98 terms

# Radiology Physics Chapters 1, 2, and 3 Pt 1

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Heat
the kinetic energy of the random motion of molecules
Potential Energy Formula
PE=mgh
Potential energy=mass x gravity x distance above earth's surface
Kinetic Energy depends on ....
the mass of the object and on the square of its velocity
Two forms of mechanical energy
Kinetic Energy (KE)
Potential Energy (PE)
Calorie
the heat necessary to raise the temperature of 1g of water through 1 degree Celcius
Heat Transfer
Conduction
Convection
Radiation
Conduction
the transfer of heat by touching or through material
Convection
the mechanical transfer of "hot" molecules in a gas or liquid from one place to another
Radiation
thermal transfer of heat by emision of infared radiation, how x-ray tube cools
F to C
C= 5/9 (F-32)
C to F
F= 9/5 (C+32)
C to K
K=C+273
How is a thermometer calibrated?
Freezing and boiling points
Approximate Temperature Conversion
F -> C = -30, /2
C -> F = double, +30
ICRU
International commission on radiation units and measurement

SI units
Gy +
unit of radiation, absorbed dose
Gy a
(R) Roentgen
Unit of radiation exposure or intenstiy
Sv
rem
occupational radiation exposure
Bq
Curie
radioactivity
Kinetic energy formula
KE= 1/2 x mv squared
Law of energy conservation
energy may be transformed from one form to another but it cannot be created or destroyed
Work
force applied times the distance over which itis applied
Joule
Product of force and distance
Work formula
w=fd
work = force times distance
Momentum formula
p=mv
momentum=mass x velocity
Momentum
the pruduct of mass and velocity
increased velocity = increased momentum
the total momentum before any interactino is equal to the total momentum after the interaction
Gravity in outer space = ______
0
The value of acceleration due to gravity on the moon is about ___ that on the earth
1/6
Weight formula
Wt=mg
Weigh= mass x gravity
The acceleration of gravity on earth
1 lb = 4.5 N
Weight (WT)
a force on the body caused by the pull of gravity on it
Acceleration due to gravity
objects that fall to Earth accelerate at a constant rate
Newton's Law of Acceleration/Reaction
For every action there is an equal and opposite reaction
Force Formula
F=ma
Force = mass x acceleration
SI unit of force
Newton = N
Friction
the force present that will slow down a moving object
Kinetic Energy
energy of motion
can do work because of thier motion
Found that ________ were occuring in radiologists at a much higher rate
blood disorders
ALARA
as low as reasonably achievable
Filtration
metal- aluminum, copper
inserted into x-ray housing so that low-energy x-rays are absorbed before they reach tehe patient (little diagnostic value)
Collimation
restrics the useful x-ray beam to that part of the body to be imaged and thereby spares adjacent tissue from uneccessary radiation

lower scatter = higher contrast
Intensifying Screens
cassette with radiographic intensifying screens on both sides
reduced exposure time with glass photographic plates
Abdominal/Pelvic x-ray exaominations of expectant mothers should not be conducted during....
first trimester unless absolutly necessary
H. Potter
1921
Helped with Potter-Bucky grid
Gustav Bucky
1913
invented the stationary grid "Glitterblende"
2 months later- another patent was unknown because of the first world war (H.Potter)
When did acceptable kVp and mAs levels become possible
matching of the coolidge tube with the snook transformer
William D Coolidge
1913
hot-cathode x-ray tube, far superior to crookes tube
vacume tube that allowed x-ray intensity and energy to be selected seperately and with great accuracy
what x-ray tubes mainly are today
Transformer
substitute high-voltage power supply
H.C. Snook
1907
transformer- exceeded the capability of the Crookes tube
Clarence Dally
Edison's Friend
Severe x-ray burn, amputation of both arms
died 1904, first x-ray fatality in the U.S.
Fluoroscope
1898
Thomas A. Edison
barium platinocyanide found zinc cadmium sulfide and calcium tungstate
Cellulose Nitrate
demands of army for inscreased radiologic services
substitue for glass plate
Charles L Leonard
Found that by exposing two glass x-ray plates with the emulsion surfaces together exposure time was halved and the image was enhanced
1904 double emulsion film
1918 commercially available
Michael Pupin
1896
demonstrated the use of intensifying screen
William Rollins
dentist sheet of lead with hole (diaphragm) inserting a leather or aluminum filter improved diagnostic quality and reduce patient exposure, collimation and filtration
Wilhelm Roentgen
November 8, 1895
Crookes tube
plate coated with barium platinocyanide glowed when next to the crookes tube fluorescence
1901
Roentgen first nobel prize in physics
How to provide an x-ray beam that is satisfactrory for imaging
you must supply the x-ray tube with a high voltage and a sufficient electric current
x-ray volages are measured in
kVp
1000 v of electric potential
x-ray current are measured in
mA
electric current
m=1/1,000 or .001
Fast moving particles
particles with high kinetic energy
mrem
1/1000 if a rem
rem
radiation equivalent man
ionizing radiation
x-rays
any type of radiation that is capable of removing an orbital electron from the atom with which it interacts
natural environmental radiation
cosmic rays
terrestrial radiation
internally deposited radionuclides
Human evolution has been influenced by
natural environmental radiation , ionizing radiation
Radon
largest source of natural environmental radiation
a radioactive gas that is produced by the natural radioactive decay of uranium
emits alpha particles, radiation to lung only, non penetrating
man made radiation
60 mrem/year
largest- diagnostic x-rays (catscan)
nuclear power, research applications industrial sources, consumer items
Cathode rays
electrons
Crookes Tube
partially evacuated glass tube
cathode rays experimented with by sir William crookes
1870's-1880's
Electromagnetic energy
least familiar level but the most important in x-ray
radiowaves, microwaves, ultraviolet rays, infared, visable light
Electromagnetic Radiation
visible light radiated by the sun
Theory of relativity or Mass-Energy formula
E=mc^2 (squared)
energy= mass x speed of light in a vacum tube squared
Albert Einstein
mass-energy equivalence theory
Radiation
energy emitted and transferred through space
the transfer of energy
exposed/ irradiated
matter that intercepts radiation and absorbs part or all of it
negative ion
the electron from ionization
positive ion
the remaining atom from ionization
Electrical energy
the work that can be done when an electron moves through an electric potential difference (voltage)
Thermal energy (heat)
the energy of motion at the molecular level
faster= increased thermal energy
Nuclear energy
energy that is contained within the nucleus of an atom
Biochemistry
chemical energy at the molecular level
Ion Pair
orbital electron and the atom from which it was seperated from
Mechanics
a segment of physics that deals with objects at rest (statics) and objects in motion (dynamics)
When one si working on problems on reporting answers
the same system of units must always be used
Two parts of measurements
magnitude, unit
100 cm
3 measurable quantites
mass
length
time
Second
standard unit of time
rotation of the earth on its axis, solar day
Secondary quantities
derrived quantities
because they are derived from a combination of one or more of the three basic quantities

energy, power, work, momentum, force, velocity, acceleration
Special quantities
designed to support measurement in specialized areas of science and technology

exposure, dose, equivalent dose, radioactivity
Length
distance between two lines engraved on a platinum - iridium bar kept at the international Bureau of weights and measurements in paris - 1 meter
Meter is based on
speed of light
Mass
kg = mass
unit of weight
newton
pound
kg is the mass of...
1,000 cm^3 of water at 4 degrees C
Physics
the study of interactions of mater and energy in all thier diverse forms
Average velocity equation
average velocity= final velocity + initial velocity
over 2 (divided by )

_
V = Vf + Va
------------
2
Constant velocity of light
c=3 x 10^8 m/s
The motion of an object=
velocity
Acceleration