gy = 1 RAD REM/sievert SV = radiation equivalent man (RAD X man’s biologic equivalent) 1 X 10-2 SV = 1 REM

13. RAD units con’t • Curie (CI)/Becquerel )Bq) = radioactive disintegration 3.7 X 1010Bq= 1 CI

14. Curves • Characteristic curve (H & D, Solarization, Hortchkoff) optical density (OD) verses log relative exposure (like mAs – to the .3 log) • X-ray emission spectrum – height of the curve = mAs – skew to the right/left is based on kVp

15. Review of Units • 3 Measurable quantities of all others • Length, mass and time • Secondary quantities are derived from a combination of two or more of the three • Radiography units are: exposure, dose, dose equivalent and radioactivity

16. Standardized Units • Unit of length = meter • Unit of time = second • Unit of mass - kilogram

17. System of Measurement • SI (meter, kilogram, second) • MKS (meter, kilogram, second) • CGS (centimeter, gram, second) • British (foot, pound, second)

18. Mechanics • Deals with objects at rest (static) & in motion (dynamic) • Velocity = how fast an object is moving • Acceleration = rate of change of velocity over time

19. Newton’s Laws of Motion • A body will remain at rest or continue to move with constant velocity unless acted upon • The force acting on an object with acceleration is equal to the mass multiplied by acceleration • Action/reaction = for every action there is an equal and opposite reaction

20. Weight/Momentum/Work/Power • Weight is the force of an object caused by the downward pull of gravity (mass X gravity) • Momentum is the product of the mass of an object and it’s velocity • Work is force applied to an object over a distance • Power is the rate of doing work or work over a period of time

21. Energy = ability to do work • Si unit is the joule • Mechanical energy • Kinetic energy = energy in motion • Potential energy = stored energy by virtue of position

22. Heat = kinetic energy of the random motion of molecules • Can be transferred a variety of ways: • Conduction = transferred by touching or through a material • Convection = mechanical transfer of “hot” molecules in gas or liquid from one place to another • Thermal = red glow of hot objects (infrared emission)

23. Heat measurement via thermometer • Three scales of heat measurement exist: Celsius (C) Fahrenheit (F) Kelvin (K)