1. Physics That branch of science that deals with matter and energy and their relationship to each other. Examples: Magnetism Electricity Electromagnetism

2. Equivalencies – English, Metric, Scientific Notation Some Relationships You Must Know:

3. Fundamental Units of Measure Consist of measurements relating to length, mass and time. Length: Fundamental unit – Meter (approx. 3 ft) 100 cm in meter =.01 meter, 10 -2, 1/100 1 inch = 2.54 cm Conversion from English to metric system (# Total inches X 2.54) – 4 inches X 2.54 = 10.16 c.m. Conversion from metric to English system (# Total c.m. / 2.54) 10.16 c.m./ 2.54 = 4 inches (40 inch SID X 2.54 = 101.6 c.m.) In radiology, the angstrom is often used to measure wavelength of x-rays and light. 1 A = 1 X 10 -10 meters

4. Fundamental Units of Measure Mass – The quantity of matter in a body (inertia) Determined by weighing unit of mass = kilogram 1 kg = 2.2 lb conversion from English to metric ( # total lbs/ 2.2), 120 lbs/ 2.2 = 54.54 kg conversion from metric to English (# total kg X 2.2), 54.54 kg X 2.2 = 119.988 lb

5. Fundamental Units of Measure Time unit of measure is seconds milliseconds are used often in radiology milli = 1/1000 sec.,.001 s, 10 -3 To convert milliseconds to seconds, move the decimal point 3 places to the left. To convert seconds to milliseconds, move the decimal point 3 places to the right

6. Other Commonly Used Units of Measurement in Radiology Amps – # of electrons flowing per second Often expressed in milliamps 300 mA =.3 A Exposure REM – Measures biologic effect of radiation Often given in millirem (mrem) 50 mrem =.05 rem RAD – Measures absorbed dose Roentgen – Ionization in air Voltage – Energy (push) behind electrons Usually given in kilovoltage (kVP) 100 kVp = 100,000 volts

8. Know what each of the above units measure

9. Energy The ability to do work Potential Energy – The ability to do work by virtue of position Kinetic Energy – Energy in motion

10. Law of Conservation of Energy Energy can neither be created nor destroyed If may change forms, but will not cease to exist Examples: - Production of x-ray results in changing electron’s energy to x-ray and heat - Interaction between x-ray and body matter results in transferring original energy of radiation to electrons or nucleus of atoms