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Radiology exam 1
exam 1
103
Other
Professional
08/16/2008

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Term
x-radiation
Definition
a high-energy radiation produced by the collision of a beam of electrons with a metal target in an x-ray tube
Term
radiation
Definition
a form of energy carried by waves or a stream of particles
Term
x-ray
Definition
a beam of energy that has the power to penetrate substances and record image shadows on photographic film
Term
radiology
Definition
The science or study of radiation as used in medicine; a branch of medical science that deals with the use of x-rays, radioactive substances, and other forms of radiant energy in the diagnosis and treatment of disease
Term
radiograph
Definition
a picture (visable photographic record) on film produced by the passage of x-rays through an object or body; also called x-ray film
Term
What is the importance of radiographs?
Definition
they give us the ability to see and diagnose conditions of the teeth and bones that we may not other wise see.
Term
What information do radiographs help to detect?
Definition
detect lesions, diseases, and conditions of the teeth and surrounding structures that cannot be identified clinically.
Term
What can radiographs help to confirm?
Definition
confirm or classify suspected disease
Term
What do radiograhps help to localize?
Definition
localize lesions or foreign objects
Term
What type of information do radiographs help to provide?
Definition
provide information during dental procedures (eg root canal therapy)
Term
What can radiographs help to evaluate?
Definition
evaluate growth and development
Term
What do radiographs help us to illustrate?
Definition
illustrate changes secondary to caries, periodontal disease, and trauma
Term
What do radiographs help us to document?
Definition
Document the condition of a patient at a specific point in time
Term
cathode ray
Definition
a stream of high speed electrons that originates from the cathode in an x-ray tube.
Term
cathode
Definition
the negative electrode in the x-ray tube; consists of a tungsten wire filament in a molybdenum cup; supplies the electrons necessary to generate x-rays
Term
vacuum tube
Definition
a sealed glass tube from which most of the air has been evacuated
Term
fluorescence
Definition
the emission of a lowing light by certain substances when struck by a particular wavelength
Term
fluoresce
Definition
to emit visible light in the blue or green spectrum
Term
bite-wing technique
Definition
an intraoral radiographic technique in which the interproximal surfaces of the teeth are examined.
Term
bisecting technique
Definition
an intraoral radiographic technique used to expose periapical films: film is placed along lingual surface of tooth; central ray of x-ray beam is directed perpendicular to imaginary bisector formed by film and long axis of tooth; and film holder or patient's finger is used to stabilize film.
Term
parallel technique
Definition
an intraoral radiographic technique used to expose periapical films: film is placed parallel to long axis of tooth; central ray is directed perpendicular to film and long axis of tooth; and film holder must be used.
Term
Who first discovered the x-ray in 1895?
Definition
Wilhelm Conrad Roentgen (ren ten)
Term
what is the primary benefit of dental radiographs?
Definition
detection of disease
Term
what type of information might you see on a dental radiograph?
Definition
missing teeth, extra teeth, impacted teeth, dental caries, periodontal disease, tooth abnormalities, retained roots, cysts and tumors
Term
interpersonal skills
Definition
skills that promote good relationships between individuals
Term
facilitation skills
Definition
interpersonal skills used to ease communication an develop a trusting relationship
Term
name some methods you can use for pt education
Definition
you can talk to them, show them written brochures or other visual aids, show them their films, demonstrate on models etc
Term
can a dental axillary answer questions about diagnosis?
Definition
NO all questions about diagnosis must be answered by the dentist
Term
are x-rays really necessary?
Definition
yes, there are many diseases and conditions such as decay, gum disease, cysts and tumors that cannot be detected by visual inspection alone.
Term
how much radiation does the pt get from dental x-rays?
Definition
a very little amount and measures such as lead vests, thyroid collars and fast film all help to minimize the amount of radiation needed. The actual amount received will depend on the film speed, technique and exposure factors, but in general around 125 milliroentgens.
Term
are x-rays safe?
Definition
No amount of radiation is safe. The benefit must outweigh the risk. In the case of dental x-rays, the risk of developing cancer from a dental x-ray is 3 in 1 million, where as the risk of spontaneously developing cancer is 3,300 in 1 million.
Term
does an RDH need to obtain a separate radiology license?
Definition
no, neither does a DDS, but non licensed employs (such as DAs) do
Term
what are the 4 elements of patient informed consent?
Definition
1. the purpose of the procedure and who will perform it
2. the potential benefits of receiving the procedure
3. the possible risks involved in having the procedure performed, as well as the possible risks of not having it performed
4. opportunity for the patient to ask questions and obtain complete information
Term
why are patient records important?
Definition
complete dental records are important to ensure continuity of pt care and to provide legal documentation of pt condition.
Term
what must you document when taking radiographs?
Definition
1. informed consent
2. number and type of radiographs exposed
3. rationale for exposing radiographs
4. diagnostic information obtained from interpretation of the radiographs
Term
who owns the exposed radiographs?
Definition
the owner of the practice, however the pt must be allowed to have a copy (extra fees may apply)
Term
if a patient refuses to have radiographs taken can they still receive treatment?
Definition
In most cases no. The dentist must decide whether an accurate diagnosis can be made and whether treatment can be provided.
Term
name some possible routes of transmission
Definition
direct, indirect, airborne
Term
asepsis
Definition
the absence of pathogens
Term
antiseptic
Definition
a substance that inhibits grown of pathogens
Term
infectious waste
Definition
anything saturated with blood or saliva
Term
parental exposure
Definition
puncture through the skin
Term
sharp
Definition
any object that can puncture the skin
Term
universal precautions
Definition
a method of infection control in which all human blood and certain body fluids are treated as know to be infectious with HIV, HBV, etc
Term
what protective clothing is needed when taking radiographs?
Definition
you must wear an appropriate covering such as a gown or lab coat as well as gloves, masks and eye protection.
Term
where should you never place a film holder?
Definition
on an uncovered surface
Term
how should you transport exposed film?
Definition
in a cup that is clean on the outside. Never touch the outside of the cup with gloved hands
Term
when opening an exposed film packet what precautions should you use?
Definition
wear gloves to protect yourself, but do not touch film as packet is opened; dropped film into clean container.
Term
critical instruments
Definition
used to penetrate soft tissue or bone. MUST be sterilized!
Term
semicritical instruments
Definition
contact soft tissue or bone but do not penetrate. MUST be sterilized!
Term
noncritical instruments
Definition
do not come in contact with mucous membranes. Intermediate or low level disinfection
Term
intermediate level disinfectants
Definition
EPA registered chemical germicides labeled both hospital disinfectants and tuberculocidals
Term
low level disinfectants
Definition
labeled germicide or hospital disinfectant. General house keeping only!
Term
matter
Definition
anything that occupies space and has mass
Term
energy
Definition
the result of altered matter
Term
atom
Definition
the fundamental unit of matter
Term
nucleus
Definition
dense core of the atom
* K shell is closest to the nucleus and has the highest energy
Term
neutrons
Definition
located in nucleus of atom, has neutral charge
Term
protons
Definition
located in nucleus of atom, has positive charge
Term
electrons
Definition
tiny, negatively charged particles that have very little mass, travels around nucleus in well defined paths known as orbits or shells.
Term
binding energy
Definition
the attraction between protons and electrons. it keeps the electrons in their orbiting shells and is determined by the distance between the nucleus and that particular electron.
Term
molecule
Definition
2 or more atoms bound together
Term
ionization
Definition
the addition or removal of an electron from an atom. Changes the atom to an unstable, no longer neutral charge
Term
ion
Definition
an unbalanced atom
Term
ionization
Definition
the production of ions. when an electron is removed from an atom an ion pair results. the pair contains one positive ion and one negative ion. The Ion pair reacts with other ions until electrically stable, neutral atoms are reformed.
Term
radiation vs. radioactive
Definition
radioactivity refers to unstable elements that exist naturally. Radiation is man made and controlled.
Term
Ionizing radiation
Definition
radiation that is capable of producing ions. Can be classified into two groups: particulate radiation and electromagnetic radiation.
Term
particulate radiation
Definition
tiny particles of matter that possess mass and travel in straigh lines at high speeds. Four types of particulate radiation are recognised:
1. electrons- beta particles or cathode rays
2. alpha particles
3. protons
4. neutrons
Term
electromagnetic radiation
Definition
propagation of wavelike energy without mass through space or matter. The energy is accompanied by oscillating electric and magnetic fields positioned at right angles to each other.
Term
properties of electromagnetic radiation
Definition
  • it has no mass or weight
  • has no electrical charge
  • travels at the speed of light travels as both a particle and a wave
  • propagates an electric field at right angles to path of travel
  • propagates a magnetic field at right angles to the electric field
  • has different measurable energies (frequency and wavelength)
Term
properties of x-rays
Definition
  • invisible and cannot be detected by any of the senses
  • no mass or weight
  • no electrical charge
  • travel at the speed of light travel in waves and have short wavelengths with a high frequency
  •  travel in straight lines and can be deflected/scattered
  • cannot be focused to a point and always diverge from a point
  • can penetrate liquids, solids and gases. The composition of the substance determines whether the ray passes through or is absorbed.
  • are absorbed by matter, amount depends on the structure and wavelength of ray
  • interacts with materials and causes ionization
  •  causes certain substances to fluoresce or emit radiation in longer waveslengths
  • can produce an image on photographic film
  • causes biological changes in living cells
Term
particle concept
Definition
characterizes electromagnetic radiation as discrete bundles of energy called photons and quanta.
Term
photons/ quanta
Definition
bundles of energy with no mass or weight that travel as waves at the speed of light and move through space in a straight line carrying the energy of electromagnetic radiation
Term
wave concept
Definition
characterizes electromagnetic radiation as waves and focuses on the properties of velocity, wavelength and frequency
Term
velocity
Definition
speed of wave
Term
wavelength
Definition
distance between the crest of one wave and the crest of the next. wavelength determines the energy and penetrating power of the radiation; the shorter the distances between the crests, the shorter the wavelength and the higher the energy and ability to penetrate matter.
Term
frequency
Definition
number of wavelengths that pass a given point in a certain amount of time. Frequency and wavelength are inversely related; if the frequency of the wave is high, the wavelength will be short
Term
x-radiation
Definition
high-energy, ionizing electromagnetic radiation. x-rays have properties of both waves and particles.
Term
what is the function of the insulating oil within the x-ray tube head?
Definition
to absorb heat
Term
what controls are on the x-ray machine control panal?
Definition
on/off
exposure
time
kilovoltage
milliamperage
Term
what is the x-ray tube?
Definition
the heart of the x-ray generating system. is a lead lined, glass vacuum tube containing a negative cathode and a positive anode.
Term
what is the purpose of the transformer within the x-ray machine?
Definition
to decrease or increase the voltage to heat the tungsten filament and move electrons across the x-ray tube anode towards the tungsten target.
Term
what is the purpose of the aluminum disks within the tube head?
Definition
to filter out low frequency wavelengths
Term
what is the purpose of the lead collimator within the tube head?
Definition
restricts the size of the x-ray beam to try and prevent divergence
Term
what is the purpose of the position indicating device?
Definition
it's a lead lined cylinder that aims and shapes the x-ray beam. some times referred to as the cone.
Term
what is the purpose of the leaded glass housing?
Definition
to prevent x-rays from going everywhere
Term
molybdenum cup
Definition
contains the tungsten filament, focuses electrons into narrow beam and directs the beam across the tube toward the tungsten target of the anode.
Term
tungsten filament
Definition
a coiled wire made of tungsten which produces electrons when heated.
Term
anode
Definition
contains the tungsten target and copper stem

positive electrode, consists of a wafer thin tungsten plate embedded in a solid copper rod. converts electrons into x-ray photons.
Term
copper stem
Definition
located in the anode, functions to dissipate the heat away from the tungsten target.
Term
cathode
Definition
negative electrode
consists of a tungsten wire filament in a cup shaped holder made of molybdenum. Cathode supplies electrons necessary to generate x-rays.
Term
amperage
Definition
# of electrons moving through a conductor
Term
voltage
Definition
measurement of electrical force that causes electrons to move from a neg pole to a pos pole
Term
explain the process of electricity moving through the transformers of the x-ray machine
Definition
First 220v comes in the machine and goes through the step down transformer and goes to 3-5v. It then heats the tungsten filament and electrons are boiled off. The current is next going through the step up transformer to go to 65-100kv and causes the ions to line up and go to the tungsten target.
Term
thermionic emission
Definition
release of electrons from tungsten filament when electrical current passes through and heats filament. The outer shell electrons quire enough energy to move away and form a cloud.
Term
what types of x-rays are produced?
Definition
a variety of wavelengths are produced. 70% are general/braking radiation. 30% are characteristic radiation
Term
general/braking/bremsstrahlung radiation
Definition
electrons hits nucleus of tungsten atom or passes very close. is attracted and slows down. produces low energy ray
*majority of x-rays are from general radiation
Term
characteristic radiation
Definition
high speed electron disoges an inner shell electron of tungsten atom and causes ionization of that atom. causes original electrons to rearrange, emits x-ray.
Term
primary radiation
Definition
synonymous with primary beam, useful beam, and penetrating beam
is the x-ray produced at the target of anode and exits tube head
Term
secondary radiation
Definition
primary beam that has reacted with matter (eg hits pt face)
this is the beam that develops film
Term
scatter radiation
Definition
  • secondary radiation that has hit something and changed direction
  • there are two types of scatter
  1. Compton scatter
  2. coherent scatter
Term
compton scatter
Definition
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