Term
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Definition
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Term
| Date x-rays were discovered |
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Definition
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Term
| What was the paper Roentgen presented to the Wurzburg Physico-Medical Society? |
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Definition
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Term
| Who is credited with inventing the fluoroscope? |
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Definition
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Term
| The first death in the United States due to x-radiation poisoning was _______. |
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Definition
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Term
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Definition
center of the atom;
contains the protons and neutrons |
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Term
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Definition
contained in the nucleus;
positive electrical charge;
their number (Z) determines the element |
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Term
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Definition
contained in the nucleus;
no charge;
neutron + protons = mass of the atom |
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Term
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Definition
orbit the nucleus;
have a negative electrical charged |
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Term
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Definition
the electrons' orbiting pathway around the nucleus;
labeled k, l, m (inner most first, outward) |
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Term
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Definition
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Term
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Definition
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Term
| A balanced atom has an equal number of _______. |
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Definition
| protons, neutrons, and electrons |
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Term
| If an atom is missing an electron it is called a(n) _______. |
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Definition
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Term
| If an atom has fewer or greater number of neutrons than protons it is called a(n) _______. |
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Definition
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Term
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Definition
the ability to do work;
moving an object against a resistance |
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Term
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Definition
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Term
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Definition
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Term
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Definition
energy in motion;
radiating |
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Term
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Definition
| the removal of electrons from an atom |
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Term
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Definition
energy that has sufficient energy to ionize;
requires a very high frequency and is what makes it dangerous since it can cause biological damage |
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Term
| properties of electromagnetic radiation |
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Definition
travel in a waveform;
travel at the speed of light;
has no mass or charge;
can ionize |
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Term
| 2 examples of electromagnetic radiation |
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Definition
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Term
| properties of particulate radiation |
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Definition
have mass and charge;
can ionize |
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Term
| 2 examples of particulate radiation |
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Definition
| alpha particles & beta particles |
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Term
| characteristics of x-rays |
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Definition
invisible ionizing photons
no mass or charge
travel in a waveform at the speed of light
travel in a straight but diverging path
highly penetrating
poly-energetic
energy is related to frequency
higher frequency = greater energy = greater penetration
can cause certain crystals to fluoresce (emit a light) |
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Term
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Definition
negative side of the tube;
contains the filaments |
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Term
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Definition
| when heated become the source of free electrons, forming the electron cloud |
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Term
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Definition
positive side of the tube;
contains the focal track |
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Term
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Definition
a separate electrical circuit from the tube circuit;
responsible for heating the filament to the point of thermionic emission |
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Term
| composition of the filament |
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Definition
| 98% tungsten & 2% thorium (thorated tungsten) |
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Term
| size of filament determines? |
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Definition
The electron beam size;
which determines the actual FSS;
which determines the effective FSS
which in turn determines spatial resolution |
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Term
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Definition
| to provide free electrons by thermionic emission |
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Term
| thermionic emission point of tungsten |
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Definition
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Term
| melting point of tungsten |
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Definition
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Term
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Definition
| enlarging of the electron cloud size due to the electrons repelling each other |
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Term
| composition of the focusing cup |
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Definition
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Term
| function of the focusing cup |
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Definition
controls blooming;
has greater negative charge than the total negative charge of the electron cloud;
compresses the electron cloud |
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Term
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Definition
| space between the filament and focal track |
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Term
| What determines the speed of the electrons traveling from the cathode to the anode? |
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Definition
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Term
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Definition
| tungsten & rhenium focal track embedded in a molybdenum disk, with a graphite backing |
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Term
| composition of the focal track |
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Definition
90% tungsten & 10% rhenium;
provides the surface for the bombardment of electrons, creating x-rays |
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Term
| purpose of the anode spinning |
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Definition
| increases surface area of the focal track; dissipates heat |
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Term
| bevel of the anode & reason |
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Definition
| 12 -14 degrees, needed to cover a 17" field of view (FOV) at 40" SID |
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Term
| function of the graphite backing of the anode |
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Definition
lowers the mass of the anode;
dissipates heat |
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Term
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Definition
axel of the anode;
made of molybdenum |
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Term
| description & function of the rotor |
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Definition
half of an induction motor;
located inside the glass envelope;
spins the anode; 3,400 rpm |
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Term
| description & function of the stator |
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Definition
half of an induction motor;
outside the glass envelope;
remains stationary |
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Term
| glass envelope composition and function |
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Definition
Pyrex glass;
vacuum sealed to remove air molecules |
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Term
| tube hosting characteristics |
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Definition
| lead line to prevent radiation leakage |
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Term
| purpose of circulating oil |
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Definition
| electrical insulation & heat dissipation |
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Term
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Definition
| path of electrical current flow |
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Term
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Definition
| number of electrons flowing in a circuit |
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Term
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Definition
aka electromotive force (emf) or potential difference;
the push behind the electron moving in an electrical circuit |
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Term
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Definition
| anything that impedes electrical flow |
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Term
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Definition
| unit of measure of all electron charges in a given area |
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Term
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Definition
explains the relationship of voltage (V), amperage (I), and resistance (R);
expressed as V=IR; I = V/R; R = V/I |
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Term
| series circuit (recognize) |
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Definition
Current/electrons has only one route;
the electrical current must go through 1st “load” to get to 2nd load |
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Term
| parallel circuit (recognize) |
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Definition
| has an alternate route; does not have to go through 1st “load” (light bulb) to get to 2nd load (light bulb) |
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Term
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Definition
flows in one direction;
voltage is constant;
cannot be transformed, i.e., cannot be changed for low to high voltage or vice-versa |
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Term
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Definition
flows in alternating (back & forth) directions;
has a negative alternation;
voltage is constantly fluctuating;
can be transformed, i.e., changed from low to high voltage or vice-versa |
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Term
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Definition
| electron movement (e.g., current) sets up a surrounding electromagnetic field; |
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Term
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Definition
| when one conductor induces a current to flow in a second conductor |
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Term
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Definition
| when the loops of a coiled conductor induces an opposite current in the other loops near it |
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Term
| order of tube (high-voltage) circuitry |
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Definition
| line voltage - auto-transformer - high-voltage transformer - rectifier - tube |
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Term
| order of filament circuitry |
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Definition
| line voltage - step-down transformer - rheostat (mA selected) - filament |
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Term
| components located on the primary side of the tube circuit |
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Definition
line voltage;
filament circuit;
control panel;
auto-transformer;
1⁰ side of high-voltage transformer |
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Term
| components located on the secondary side of the tube circuit |
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Definition
2⁰ side of high-voltage transformer; rectifier;
cathode;
anode |
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Term
| step-up transformer & recognize |
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Definition
converts low-voltage into high-voltage;
has more turns on the secondary side than on the primary side;
has a fixed ratio;
works by mutual induction |
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Term
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Definition
converts high-voltage into low-voltage;
has more turns on the primary side than the secondary side;
work by mutual induction |
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Term
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Definition
primary and secondary turns (wires) are the same;
can varying ratios;
steps down line voltage before it goes to the high-voltage transformer |
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Term
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Definition
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Term
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Definition
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Term
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Definition
conductor that allows electrical flow in only one direction;
used in rectifiers |
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Term
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Definition
| device that converts AC into pulsating DC |
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Term
| recognize self-rectification waveform & know ripple |
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Definition
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Term
| recognize half-wave rectification waveform & know ripple |
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Definition
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Term
| recognize full-wave rectification waveform & know ripple |
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Definition
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Term
| recognize a three-phase waveform & know the ripple for a 6-pulse and a 12-pulse |
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Definition
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Term
| recognize a high-frequency (H-F) waveform & ripple |
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Definition
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Term
| What happens when mA is increased? |
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Definition
resistance in the filament increases and more
electrons are boiled off, making the electron cloud larger |
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Term
| What percent of the kinetic energy crossing the tube is converted into light & heat? |
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Definition
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Term
| What percent of the kinetic energy crossing the tube is converted into x-rays? |
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Definition
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Term
| What happens when kVp is increased? |
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Definition
| faster the electrons cross the air gap and the harder they collide with the focal track, creating stronger x-rays |
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Term
| describe Bremsstrahlung x-ray production |
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Definition
high speed negative electron comes near the positively charged nucleus and the electron is pulled off it path;
to change direction the electron must break, which creates an x-ray |
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Term
| What factors determine the energy level of a Brems x-ray photon? |
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Definition
kVp;
energy of the incident electron (random);
how close the incident electron is to the nucleus when it is pulled off course |
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Term
| describe characteristic x-ray production |
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Definition
an incident electron collides with a k-shell electron of an atom;
if the incident electron's energy is greater than the k-shell electron's binding energy (the energy needed to hold it in its orbit) it dislodges its;
an l-shell electron drops into the k-shell hole, but to drop into the k-shell, the l-shell electron must slow down;
in order to slow down, its excess energy creates and x-ray |
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Term
| What is the binding energy of tungsten's k-shell electron? |
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Definition
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Term
| What is the binding energy of tungsten's l-shell electron? |
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Definition
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Term
| What is the energy of a characteristic x-ray photon? |
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Definition
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Term
| What type of x-rays are produced at below 70 kVp? |
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Definition
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Term
| What type of x-rays are produced at or above 70 kVp? |
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Definition
| Brems (90%) & characteristic (10%) |
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Term
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Definition
number of x-rays produced;
determined by mAs |
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Term
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Definition
| the average energy level of the x-ray photons (i.e., its penetrating ability); determined by kVp |
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Term
| What is it that the FSS controls? |
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Definition
| determines spatial resolution (detail) |
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Term
| the relationship between mA and patient exposure |
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Definition
mA – direct (proportional)
↑ mA ↑ patient exposure
↓ mA ↓ patent exposure |
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Term
| the relationship between time (s) and patient exposure |
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Definition
time – direct (proportional)
↑ s ↑ patient exposure
↓ s ↓ patient exposure |
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Term
| the relationship between mAs and patient exposure |
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Definition
mAs – direct (proportional)
↑ mAs ↑ patient exposure
↓ mAs ↓ patent exposure |
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Term
| relationship between kVp and patient exposure |
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Definition
kVp = inverse
↑ kVp ↓ patient exposure
↓ kVp ↑ patient exposure |
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Term
| relationship between SID and patient expsoure |
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Definition
if not compensated for - inverse to the square of the distance
↑ SID ↓ patient exposure
↓ SID ↑ patient exposure
if compensated for, no change |
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Term
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Definition
| number of x-ray photons in the beam; quantity |
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Term
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Definition
x-ray photons that have exited the tube, but have not hit the patient;
aka incident beam |
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Term
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Definition
x-ray photons that have exited the tube, but have not hit the patient;
aka primary beam |
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Term
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Definition
x-ray photons that exit the patient, but have not hit the IR;
aka exit beam |
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Term
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Definition
x-ray photons that exit the patient, but have not hit the IR;
aka secondary beam |
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Term
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Definition
decrease in the number of x-ray photons in the 1⁰ beam as it goes through the patient and becomes the 2⁰ beam
1⁰ beam minus 2⁰ beam = attenuation;
absorbed dose + scattered that misses the IR are the reasons for attenuation |
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Term
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Definition
photons pass through the patient unaffected;
image carrying photons, “the good stuff” |
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Term
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Definition
photons collide with atoms within the photons collide with patient’s tissue and changes direction;
called scatter |
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Term
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Definition
photons that transfer all their kinetic energy into the tissue;
patient dose |
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Term
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Definition
misdirected x-rays due to collision with an atom's electrons;
is the source of exposure to the radiographer |
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Term
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Definition
removes the "soft" weak photons ("hardening the beam");
the purpose of filtration is to save the patient exposure to weak photons that have no opportunity to penetrate to the IR |
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Term
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Definition
filtration done by the components of the tube
glass
circulating oil
mirror |
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Term
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Definition
| filtration that is added by the manufacturer; sheets of aluminum |
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Term
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Definition
| inherent filtration + added filtration |
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Term
| relationship between attenuation and part thickness |
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Definition
↑ tissue thickness (more atoms stacked)
↓penetration
↑ absorption
↑ scatter |
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Term
| relationship between attenuation and part denseness |
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Definition
↑ tissue denseness (more atoms packed together)
↓penetration
↑ absorption
↑ scatter |
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Term
| 3 types of interaction with x-ray photons and tissue |
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Definition
coherent (classical)(Thompson) scattering
Compton (incoherent) scattering
photoelectric (effect) absorption |
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Term
| describe coherent or Thompson or classical scatter |
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Definition
incident x-ray photon collides with an outer shell electron;
electron absorbs all the incident photon’s energy;
electron vibrates due to its excess energy;
rids itself of the excess energy by emitting an x-ray photon;
the secondary x-ray has the equal energy as the incident photon (no net loss of energy), but is now traveling in a different direction |
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Term
| describe Compton scattering |
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Definition
| incident x-ray photon interacts with an outer shell electron; outer shell electron does not absorb all the photon’s energy, but it does absorb enough energy to be ejected from its orbit; ejected electron is called a recoil or a Compton electron; the x-ray photon, with its degraded energy, continues in a different direction |
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Term
| describe photoelectric effect (absorption) |
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Definition
an incident photon interacting with an inner shell electron, usually in the k-shell;
the inner shell electron absorbs all the energy of the incident photon;
causes the k-shell electron to be ejected from its orbit;
the ejected electron is called a photoelectron;
an l-shell electron moves in to fill the hole left in the in the k-shell, l-moves into m-shell, and so forth;
each time an electron shifts it must slow down, and to do so it creates an x-rays;
the incident x-ray's energy is divided over the weaker created x-rays and they are absorbed by the patient |
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Term
| difference between characteristic x-ray production and photoelectric effect (absorption) |
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Definition
characteristic x-ray production is an interaction between an incident electron and a k-shell electron in the anode;
photoelectric effect is an interaction between an incident x-ray photon and a k-shell electron inside the patient |
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Term
| relationship between Zeff and attenuation |
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Definition
↑ tissue Zeff (the larger atoms)
↓ penetration
↑ absorption
↑ scatter |
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Term
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Definition
during a photoelectric absorption, the movement of the l-shell electron into the k-shell hole, then the m-shell electron into the l-shell hole, etc.;
this shifting is called the cascade effect |
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Term
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Definition
during a photoelectric absorption, several x-rays are created by the shifting electrons moving into vacant hole;
the total energies of these x-rays is called fluorescent yield |
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Term
| 6 radiographic quality factors |
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Definition
IP exposure (indicator number)
Brightness (density)
Contrast (dynamic range)
Spatial resolution (detail)
Noise
Distortion |
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Term
| indicator numbers (indices) |
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Definition
a number determined by the digital processor which indicates the amount of exposure to the IP;
the only way to tell if the IP is properly exposed |
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Term
| 8 factors that affect IP exposure |
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Definition
mAs (mA & s)
kVp
SID
OID
filtration
beam restriction (collimation)
patient factors
anode heel affect |
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Term
| 4 patient factors that affect IP exposure |
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Definition
part thickness
part denseness
Zeff
pathology |
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Term
| What is the relationship of mAs to IP exposure? |
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Definition
direct proportional relationship
Direct – both move in the same direction
↑ mAs ↑ IP exposure
↓ mAs ↓ IP exposure
proportional – both move in equal amounts
double mAs – double IR exposure
halve mAs – halve IP exposure |
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Term
| What is the relationship of kVp to IP exposure? |
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Definition
direct relationship
Follows the 15% rule
↑ kVp by 15% ↑ IP exposure by 100%
↓ kVp by 50% ↓ IP exposure by 50% |
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Term
| What is the relationship of SID to IP exposure? |
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Definition
inverse relationship
follows the inverse-square law
if not compensated for:
↑ SID ↓IP exposure
↓ SID ↑IP exposure
if compensated for, no affect on IP exposure |
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Term
| inverse-square law (defintion) |
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Definition
intensity of the beam is inversely proportional to the square of the distance
if not compensated for:
double SID = intensity decreases to 1/4
half SID = intensity increase by factor of 4
if compensated for:
double SID = increase mAs x 4
halve SID = decrease mAs to 1/4 |
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Term
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Definition
non-compensating formula
id2 x ID2
like goes with like
compensating formula
iD2 x Id2
if you need to change your mAs to compensate, change their partners |
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Term
| What is the relationship of SID to IP exposure? |
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Definition
inverse relationship
↑ OID ↓ IP exposure
↓ OID ↑ IP exposure |
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Term
| Why does the inverse-square law work? |
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Definition
| the divergence of the beam "thins" the beam |
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Term
| Why does the (OID) "air-gap" technique |
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Definition
as OID increases the angle of deflection needed for scatter to miss the IR becomes less and less
"scatter pie" |
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Term
| What is the relationship between OID and IP exposure? |
|
Definition
inverse relationship
↑ OID ↓ IP exposure
↓ OID ↑ IP exposure |
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Term
| What relationship does field size have on IP exposure? |
|
Definition
direct relationship
↑ field size ↑ IP exposure
↓ field size ↓ IP exposure |
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Term
| What relationship does filtration have on IP exposure? |
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Definition
inverse relationship
↑ filtration ↓ IP exposure
↓ filtration ↑ IP exposure
Why? filtration by definition is to "remove" |
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Term
| What relationship does anode heel effect have on IP exposure? |
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Definition
| intensity of the beam is greatest under the cathode - "fat cat" |
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Term
| What relationship does part thickness have on IP exposure? |
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Definition
inverse relationship
↑ part thickness ↑ atoms ↓ IP exposure |
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Term
| What relationship does part denseness have on IP exposure? |
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Definition
inverse relationship
↑ part denseness ↑ atoms ↓ IP expos |
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Term
| What relationship does part's Zeff have on IP exposure? |
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Definition
inverse relationship
↑ part Zeff ↑ size of atoms ↓ IP exposure |
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Term
| What relationship does pathology have on IP exposure? |
|
Definition
additive pathologies ↑ atoms ↓ IP exposure
subtractive pathologies ↓ atoms ↑ IP expsoure |
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