Transcript basic concepts - Montgomery College

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?
 ANSWER…QUANTITY
 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?
Types of energy (joules or eV)
Potential
 Kinetic
 Chemical
 Electrical
 Thermal
 Nuclear
 Electromagnetic

RADIATION
ENERGY EMITTED AND
TRANSFERRED THROUGH SPACE
 PIANO STRING=RADIATE SOUND
 RIPPLES OR WAVES=WAVES
RADIATE

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

Manmade
–
–
–
Terrestrial
–
–
–
Naturally occurring
radionucleides in the
human body
–
–
–
medical x-rays
nuclear power plants
industrial sources
watch dials*
smoke detectors*
TV*
Airport surveillance
systems*
DID YOU KNOW?


Naturally + man-made radiation occurring
radiation contributes 360 mrads to the average
absorbed dose to humans.
Diagnostic x-rays make up the largest source of
man-made radiation (39 mrem per year-50 mrem
per year)
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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