BASIC CONCEPTS
How much do you already know?
????QUESTIONS???
MATTER
Occupies_____________
is a material substance
Has________and shape
Building blocks of matter are_______and __________.
????QUESTIONS???
MATTER
The primary characteristic of matter is _____________
Mass is the quantity or quality of an object?
Does mass change when matter changes?
Give an example of a change of matter.
????QUESTIONS???
WEIGHT
is the mass of matter in an object in ?
Why do we weigh less on the moon
than on earth?
IONIZING RADIATION(AGAIN!!!)
Removes orbital electron from atom
this electron can disrupt surrounding atoms by transferring energy to them.
This renegade(free) electron- negative ion
The atom that lost the electron- positive ion
negative ion & positive ion = ion pair
What two forms of electromagnetic radiation ionize matter?
X-rays
Gamma rays
What two particulate forms of radiation ionize matter?
alpha
beta
SOURCES OF RADIATION HARMFUL TO HUMANS
Natural
Cosmic
Terrestrial
Naturally occurring radionucleides in the human body
Manmade
medical x-rays
nuclear power plants
industrial sources
watch dials*
smoke detectors*
TV*
Airport surveillance systems*
DID YOU KNOW?
Naturally occurring radiation contributes 360 mrads to the average absorbed dose to humans.
Of that 360 40 mrads is x-rays or 13%.
IN THE EARLY YEARS OF USING X-RAYS
Skin damage (erythema)
loss of hair (alopecia)
low red blood cell counts(anemia)
INJURIES DUE TO
low energy radiation
looooonnnngggg exposure times
(30 minutes!!!!!!!!!!!!!!!)
REDUCTION TO RADIATION EXPOSURE
Coolidge tube (Hot-cathode x-ray tube)
vacuum tube
intensity and energy to be selected (1913)
Snook transformer
High voltage power, induction coils (1910)
Potter-bucky grid (1921)
PROTECTIVE APPAREL WAS DEVELOPED WHEN IT WAS NOTED THAT RADIOLOGISTS WERE DEVELOPING AT A HIGH RATE OF LEUKEMIA AND APLASTIC ANEMIA
Effects of radiation
Early
blood changes
decreased sperm count
Latent
cancer changes
possible genetic effects
REGULATION HISTORY
1966- ICRP developed
ALARA
Radiation must have a benefit
Dose should not exceed limits for specific circumstances
REGULATION HISTORY
1987- NCRP established
limits for radiation exposures for radiation workers and non-radiation workers
limits were to minimize potential harm
CARDINAL PRINCIPLES OF RADIATION PROTECTION
T
D
S
DEVICES FOR MINIMIZING RADIATION TO PT/WORKER
Filtration
collimation
Intensifying screen
Protective barriers
Protective apparel
Technical factors (Highest optimal kVp, shortest time)
"The risk of radiation exposure in diagnostic imaging departments is minimal.
Radiography is now considered a radiation safe occupation."
RADIOLOGIC SCIENCE FOR TECHNOLOGISTS,Stewart Bushong, 1997
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