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Radiology Test 1

QuestionAnswer
proton is mass and has positive 1 charge
neutron is no charge has mass
electron has smaller, negative 1 charge, has mass
what is binding energy? the amount of energy required to remove an electron from a given shell must exceed the electrostatic force of attraction between it and the nucleus
which shell would have the greatest binding energy? K because it is closest to the nucleus
what is an ion? charged particle either positive or negative
what is an ion pair? positive ion or negative ion
atom minus and electron would have what charge positive ion
a free electron would have what charge negative ion
an atom plus an electron would have what charge? negative ion
ionization is... process by which an electrically neutral atom loses or gains an electron and becomes electrically unbalanced the result of ionization is an ion pair
ionizing radiation is... capable of producing ions by removing or adding an electron to an atom such as X-rays
radiation definition is transmission of energy through space or matter
what are the two forms of radiation? particulate radiation electromagnetic radiation
what is particulate radiation? particles have mass and energy particles can be positive, negative, or neutral particles are moving at high velocity
what are some examples of particulate radiation? alpha particles beta particles cathode rays
what is electromagnetic radiation? has neither mass nor charge
what are some examples of electromagnetic radiation gamma rays, x-rays, ultraviolet rays, visible light, infrared radiation (heat), microwaves, radio waves
what are types of electromagnetic radiation? divided by energy: non-ionizing radiation and ionizing radiation
ionizing radiation is has enough energy to remove an orbital electron from an atom
what are ionizing rays? X-rays, ultraviolet, cosmic rays, gamma rays
what are the two theories that explain electromagnetic radiation? wave theory particle or quantum theory
wave theory is what? radiation is propagated in the form of waves consisting of electrical and magnetic fields oriented in planes at right angles to one another oscillating perpendicular to the direction of motion
what is wavelength? the distance from crest to crest or valley to valley or between points on consecutive waves
what is frequency? the number of waves passing a point in a unit of time
velocity = wavelength times frequency
short wavelength has... high frequency
long wavelength has... low frequency
what is quantum theory radiation is depicted as small bundles of energy called photons each photon travels at the speed of light and contains a specific amount of energy
SHH short wavelength, high frequency, high energy
LLL long wavelength, low frequency, low energy
the X-ray tube is made up of cathode anode
cathode is... negative
anode is... positive
power supply is made up of tube current and tube voltage
cathode is made up of tungsten filament and molybdenum focusing cup
what does the tungsten filament do? source of electrons heat releases electrons
what does the molybdenum focusing cup do? concave reflector that focuses the electrons it is not made of tungsten
cathode overall does what generates electrons, production of high speed electrons focusing electrons stopping of high speed electrons at the target
anode is composed of what? tungsten target copper stem
why do we use tungsten on the tungsten target? high atomic number, high melting point, high thermal conductivity low vapor pressure
what does the tungsten target do converts the kinetic energy of the electrons from the filament into x-ray photons
where are electrons generated anode tungsten target focal spot of anode tungsten target
what does the focal spot do? area on the target to which the focusing cup directs the electrons from the filament place that generates X-rays
the smaller the focal spot the sharpness of image increases the heat generated per unit increases
actual focal spot sits about how many degrees off target 20 degrees
what would you like to see for an x-ray machine in regards to actual and effective focal spot? smaller effective focal spot for increase in sharpness and image larger actual focal spot for heat dissipation
what does the copper stem do? good thermal conductor, dissipates heat from the tungsten
the glass envelope or tube does what? provides a vacuum environment withstands tremendous heat
what does the x-ray tube window do? allows the maximum emission of x-rays and minimum absorption by the glass
what does oil bath in older x-ray machines do? electrical insulator, thermal cushion disperse heat
what is the protective housing in x-ray machines lead lined metal casing provides mechanical support prevents excessive radiation exposure and electrical shock
what does the aluminum filter do in x-rays? remove low energy photons
what does a collimator do? limits x-rays to patient (7 cm) restrain size of x-rays
low voltage does what for x-ray machines from the cathode side, provides current and generate heat
high voltage does what for x-ray machines anode and cathode potential controls potential between them and how fast electrons travel
direct current is what? electrons flow in one direction only power supply by battery constant current and uniform spectrum
what is alternating current? electrons flow in alternating directions 60 cycles
what is rectification? process of converting an alternating current voltage into a direct current voltage anode negative, cathode positive (NO CHARGE)
milliaperage (mA) is... low voltage controls the temperature of the tungsten filament and thus how many electrons are available
kilovoltage (kVp) is... high voltage, controls the difference between cathode and anode side
what does the timer do on the x-ray machine? determines the length of time electrons will flow from the cathode to the anode and thus the number of x-rays produced
the kinetic energy of electrons is converted to... X-rays (1%) thermal radiation (99%)
what are examples of X-ray radiation bremsstrahlung radiation characteristic radiation
Bremsstrahlung Radiation direct hit what happens? electron from cathode strokes tungsten filament on anode side hits nucleus and releases bremsstrahlung radiation a photon of maximal energy is released
Bremsstrahlung Radiation near miss what happens? electron from cathode side hits tungsten filament on anode side it nearly misses the nucleus but has an altered path kinetic energy is released and converted to low energy
what is the primary source of radiation in an x-ray tube? bremsstrahlung radiation
what is characteristic radiation radiation originating in ana tom following the removal of an electron from shell
what happens during characteristic radiation high energy electron from the filament displaces an electron from a shell of tungsten (ionization) higher energy electron in an outer shell of tungsten atom fills vacancy
what produces monochromatic radiation? characteristic radiation
what produces polychromatic radiation? bremsstrahlung radiation
what is quantity of X-ray beam entail? the number of photons generated
what dictates high quality and low quantity? more photons, high quantity less photons, low quantity
what is quality of X-ray beam entail? the mean energy of photons generated the maximal energy of photons generated Penetrating power the the beam
what dictates high quality and low quality? high quality has enough energy to penetrate long distance through matter low quality has short distance and stop inside tissue and do not go through patient
what is the major factors affecting X-ray beam quantity Time, milliamperage, kilovoltage, filtration
what are the major factors affecting X-ray beam quality kilovoltage and filtration
increased photons (higher quality) = higher quality
increased time does what to quantity? increased quantity more photons
what does milliamperage (mA) control? controls the temperature on the cathode side the higher the temperature the more photons
increase mA will do what to quantity? increase quantity
what does kilovoltage affect? quantity and quality
Increased kVp will do what to quantity and quality increase quality increase quantity
what is filtration process of selectively removing x-rays from the beam removes low energy or non-penetrating X-rays
what does filtration affect? quantity and quality
increased filtration does what to quantity and quality? increased quality but decreases quantity
what is the regulation for x-rays for equal to or less than 70 kVp greater than or equal to 1.5 mm aluminum
what is the regulation for x-rays for greater than 70 kVp greater than or equal to 2.5 mm aluminum
what is collimation? the process of restricting the size and shape of the x-ray beam
what are the federal regulations for the collimation less than or equal to 2.75 inches less than or equal to 7 centimeters
what is the basic idea of inverse square law? higher intensity the closer to the source lower the intensity further away from the source
coherent or classic scattering is... x-rays are deposited on the patient low energy photon in outer shell takes get bounced out and receives energy of the incident photon (no loss in energy)
coherent or classic scattering affect on patient and film... no significant effect to patient or film
what is the major portion of radiation interactions compton scattering
what is compton scattering incident photon interacts with a loosely bound outer shell electron and knocks it out of orbit into recoil electron as binding energy is overcome
what are the patient indications for compton scattering good for patient but produces film fog energy isn't deposited on patient
what is photoelectric absorption? an incident photon interacts with an inner shell electron, binding energy is overcome and photoelectron is produced when removing
what is the indications for the patient and film for photoelectric absorption? produce radiation inside patient's body produces characteristic radiation, but inside patient's body high quality x-rays are produced (no scatter)
coherent scattering makes up what percentage? less than 10%
compton scattering makes up about what percentage? 60%
photoeletric absorption makes up about what percentage 30%
no interaction makes up about what percentage less than 10%
beam attenuation is... the intensity of an x-ray beam is reduced by interaction with the matter it encounters
what is a half value layer? thickness of this material that is required to reduce the x-ray intensity to one half of its original value
beam attenuation is dependent on thickness of the absorber mass of the absorber energy of the beam
thicker the tissue does what to beam attenuation? less x-ray penetration more x-rays absorbed by material (lighter film)
the higher the density of the object on beam attenuation more photons are absorbed and less x-rays will be transferred to film
which type of energy beam (low or high) are much more likely to be absorbed? low energy photons are much more likely to be absorbed than high energy photons
as an x-ray beam passes through matter...the intensity of beam does what decreases but the mean energy of the resultant beam increases
1 R (roentgen) is how many mR? 1,000 mR
1 gray is how many rad? 100 rad
1 sievert (Sv) is how many grays? 1 gray diagnostic x-ray examinations
1 sievert equals how many rem? 100 rem
what is dosimetry? determining the quantity of radiation exposure or dose
what is exposure? measure of radiation quantity the capacity of radiation to ionize the air under standard conditions of temperature and pressure
what is absorbed dose? measure of the energy absorbed by any type of ionizing radiation per unit mass of any type of matter
what is equivalent dose? used to compare the biologic effect of different types of radiation on a tissue organ
what is density? overall degree of darkening of an exposed and processed radiograph
what is radiolucent dark area in the radiographic image, resulting from more exposure of the film by radiation passing through the less dense anatomic structure
what is radiopaque? light area in the radiograph image resulting from less exposure of the film by radiation being absorbed by the dense anatomic structure
metals show up as what on x-rays? white or radiopaque
bone shows up as what on x-rays? light area
muscle shows up as what on x-rays dark gray
air shows up as what on x-rays? black or radiolucent
what is the major control image density? mA or milliaperage-second
what are the factors that affect image density? kVp, collimation, filtration, patient factors, focal spot to film distance
increasing the mA will do what to the density? increase density (DARKER image) more electrons reach the anode side and generate more x-ray photons
high contract is what kind of gray scale? short gray scale reduced range of grays between the black area and white areas in a radiographic image
low contrast is what kind of gray scale? long gray scale increased range of grays between the black areas and a white areas in a radiographic image
40 kVp will have what kind of contrast? high contrast short gray scale
100 Kvp will have what kind of contrast? low contrast long gray scale
what is the major factor affecting image contrast? Kilovoltage (kVp)
increase in kVp will do what do contrast? decrease the contrast
increase in collimation will do what to density? decrease density
increase in collimation will do what to contrast? increase contrast
increase in mA will do what do the image increased density and darker image more electrons are boiled off and more hit the film because more photons are generated
increase in time will do what to density? increase density and darker image more photons
increase in mA does what to density and contrast? increased density, darker image no change in contrast
increase in kVp does what to density and contrast? increase density, darker image decrease in contrast, low contrast
increase focal spot to film distance does what to density and what to contrast? decreases density, image is lighter no change in contrast
increased collimation does what to density and what to contrast? decreased density, image is lighter increased contrast, high contrast
increased filtration does what to density and what to contrast? decrease in density, image is lighter decrease in contrast, low contrast
increased thickness in patient will do what to density? decrease density and a lighter image
photons come from which side? anode
electrons come from which side? cathode
what is the measurement of the capacity of radiation to ionize air under standard conditions of temperature and pressure? Roentgen (mR) coulombs per kilogram
what is the measure of the energy absorbed by any type of ionizing radiation per unit mass of any type of matter? gray rad
what is the measure to compare the biological effects of different types of radiation on a tissue or organ? sievert rem
what is a penumbra? photons originating at different places on the focal spot resulting in a penumbra or zone of unsharpness on the radiograph
what is image sharpness? measures how well a boundary between two areas of differing radio density is revealed
what is image resolution? measures how well a radiograph is able to reveal small objects that are lose together
what are the factors that affect image definition focal spot size focal spot to object distance object to film distance
the smaller the focal spot size, what happens to penumbra, image sharpness and resolution? smaller the penumbra, the higher the image sharpness and the higher the resolution
the smaller the target angle... what happens to penumbra and sharpness? higher the sharpness and the smaller the penumbra
for focal spot size, the penumbra is... directly related to the size of the effective focal spot
what is principle 1 for focal spot size? use as small an effective focal spot as practice need to be large enough to disperse heat
focal spot to object distance, the penumbra is... penumbra is inversely related to the focal spot to object distance
what is principle 2 for focal spot to object distance? increase the distance between the focal spot and the object by sing a long, open-ended cylinder
for object to film distance, penumbra is... directly related to the object to film distance
what is principle 3 for focal object to film distance? decrease the distance between the object and the film
what are the factors that influence image definition? kVp and mA motion
kVp does what do image definition? kVp increases... the size of the focal spot will decrease slightly with an increase in kVp beam appears narrow when kVp is increases and the sharpness of the image increases
what does mA do to image definition? mA increases... the size of the focal spot will increase slightly with an increase in mA temperature increases, more electrons, spread out towards anode side
magnification is... refers to an increase in size of the radiographic image as compared with the actual size of the object
what are the control factors for magnification? focal spot to film distance object to film distance
analog is... continuous values smooth transition
digital is... discrete values discrete steps, steps are numerous and small so looks small
what is digital radiography the image is recorded electronically rather than on film
what is direct imagining? intra-oral receptor inside the mouth making a radiograph
what is still required for digital radiography? x-ray generator
what are the three types of digital radiography CCD, CMOS, PSP
how does film work? put sensor in and expose to radiation image is recorded on film film is put into a processor and proceed and same film comes out with image
How do solid film work? put senor in and expose to radiation image captured on image receptor and transferred to computer the image is recorded digitally
how do the solid phosphor plates work? put sensor in and expose to radiation take film out and put into laser reader image is erased on plate and transferred to CPU
hardware for digital radiography is image receptor and computer equipment
software for digital radiography is program used to manipulate and display images
how is the image created for CCD and CMOS? image is created when the x-ray photon interacts with a silicon atom
CCD darker areas are where lots of electrons are trapped in electron wells
CCD light areas are where less or no electrons are trapped in electron wells
scintillation is extra layer added to make the sensor more sensitive, less radiation is needed to make the image but the sensor becomes larger
how is CMOS different than CCD CMOS had a microprocessor in the electron wells so when photons interact with silicon the electrons are counted and information is received a bit faster
spatial resolution is a measure of fine detail
all sensors have a higher spatial resolution than storage phosphor
CMOS and CCD have what kind of spatial resolution? same spatial resolution
film has what kind of spatial resolution when compared to CCD higher or equal spatial resolution to CCD
PSP has what kind of latitude when compared to CCD higher latitude than CCD
CMOS and film have what kind of latitude same latitude
when an x-ray sensor is fast, what does that mean how much radiation exposure is required to get a diagnostic image
cathode ray tube (CRT) is best at... shades of gray wider viewing angle
thin film transistor (TFT) is best at... superior in color fixed resolution narrower range of gray shades higher contrast
lossless storage is... reversible: no data is lost lower compression ratios
lossy storage is... irreversible: data is lost higher compression ratios
CCD and CMOS summary usually wired inflexible and thicker limited area 1 step procedure
PSP summary no wires some flexibility larger active area 2 step process
which of the following is NOT considered to be "particulate" radiation X-rays
long wavelength x radiation has _____ low energy and low frequency
in the Bohr atomic model, what is the designation of the inner electron shell? K
to ionize an atom, the incoming x-ray photon must have enough energy to exceed the ____ energy of the electron that it ejects binding
which of the following is NOT a characteristic of X radiation travels at a variety of speeds
x rays differ from visible light in that they.... have higher energy than visible light
the target of the x-ray tube is typically made of tungsten
the filament of an x-ray tube is heated by the _____ voltage circuit which contains a _____ transformer low voltage step-down
the timer on a self rectified dental -ray unit is set at 30 impulses that is the equivalent of... 0.50
which of the following is a part of the anode in an x-ray tube copper stem
which of the following controls the energy of the x-ray beam kVp
which of the following controls the quantity of photons in the x-ray beam kVp exposure time milliamperage
the line focus principle has to do with the... size of the focusing cup
filtration of the x-ray beam removes... long wavelength photons
if a high speed electron makes a direct hit on the nucleus of the target atom, what type of radiation is produced? bremsstrahlung
the oil surrounding the glass x-ray tube is considered to be part of the ____ filtration of the beam inherent
the half value layer of an x-ray beam is used to describe the ____ of the the beam quality
what effect will increasing the kVp have on an x-ray beam number of photons will be increased the mean energy of the beam will be increased the maximum energy of the beam will be increased
the first step in characteristic radiation production is when an incoming high energy electron collides with a ____ of the target atom creating a vacancy electron
the majority of the x-ray beam spectrum is ____ radiation bremsstrahlung
a low energy photon interacts with an outer shell electron and ejects it. what type of interaction occurred? compton scattering
a recoil electron is NOT part of which interaction? coherent (classical scattering)
what unit is used to measure radiation exposure in air coulombs per kilogram
an x-ray photon passes through an object without interacting with any atoms when it exists the object, it is referred as ____ radiation remnant
the overall degree of darkening on a processed x-ray film is called ___image density
a film comes out of the processor and it is too light because the patient is very large. which of the following techniques changes would increase the radiographic density increase the exposure time
metal object (like amalgam) absorb virtually all of the x-ray photons that they are exposed to. thus they appear ____ on the processed x-ray film radiopaque
before making a radiograph, you increase the kVp on an x-ray machine and keep all other technique factors. this will make the image on the processed film have.... less contrast and greater density
which of the following decreases penumbra? decreasing effective focal spot size
the x-ray beam is perpendicular to the film, but not the object, which of the following describes the results foreshortening
the image of the edge of an object typically appears slightly blurred, this blurred zone is called... penumbra
as the object to film distance increases what is the effect on the image? increased magnification
the ability of a radiograph to distinguish small structures or objects that are close together is called resolution
a large number of shades of gray or long gray scale implies low contrast
when the bombarding electron stream interacts with the target, the majority of the kinetic energy of the electrons is converted to heat
as the filament of the x-ray tube is heat _____ are emitted or bubbled off forming a cloud. this process is thermionic emission electrons
the exposure factor that is the primary control for radiographic contrast is... voltage
soft tissue structures such as the tongue are said to have low subject contrast and low subject density
which of the following is NOT found in dental x-ray film packets intensifying screen
according to the wave theory of electromagnetic radiation frequency and wavelength are inversely related
gamma rays originate... in the nucleus of radioactive atoms
ionization occurs when an electrically neutral atom loses and electrons
particulate radiation consists of consists of atomic nuclei or subatomic particles moving at high velocities
the milliamperage control of the x-ray generating unit regulates the... availability of electrons for the generation of x-rays
in an x-ray tube, the face of the anode is placed at an angle to the electron beam to... improve radiographic image sharpness and increase the heat capacity of the anode
in standard x-ray machines the quality of x-radiation produced during exposure is controlled primarily by the kVp
at diagnostic levels, what percentage of the projectile electrons kinetic energy is converted to x-ray radiation at the anode less than 1%
increasinf the operating kVp of an x-ray machine increases the.... number and energy of x-ray photons generated
the majorityof electromagnetic radiation produced in a dental x-ray tube is... thermal radiation
bremstrahlung radiation is generated as a result of... interactions between a projectile electron and the nucleus of a target atom
what refers to the anode it serves as an electrical conductor and provides mechanical support for the target
which of the following refers to the cathode consists of a filament and focusing cup
which of the following refers to the radiographic tube housing it prevents excessive radiation exposure
the radiation that occurs when an electron moves from an outer orbit to fill a vacancy in an inner orbit is called characteristic radiation
the longer the x-ray wavelength... the less penetrating the x-ray photos
an x-ray beam is heterogeneous or polychromatic because the potential across the tube changes constantly as the AC voltage caries
the reduction in radiation intensity as it passes through material is termed attenuation
the x-ray beam is made more penetrating by... increasing the kVp
if the milliamperage is doubled what must operator do to the exposure time to maintain the intensity of the x-ray beam if all other factors are held constant reduce exposure time by one half
the beam of radiation emitted from the radiographic tube housing consists of... x-ray photons of many different energies and wavelengths
the radiation which produces the diagnostic image consists of remnant radiation plus scatter radiation
remnant radiation is... a component of an image producing radiation
quality of the x-ray beam can be most accurately measured by which of the following half value layer
both milliamperage setting and the exposure time determine the number of x-rays produced
Created by: Chobchi