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UNIT ONE RAD 201
CHAPTER ONE AND FOUR
Question | Answer |
---|---|
radiation | transfer of energy |
decay | breakdown of radioactive substances |
ionizing | positive and negative charges created when radiation passes through matter |
biological damage | damage caused to cells, tissues, molecules within the body by radiation exposure |
terrestrail source | natural source of radiation from radioactive materials in the earth. ex uranium, thorium, potassium |
radon | gas produced from the decay of uranium that can pentrate soil and enter buildings through basement; small traces are found within the earth |
extraterrestrial source | cosmic radiation from the sun and stars; as the altitude increases radiation levels increases; radiation levels are greater at the north and south poles |
artificial source | man-made; x-ray, airport surveillance; accounts for 65 mr. per year |
patient dose | indicated as skin dose, organ dose, and fetal dose; amount of radiation the patient receives |
erythema | skin reddening |
skin erythema dose | amount of exposure that causes reddening of the skin |
Roentgen(R) | unit of exposure in air |
exposure | volume of air irradiatied with x-ray or gamma rays causing air to become ionized |
RAD | traditional unit; radiation absorbed dose; the amount of energy unit mass absorbed by an irradiated object |
REM | traditional unit of effective dose; radiation equivalent in man; used to calculated occupational exposure; also uded for radiation protection purposes; takes into account the biological effects of radiation exposure |
Gray | Si unit; similar to RAD |
Sievert | Si unit; used to measure occupational exposure of effective dose; similar to REM |
LET | Linear Energy transfer |
ICRU | International Commission on Radiological Units and Measurement; created 1925; first standard of measurements |
November 8, 1895 | Roentgen announced his discovery of x-ray |
December 28, 1895 | Roentgen wrote a report call "a New kind of Ray" |
Michael Pupin | Professor at Columbia University developed intensifying screens and use in conjunction with glass plates in 1896 |
1904 | Thomas Edison's assistant had to have his hands cut off because of cancer from holding the intensifying screens |