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61 Cards in this Set
- Front
- Back
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Matter Conversions
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Physical and Chemical
Ex. Solid (ice) melts into liquid (water) |
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Science/Physics uses both ___ and ___ to study the properties of matter
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Analysis: study by breaking down the parts or facts.
Synthesis: study by combining the parts/facts. |
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Subdivisions of Matter
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1. Elements (simple)
Atom (smallest unit of an element) A&E 2. Compounds (complex) Molecules (smallest unit of a substance) S&M |
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Matter Defined
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1. Anything that has mass and occupies space.
2. All matter has inertia 3. Matter can be converted into energy 4. Made of atoms |
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Inertia
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the resistance a body offers to any change in position
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Three Basic States of Matter
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Gas
Liquid Solid Law of Conservation of Matter: "Matter can neither be created or destroyed, but converted from one form to another by physical or chemical means." |
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Gas
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Flows Freely
Low Density Easy to Compress No surface |
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Liquid
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Flows
Medium Density Weak molecular attraction Difficult to compress Has a surface |
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Solid
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Does not flow
Particles close together Particles have strongest molecular attraction Med-high density Difficult to compress Rigid surface |
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Atoms
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Neils Bohr
Tiny solar system Smallest fraction of an element Invisible Neutral No charge Constant Motion Mainly Space |
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Atom vs. Ion
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Atoms have no charge
p=e Ion: Charged particle p =/= e If one electron is lost: + If one electron is added: - |
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Hydrogen
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Simplest atom known
Only one particle in nucleus (1 proton, 0 neutrons) 1 electron in orbital shell No charge (p=e) #1 on Periodic Table Symbol: H |
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Particles
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Atomic Particles: involves all three fundamental units of the atom, p, n, e-
Ex. Atomic Energy Nuclear Particles: Involves just the two fundamental units in the nucleus of the atom: p and n Ex: Nuclear energy |
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Z#
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Protons:
Atomic number (# of p) As Z# increases, absorption of x-rays increases. |
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A#
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Atomic mass number
(p+n) |
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Neutron (n)
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A# - Z# = # of n
*Located in nucleus *No charge *Mass = 1 (slightly heavier than p) Nucleons: *p's and n's in nucleus *same as atomic mass number (A#) *p+n=A# * A# - Z# = # of n *Held together by stron nuclear force |
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Electron Shells
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*Each shell is labeled
*Starts with K (1st shell) *Principle Quantum Number (maz # of e- in shell) (2n^2) where n = # of shell *Valence: # of e- in the outermost shell (determines ability to combine with other elements) |
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How many electrons will occupy the L shell if the atom has 7 protons?
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Atom means p = e; so there are 7 electrons;
K shell = 2 L shell = 5 *K shell can only hold 2 e- *L shell can only hold 8 e- |
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Binding vs. Shell Energy
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Binding Energy (Eb): Energy that holds an e- in an orbital shell around the nucleus of the atom.
*As distance from nucleus increases, Eb decreases Shell Energy (SE): Amount of energy the e- has in an orbital shell *As distance from nucleus increases, SE increases |
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Binding Energy Example:
How much energy is required to ionize tungsten by removal of a K-shell e-? |
Tungsten (W) K-shell e- has the Eb=69.53 keV; it will take at least 69.53 keV of energy to know out the e- from its orbit
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Molecules & Elements
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Elements: found on periodic table
Ex. O, Na, Al, Ba Molecules: combos of elements Ex. H2O (2 elements & 3 atoms total) |
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Proton
Symbol, Charge, Mass |
p
+ 1 |
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Neutron
Symbol, Charge, Mass |
n
0 charge 1 (slightly heavier than p |
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Electron
Symbol, Charge, Mass |
e-
-1 0.00055 (2000 times lighter than p) |
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Types of Radiations
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*Ionizing Radiation: radiation that knocks out orbital e- in matter; occurs only when radiation is in motion (KE)
*Two main Groups: 1. Particulate Radiation (particles) a. Alpha particles (emission) b. Beta particles (emission) 2. Electromagnetic radiation (waves) a. Gamma rays b. X-rays |
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Electromagnetic Radiation
(EMR) |
Wavelike fluctuations of electric and magnetic fields set up in space by oscillating (vibrating) e- that travel at the speed of light
All electromagnetic waves have similar shape and same travel speed (c), they differ in wavelength, frequency, range, and energy |
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speed of light
c = |
c = 3 x 10^8 m/sec
3 x 10 ^10 cm/sec 186,000 miles/sec Speed of Light |
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EMR Spectrum
(Electromagnetic Spectrum) |
Ranking least to highest in energy:
AM radiowaves FM radiowaves Microwaves Infrared Visible light Ultraviolet X-rays Gamma rays Cosmis ray AFM IVU XGC (least -> highest) |
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Visible Light Wavelengths
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wavelengths
shortest -> longest Violet (purple) blue green yellow orange red ROY - G - BIV longest -> shortest |
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Wavelength ( y )
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distance between two consecutive crests
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Frequency ( v )
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# of crests that pass in 1 sec
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Amplitude
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distance from baseline to crest
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Angstrom ( A )
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units for wavelength
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Photons (Quanta)
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bundles of energy
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Ionizing radiations
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*X-rays
*gamma rays (y-rays) *beta particles (B) *electron beams *alpha particles (a) |
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NOT ionizing
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lazers
ultraviolet (UV) infrared (IR) ultrasound MRI Microwave Radiowaves |
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X-rays (x) vs Gamma (y)
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X-Rays:
man-made longer wavelength lower frequency Gamma Rays: Natural (emitted from nucleus of radio-isotope) Higher frequency Most penetrating |
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X-rays
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Man-made in x-ray tube
Wavelength: longer than gamma Frequency: lower than gamma Unlimited range in matter No mass No charge Stopped by lead or concrete Usual range of wavelengths: 0.1 - 0.5 A |
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Gamma Rays
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Origin: emitted from nucleus of radio-isotope
Wavelength: shorter than x-ray Frequency: higher than x-ray Most penetrating type of radiation Unlimited range in matter No mass, no charge Stopped by lead or concrete |
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Formula: c
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c = lambda x nu
c = h x v c = wavelength x frequency ____c____ h x v As wavelength increases, frequency decreases |
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12 Properties of X-Rays
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1. Highly penetrating, invisible
2. Electrically neutral 3. Polyenergetic & heterogeneous 4. Releases small amts of heat as it passes thru matter 5. Travels in straight lines 6. Travels at speed of light 7. Ionize Matter 8. Cause Fluorescence of certain crystals 9. Cannot be focused by a lens 10. Affect photographic emulsions 11. Produce chemical * biological changes in matter thru ionization and excitation 12. Produces secondary & scatter radiation |
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12 Properties of X-Rays
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1. Penetrating & Invisible
2. Neutral 3. Polyenergetic & heterogeneous 4. Releases heat 5. Straight Lines 6. Travels @ Speed of Light 7. Ionizing 8. Fluorescence 9. Cannot be refracted by lens 10. Affect photographic emulsions 11. Chemical & Bio changes 12. Scatter radiation |
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12 Properties of X-Rays
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1. Penetrating
2. Neutral 3. Polyenergetic 4. Heat 5. Straight 6. SOL 7. Ionizing 8. Fluorescence 9. Lens (cannot bend) 10. Emulsions 11. Chemical 12. Scatter |
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kV and Wavelength
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*kv: kilovoltage
*Determines the wavelength of an x-ray *Wavelength (y) determines how the radiation will penetrate the body part *As kV increases, wavelength (h) decreases, frequency (y) increases. Thus penetrating ability of x-ray /\ and radiation dose to patient \/ |
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X-ray production
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*Date of discovery: Nov. 8, 1895
*Wilhem Conrad Roentgen *Roentgen used a Crooke's tube (cold cathode) *Modern tubes: like a Coolidge tube (hot cathode) |
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X-ray Equipment's Function
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To convert electrical energy into electromagnetic energy (x-rays or radiant energy)
Law of conservation of Energy: "Energy cannot be created or destroyed but changes from one form to another; energy is constant in the universe." |
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Tube Housing
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*Houses the x-ray tube(insert)
*Controls leakage/scatter *Isolates high voltage *Provides a means to cool the tube *Leakage Rad: must not exceed 100 mR/hr at 1 meter *Dielectric oil: used to fill the space b/w the glass envelope and the tube housing; has expandable gasket *Oil insulates and absorbs head *Mounted cooling fan: helps remove heat |
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Tube: Major Parts
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Cathode
Anode Glass Envelope Focusing Cup Window/Port Filament Connecting Wires Anode Stem Focal Spot |
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Three Things Needed for X-ray Production
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1. Source of electrons (Filament on cathode)
2. Force to move the e- across the tube gap (kV) 3. Area to stop e- (focal spot on anode) |
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X-rays and Heat
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Heat= 99.8% X-rays= 0.2%
Tube is cooled by two methods: 1. Conduction - transfer of heat to another area 2. Thermal radiation - transfer of heat thru infrared radiation |
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Four Qualities of Radiography
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Geometric Qualities:
*Recorded Detail *Distortion Photographic qualities: *Density *Contrast |
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Recorded Detail & Distortion
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Recorded Detail: the sharpness of details in image
*Depends on OID, SID, EFSS, Film/Screen speed Distortion: misrepresentation of anatomic structures on the recorded image; size & shape *Depends on: OID, SID, tube-part alignment |
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mAsdn
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mAs: milliamperage per second
d: density n: number (quaNtity) of radiation mAs controls film density |
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KCCL
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K: kVp
C: controls C: contrast L: quaLity of radiation (energy; penetrating power of x-rays) |
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Density
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*Must use optimum kV level then adjust mAs according to pt thickness
*No amt of mAs can compensate for lack of kVp *Film too light: needs more mAs *Film too dark: needs less mAs *As mAs /\ , Density /\ *As mAs \/ , density \/ |
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High kVp
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Short wavelengths
More penetrability Long scale contrast Low contrast Many shades of gray B/////////////////////////W |
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Low kVp
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Long wavelengths
Less penetrability Short scale contrast High contrast Blacks to white with few shades of gray B /// W |
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Subject Contrast
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The range of differences in the x-ray beam after it attenuates the patient
Dependent on: 1. kVp (mainly) 2. Amount of area irradiated 3. Type of material irradiated |
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Film Contrast
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The range of densities that the IR is capable of recording
Dependent on: 1. Intensifying screens 2. Film density 3. H&D curve 4. Processing |
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High Contrast
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Few shades of gray
Increased contrast Low kVp Short scale contrast |
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Low Contrast
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Many shades of gray
Decreased contrast High kVp Long scale contrast |
