Download Technological Sciences for the Operating Room Physics for the

Technological Sciences
for the Operating Room
Physics for the Surgical
Technologist
Why Study Physics?
Physics involved in all aspects of O.R.
No longer sufficient to only know how to
operate machines
Basic concepts of equipment design must
be understood
Surgical technologist must evolve as the
O.R. advances into the future
Surgical Applications
Physicists have contributed to practice of
medicine
– Wilhelm Conrad Röntgen:
Discovered X-rays
– Thomas Edison: Further X-ray
technology
EKG: measures electrical activity of heart
EEG: measures electrical activity of brain
Surgical Applications
CAT Scan
– Uses X-rays for detailed imaging of tissues
MRI
– Uses radio frequencies to excite protons in
tissue
– Protons return to equilibrium, emit RF signal
analyzed as image
Ultrasound Imaging
– Transforms sound waves into images
– Tissue reflects source signal
– Image is created from “echoes”
Surgical Applications
PET
– Patient consumes radiopharmaceutical
agent that emits positron
– When positron meets electron, both are
destroyed
– Gamma rays are emitted
– Detectors locate each destruction event;
creates colored image indicating activity
Mechanics
Study of objects in motion
– Dynamics: Study of motion & forces that
cause it
– Kinematics: Study of objects in motion;
does not include study of the forces that
caused motion
Speed and Velocity
Speed:
– Describes how fast something is moving
Important: Direction is not considered
– Average Speed = distance traveled ÷
time taken to travel distance
Velocity
– Involves direction and speed
Acceleration
Acceleration:
– Object’s velocity has changed
– Change in velocity over time
Involves change in direction, speeding up,
slowing down
Projectile Motion
Motion of any object launched into air at
an angle
– Projectile launched vertically
– Comes back to launching level in
accelerated motion
Satellite
– Projectile since gravity acts upon it
– Falls toward earth, but does not
complete descent due to earth’s
curvature
Newton’s Laws of Motion
First Law
– Expresses physical concept of inertia
– Object will not move unless outside
force acts upon it
– Object moving at constant velocity will
continue so in a straight line until acted
upon by an object
Second Law
– External force causes an object to
accelerate
Newton’s Laws of Motion
Third Law
– Also called Law of Conservation of
Momentum
– Whenever force is exerted, equal and
opposite force occurs in reaction
Momentum
A force exerted on an object causes force
on other object in opposite direction
– Cannon recoils after shooting cannonball
Total momentum before event is equal to
momentum after event
– Before cannonball is fired, momentum of
cannon and ball is zero
Recoil of cannon after firing gains opposite
direction momentum; equalizes momentum
Simple Harmonic Motion
Object displaced from equilibrium will
oscillate about its equilibrium position
Work and Energy
Work
– Force acting upon an object to cause
displacement
Energy
– Forms of energy that produce changes in matter
Light, electricity, sound, and heat are forms of
energy
Mechanical Energy
– Most common form of energy
– Energy that makes objects move
– Measured by amount of work object can do
Potential Energy
Energy object has stored due to position
relative to zero position
– Gravitational Potential Energy
Cart on top of a hill.
– Chemical Potential Energy
Batteries, firecrackers
– Elastic Potential Energy
Bungee cords
Kinetic Energy
Kinetic Energy
– Energy of Motion
Cart rolling down the hill
Power
Rate at which work is done
– Watt: Standard metric unit of power
– Horsepower = 750 W
Atom Structure: Bohr Model
Electrons: Negative charge
Protons carry a positive charge
Atomic Number indicates number of
protons
Equals number of electrons (usually)
Protons and neutrons compose atomic
mass; reside in nucleus
Neutrons carry a neutral charge
Elements
All matter made up of elements
– 92 natural elements
– Periodic Table of Elements
– Living organisms are composed of
chemically reactive gases like hydrogen,
carbon, nitrogen, oxygen
Elements
Atom Electron Configuration
– Atoms seek electron stability
– Obtain stability by losing, sharing,
gaining electrons
Ionization of Atoms
– Gain or loss of electrons
Loss: Atom is + charged ion
Gain: Atom – charged ion
Molecules
Groups of atoms joined by chemical bonds
Molecular Weight
– Equals the sum of atomic weights of
atoms in a molecule
Matter
Three States
– Solids: has definite shape and volume
– Liquids: has volume, but no shape
– Gases: has no volume or shape
– Plasma
High-energy form of matter
Sometimes defined as a fourth state
Matter
Matter in continual state of flux
– Physical Changes:
ice to water; reversible
Identifying characteristics retained
– Chemical Changes: irreversible
identifying characteristics altered
Pressure
Can be evaluated for solids, liquids, gases
– Pressure exerted by object against a
surface depends on area of contact
Liquid
– Exerts pressure on sides of container
– Exerts pressure on object placed inside
Pressure
Gas
– In addition to pressure other properties that can
be measured are temperature, mass, volume
Related & values determine state of gas
– Boyle’s Law
Boyle studied relationship between pressure
and volume of confined gas at constant
temperature
Observed volume is inversely proportional to
temperature
When pressure is increased, the volume is
decreased.
Heat Transfer
Temperature is the degree of heat or cold of an
object upon touch
Thermal Equilibrium
– Two objects touch, one cold, other warm
Cold object warms up, warm object cools
down
Reach point when no change occurs
Conduction
– Transference of thermal energy by contact
Heat Transfer
Convection
– Liquid and gases poor conductors
– Transfer heat through convection
– Movement of energetic molecules in liquid or
gas
Thermal Radiation
– Does not require contact for transfer of heat
– Sun warming the earth; wood stove fire
– Greenhouse effect
Waves
General Properties
Transfers energy
Wave: repeating and periodic
disturbance moving through medium
–Wave temporarily displaces
particles in medium; seek original
position
–Unique property of wave is ability to
transfer energy without transporting
matter
Electromagnetic Waves
Visible Light originates in electric and
magnetic fields
Electromagnetic waves
– Include radio waves, microwaves,
infrared waves, visible light, ultraviolet
light, x-rays, gamma rays
– Listed in order of vibration – slow to fast
Electromagnetic Waves
Wavelength
– Ultraviolet Region includes short waves,
beyond violet end of spectrum
– Infrared Region includes long waves,
beyond red end of spectrum
ROY G. BIV
X-rays
Waves shorter than ultraviolet
Discovered by Wilhelm Röntgen
Pass thru objects made visible on fluorescent screen
Thomas Edison invented fluoroscope
X-ray Machine
– Cathode Tube (Coolidge tube)
Aims accelerated electrons at heated atoms
(Tungsten filament)
– Anode: electrons strike metallic electrode
– Electrons slow down
– Electrons penetrate metal
– Stopping of electrons produces X-rays
Sound Wave
Produced by vibrating object causing air
molecules to vibrate
Oscillating air molecules create pressure
wave of compressions and rarefactions
– Compressions are regions of high
pressure
– Rarefactions are regions of low pressure
– Sound Wave: alternating compressions
and rarefactions
Sound Wave
Number of waves in one second
– Equals number of vibrations per second sent
by vibrating object
Cycle
– One wavelength is the distance between two
successive areas in same state of
compression
Hertz (Hz) is wave cycles per second
– 1 Hz = 1 cycle per sec.
– Human Ear: perceive 20 Hz to 20,000 Hz
– Megahertz (MHz): ultrasonic frequencies; 1
million cycles/sec.
Sound Wave
Longitudinal and Transverse Waves
– Sound wave travel thru solids
– Gases and liquids: only longitudinal waves
Speed increases with temperature and
depends on level of humidity
– Speed of sound depends on temp. of medium
– Speed of sound thru air: 770 mph
– Speed of sound thru water: 4,820 ft/sec.
Doppler Effect
Shift in frequency and wavelength
of waves resulting from source
that is moving.
– Train approaching and passing.
Light
Speed of Light
– 186,000 miles per second
Light travels in straight line; cannot bend
Light wave can be
– Absorbed, converted to heat
– Reflected
– Transmitted
Reflection
Law of Reflection
– Angle of reflection = angle of incidence
Specular Reflection
– Light travels to mirror in one direction &
reflects from mirror in one direction
Diffuse Reflection
– Objects send light in all directions
– Irregularities on surface of object larger
than wavelength of light send light in
many directions
Refraction
Bending of light ray as it passes from one
substance to another
Color
Dispersion
Separation of light into different
wavelengths show colors of visible light
– Longer wavelengths: red
– Shorter wavelengths: violet
– Spectrum of wavelengths is range between
red and violet
– White
All wavelengths of spectrum strike eye at
same time
– Black
Absence of the wavelengths of visible light
spectrum
Laser
Light Amplification Stimulated Emission of
Radiation
Device that transforms energy into
electromagnetic radiation
– Light with electrons that radiate in
synchronous vibration
Laser Components
Pump Source
– Sets particles from energy source in motion
– Energy emitted from laser as electromagnetic
radiation
Gain Medium
– Made of solid, liquid, or gas
– Amplifies light as it passes thru material
– Determines type of laser: solid state,
semiconductor or liquid
– Solid State: Pulse beam has the most power
output
Laser Components
Resonator Cavity
– Mirrors that direct and redirect particles
through the gain medium
Nuclear Physics
Study of the properties of atomic nucleus
Nucleons are protons and neutrons
– Quarks: Subatomic particles that make
up nucleons
Repulsive Force
– Keeps tightly packed nucleons from
overlapping
– Nucleus appears as closely packed
spheres, almost touching
– Binding Energy: Forces apart nucleons
Nuclear Physics
Relationship of Energy and Mass
– Einstein’s Equation
E = mc²
Mass and energy are same thing
Small amount of mass holds a lot of
energy
Matter can be converted from one energy
form to another
– Particle accelerators and nuclear
reactors
Physics for the Surgical
Technologist
QUESTIONS?
I DON’T’ THINK SO!