Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
133 Cards in this Set
- Front
- Back
|
Who discovered x-rays? |
William Roentgen |
|
|
Who discovered the Hittorf tube? |
William Crookes |
|
|
What is the Hittorf tube? |
Discharge tube w/partial vacuum |
|
|
What is a cathode? |
Negative stream of electrons |
|
|
What is an anode? |
Positive stream of electrons |
|
|
What electrons were in Crookes tube? |
anode & cathode |
|
|
When high voltage is applied between electrode, electrons or cathode rays are? |
projected into straight lines |
|
|
What is fluorescence? |
instantaneous emission of light |
|
|
Where do fluorescences occur from? |
Stimuli (light chemicals & ionizing radiation) |
|
|
What are the substances called that cause fluorescence? |
Phosphors |
|
|
It was concluded that fluorescence was due to what? |
an unknown ray that penetrated both the glass & paper Unknown rays were called "x-rays" |
|
|
When Roentgen obtained x-ray of wife Bertha's hand what was the exposure time? |
15 minutes |
|
|
who made the first dental radiograph of a pts jaw in Germany? |
Dr. Otto Walkoff expo time 25 mins |
|
|
Who made the first dental radiograph in western hemisphere, develop a film holder to hold glass plate, pay price for poor radiation protection, and hit a female assistant |
Edmund Kells of NOLA expo time 15 mins |
|
|
Who was first educator to bring radiology into dental school clinic on a regular basis, invent bitewing technique, and publish first book on radiology? |
Howard Raper |
|
|
Who invented a new evacuated x-ray tube |
William David Coolidge |
|
|
How are x-rays produced? |
Rapidly moving electrons from cathode are suddenly stopped as they strike the metal target or anode of the tube |
|
|
What is an intraoral radiograph? |
image receptor is placed inside pts mouth & x-ray source is outside PA & bitewings |
|
|
What is an extra oral radiograph? |
image receptor AND x-ray source are outside of pts mouth Pano |
|
|
What are sizes 0, 1, and 2 film size used for? |
PA and bitewings |
|
|
What is size 3 film used for? |
Bitewings only |
|
|
What is size 4 film used for? |
Occlusal radiography |
|
|
What does PA and FMX stand for? |
Periapical; full mouth x-ray |
|
|
What does a PA show? |
entire tooth & its surrounds/uself to establish crown/root ratio, root morphology, and evaluate status of periapical bone |
|
|
What does a bitewing show? |
Crowns, necks, and inter proximal surfaces of teeth & supporting marginal alveolar bone of both arches Detects decay inter proximally on coronal and cervical regions and examines inter proximal crest bone |
|
|
What does occlusal radiographs show? |
Large areas of maxilla or mandible Useful for fractures, pathology, root fragments, & unerupted teeth that can't be seen on PA |
|
|
What is adv & disadv of pano image? |
Adv: broad anatomical coverage Disadv: lack of fine anatomical detail |
|
|
What is the sagittal plane? |
sections that body into right and left portions |
|
|
What is the coronal plane? |
divides the head into anterior & posterior portions |
|
|
What is the axial plane? |
Divides the body in upper and lower portions |
|
|
Radiopaque: |
light/white |
|
|
Radiolucent: |
dark/black |
|
|
How many images are in an FMX at COD? |
22 |
|
|
how much of a tooth should be shown in a PA? |
full length of a tooth 2-4 mm surrounding normal bone |
|
|
What does BID stand for? |
beam indicating device |
|
|
What does PID stand ford? |
position indicating device |
|
|
What do bitewings record? |
coronal part of tooth & bone of both arches |
|
|
what is the imaginary beam of x-rays that travels through the center of the BID? |
central ray |
|
|
What is the central ray used for? |
reference point for discussing the orientation of the beam to the oject |
|
|
What is vertical angulation? |
up and down motion of the x-ray tube in relation to the occlusal plane |
|
|
What is horizontal angulation? |
motion of the tube around the pts head in relation to the midsagittal plane |
|
|
What does XCP stand for? |
extension cone paralleling |
|
|
what does the XCP consist? |
anterior & posterior bite blocks Indicator rod aiming ring |
|
|
what is the XCP used for? |
acts as an external guide for positioning the x-ray beam vertically & horizontally Establishes a point of entry for the beam |
|
|
Adv of XCP device: |
prevents BID or cone cuts aiming ring is compatible w/rectangular & round BID indicator arm guides BID for proper alignment reduces distortion steam autoclavable |
|
|
what is the parallel tip of maxillary teeth from canine to third molar & easier to visualize when pt has a close mouth? |
ala-tragus line |
|
|
What is overangulation? |
teeth appear shortened or cramped BID is tooth high & too far up towards head |
|
|
Overangulation results in? |
foreshortening of structures teeth & crowns cut off & too much periodical bone is seen |
|
|
What is underangulation? |
Teeth appear elongated BID is too low Bring it up to correct |
|
|
Underangulation results in? |
Elongation of the structures, apices are cut off, and no apical bone is seen |
|
|
Faulty vertical angulation would result in? |
elongation & foreshortening |
|
|
Faulty horizontal angulation would result in? |
Overlapped structures |
|
|
What are the two periapical radiographic techniques? |
paralleling (preferred) & bisecting |
|
|
What is density? |
Blackness |
|
|
What does high contrast produce? Low contrast? |
More black & white; more gray |
|
|
What happens when the x-ray goes through air? |
radiolusency (black) |
|
|
what happens when the x-ray goes through the bone? |
radiopaque (white) |
|
|
what receptor has an instant view on monitor? |
sensors |
|
|
what receptor requires scanning before image display? |
PSP plates |
|
|
what is sampling? |
small range of voltage values are grouped together as a single value |
|
|
what is quantization? |
every sample is assigned a value |
|
|
Voltage of the output signal is measured & assigned a number from? |
0 (black) to 255 (white) |
|
|
Each cell of an image matrix is called a? |
Pixel |
|
|
a standard image shows how many shades of ray? |
256 |
|
|
Lower the pixels... |
poorer the resolution |
|
|
A fiber optic plate is present between the |
scintillation screen and the activator screen |
|
|
a red light is not safe for?
|
exposed PSP |
|
|
What is Bohrs model? |
says that structure of an atom is like a miniature solar system w/nucleus in the center & revolving electrons |
|
|
an atom is made up of what? |
a nucleus, protons, and neutrons |
|
|
atomic number: |
number of protons in the nucleus |
|
|
atomic mass: |
total # of protons in the nucleus |
|
|
What is electron binding energy? |
energy required to remove an electron from an orbital shell |
|
|
the energy to remove an electron must be greater than? |
the electrostatic force of attraction between the electron and the nucleus |
|
|
when electrons move from a outer shell to inner shell the energy is released in the form of? |
electromagnetic radiation |
|
|
Inner shell electrons: |
higher binding energy tightly bound |
|
|
Outer shell electrons: |
loosely bound |
|
|
Examples of particulate radiation? |
alpha and beta particles |
|
|
alpha particles: |
positive charge and more damaging |
|
|
beta particles: |
negative charge |
|
|
What is LET? |
liner energy transfer capacity of particulate radiation to ionize atoms depends on its mass, velocity, and charge |
|
|
where do x-ray originate from? |
interaction of cathode electrons w/a target atom in the x-ray machine |
|
|
short wavelengths= |
higher frequency waves |
|
|
long wavelengths= |
low frequency waves |
|
|
What is a wavelength? |
distance between the crests of two waves |
|
|
What is the frequency? |
# of waves passing through a point per second |
|
|
What waves penetrate more? |
short wavelengths=high frequency=high proton energy |
|
|
What waves penetrate less? |
long wavelengths=low frequency=small proton energy |
|
|
primary radiation originates from? |
the target, focal spot, and has high energy |
|
|
Secondary radiation is? |
new radiation created by primary radiation acting on or passing through matter |
|
|
Scatter radiation is? |
radiation whose direction has been altered |
|
|
Leakage radiation is? |
escape of radiation through the protective shield |
|
|
Components of x-ray machine: |
x-ray tube head, power supply, control panel, and exposure button |
|
|
Components of x=ray tube head: |
metal housing, immersion oil, x-ray tube, unleaded glass window, aluminum filter, lead collimator, BID/PID, transformers |
|
|
components of the transformer: |
two copper wire coils wrapped around opposite end of iron core |
|
|
Step down transformer: |
decerase voltage, increase current |
|
|
Step up transformer: |
increase voltage, decreases current |
|
|
what is the target? |
wafer of tungsten embedded in the face of anode Surrounded by copper |
|
|
what is the source of electrons in the X-ray tube? |
tungsten coil or filament |
|
|
higher mA or exposure time: |
more electron production from the filament=more x-ray generation in a unit of time |
|
|
Higher kVp= |
greater speed of the electrons as they strike the target |
|
|
Compton scatter: |
moderate energy x-rays strike outer shell |
|
|
Coherent scattering: |
low energy incident photon direction changed |
|
|
What is collimation? |
restricts the size and shape of x-ray beam |
|
|
the thicker the object of an x-ray beam passes through.... |
the greater will be the attenuation of the beam |
|
|
Quality is: |
energy of particular x-ray photons |
|
|
Quantity is:
|
number of photon in the beam, each w/particular energy |
|
|
A dosimeter may be used? |
to calibrate x-ray generators & to monitor safe work practices |
|
|
What is dosimetry? |
determine the quality of radiation exposure or dose |
|
|
What is a dosimeter?
|
device for measuring does of radiations or radioactivity |
|
|
the dental x-ray beam consists of photons of many different energies/wavelengths, w/the shortest wavelength photon determined by? |
kVp |
|
|
what transformer is used to head the filament of the x-ray tube? |
step down, low voltage |
|
|
in x-ray tube, the x-rays originate from the? |
anode and target |
|
|
Smaller the focal spot.. |
sharper the image |
|
|
Which of the following are NOT used as landmarks when mounting films? |
arranging x-rays in the mount form pts left to pts right |
|
|
When duplicating a film in the dark room, the duplicate appears lighter and blurrier than the original. What could have gone wrong? |
Too much exposure time OR insufficient distance between the original and the duplicate film |
|
|
The network of an individual silver dodo-bromide crystal contains tungsten, bromine, and iodine ions held together by electrovalence forces. When an ex-ray photon interacts w/these atoms of the crystal, free neutrons are released. (T OR F) |
False |
|
|
Safe illumination in the darkroom is dependent on the wattage of the bulb and the distance the safelight is from the workbench. (T OR F) |
True |
|
|
The two types of thermometers used in processing film are the tank thermometer and the digital thermometer that is used to mix processing solutions. (T OR F) |
False |
|
|
Where should the automatic or manual processor be placed? |
Dark room |
|
|
What temperature of processing solutions in insert tanks are recommended? |
70-degrees F |
|
|
What are the steps for manual processing? |
1) Stir the solution 2) Check the solution level of developer & fixer 3) Check the temperature of the solutions 4) Turn on the safe light 5) Unwrap the exposed film |
|
|
the function of a safelight is to provide enough illumination in the dark room so that the central processing activities can be accomplished w/a minimum amount of errors, w/out fogging the film. (T OR F) |
True |
|
|
Exposing the film (chemically or by light) beyond that which produces maximum density until a decrease in density occurs is: |
Solarization of a film |
|
|
When a latent image is formed, the network of an dodo-bromide crystal contains what ions that are held together by electrovalence forces? |
Silver, Bromine, and Iodine |
|
|
The ____ film shows the crowns of the teeth of both arches and their inter proximal alveolar crests on one film. |
Bitewings |
|
|
All unopened film should not be stored in a cool place, such as a refrigerator. It should not be stored beyond the expiration date. (T OR F) |
The first statement is false, the second is true. |
|
|
The efficiency w/which film response to x-ray exposure is known as film sensitivity, or more commonly, speed. (T OR F) |
True |
|
|
W/a speed range of 48.0-96.0 reciprocal roentgen, this film is considered to be the fastest intramural film: |
F |
|
|
When manual processing radiographs, chemicals in processing solution above 75-degrees F will work too rapidly & may produce_____/ |
Fogging |
|
|
______ radiographs typically use a size 4 film. |
Occlusal |
|
|
By switching to ____ film, dentists currently using D speed film can lower their radiation exposure settings by 60%. |
Kodak INSIGHT & F speed film |
|
|
Which of the following may makeup the base of an x-ray film? |
Thin clear plastic, triacetate, & polyester |
|
|
____ often absorb x-rays differently from normal structures. |
Diseased structures & bones w/less calcium |
