Radiology Midterm 2
Which of the following is used as a collimator?
Lead plate
The unsharpness or blurred edges seen on a radiograph image is termed:
Penumbra
fixer cutoff
Straight black border on film= low levels of fixer
The safety of a darkroom safelight depends on the:
Distance of the safelight from the workbench, time the films are exposed to the safelight, speed of the film
MAximum Permissible dose for nonoccupational exposed person:
.5 Rem/yr (.005 Sv/yr)
A variation in the true size and shape of the object being radiographed is termed:
Distortion
Machines operating at 70 kVp or lower require________mm aluminum
1.5
In manual processing, the fixing time for films is usually:
10 mintues
What is the average dose of background radiation received by an individual in the US?
150-300 mrads(.0015-.003Gy)
Machines operating at 70kVp or higher require________ mm aluminum
2.5
For dental radiography, the recommended collimation of the radiation beam of the BID at the patient's skin:
2.75 in.
Which of the following is the recommended size of the beam at the patient's face?
2.75 inches
In hand processing, films should be washed in running water for at least:
20 minutes
A single intraoral radiograph (D-speed film, 70 kVP, long PID) results in a mean surface exposure of:
250mR
A free radical:
Is an uncharged molecule, has an unpaired electron in the outer shell, is highly reactive and unstable, combines with molecules to form toxins
The safelight must be placed a minimum of what distance from the film and working area?
4 feet
The optimum time and temperature for hand development of film is:
4.5 to 5 min. at 68-70 degrees F
At 68 degrees F, what is the optimum development time?
5 minutes
Maximum Permissible dose for occupational exposed person:
5.0 Rem/yr(.05 Sv/Yr)
What is the dose at which leukemia induction is most likely to occur?
5000 mrads (0.05 Gy)
The optimal temperature for the developer solution is:
68 degrees F
Which of the following describes the relationship of the central ray to the film paralleling technique?
90 degrees to the film and long axis of the tooth
What is the angle that the dental radiographer should stand to the primary beam:
90-135 degrees and 6ft away
The type of contrast preferred in dental radiography is:
A compromise b/w short-scale contrast and long-scale contrast
Occlusal Film
A film used to examine a large area of the maxilla or mandible in one film
Bite-wing Film
A film used to examine the crowns of the upper and lower teeth on a single film
Periapical Film
A film used to examine the entire tooth and supporting bone
Which of the following describes the use of a filter in a dental x-ray tubehead?
A filter removes the low energy x-rays
Which of the following is not a component of inherent filtration?
A leaded cone
Which of the following appears most radiolucent on a dental radiograph?
Air space
Which of the following is correct concerning film placement?
Anterior films are placed vertically and posterior films are placed horizontally.
Fogged Film
Appears gray and little detail=improper film storage/outdated films
Static electricity
Black branching lines= opening film packet too quickly
Fingernail artifact
Black, crescent-shaped marks=rough handling
The hydroquione in the developer brings out the _______ tones, whereas the Elon in the developer brings out the _________tones on a dental radiograph.
Black;gray
An example of a radiopaque structure seen on dental x-rays:
Bone, enamel, and dentin
Which of the following can be used to clean the processing tank?
Both commercial tank cleaners and hydrochloric acid(1.5 ounce) with 128 ounces of water solution.
Which of the following controls total magnification (included penumbra) of the radiographed object?
Cathode size, object-film distance, focal spot-film distance, focal spot size
Unopened boxes of radiographic film should bot be stored in the darkroom b/c:
Chemical fumes from processing solutions may fog the film
Which of the following devices restricts the size and shape of the x-ray beam?
Collimator
A replenisher is added to the processing solution to:
Compensate for the loss of solution strength, ensure uniform results b/w solution charges, compensate for the loss of volume of solution, compensate for oxidation.
The difference in the degrees of blackness b/w adjacent areas on a dental radiograph is termed:
Contrast
An organ that if damaged diminishes the quality of an individual's life is termed:
Critical organ
Developer spots
Dark spots of film
Beam perpendicular to object and film=
Decrease distortion
Object and film are parallel=
Decrease distortion
Decrease Object-film distance=
Decrease magnification
Increase Target-film distance=
Decrease magnification
Increase crystal size=
Decrease sharpness
Increase movement=
Decrease sharpness
Replenisher pump
Delivers developer and fixer solution to compartments
The overall blackness or darkness of a dental radiograph is termed:
Density
The thermometer for manual processing should be placed in the:
Developer solution
The first step in film processing is:
Development
Which of the following is incorrect concerning the exposure sequence for pericapical films?
Either posterior or anterior films may be exposed first.
Processor housing
Encases component parts of automatic processor
Light leak
Exposed area is black= exposed to light
he latent period in raditation biology is the time between:
Exposure to x-radiation and clinical symptoms
Overdeveloped Film
Film appears too dark b.c of excess dev. Time & high dev. Temp.
Underdeveloped film
Film appears too light b/c of low dev. Time, depleted dev. Solution
Which of the following is true of film badges?
Film badges should be worn at the waist level when exposing x-ray films
Any leaks of white light into the darkroom will cause:
Film fog
The amount of radition exposure an individual receives varies depending on which of the following factors?
Film speed, Collimation, technique. Exposure factors
Which of the following will not produce film fog?
Films stored in a refrigerator in the lab
The film emulsion is hardened during:
Fixation
Radiation injuries that are not seen in a person irradiated but that occur in future generations are termed:
Genetic effects
Which of the following is a unit of radiation absorbed dose expressed in joules per kilogram of irradiated tissue?
Gray (Gy)
The radiation weighting factor is used in the determination of which of the flowing radiation units?
Gy
The unit of x-radiation measurements that deals with the absorbed energy per kilogram of tissue is the:
Gy
Drying chamber
Heated air is used to dry wet films
When viewed on a light source, a dental radiograph that demonstrates very dark areas and very light areas is said to have:
High contrast
Which of the following reduced the radiation dose to the patient?
High-speed film, Collimator, digital imaging, gonadal shields
The Size of a darkroom is determined by all the following except:
Humidity level of the room
Which of the following is correct concerning the lack of parallelism between the film and the long axis of the tooth?
If less than 20 degress, the film is generally acceptable.
BID (cone) cutting (partial image) on a radiograph is caused by:
Improper coverage of the film with the beam of radiation.
What is the cause of yellow or brown stains appearing on films some time after processing?
Incomplete fixing and washing
Increase Object-film distance=
Increase magnification
Decrease crystal size=
Increase sharpness
Decrease focal spot size=
Increase sharpness
Decrease movement=
Increase sharpness
dental patient had thick soft tissues and dense bones. To compensate for this increase in subject thickness and provide a film of diagnostic density, the dental radiographer:
Increase the mA, kVp, and exposure time
Increasing the mA will cause:
Increases the density and makes the film darker
increasing the exposure time will cause:
Increases the density and makes the film darker
increasing the kVP will cause:
Increases the density and makes the film darker
The GBX-2 safelight filter by Kodak is recommended for:
Intra and extraoral films
The intensity of x-radiation at any given distance from the source of radiation varies:
Inversely with the square of the distance
Which of the following effects can be associated with low-dose, whole body radiation?
Leukemia
Which of the following will produce film fog?
Light leaks in the dark room, films stored for a ling time in an unsafe place, unprotected films in the x-ray room or x-ray equipped operatory.
Fixer spots
Light or white spots on film
Which of the following relationships describes the response of tissues to radiation:
Linear; nonthreshold
Which of the following statements is correct?
Long-term effects are seen within small amounts of radiation absorbed in a long period
When viewed on a light source, a dental radiograph that demonstrates many shades of gray is said to have:
Low contrast
The geometric characteristics that refers to a radiograph image that appears larger than its actual size is termed:
Magnification
Which of the following is considered radioresistant?
Mature bone cells
Which of the following terms describes the dose of radiation that the body can endure with little or no chance of injury?
Maximum permissible Dose
What is the greatest contributor to artificial radiation exposure?
Medical radiation
The sensitivity of tissues to radiation is determined by:
Mitotic Activity, cell differentiation, cell metabolism
Film recovery slot
Opening where processed films emerge
The one exposure factor that has a direct influence on the contrast of a dental radiograph:
Operating kVp
A breakdown of chemicals in the processing solution that results from exposure to air is termed:
Oxidation
Differences between manual and automatic processing include which of the following?
Processing solution chemistry, solution temperature, solution concentration, time to completion of processing
When an 8in. target-film distance is changed to a 16in. target-film distance (kVp and mA kept constant), the exposure time should be:
Quadrupled
The unit for measuring the absorption of x-rays is termed:
Rad
The portion of a processed radiographed that appears dark or black is termed:
Radiolucent
the portion of a processed radiograph that appears light or white is termed:
Radiopaque
Which of the following position-indicating devices is most effective in reducing patient exposure?
Rectangular PID
Which of the following describes the function of filtration?
Reduced low energy waves
The quality factor (QF) is used to determine which of the following radiation units?
Rem
The superconcentrated solution that is added to the processing solution to compensate for the effects of oxidation is termed:
Replenisher
Which of the following is the most radiosensitive?
Reproductive organs
Which of the following definitions is incorrect? Which of the following definitions is incorrect?
Right angle:formed by two parallel lines→ should be perpendicular
n film processing, the rinsing step is necessary because:
Rinsing removes the developer from the film and stops the development process
The capability of the x-ray film to reproduce distinct outlines of an object is termed:
Sharpness
Which of the following is not critical factor in the radiation response of cells?
Size of cells
Which of the following is most susceptible to ionizing radition?
Small lymphocyte
Air bubbles
Small white spots=need to stir film racks after placing in processing solution
Replenisher solutions
Solutions used to maintain proper concentration and levels of developer and fixer
Which of the following is used only for x-rays?
The Roentgen
Which of the following traditional units does not have an SI equivalent?
The Roentgen
The traditional unit for measuring x-ray exposure in air is termed:
The Roetgen
Which of the following describes the relationship of the film and the long axis of the tooth in the paralleling technique?
The film and tooth are parallel to each other.
Which of the following describes the distance between the film and the tooth in the paralleling technique?
The film is placed away from the tooth and toward the middle of the oral cavity.
Occlude
To close or bite
All the following factors affect the life of the processing solutions except:
Type of safelight filter used
The long BID (Cone) is recommended when using the paralleling technique bc we can:
Use a longer focal spot-film distance to compensate for a greater object-film distance to reduce magnification and distortion.
What is the main cause of foreshortening in the bisecting-angle technique?
Vertical angulation of the BID is insufficient
Overlap film
When two films come into contact-in dev =white areas/ in fixer=black areas
How often should the processing tank be cleaned?
Whenever solutions are changed
Dentulous
With teeth
Enentulous
Without teeth
Which of the following statements is incorrect?
X-radiation is not harmful to living tissues.
Indirect radiation injury occurs when:
X-ray photons are absorbed and form toxins
Direct radiation injury occurs when:
X-ray photons hit critical targets within a cell
Formula for Maximum accumulate dose:
[N-18] x 5.0 rems/yr
Which of the following conversions is correct?
all of they above.
X-ray filters are usually made of:
aluminum
The technique that shows the upper and lower crowns and associated alveolar bone on the same radiograph is called the:
bitewing technique
Scratches
black branching lines= opening film packet too quickly
Which of the following tissues is most susceptible to radiation?
blood-forming tissue
In hand processing, if you place the film in the fixer first, this results in:
clear film
Intensifying screens are used with extra oral and panoramic films to:
decrease the radiation to the patient
The size of the focal spot in the x-ray tube influences radiographic:
definition
The optimal density of an intramural film indicates the:
degree of darkness in an image
To test for chemically fogged or age-fogged film:
develop the film without exposing it
List three types of intaoral radiographic examinations:
eriapical, Bite-wing, and Occlusal
Relative to radiation biology, the latent period is that period between:
exposure to radiation and the appearance of clinical symptoms
Which of the following is the most effective method of reducing patient exposure to radiation?
fast films
Which of the following effects is not considered to be dependent on dose rate?
genetic effects
Yellow-brown stains
hausted developer or fixer, insuff. Rinsing or fixation time
Which of the following are advantages of the paralleling technique?
increased accuracy, simplicity of use, and ease of duplication
The primary advantage of the paralleling technique over the bisecting-angle technique is:
increased anatomic accuracy of the image
fog affects the contrast of an intramural film b/c it:
increases film density
The paralleling technique is recommended over the bisecting-angle technique bc:
it gives less-distorted picture of root length
Subject contrast is primarily a function of:
kVp
Optimal density is a function of :
kVp, mA, exposure time
Collimators are usually made of:
lead
A pregnant patient:
may be irradiated for dental radiographs by taking the proper precautions.
Roller film transporter
moves the film through the automatic processor
which of the following films can be used intraorally and extra orally?
occlusal film
Film/feed slot
opening to insert films
Which of the following factors contributes to radiation injury?
otal dose, dose rate, cell sensitivity, & age
Regardless of the target-film distance, incorrect horizontal angulation will cause:
overlapping of teeth in the x-ray image
In the bisecting-angle technique, the central ray of the beam is directed:
perpendicular to a line bisecting the angle formed by the object and the film packet.
Which is the hardening agent in film processing?
potassium alum
Which of the following is the most effective in reducing patient radiation dose?
proper collimation
Developer cutoff
straight white border on film= low levels of developer
True or False
the long BID is used with the paralleling or the bisecting-angle technique
Which of the following is a correct statement about intensifying screens?
thicker phosphor layers result in faster screens.
Why is the long BID considered a necessary adjunct to the paralleling technique?
to avoid magnification of the image
The stepwedge is used for all of the following except:
to increase the penetrating quality of the x-ray beam
The advantages of the paralleling technique outweigh the disadvantages:
true
A film is stripped from its packet and exposed to light. After processing it will:
turn black
