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RT 20 Final 2014
CH's 2-6 part of 7 to Pg128
| Question | Answer |
|---|---|
| The strength of attachment of an electron to the nucleus | electron binding energy |
| An x-ray photon is a quantum of | electromagnetic energy |
| is one half the range from crest to valley over which the sine wave varies | amplitude |
| the number of wavelengths that pass a point of observation per second | Frequency |
| the properties of electromagnetic energy include | frequency, wavelength, velocity, and amplitude. |
| the reduction in intensity htat results from scattering and absorption | attenuation |
| structures that absorb x-rays are called | radiopaque |
| structures that transmit x-rays are called | radiolucent |
| the study of stationary electric charges | electrostatics |
| the quantity of matter as described by its energy equivalence | Mass (Kg) |
| the ability to do work | energy |
| energy is measured in | Joules (j) |
| In radiology, the Unit or energy is oftened used is known as | Electron Volt (eV) |
| Theory first described by Einsten that matter and energy are interchangeable | Theory of Relativity |
| energy emitted and transferred through space | radiation |
| Natural environmental radiation annual dose | 3 mSv |
| currently accepted approx. annual dose resulting from medical applications of ionizing radiation is | 3.2 mSv |
| X-rays accidentally discovered by Wilhem Roentgen on | Nov. 8, 1895 |
| roentgen discovered x-rays by while experimenting with | a type of crookes tube while trying to visualize cathode rays. |
| 3 general types of x-ray exams | Radiography, fluoroscopy, and computed tomography. |
| to provide an x-ray beam that is satisfactory for imaging,you must supply an x-ray tube with a | high voltage and an electric current |
| x-ray voltages measure in | kilovolt peak kVp |
| the first recorded death from x-ray in 1904 was | thomas edisons research assistant clarence Dally. |
| one unit of negative electric charge, fixed orbits, and atomic mass number is 0 | electron |
| one unit of positive electric chargem atomic mass number is 1 | proton |
| carries no charge, atomic mass number is 1 | neutron |
| unstable atoms that have an unstable nucleus that spontaneously emits particles and energy ans transforms itself into another atom in the process | radioactive decay |
| 2 ways for radioisotopes to decay are by | beta (more frequent) and alpha emissions. |
| the time for a quanitity of radioactivity to be reduced to one half its original value is | radioactive half life |
| radioactive material never quite reaches | 0 |
| x-rays and gamma rays are called_____ and have no_____or______ | photons, charge or mass. |
| travel at the speed of light and are considered enery disturbances in space. | photons |
| only difference between x-rays and gamma rays is | thier origin |
| electromagnetic energy exists over a wide range called an | energy continuum |
| speed and direction in which an object moves. | velocity |
| the energy of a photon is ______ perportional to its frequancy | directly |
| unlike charges_____: like charges______ | attract,repel |
| law that states when force is strong close together and decreases rapidly when separates | coulomb's law |
| electric charge is distributed______ throughout a surface. | uniformly |
| electric charge of a conductor is concentrated along | sharpest curvature of the surface |
| the study of electric charges in motion | electrodynamics |
| any substance in which electrons flow easily | conductor |
| any material that does not allow electron flow | insulator |
| materials that under some conditions act as an insulator and in other conditions act as a conductor | semiconductor |
| the property of some materials such as titanium to exibit no resistance to electron flow below a critical temperature | superconductor |
| the three principal parts of an x-ray imaging system | x-ray tube, operating console, and high voltage generator |
| refers to the number of x-rays or the intensity of the x-ray beam | radiation guantity (mGya) |
| refers to the penatrability of the x-ray beam and is expressed in Kilovolt peak or more precisely, HVL | Radiation quality |
| measures he voltage provided to the x-ray imaging system and adjusts that voltage to precisely 220 V. | Line Compensator |
| has a single winding and is designed to supply a precise voltage to the filament circuit and to the high-voltage circuit of the x-ray imaging system. | Autotransformer |
| Determines the quality of the x-ray beam | kVp |
| the x-ray tube current crossing from cathode to anode is measured in | milliamperes mA |
| the number of electrons emitted bt the filament is determined by | the temperature of the filament |
| the filament temperature is controlled by the | filament current |
| is the release of electrons from a heated filament | thermionic emission |
| guards against exessive radiation exposure and electric shock, mechanical support, and rough handling | protective housing |
| x ray that escape through the protective housing are called | leakage radiation |
| when x-rays are produced they are emitted isotropically, that is they are emitted | with equal intensity in all directions |
| _____or_____ ______ matiains a vacuum inside the tube that alows for more efficient x-ray production and longer tube life | glass or metal enclosure |
| the negative side of the x-ray tube | cathode |
| two primary parts of the cathode are | filament and focusing cup |
| a coil of wire approx 2mm in diameter and 1 to 2 cm long usually made of tungsten | filament |
| the most common cause for tube failure is | tungsten vaporization with deposition on the inside of the glass enclosure. |
| is negatively charged so that it electrostatically congines the electron beam to a small area of the anode, where the filament is embedded | focusing cup |
| a cloud of electrons formed around the filament that makes it difficult for subsequent electrons to be emitted bt teh filament, | space charge |
| the positive side of the x ray tube, conducts electricity, radiates heat, and contains the target | anode |
| atomic number of tungsten is | 74 |
| the atomic number of molybdenum | 42 |
| the atomic number of rhodium | 45 |
| results in a an effective focal spot size being much less than the actual focal spot size | line focus principle |
| results in a smaller effective focal spot and less radiation intensity on the anode side of the x-ray beam | heel affect |
| The most frequent cause of abrubt tube failure is | electrons arcing from the filament to the enclosure because of vaporized tungsten. |
| energy in motion | kinetic energy |
| electrons travel from | cathode to anode |
| electrons traveling from cathode to anode constitute the x-ray tube current and are sometimes called | projectile electrons |
| approximately 99% of the kinetic energy of projectile electrons is converted to | heat |
| approximately 1% of the projectile electron kinetic energy is used for | x-ray production |
| in the diagnostic range, heat production increases directly with increasing | kVp |
| the production of heat in the anode increases directly with increasing | x-ray tube current |
| if the projectile electron interacts with an inner shell electron of the target atom rather than an outer shell electron | characteristic x-rays can be produced |
| are emitted when an outer shell electron fills and inner shell void | charactaristic x-rays |
| only the ____ charactaristic x-rays of tungsten are useful for imaging | K |
| produced when a projectile electron is slowed bt the nuclear field of a target atom nucleus | bremsstrahlung x-rays |
| in the diagnostic range, most x-rays are | bremstrahlung x-rays |
| bremsstralung x-rays have a range of energies and form a | continuous emission spectrum |
| max x-ray energy is associated with the minimum | x-ray wavelength |
| A change in mA or mAs results in a proportional change in the_______ of the xray emission spectrum | amplitude |
| how does filtration effect the emission spectrum? | Decreases amplitude shifts to right |
| if filter thickness is reduced, x ray is | increased |
| changes in ________ result in Directly proportional changes in the amplitude of the emission | MA/time |
| efficiancy of x-ray production increases as_____ increases | kvp |
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