Exam 1

comprehensive

One reason dental radiographs are important because they are ___________ which help view the pt as a whole

identify

One reason dental radiographs are important because they _________ conditions that would otherwise go undetected

diagnostic

One reason dental radiographs are important because they can be used as a __________ interpretation to determine disease

dentist

who prescribe x-rays based on pt selection

patient selection

examining pt or looking at medical records that can be only done by dr

seen

These are _____ on dental images

* anatomy
* supernumery
* missing teeth
* cysts & tumors
* dental caries
* air space
* evidence of periodontal disease
* calcified arteries

dental radiographer

person who positions, exposes and processes dental x-ray

* must have a basic understanding and familiar with equiptment

duties

________ of dental radiographer

* positioning and exposure
* processing film
* data retrival
* mounting dental radiographs
* maintenance of darkroom
* quality control

protection

Pt ________ is top priority by

* using lowest level of x-radiation
* retakes should be avoided
* pt protection equiptment
* film based handling and processing must be meticulous to avoid retakes
* pt selection criteria

wilhem roentgen

father of x-ray

* discovered x-ray
* did the first x-ray on his wives hand

otto walknoff

did first dental radiograph on himself

C. edmund Kells

did first dental radiograph on live pt

William D. Coolidge

invented x-ray tube

* coolidge tube allowed increased safety and visulization
* tubes haven’t changed mcuh

dangers

_________ of radiation started to be noticed because things thats shouldn’t be happening to tissues were happening. Occupational exposure, lead aprons, etc are used to help combat this

kodak

created the first x-ray film

* made it more comfy for pt to take x-rays

digital imaging

* introduced in France
* 1st publication in the U.S about digital imaging
* allows instant and easy transmission of images and electronic storage
* requires less radiation and faster than film

protons; neutrons

______ and ____________ are in the nucleus of an atom

electrons

orbit the nucleus in shells

k

___ shell has the strongest binding energy

q

__ shell has the weakest binding energy

stable

______ atoms:

* number of proton and number of electrons are equal
* chemically inactive
* atoms like to be in this state

tungsten

* atomic number 74
* 6 orbits
* noncorrosive
* can be in high temps

ionization

* when energy knocks off an electron from an atom
* left with and ion and an electron

ionizing radiation

* radiation that knocks of electrons
* two types
* electromagnetic radiation
* particulate radiation

particulate radiation

form of ionizing radiation in which, tiny particles of matter that have mass and travel in straight line at high speeds

* 4 types
* e- type
* beta → radioactive
* cathode → x-ray tube
* alpha particles
* protons
* neutrons

electromagnetic radiation

form of ionizing radiation in which have:

* wavelike energy
* no mass
* travels in straight line at the speed of light
* can’t be focused
* absorbed differently by different materials
* man-made or naturally occurring
* can harm tissue
* gamma rays
* x-rays

velocity

refers to the speed of the wave

wavelength

the distance between the crest of one wave and the crest of the next

short

_______ wavelength has more energy and penetrating power and high frequency

long

_______ wavelength has less energy and penetrating power and low frequency

radiation

a form of energy carried by waves or stream of particles

x-radiation

a high-energy radiation produced by the collision of a beam of electrons with a metal target in x-ray tube

x-ray

a beam of energy that has the power to penetrate substance and record image shadows on receptors

radiology

the science or study of radiation

radiograph

an image or picture produced on a receptor by exposure to ionizing radiation; a 2D representation of a 3D object

* some distortion and magnification

dental radiograph

a photographic image produced on a receptor by the passage of x-rays through teeth and related structures

radiography

the art science of making radiographs by the exposure of a receptor to x-rays

dental radiography

the production of radiographs of the teeth and adjacent structures by the exposure of an image receptor to x-rays

image

a picture of likeness of an object

image receptor

a recording medium; examples include x-ray film, phosphor plate or digital sensor

dental imaging

the creation of digital, print, or film representations of anatomic structures for the purpose of diagnosis

aren’t

X-rays ______ (are or aren’t) predetermined for ex. every 2 years 4 bitewings

invisible

Property of X-ray:

* Its appearance is ________

electromagnetic

X-rays are a form of ______________ radiation so they have similar properties

weightless

Property of X-ray:

* For mass it is ____________

charge

Property of X-ray:

* It does not have a _________

light

Property of X-ray:

* It travels at the speed of ________

short; high

Property of X-ray:

* It has ____ wavelengths with_____ frequency

straight; deflected

Property of X-ray:

* Pathway: It travels in a ______ line but can be _______

diverge

Property of X-ray:

* Focusing capability: it will always ________ from a point

penetrate

Property of X-ray:

* It can ___________ solids, liquids and gases

absorbed

Property of X-ray:

* It can be __________ by matter

ionization

Property of X-ray:

* It causes ___________
* the process of knocking off an electron

fluorecent

Property of X-ray:

* It will cause certain substances to be ___________

Receptor

Property of X-ray:

* It can produce an image on a __________

biologic

Property of X-ray:

* It can cause ________ changes in living cells

Intraoral

___________ x-ray machine have not changed much in structure over the years

Extension arm

* suspends the x-ray tubehead
* houses electrical wires
* allows for movement and positioning

Yoke

at the end of the extension arm

* allows for 360 degree and vertical movement

control panel

contains an on/off switch, indicator light, exposure button and control device

tubehead

the part attached to the extension arm

* Inside it contains
* metal housing
* insulating oil
* tubehead seal
* x-ray tube
* transformers
* aluminum disk
* lead collimator
* Outside there is a projection
* positioning-indicating device (PID)

Metal housing

* Within the tubehead
* Surround the x-ray tube and transformers
* It is filled with insulating oil
* Protects the x-ray tube
* Ground the high voltage components

Insulating oil

* Within the tubehead
* Surround the x-ray tube and transformers
* Prevents overheating by absorbing the heat produced during x-ray production

Tubehead seal

* Within the tubehead
* aluminum or leaded glass covering
* allows x-rays produced to exit the tubehead
* seals the oil within the tubehead
* acts as a filter of the x-ray beam

Transformer

* Within the tubehead
* Associated with electricity
* 3 types
* step-down, step up and autotransformer

Step-down transformer

Used to decrease the voltage from the incoming electrical line

Step-up tranformers

Used to increase the incoming voltage

Autotransformer

Compensates for minor electrically fluctuations

Aluminum disk

* Within the tubehead
* Filters out long wavelengths (bc they don’t penetrate and to prevent unnecessary radiation exposure)
* Important for radiation safety

Lead collimator

* Within the tubehead
* Lead plate with hole in center, shapes may vary
* Fits directly over the metal housing, where x-rays exit
* Restricts the size and shape of the beam
* Important in radiation safety

Position-Indicating Device

* Within the tubehead
* aka PID or cone
* open ended lead cylinder
* Extends from the opening in metal housing of tubehead
* Aims and shapes the x-ray beam
* Plays roles in safety

X-ray tube

* Within the tubehead
* Critical for x-ray production (where they are made)
* Glass vacuum tube in which all air has been removed
* Components include:
* Lead glass housing
* cathode (-)
* anode (+)

Lead glass housing

* Within x-ray tube which is in tubehead
* Leaded glass vacuum
* Prevents x-rays from escaping in all directions
* Leaded glass has window which permits x-rays to exit
* Directs x-rays toward aluminum disks, lead collimator and PID

Cathode

* Within x-ray tube which is in tubehead
* Negative electrode
* Consists of a thin spiraled tungsten wire filament in a focusing cup
* Gets heating and becomes incandescent
* Electrons are produced here

Anode

* Within x-ray tube which is in tubehead
* Positive electrode
* Thin tungsten plate embedded in a soild cooper rod
* The tungsten plate (tungsten target) serves as a focal spot for the bombarding electrons produced at the cathode
* The cooper stem functions to dissipate the heat away from the tungsten target

Photon

Tiny particle thats comprises waves of electromagnetic radiation

electricity

The first step in the production of x-radiation:

* turn on the x-ray machine - __________ from the outlet travels to control panel to tubehead

step down

Second step in the production of x-radiation

* The ____ - ______ transformer reduced the current from 110 or 220 line voltage to 3 to 5 volts so that it is useable for the machine

cathode

The third step in the production of x-radiation

* The 3 to 5 volts heat the tungsten filament ( ______ -) The result is thermionic emission creating an electron cloud around the tungsten filament (NO X-RAYS YET)

Step up

The fourth step in the production of x-radiation

* The high voltage circuit ( _______ - ________ transformer) is activated when the exposure button is pushed

anode

The fifth step in the production of x-radiation

* electrons in the cloud around the tungsten filament are accelerated to the tungsten target ( _________ +)

x-ray

The sixth step in the production of x-radiation

* when the electrons strike the tungsten target their kinetic energy is converted to _____ energy

anode

Where are x-rays and heat made?

1; 99

The seventh step in the production of x-radiation

* The production of x-rays produce ___ % x-ray energy and __% heat

insulating oil

The eighth step in the production of x-radiation

* the heat produced is carried away by the cooper stem and absorbed by the _________ ___ in the tubehead

seal; disk

The ninth step in the production of x-radiation

* a small number of x-rays exit the x-ray tube through the unleaded glass window and proceed to the tubehead ____ and the aluminum ___

longer

The tenth step in the production of x-radiation

* the aluminum disk filters out _____ wavelengths away from beam

collimator

The eleventh step in the production of x-radiation

* The x-rays continue on through the lead ________ which restricts the size and shape of the x-ray beam

PID

The twelfth step in the production of x-radiation

* The beam travels down the _____ and exits the tubeheaad

primary

The thirteenth step in the production of x-radiation

* The ________ x-ray goes through teeth and related structures then hits the recpeetor and creates an image

secondary

The fourteenth step in the production of x-radiation

* X-rays are absorbed by matter _____ radiation produced and deflected this radiation is produced (scatter radiation)

Bremsstrahlung radiation

* mechanism of x-ray production (occurs at anode)
* aka braking or general
* The sudden stop of the electrons by the tungsten nuclei or very close to the nuclei (direct hit)
* the kinetic energy of the electron is converted into a X-ray photon
* depending on if it is a direct hit of near the nuclei will result in x-rays with varying levels of energy and wavelengths
* about 70% x-rays are produced in this manner (used more)
* occurs at the same time as the other type of mechanism

Characteristic radiation

* mechanism of x-ray production (occurs at anode)
* high speed electrons dislodge an inner shell electron from a tungsten atom
* causes ionization of the atom
* electron is dislodged leading to the remaining orbiting electrons rearranging to fill the vacancy
* the result is the production of an x-ray photon
* accounts for small portion of x-rays produced in the dental x-ray machine
* occurs at the same time as the other type of mechanism

Primary radiation

refers to the penetrating x-ray beam that is produced at the target of the anode and exits tubehead

* aka useful radiation
* most penetrating power
* once it hits an object it slows or deflects

Secondary radiation

refers to x-radiation that is created when primary beam interacts with matter

* less penetrating than primary

Scatter radiation

a form of secondary radiation and is a result of the x-ray beam being deflected in all directions

* not useful
* Unnecessary exposure is why protection equipment is used and why operator leaves room

no interaction

Type of interaction of x-radiation:

* x-ray photon passes through matter without any interactions
* x-ray photon and the atom it passed through are both unchanged
* makes dental radiographs possible, produced densities on the dental radiograph

absorption of energy

Type of interaction of x-radiation:

* the total transfer of energy from the x-ray photon to the atoms of matter through which the x-ray beam passes
* dependent of energy of x-ray beam and composition of the matter

compton scatter

Type of interaction of x-radiation:

* most of scatter radiation
* ionizing takes place
* x-ray photon collided with outer shell electron
* x-ray photon loses energy and continues (scatter on a different direction)
* result: this electron has a negative charge, the remaining atom has a positive charge, and the x-ray photon will continue to interact until all its energy is gone

coherent scatter

Type of interaction of x-radiation:

* x-ray photon path is alter by matter (deflected)
* low energy x-ray photon interacts with an outer-shell electron
* no change in the atom (no ionization) x-ray photon of scatter radiation is produced and scatter in different directions
* no loss of energy
* x-ray photon scatters
* makes up a little of the scatter radiation