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89 terms

DANB Radiology exam

STUDY
PLAY
Harmful effects of radiation on human tissue are?
Cumulative
How much lead should the apron have?
0.25mm
What is the correct vertical angulation used when taking a bitewing x-ray?
+10 degrees
What do full mouth x-rays consist of?
Always has periapical and bitewing films
What needs to happen when exposing a full mouth set of radiographs?
The exposure button should be covered with a plastic barrier
What Radiographic tech. records accurate images of crowns, roots, and supporting structures of a selected area of the oral cavity?
Periapical films
#1 film should be used to x-ray what areas?
Incisors and cuspid
What is the sequence for developing and processing manual processing?
develop, rinse, fix, and wash
What chemical in fixer clears unexposed halide crystals?
ammonium thiosulfate
Electrons from the cathode and anode produce how much energy in the collision?
99%
what landmarks do you look for if the patient has no teeth?
Tuberosity and near the outer corner of the eye
Most likely cause of black spots on a bitewing x-ray?
Developer splash
How does radiolucent look on an x-ray
dark
What restorative material appears radiopaque on a radiograph?
amalgam and gold crowns
what will too much vertical angulation cause?
foreshortening
what is the use for occlusal x-rays?
locate foreign bodies
what do intensifying screens do?
contain phosphors that emit blue or green light
while taking a panoramic extra oral x-ray where should the assistant instruct the patient to place tounge?
on roof of the mouth
which of the following is not classified as a developmental dental abnormality?
periapical abscess
What do filters do in the x-ray beam?
Reduce patient radiation dose and remove the long waves
what is the recommended collimation of the radiation beam at the patients skin surface?
2.75mm
what does ALARA concept stand for?
as low as reasonably possible
what are examples of personnel monitoring devices?
film badge, pocket dosimeter, and film ring
The transfer of energy as it passes through matter is called?
absorption
what is it called when a lead disc is used for the elimination of the peripheral portion of the x-ray beam?>
collimation
in dental radiography, what infection control procedures are included?
sterilization and disinfection
what does immersing the contaminated exposed film packet in a disinfecting solution do?
destroys film
where in the x-ray head does thermionic emission take place?
tungsten filament
What is the primary diagnostic use of bitewing radiograph?
check for interproximal decay and crestal bone level
what causes a herringbone pattern across a film with low density?
the film packet placed backwards
what determines the speed of the film?
the size of the halide crystals
what does the term radiographic density describe?
degree of darkness or blackness of film
a double exposure occurs when
the same film is exposed to radiation twice
which term describes the loss of electrons from a substance?
ionization
which of the following materials is most resistant to the penetration of ionizing radiation?
Lead
which of the following appears radiolucent on a radiograph?
dental pulp
what causes light films?
under developing, underexposure ,not enough mA or KV
which of the following is a helpful hint for mounting a full- mouth set of radiographs?
The overall appearance of the radiographic survey will hace an upward curve like a smile
A charged coupling device (CCD) is primarily made of what substance?
silicon
if a patient is positioned in a panoramic unit with his or her chin too low,which of the following images might be seen on the resultant radiograph?
exaggerated curve of spee
what technique is best when exposing intraoral films prior to placing an implant?
panoramic technique
Film density?
Overall darkness or blackness of a film
Film speed?
the sensitivity of the emulsion on the film
Kilovoltage
changes density and contrast
Latent image
invisible image on the x-ray film after exposure but before processing
Millamperage
affects density
Maximum permissible dose MPD
( N-18) x 0.05 SV/year
Ionization is?
When an electron is removed from the orbital shell of the electronically stable atom
who discovered x-ray and what year?
Wilhelm Roentgen and in Nov. 1895
Who made the first dental radiograph?
Otto Walkhoff
who performed the first dental radiograph on a live patient?
C. Edmund Kells
Who invented the x ray machine and what year?
Victor Radiograph in 1923
Electromagnetic radiation is?
Visible light, radar, radio, tv waves, as well asx-rays
Particulate radiation is?
Postively charged alpha and negatively beta
Characteristic of x-ray beams?
Invisible and undetectable by sense, no mass, no charge, travel at speed of light, travel in short and high frequency waves, travel in straight line & can be deflected or scattered, absorbed by matter, causes ionization, can cause certain substance to fluoresce, can produce image on photographic film, cause changes in living cells
Primary Radiation
Useful beam
Secondary radiation
Formed after primary beams comes in contact with matter and its not useful
Scattered radiation
It occurs when an x-ray bean has been deflected from its path by interaction with matter
What does the collimator do?
Helps reduce scatter radiation and limits size of the primary beam
What is the heart of the x- ray generating system?
X-ray tube
What regulates Milliamperage and Kilo voltage peak?
The selector button
What does the aluminum filter remove?
Harmful low energy, long-wavelength sand least penetrating x-rays frin the beam
What do impulses affect?
Density (the lower the impulse or time the lower the density)
Inverse square law is?
The intensity of the radiation become weaker as it spreads out over a larger area
What is exposure measured in?
Roentgen (R)
What is acute radiation exposure?
When a large does of radiation is absorbed in a short period of time
Chronic radiation is?
Is absorbed in a short period of time.
How far must you stand from the x-ray unit during exposure?
6 ft.
Where is intraoral film placed?
It is used inside the mouth and used to examine the teeth and supporting structures
Extraoral film is placed?
it is placed outside of the mouth and used to examine the large areas of the head and jaw
Intraoral has three types of projections called?
bitewing , peariapical , and occlusal
Extral oral film has 2 projections called?
Panoramic and Cephalometric
What are the two types of intraoral x-ray techniques?
paralleling and bisecting
What are the steps in manual film processing?
Developer, rinse, fixer, wash, dry/mount
What does using an XCP help to avoid?
Excessive angulation
When PID is properly aligned what will you avoid?
Cone cutting
If you have two films together what can happen?
You can have double image
What will happen if you place the white side of film away from the PID?
you will get the Herringbone pattern
What happened if your film is black?
Film got exposed to light
Fogged film occurs when?
The temperature is chaged and the age of the solution.
If streaks show up on film what happened?
YOur rollers need to be cleaned in the automatic processor
What is the Alveolar bone?
Its the bone the teeth go into
What is the fastest film speed?
F- speed film
What is the nutrient canal?
It is the pulp tissue
How many roots do the Mandibular molars have?
2 roots
How many roots do the maxillary molars have?
3 roots
The dot on the film is called?
Labial mounting
What is your check bone called?
zygoma
What is the preferred holder for film?
XCP