Studies relationships between matter and energy
Physics
Has mass and occupies space
Matter
The quantity of matter contained in an object
Mass
Force used to do work
Energy
Smallest particle of an element that still possess the chemical properties of that element
Atom
Simple substances
Element
Complex substances
Compound
A material that has definite constant composition
Simple vs complex, elements vs compounds, atoms vs molecules
Substance
Two or more substances combined
Mixture
Smallest particle of a compound possessing characteristics of the compound
Molecule
3 states of matter (dependant upon varying degrees of molecular attraction largely due to temperature)
Solid
Liquid
Gas
E=mc^2
<p>Law of conservation of energy (E = energy, m = mass, c = speed of light)</p>
<p>Unit of energy</p>
<p>Joule</p>
<p>Energy is emitted and transferred through matter; heat and light both come from the sun</p>
<p>Radiation</p>
<p>Mini solar system
| Electrons don't orbit perfectly, more like beehive</p>
<p>Bohr (1913)</p>
<p>Small dense center of atom that contains nucleons, protons and neutrons</p>
<p>Nucleus</p>
<p>Electrons can't be divided
Protons and neutrons made up of quarks
M theory (string theory): links this and relativity</p>
<p>Quantum physics</p>
<p>Distinguishes elements by number of protons contained in nucleus</p>
<p>Atomic number (Z#)</p>
<p>Atoms that have the same number of protons in the nucleus but differ in the number of neutrons</p>
<p>Isotope</p>
<p>Adding or removing of electrons from an atom
X-ray photons can interact with atom, results in the ejection of electrons
Changes charges between atoms
Causes disruptions in body's metabolic relationships (can harm patient) so exposing patients to this radiation thus requires order from licensed practitioner</p>
<p>Ioniziation</p>
<p>An atom that has gained or lost an electron</p>
<p>Ion</p>
<p>How many protons and neutrons in atom, neglects mass of atom's electrons
Mass of proton 1836 times greater than electron, mass of neutron 1838 times greater than electron</p>
<p>Mass number (A#)</p>
<p>Defines location where electron might be at any given time</p>
<p>Orbital</p>
<p>Chemical combining characteristics that describe how an atom will bond with other atoms
\+1 atoms gives up and electron, -1 atom gains an electron</p>
<p>Valence</p>
<p>Energy needed to eject an electron from an atom, how tightly bound electrons are bound to the nucleus of that particular atom
Related to how close electron is related to nucleus
Increases as atomic number increases
K shell energy greatest (electrons bound tighter than in other shells)
Depending on how many protons are in the nucleus, the binding power will be stronger the higher the proton number (ex: H vs lead)
Atoms have different number of protons in the nucleus which affect how tightly bound electrons will be
Unit: electron volts (eV); energy of one electron when accelerated by one volt = keV</p>
<p>Electron binding energy (Eb)</p>
<p>Atom never has more than eight electrons in its outer shell, for this reason atoms begin to fill in next shell before maximum is reached
Atom with eight electrons in outer shell chemically stable (inert)</p>
<p>Octet rule</p>
<p>Ability to do work, force acting upon object over distance expends this
Work = force x distance</p>
<p>Energy</p>
<p>Action of physical movement</p>
<p>Mechanical energy</p>
<p>2 types of mechanical energy</p>
<p>Potential
| Kinetic</p>
<p>Energy released from a chemical reaction
Ex: body converts this energy from food into mechanical energy or mood; battery converts this energy into electrical energy</p>
<p>Chemical energy</p>
<p>Results from movement of molecules, temperature measures it
Ex: toaster converts electrical energy to this</p>
<p>Heat/thermal energy</p>
<p>Electricity, results from movement of electrons in conductor
Ex: light bulb converts electric energy to light</p>
<p>Electrical energy</p>
<p>Obtained by breaking bonds between particles within nucleus
Ex: nuclear power plants convert this energy to electricity</p>
<p>Nuclear energy</p>
<p>Combination of electric and magnetic fields travelling through space, results from acceleration of a charge
Can travel through medium or vacuum (x-ray tube = vacuum)
Wave/particle duality
Can cause excitation/ionization</p>
<p>Electromagnetic (EM) energy</p>
<p>EM travels in waves and there are little particles within each wave</p>
<p>Wave/particle duality</p>
<p>The distance between any two successive points on a wave; distance between two peaks</p>
<p>Wavelength</p>
<p>Number of waves that pass a particular point in a given time frame</p>
<p>Frequency (hertz, Hz)</p>
<p>Intensity of the wave defined by its maximum height</p>
<p>Amplitude</p>
<p>Waves are disturbances in a medium; ex: ocean, sound, etc.
Wavelength: angstrom
Frequency (v): cycles per second (Hz)</p>
<p>Wave theory</p>
<p>Frequency and wavelength are inversely related
Velocity = frequency x wavelength (V = v x wavelength)
Velocity of all EM radiation is c, c = 3 x 10^8 m/s
c = v x wavelength</p>
<p>Wave equation</p>
<p>High frequency, high energy EM radiation
Interacts like particle when contacting matter
Photon (bundle of energy) energy and frequency directly related
When bundle of energy interacts with something, it's able to break it apart; different bundles of energy in each x-ray
If frequency doubled, energy doubles; E=hv</p>
<p>Particle theory</p>
<p>Who discovered x-rays and when?</p>
<p>Wilhelm Conrad Rontgen in 1895</p>
<p>12 x-ray properties</p>
<p>Penetrating and invisible form of EM radiation (can't be seen, stopped by lead)
Electrically neutral (not affected by electric or magnetic field)
Polyenergetic or heterogeneous energies (various energies/wavelengths)
Release heat when passing through matter
Travel in straight lines
Travel at speed of light
Can ionize matter
Cause fluorescence in certain crystals
Cannot be focused by lens
Affect photographic film
Produce chemical and biological changes in matter (patients) through ionization and excitation
Produce secondary and scatter radiation</p>
<p>2 responsibilities of radiographers</p>
<p>Minimize dose
| Protect patients and others from unnecessary exposure</p>
<p>2 sources of ionizing radiation</p>
<p>Natural
| Man-made</p>
<p>2 groups of ionizing radiation</p>
<p>Particulate
| Electromagnetic</p>
<p>High-energy electrons, neutrons and protons
From radioactive decay
Alpha and beta particles
Used in nuc med</p>
<p>Particulate radiations</p>
<p>High-energy helium nucleus (two protons and two neutrons)
Decaying radioactive material
Large amount of mass and charge
Can travel 5 centimeters (cm) in air, not very harmful external source but if injected in you it is one of the worst types of radiation
Weighting factor of 20</p>
<p>Alpha particles</p>
<p>2 types of particulate radiation</p>
<p>Alpha
| Beta</p>
<p>Electrons from decaying radioactive material
Little mass and charge
Can travel 10-100 cm in air, not as dangerous as alpha</p>
<p>Beta particles</p>
<p>2 types of biologic damage</p>
<p>Direct interaction
| Indirect interaction</p>
<p>X-rays interact with water molecules which produce free radicals that cause damage
More damage done in diagnostic field</p>
<p>Indirect interaction</p>
<p>2 classifications of biological effects of ionizing radiation</p>
<p>Somatic
| Genetic</p>
<p>Evident in individual, w/in person who receives rad (patient or radiographer)
Ex: burns, erythema (redness), cataracts, cancer</p>
<p>Somatic</p>
<p>Evident in offspring of individual
| Birth defects</p>
<p>Genetic</p>
<p>6 things influenced by biological effects of ionizing radiation</p>
<p>Total dose received Rate of dose Age at exposure Type of radiation Sensitivity of cells Body part irradiated</p>
<p>2 sources of ionizing radiation exposure</p>
<p>Natural
Man-made
</p>
<p>3 natural sources of ionizing radiation exposure</p>
<p>Cosmic radiation
Terrestrial radiation
Radionuclides naturally present (internal and external, injected in body for nuc med scans)</p>
<p>6 man-made sources of ionizing radiation exposure</p>
<p>X-rays Radiopharmaceuticals Consumer products (smoke detectors) Air travel (closer to sun) Nuclear fuel production Fallout</p>
<p>5 major areas of radiation exposure in U.S.</p>
<p>Ubiquitous background, including Radon Medical procedures Consumer products Industrial and security activities Occupational exposure</p>
<p>Number of ionizations in given quantity of air
When you make an exposure, there are a bunch of photons that come out of the tube and through air and cause ionization
Exposure in air; quantity of x-rays</p>
<p>Exposure</p>
<p>“The quantity of x-rays or gamma rays required to produce a given amount of ionization charge in a unit of mass air”; used in inverse square law</p>
<p>Roentgen (R)</p>
<p>Units of exposure</p>
<p>1 R = 2.58 x 10-4 C/kg
| Roentgen (R)</p>
<p>Measures amount of energy absorbed
| Unit can be used to measure any material</p>
<p>Absorbed dose</p>
<p>Conventional unit of absorbed dose</p>
<p>1 rad = 100 ergs/gm</p>
<p>SI unit of absorbed dose</p>
<p>1 Gray (Gy) = 1 Joule/kg</p>
<p>Kinetic Energy Released in Matter
Radiation interacts with matter: energy carried by photon is transformed to kinetic energy to particles (electrons)
At diagnostic energies equivalent to dose (rads/gray)
Unit Gy</p>
<p>Kerma</p>
<p>Kinetic energy released per unit mass of air
Used to describe tube output ant input to image receptors
This of 1 cGy = 1 rad
Equivalent to 1 R of exposure
</p>
<p>Air kerma</p>
<p>Total amount of energy deposited in matter
Ex: CT Abdomen
1 section delivers dose of 1 rad, 20 slices total
Tissue volume of each section 1 rad = 20 rad
No radiation in CT</p>
<p>Integral dose</p>
<p>Product of absorbed dose in tissue and radiation weighting</p>
<p>Equivalent dose (Ht)</p>
<p>Different types of ionizing radiation produce different biological responses
X-rays have weighting factor of 1</p>
<p>Radiation weighting</p>
<p>Conventional unit of equivalent dose</p>
<p>rem</p>
<p>SI unit of equivalent dose</p>
<p>Sievert (Sv)</p>
<p>Sum of equivalent doses of specific tissues
| Not all tissues are equally sensitive to radiation</p>
<p>Effective dose (E)</p>
<p>Describes quantity of radioactive material
Expressed as number of radioactive atoms to decay per unit time
Nuc med</p>
<p>Activity (A)</p>
<p>Conventional unit of activity</p>
<p>Curie (Ci)
| 1 Ci = 3.7 x 1010 disintegrations per second (dps)</p>
<p>SI unit of activity</p>
<p>Becquerel (Bq)
| 1 Bq = 1 dps</p>
<p>Dose-measuring device</p>
<p>Dosimeter</p>
<p>2 classifications of dosimeters</p>
<p>Field survey instruments
| Personnel monitoring devices</p>
<p>3 types of field survey instruments</p>
<p>Geiger-Mueller survey instruments
Scintillation detection devices
Ionization chamber instruments</p>
<p>Gas-filled detector (volume of gas between two electrodes)
Ionizing radiation creates ion pairs in gas
Used to demonstrate presence of radiation
Not for precise measurement
Most effective with particulate radiation
Common use in nuc med
Least effective in detecting x- or gamma radiation</p>
<p>Geiger-Mueller Survey Instruments (GM counters)</p>
<p>Emit light when stimulated by ionizing radiation
Light converted to electric signal
Commonly used in nuclear medicine and CT scan equipment</p>
<p>Scintillation detection devices</p>
<p>Diagnostic
Used to evaluate equipment performance, leakage radiation and patient exposure
Gas filled chamber, anode, cathode &amp; automatic readout
Configuration
Mechanism of action</p>
<p>Ionization chamber instruments</p>
<p>Provided to workers who could accumulate 1/10 of recommended dose limit
Should be worn at level of collar</p>
<p>Personnel Monitoring Devices</p>
<p>4 personnel monitoring devices</p>
<p>Optically stimulated luminescence (OSL) dosimeter Film badge dosimeter Thermoluminescent dosimeter (TLD) Pocket dosimeter</p>
<p>Most common type of personnel monitor
Detector: thin layer of aluminum dioxide
Laser light processing of aluminum dioxide causes luminescence (level of luminescence proportional to amount of exposure received)
Filters of copper and tin and an open window demonstrate energy of exposure and if exposure occurred while static or in motion
Issued on monthly or quarterly basis
Sensitive to 1 millirem (mrem): picks up on very small amount of radiation (better than others)
Environmentally stable and durable</p>
<p>Optically stimulated luminescence (OSL) dosimeter</p>
<p>Detector: two pieces of film in light tight packet
Packet placed in holder with filter elements (copper, cadmium, and aluminum; filters provide information on energy of radiation)
Film processed and optical density evaluated
Demonstrates amount of exposure
Sensitive to 10 mrem, readings under 10 mrem not detectable (reported as M)
Environmentally sensitive to heat, humidity, pressure, prolonged exposure to light</p>
<p>Film Badge Dosimeter</p>
<p>Detector: lithium fluoride crystals
Crystals store energy when exposed to ionizing radiation and release stored energy when heated as visible light
Amount of light released proportional to amount of exposure
Sensitivity similar to film badge: 10 mrem
Environmental sensitivities also similar to film badges
Heat, humidity, temperature, pressure, and prolonged exposure to light
Compact design
Desirable for extremity badges
Small &amp; often made into rings</p>
<p>Thermoluminescent dosimeter (TLD)</p>
<p>Ionization of air in small chamber
Readout occurs digitally
Can be read from display on side of dosimeter
No permanent record</p>
<p>Pocket dosimeter
| Electronic Personal Dosimeter</p>
