Glossary of Quiz Bowl I

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The many different types of x-ray machines are usually identified according to what?
either the energy of the x-rays they produce, or the purpose for which those x-rays are intended
What are the maximum voltages in which an x-ray machine usually operates?
25 to 150 kVp
What are the maximum tube currents in which an x-ray machine usually operates?
25- 1200 mA
Every x-ray machine, regardless of its design, has 3 principal parts.
X-Ray tube
High voltage section or generator
Control Console
What are the 2 primary parts of an x-ray tube?
What are the 2 primary components of an x-ray tube, also known as?
Any tube with 2 electrode is called what?
What 2 serious hazards that plagued early radiology is the protective housing designed to control?
Excessive radiation exposure
Electric shock
What is the term used to describe when x-rays are emitted with equal intensity in all directions?
What is the espically designed port in which the useful beam is emitted through?
What are the x-rays called which are emitted through the window?
useful beam
What are the x-rays which penetrate through the protective housing?
Leakage radiation
When operated at maximum conditions, a properly designed protective housing reduces the level of leakage radiation to what?
Less than 100mR/hr at 1 meter
The protective housing incorporates specially designed high-voltage receptacles to protect aganist which?
Accidental electric shock
The protective housing also provides what for the x-ray tube and protects the tube from damage caused by rough handling?
Mechanical support
What purpose does the oil in the protective housing around some x-ray tubes serve as?
Electrical insulator
Thermal cushion
What is the purpose of the glass envelope?
Maintain a vacuum inside the tube
What is the purpose of the vacuum inside the tube?
Allows for more efficient x-ray production
Longer tube life
What does the thin window of the glass envelope serve to do?
Allows for maximum emission of x-rays with minimum absorption in the glass
What are the 2 primary parts of the cathode
Focusing Cup
What is the phenomenon in which the current through the filament is sufficiently and the outer-shell electrons of the filament atom are literally boiled off and ejected from the filament?
Thermionic emission
What are the filaments usually made of?
Thoriated tungsten
What is the melting point of tungsten?
What are the advantages of using tungsten for the filament?
Higher thermionic emission
Greater melting point
Does not vaporize easily
What is the most common cause of tube failure?
when the tungsten metal eventually does vaporize and plate out on internal components
What is the metal shroud in which the filament is embedded in?
Focusing cup
What is the effectiveness of the focusing cup determined by?
It's size and shape
It's charge
Filament size & shape
Position of filament within the focusing cup
In the grid controlled x-ray tube, what is the focusing cup?
The Grid
The relationship between filament current and tube current is dependent on what?
Tube voltage
How is the x-ray tube current adjusted?
By controlling the filament current
What is the cloud about the filament in which the negatively charged electrons momentarily remain?
Space charge
What is the phenomenon in which space charge makes it difficult for subsequent electrons to be emitted by the filament because of electrostatic repulsion?
Space-charge effect
X-Ray tubes under certain conditions of low kVp and high mA are said to be what?
Space-charge limited
What is it said to be when a diagnostic x-ray tube has 2 focal spots?
Dual-focus tube
What are the 2 types of anodes?
Stationary & Rotating
What type of anode is capable of producing high-intensity x-ray beams in a short time?
Rotating anode
What type of anode is used in dental x-ray machines, portable machines & other special purpose units where high tube current & power are not required?
Stationary anode
What are the 3 functions in which the anode serve?
Electrical conductor
Mechanical support of target
Thermal conductor
What is the most common anode material?
What is the area of the anode struck by the electrons from the cathode?
In which type of anode does the target consist of a tungsten-alloy metal embedded in the copper anode?
For what 3 main reasons is tungsten the material of choice for the target?
High atomic number
Thermal conductivity
High melting point
Most rotating anodes revolve at how many revolutions per minute?
What drives the rotating anode?
Electromagnetic induction motor
What are the 2 principal parts of the electromagnetic induction motor?
Stator & rotor
In which type of anode is the entire rotating disc the target?
Rotating anode
The part of the eletromagnetic induction motor outside of the glass envelope consists of a series of electromagnets equally spaced around the neck of the tube is known as?
What is the mechanism inside the glass envelope and is a shaft made of bars of copper and soft iron, fabricated into one mass?
What is the area of the target from which x-rays are emitted?
Focal spot
What is the principle which allows for high anode heating with small effective focal spots?
Line-focus principle
What is the effective target area projected onto the patient and the film?
Effective focal spot size
What is the advangtage of the line-focus principle?
It simultaneously provides the sharpness of image for a small focal spot and the heat accommodation of a large focal spot.
What is one unfortunate consequence of the line-focus principle?
The radiation intensity on the cathode side of the x-ray field is higher than that on the anode side.
Because of increased absorption, the intensity of the x-rays that penetrate the 'heel' of the target is lower than that of those that penetrate the 'toe' is known as what?
Heel effect
When should the heel effect be considered in radiography?
when radiographing anatomic structures of greatly different thickness or densities.
What is the appratus that allows the technologist to control the x-ray tube current and voltage so that the useful x-ray beam is of proper intensity and penetribility for producing a good quality radiograph?
Operating Console
What device incorporates a meter to measure the voltage provided to the unit and a switch to adjust that voltage to precisely 220V?
Line compensator
What device is designed to supply voltage of varying magnitude to the several different circuits of the x-ray machine, most prominently the filament circuit and the high-voltage circuit?
What principle does the autotransformer work on?
Electromagnetic self induction
Because the autotransformer operates as an induction device, the voltage it receives (primary)and the voltage it provides (secondary) are in direct relation to the number of turns of the autotransformer enclosed by the respective taps. This is known as w
Autotransformer Law
What type of meter is it will register even though an exposure is not being made and no current is flowing in the circuit?
Pre-reading voltmeter
The x-ray tube current, the number of electrons crossing from cathode to anode is measured in what?
Milliamperes (mA)
What are the 5 basic types of timing circuits?
Mechanical timing
Synchronous timing
Eletrical timing
mAs timers
What kind of timer is not used only in some portable and dental units?
Mechanical timers
What kind of timer cannot be used for serial exposures because they must be reset after each exposure, which, even when done automatically, requires too much time?
Synchronous timers
What kind of timer is the most accurate and consists of rather comlex circuitry based on the time required to charge a capacitor through a variable resistor?
Electrical timers
What kind of timer monitors the product of mA and time and terminates the exposure when the desired mAs is obtained?
mAs timer
What is the device that measures the quantity of radiation reaching the film and automatically terminates the exposure when sufficient radiation to provide the required film density has reached the film?
Name a critical component of 2 different types of phototimers?
Ionization chamber sensing device
What device should be used as a back-up timer when using phototimer in case the phototimer fails to terminate?
Manual timer
What is the simple device that can be used to check x-ray timers?
Spinning top
What device can be helpful to assessing timer accuracy for all but the shortest of exposure times with 3-phase or capacitor-discharge x-ray machines?
Synchronous spinning top
What devices are now used for most timer checks and are capable of measuring exposure times as short as 1ms?
Solid-state radiation detectors
What section of an x-ray machine is responsible for converting the low-supply voltage into a kilovoltage of the proper waveform?
High-voltage section
High-voltage generator
What are the 3 primary parts of the high-voltage generator?
High-voltage step-up transformer
Filament transformer
What is it known as when the secondary (induced) voltage is greater than the primary (supply) voltage because the number of secondary windings is greater than the number of primary windings?
High-voltage step-up transformer
What is the ratio of the number of secondary windings to the number of primary windings?
Turns ratio
According to what law is the voltage increased proportional to the turns ratio law?
Transformer Law
What is the only difference between the primary and secondary waveforms?
What is the primary voltage measured in?
What is the secondary voltage measured in?
What is the process of converting alternating voltage into direct voltage and therefore, alternatin current into direct current?
Rectification is accomplished with 2 devices called what?
Diodes (2 electrodes)
What were all diode rectifiers, which were vacuum tubes and were very similar to x-ray tubes, previously called?
Valve tubes
What has the valve tube been replaced with in nearly all x-ray machines?
Solid-state rectifers made of silicon
What is the voltage across the x-ray tube during the negative half-cycle and is harmful to the x-ray tube?
Inverse voltage
What represents a condition in which the voltage is not allowed to swing negatively during the negative half of its cycle?
Half-wave rectification
What is it known as when the x-ray tube itself serves as the rectifying diode, in which case no diodes are found in the high-voltage circuit?
How is the x-ray output from a half-wave unit and how many pulses are produced each second?
Pulsating,60 x-ray pulses per second
how many diodes does the half-wave rectified circuit have?
Either 0, 1, or 2
How many diodes are contained in full-wave rectified x-ray machines?
At least 4 diodes in the high-voltage circuit
What type of circuit is the negative half-cycle corresponding to the inverse voltage and is reversed so that a positive voltage is always impressed across the x-ray tube?
Full-wave-rectified circuits
What is the main advantage of full-wave rectification?
The exposure time for any given technique is cut in half (½)
What is the principal advantage of 3-phase power?
Higher radiation quantity and quality resulting from the nearly constant voltage supplied to the x-ray tube
What is the principal disadvantage of 3-phase x-ray apparatus?
Initial cost
What are the 2 terms used in which the motion of an object maybe described?
Velocity and Acceleration
What is a measure of how fast something is going, or more precisely, the rate of change of its position with time?
Velocity or speed
What is the rate of change of velocity with time, that is, how 'fast' the velosity is changing?
What is Newton's 1st Fundamental Law of Motion?
A body will remain at rest or continue moving with a constant velocity in a stragith line unless acted by an external force. (If not force acts on an object, there will be no acceleration)
What is Newton's 2nd Fundamental Law of Motion?
A definition of the concept of force. "If a body of mass 'm' has an acceleration 'a', then the force on it is given by the mass times the acceleration. F= ma
What is Newton's 3rd Fundamental Law of Motion?
To every action there is an equal and opposite reaction
What is force on a body caused by the downward pull on gravity on it?
What is termed the constant rate at which objects falling to earth accelarate at?
Acceleration of gravity
What is the value of gravity on the moon?
only about 1/6 that on earth
What is the value of gravity in space?
How can the weight of an abject be determined?
From the product of its mass and the acceleration of gravity (Wt=mg)
The units of weight are the same as those for force, what are they?
newtons and dynes
What is the product of the mass of an object and its velocity called?
What does the Conservation of Momentum Law State?
The total momentum before any interaction is equal to the total momentum after the interaction
What is the equation for work?
Work = Fd where work done on an object is the force applied times the distance over which it is applied
What are the units of work?
joule (J) in SI and the erg in CGS
What does CGS represent?
Centimeters, grams, seconds
What does SI respresent?
The International System: 3 base units (Meter, Kilogram, seconds) and an additional 4: Derived units and special units
What are the SI units for special radiologic quantities?
Exposure, dose, dose equilivant, and activity
What are the special names in SI given to dose, dose equilivant, and activity?
gray (gr), seivert (Sv),and becquerel (Bq)
What is the rate of doing work?
What is the defining equation of power?
Power = work/time
What is the SI unit of power and is known as the watt (W)?
Joule/second (J/s)
What is the ability to do work?
What does the Law of Conservation of Energy state?
Energy maybe transformed from one form to another, but it cannot be created or destroyed; the total energy is constant
What are the 2 forms of mechanical energy often used in radiologic science?
Kinetic Energy (KE) and Potential Energy (PE)
What is the energy associated with the motion of an object?
Kinetic Energy (KE)
What is the stored energy of position of configuration?
Potential Energy (PE)
What is a form of energy that is highly important to the radiologic technologist and is defined as the random disordered motion of molecules?
What is the unit defined as the heat necessary to raise the temperature of 1g (gram) of water 1ºC?
In what 3 ways is heat transferred from one place to another?
Conduction, convection, thermal radiation
What is the transfer of heat by molecular motion from a high termperature?
What is a method of heat transfer that depends on the temperature of the object?
Thermal Radiation
What is the mechanical transfer of 'hot' molecules in a gas or liquid from one plae to another?
Temperature is normally measured with a reproducible scale called a thermometer. It is usually calibrated at what 2 reference points?
The freezing and boiling points of Water.
What are the 3 principal scales used to represent temperature?
Celsius, Farenheit, Kelvin
What is the boiling point of water in Celsius and Farenheit?
100ºC and 212ºF
What is the freezing point of water in Celsius and Farenheit?
0ºC and 32ºF
Today over 100 substances, or elements have been identified; how many are naturally occurring, and how many have been artificially produced in high-energy particle accelerators?
92 natural, 15 artificial
Who is credited with the 1st periodic table of the elements and what did they represent?
Dmitri Mendeleev; if elements were arranged in order of increasing atomic mass, a periodic repetition of similar chemical properties occurred.
In what year and by whom was the atom decsribed that is now accepted as the atomic model most representative of the true nature of mtter?
1913, Niels Bohr
What is the smallest portion of an element?
What is the smallest portion of a compound?
The nucleus contains particles called what?
What are the 2 types of nucleons?
protons & neutrons
What are the 3 primary constituents of an atom?
electron, neutron & proton
How can the maximum number of electrons that can exist in a shell be calculated?
2n² where n is the shell number, thus the maximum number of electrons that can exist in each shell increases with distance of the shell from the nucleus
What is the maximum number of electrons allowed in the outermost shell?
No outer shell can contain more than 8 electrons
What is the only difference between x-rays and gamma rays?
Where are gamma rays emitted from?
the nucleus of a radioisotope (and are usually associated with alpha and beta emission)
Where are x-rays produced?
outside the nucleus in the electron cloud
what are the 3 radiologically important atoms?
carbon, barium, & tungsten
What is strength of attachment of an electron to the nucleus?
Electron binding energy
In the neutral atom the number of electrons equals what?
The number of protons
What is an atomic number?
The number of protons in an atom.
What is the atomic mass number?
The number of protons plus the number of neutrons in the nucleus of an atom.
Atoms that have the same atomic number but different atomic mass numbers are called what?
Isotopes of a given atom contain what?
A fixed number of protons, but varying numbers of neutrons.
Atomic nuclei that have the same atomic mass number but different atomic numbers are called what?
What is the half-life of a radioisotope?
The period of time required for a quantity of radioactivity to be reduce to ½ it's original value.
What are the 2 catagories in which all ionizing radiation can be conviently classified into?
Alpha particles and Beta particles - both of which are associated with radioactive decay.
What is the alpha particle equilivant to and what does it contain?
A helium nucleus, contains 2 protons, 2 neutrons and no associated orbital electrons.
What are the alpha particles emitted from?
Only from the nuclei of heavy elements.
How do beta particles differ from alpha particles?
Mass and charge
Where are beta particles emitted from?
The nucleus of radioactive atoms
Name 2 forms of electromagnetic ionizing radiation often called photons.
x-rays and gamma rays
What is the only difference between beta particles and electrons?
What is the ever present field, or state, of energy all around us which exists over a wide range of magnitudes?
Electromagnetic energy
What is an uninterrupted (continued) ordered sequence?
What is an atom of light according to the ancient Greeks?
What is the smallest quantity of any type of electromagnetic radiation?
What are energy disturbances moving thorugh space at the speed of light?
What is the speed of light?
186,000 mps (miles per second), in the SI system of units c=3x100,000,000 (10 to 8th) m/s
What is the term used py physicists to describe the interaction between different energies, forces, or masses that can otherwise be described only mathematically?
What is the field that governs how different masses interact?
Gravitational field
What is the field that governs the interaction of electrostatic charges?
Electric field
What is the field that governs the interaction of magnetic poles?
Magnetic field
What is the current which consists of electrons moving back and forth sinusoidally thought a wire?
Alternating elecrtic current
What is the range from crest to valley over which sine waves vary?
What is the rate of rise and fall of the sine wave called?
What is the unit of measure for the frequency, usually identified as oscillations per second or cycles per second?
What is the number of crests or the number of valleys that pass the point of an observer per unit time?
What is the distance from one crest to another, from one valley to antoher, or from any point on the sine wave to the next corresponding point?
What are 3 wave parameters that nearly all that need to be known to fully describe a photon of electromagnetic radiation?
Velocity, Frequency, and Wavelength
What is the wavelength equation?
Velocity = Frequency X Wavelength
For electromagnetic radiation, are fequency and wavelength directly or inversely proportional?
Inversely proportional
As the frequenc of electromagnetic radiation increaces, what happens to the wavelength?
The wavelength decreases
When the wide range of values which covers many types of electromagnetic radiation are grouped together they make up the electromagnetic continuum. What is it also known as?
Electromagnetic spectrum
What are 3 portions of the electromagnetic spectrum most important to radiologic technologist?
Visible light, x-radiation, and high-frequency radio waves.
Name the other portions of the electromagnetic spectrum that are not most important to radiology technologist.
Ultraviolet & Infrared light, mocrowave radiation, & radio-braodcast
What is the only difference among photons of various portions of the electromagnetic spectrum?
Frequency & wavelength
Since the velocity of all electromagnetic radiation is constant, and the wavelength and frequency are inversely related, how is the energy conatined in each photon in relation to the photon frequency?
Directly proportional
Communication broadcasts are usually identified by their frequency of transmission and are called?
Radiofrequency emmissions (RF)
In what terms does an optic physicist describe photons of visible light?
What is the deviation in the line of travel of photons of visible light pass through one transparent medium to another?
What are the 2 types of invisible light contained in sunlight refracted through a prism?
Infrared & Ultraviolet
How is ionizing electromagnetic radiation characterized?
By the energy contained in a photon
What is the only difference between beta particle and electrons?
Their origin
Where do electrons come from?
Outside the nucleus
Where do beta particles originate from?
The nucleus
How is the visible light region of the electromagnetic spectrum imprtant to radiology?
Because of the conditions under which a radiolographic or flouroscopic image is viewed are critical to the ultimate description of diagnostic information
How has the radio-frequency region of the electromagnetic spectrum taken on an added importance to radiology?
With the introduction of MRI (Magnetic Resonance Imaging)
When both types of photons exhibit both types of behavior regarding how they interact with matter, the phenomenon is known as what?
Wave-particle duality of radiation.
What is another general way to consider the interaction of electromagnetic radiation with matter?
As a function of wavelength
What is the narrow portion of the electromagnetic spectrum?
Visible light
With visible light, the shorter the wavelength, the lesser or greater is the photon energy?
What is the partial absorption of energy called?
What are the 3 degrees in which objects absorb light?
Not at all (transmission), partially (attentuation), & completely (absorption)
What are the objects associated with the 3 degrees in which light are absorbed?
transparent, translucent, & opaque.
What are the structures that absorb x-rays called?
What are the structures that attenuate x-rays to a relatively small degree called?
The Inverse Square Law describes the relationship between what?
Radiation intensity and the distance from the radiation source.
what does that Inverse Square Law state?
The intensity of light is inversly proportional to the square of the distance of the object from the source
That x-ray photons are created at the speed of light and either exist with velocity or do not exist at all is one of the substantive statements of what?
Planck's quantum theory
The photon energy is directly proportional to the photon frequency. This constant of proportionality is known as what?
Planck's constant
The longer the wavelength of radiation, the higher or lower the energy of each photon?
Matter can neither be created nor destroyed, is a law known as?
The law of conservation of Matter.
Energy can be neither created nor destroyed is a law known as?
The Law of conservation of Energy.
What is the primary function of an x-ray machine?
Convert electric energy into electromagnetic energy.
How is electromagnetic energy converted into mechanical energy?
With a device known as an electric motor
How many units and what type of charge does the proton have?
1 unit of positive (+) charge
How many units and what type of charge does the electron have?
1 unit of negative (-) charge
What is the study of fixed, or stationary, electric charges?
What is the most familiar example of a fixed electric charge?
Static electricity
What is an object said to be if it has an insufficiency or an excess of electrons?
Name 3 ways electrification can be created.
Contact, friction or induction
State the 1st principal law of electrostatics.
Like charges repel; unlike charges attract.
Electrification occurs because of the movement of negative electric charges is a law of what?
What is it said to be when the earth behaves as a huge reservoir for deposit of stray electric charges?
An electric ground
Name 4 general laws of electrostatics which describe the way in which electric charges interact with each other and with unelectrified objects.
1. Unlike charges attrach; like charges repel
2. Coulomb's Law
3. Electric-charge distribution
4. Electric-charge concentration
What is the force of attraction between unlike charges or repulsion between like charges called?
An electrostatic force
List the 5 Effects of fetal irradiation
Prenatal death
Neonatal death
Cingential Malformation
Childhood malignancy
diminished growth & development
What is the study of the effects on ionizing radiation on biological tissue?
85% of the body is composed of what 2 elements?
Hydrogen & Oxygen
In what year and by whom was the first cell names the biologic building block?
1665, Robert Hooke
INi what year and by whom conclusively showed the cell to be the basic fundamental unit of all plants & animals?
1838, Schneider & Schwann
In what year and by whom was the molecular structure of DNA described as the genetic substance of the cell?
1953 Watson & Crick
What is the term used to describe very large molecules sometimes consisting of hundreds of thousands of atoms?
What are the principle classes of organic moelcules?
Proteins, Lipids & Carbohydrates
What is the rarest molecule considered to be the most radiosensitive target molecule?
What is the simplest and most abundant molecule in the body?
What is the most abundant molecular constituent of the body?
Water makes up what percent of the human body?
What is the concept of relative constancy of the internal enviroment of the human body?
What is the term used to describe the breaking down into smaller units?
What is the term used to describe the production of large molecules from small?
Anabolism and catabolism is collectively termed what?
What are long-chain macromolecules consisting of a linear sequence of amino acids connected by peptide bonds?
What are the molecules that are necessary in small quantities to allow a biochemical reaction to continue, even though they do not directly enter into the reaction?
What are molecules that exercise regulatory control over some body functions such as growth and development?
Hormones are produced and secreted by what 6 endocrine glands?
Pituitary, pancreas, parathyroid, thyroid, adrenal & gonads
What is an invasive or infectious agent?
What constitutes a primary defense mechanism of the body aganist infection and disease?
What are the organic macromolecules composed soley of carbon, hydrogen and oxygen & serve as thermal insulators from the enviroment and store energy?
What are 2 kinds of smaller molecules in which lipids are composed?
glycerol & fatty acid

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