Radio Flashcards
Which type of digital image receptor is most common at this time?
•CID (charge injection device)
•CMOS/APS (complementary metal oxide semiconductor/ active pixel sensor)
•CCD (charge-coupled device)
CCD (charge-coupled device)
Which of the following are advantages of direct digital radiography. Select all that apply •superior gray-scale resolution •reduced patient exposure to x-radiation •increased speed of image viewing •lower equipment and film costs •sensor size •increased efficiency •effective patient education tool •enhancement of diagnostic image
- superior gray-scale resolution
- reduced patient exposure to x-radiation
- increased speed of image viewing
- lower equipment and film costs
- increased efficiency
- effective patient education tool
- enhancement of diagnostic image
A method of obtaining a digital image where the sensor captures the image and immediately transfers it to a computer is termed:
•indirect digital imaging
•direct digital imaging
•storage phosphor imaging
direct digital imaging
پیش بند سربی
گردن بند تیرویید
lead apron
thyroid collar
A patient is extremely concerned about radiation exposure. Which of the following is best for limiting the amount of exposure he will receive during a full mouth series?
•use of digital imaging
•use of E-speed films
•use of F-speed films
•substitute a panoramic image for the full mouth series
use of digital imaging
A radiograph that exhibits areas of black and white is termed high contrast and is said to have a short contrast scale; a radiograph the exhibits many shades of gray is termed low contrast and is said to have a long contrast scale.
To limit image magnification, the longest target-receptor distance and shortest object-receptor distance are used.
• both statements are true
• both statements are false
• the first statement is true, the second is false
• the first statement is false, the second is true
both statements are true
- a short contrast scale
* a long contrast scale
- low kilovoltage-high contrast (black and white)
* high kilovoltage-low contrast (gray)
Rank the following from LEAST radiopaque to MOST radiopaque. • amalgam • bone • dentin • maxillary sinus • enamel
maxillary sinus - bone - dentin - enamel - amalgam
dental radiographs are the legal property of the: • patient • dentist • state • none of the above
dentist (even though the patient or an insurance company have paid for them) because they are indispensable to the dentist as part of the patient record
They should be kept indefinitely
A dental hygienist in your practice has an adult recall patient without evidence of caries who states she needs bite -wing x-rays because it has been 6 months since her last dental images. The hygienist should tell the patient that:
•yes, she is correct, it is time for new x-ray images
•bite-wings should be taken only once per year, not twice
•images should be taken based on patient need instead of a set time frame
•none of the above
images should be taken based on patient need instead of a set time frame (should never set number, type of images and interval)
Guidelines for radiographs in the recall patient:
•with clinical caries or risk of caries
•with no clinical caries or risk of caries
•with periodontal disease
- bite-wings at 6 - 12 month intervals
- bite wings at 24 - 36 month intervals
- clinical judgment for radiographs needed to evaluate periodontal disease; selected bite-wings & periapicals
The coronoid process often appears on what periapical image? • maxillary incisor • maxillary molar • mandibular incisor • mandibular molar
maxillary molar
The pattern of stored energy on an exposed film is termed the latent image; this image remains invisible until it undergoes processing.
The function of the developer solution is to chemically reduce the exposed, energized silver halide crystals to black metallic silver.
• both statements are true
• both statements are false
• the first statement is true, the second is false
• the first statement is false, the second is true
both statements are true
structures that permit the passage of the x-ray beam allow more x-rays to reach the film & energize more ?, these result in more deposits of ?
- silver halide crystals
* black metallic silver
x-ray developer solution removes ? of exposed silver halide crystals
halide portion
x-ray fixer solution function?
- removes unexposed silver halide crystals
* hardens the film
Which ingredient in the fixer solution functions to remove all unexposed and underdeveloped silver halide crystals from the emulsion? • fixing agent • acidifier • hardening agent • preservative • none of the above
fixing agent
fixing agent composition?
ammonium thiosulfate
as a rule, fixing time is ? as long as developing time
twice (5 minutes in developer —> 30 second rinse —> 10 minutes in fixer —• at least 10 minutes in wash)
total processing time in automatic film processing is?
4-6 minutes
Your assistant has processed three panoramic films today. She noticed the films are progressively getting lighter and lighter. What should be done to
correct the problem?
• decrease the temperature of the developer
• increase the temperature of the fixer
• replenish the developer
• process the films a second time
• decrease the time in the developer
replenish the developer
Your assistant has just processed a film that appears too dark. Identify each of the potential causes of this problem. • inadequate time in developer • excessive time in developer • developer solution too cool • developer solution too hot • depleted developer • concentrated developer
- excessive time in developer
- developer solution too hot
- concentrated developer
both the developer and fixer must be replenished ? to maintain adequate freshness
daily
the developer and fixer must be changed at the same time every? or more often with high volume of processing
3-4 weeks
Black branching lines appear on a processed him. Which of the following is the most likely cause? • fixer cut-off • developer cut-off • fingernail damage • static electricity • air bubbles
static electricity (- Occurs when film packet is opened quickly - Occurs when film pack is opened before the radiographer touches a conductive object)
Dose equivalent is expressed in terms of: • coulombs/kilogram (C/kg) • gray (Gy) • sievert (Sv) • quality factor (QF)
sievert (Sv)
White spots on x-rays?
Air trapped on the film surface after being placed in the processing solutions. Gently agitate film racks after placing in processing solutions
List the following cells from most RADIORESISTANT to most RADIOSENSITIVE. • muscle • small lymphocyte • skin • thyroid gland
muscle (and nerve) — thyroid gland — skin — small lymphocyte
After the bombings of Hiroshima, there were many persons exposed to radiation. Symptoms such as hair loss did not occur until days following the exposure. The time between exposure and onset of symptoms is termed: • latent period • period of cell injury • recovery period • cumulative effects period
latent period
cells respond to radiation based on ?
- mitotic activity,
- differentiation
- cell metabolism
cells that are dividing and immature are most/least ? susceptible to radiation
most
radiation effects are classified as ?
- somatic (occur in person irradiated)
* genetic (passed on to future generation)
examples of high sensitive cells?
small lymphocyte - bone marrow - reproductive cells - intestinal mucosa
A patient with a large squamous cell carcinoma of the lateral border of the tongue is scheduled for a radical neck dissection. Prophylactic extractions of hopeless teeth must be done to prevent which of the following? • osteoradionecrosis • bisphosphonate osteoradionecrosis • periodontal disease • rampant caries • none of the above
osteoradionecrosis
The most common oral problems that occur following radiation and chemotherapy include mucositis, infection, pain and bleeding.
The oral cavity is irradiated during the course of treating radiosensitive oral malignancies, usually squamous cell carcinoma.
• both statements are true
• both statements are false
• the first statement is true, the second is false
• the first statement is false, the second is true
both statements are true
Histologic features of squamous cell carcinoma ?
3 hypos:
• hypocellular bone
• hypovascular tissue
• hypoxic tissue & bone
Radiation effects on oral tissues occurs by ? of therapy
end of 2nd week
following therapy, oral tissues heal within approximately ? months
2 months
Radiation effects on taste buds?
- taste buds are radiosensitive
- radiation therapy damages taste buds
- a loss of taste may first occur during the 2nd or 3rd week of radiation therapy
Radiation effects on salivary glands?
- there is a marked & progressive loss of salivary secretion; extent of reduced flow is dependent on dose
- causes decreases in saliva, pH & buffering capacity
- causes increased viscosity
- dry mouth (xerostomia) results & makes the patient susceptible to radiation caries - a rampant form of caries
- xerostomia causes tenderness of oral tissues and difficulty in swallowing
In the dental x-ray tube, the number of electrons flowing per second is measured by: • kilovoltage peak (kVp) • milliamperage (mA) • time (in seconds) • all of the above
milliamperage (mA)
x-ray beam quantity
When the PID length is changed from 8" to 16", the target-receptor distance is doubled. According to the Inverse Square Law, the resultant x-ray beam is: • 1/4 as intense • 1/8 as intense • four times more intense • eight times more intense • none of the above
1/4 as intense
quality refers to the average energy or penetrating power of the x-ray beam and is controlled by ?
the kilovoltage peak (kVp)
quality
kVp range for dental radiography is?
mA range for dental radiography is?
65-100 kVp
7-15 mA
mA controls ? of the filament
the temperature
to INCREASE film density & make it darker, INCREASE:
- mA
- kVp
- time
A 6'5" muscular male with a large mandible requires a complete series of dental images. You plan to increase the kVp because of his size. Identify each of the following that results with the increased kVp: • a more penetrating beam • a less penetrating beam • a reduced subject contrast • an increased subject contrast • long scale contrast • short scale contrast
- a more penetrating beam
- a reduced subject contrast
- long scale contrast
Identify each of the following that influence the density of an image: • kVp • mA • exposure time • use of a 2-film packet
- kVp
- mA
- exposure time
Increased kVp produces x-rays with increased/decreased ? energy (speed) and shorter/longer? wavelength
- increased
* shorter
Increased kVp produces which kind of contrast?
low contrast which is long-scale contrast (many shades of gray)
density is the degree of.?
silver blackening
an image of correct density allows one to view the black areas (?), white areas (?) and gray areas (?)
air space images
enamel, dentin, bone
soft tissue
Which of the following converts electrons into x-rays? • positive anode • negative anode • positive cathode • negative cathode
positive anode
what supplies electrons necessary to generate x-rays?
Cathode (negative electrode)
Which of the following focuses the electrons into a narrow beam and directs the beam across the tube toward the tungsten target of the anode? • copper stem • tungsten filament • insulating oil • molybdenum cup • lead collimator
molybdenum cup
Identify each of the following that are properties of x-rays: • no weight • travel at speed of sound • have no charge • cannot be deflected or scattered • are invisible • are absorbed by matter • do not damage living cells • do not cause fluorescence
- no weight
- have no charge
- are invisible
- are absorbed by matter
Rectification is the conversion of a direct current (DC) to an alternating current (AC).
The dental x-ray tube acts as self-rectifier in that in changes DC to AC while producing x-rays.
• both statements are true
• both statements are false
• the first statement is true, the second is false
• the first statement is false, the second is true
both statements are false (dental x-ray tube acts as a self-rectifier in that it changes AC into DC while producing x-rays; ensures that current is always flowing in the same direction from cathode to anode)
voltage is the, measurement of ? that causes electrons to move from a negative pole to a positive one; measured in volts (V) or kilovolts (kV)
electrical force
Which of the following occurs only at 70 kVp or higher and accounts for a very small part of the x-rays produced in the dental x-ray machine? • compton scatter • coherent scatter • characteristic radiation • general (Bremsstrahlung) radiation
characteristic radiation
Identify each component of inherent filtration: • insulating oil • unleaded glass window • lead lined PID • tubehead seal
- insulating oil
- unleaded glass window
- tubehead seal
purpose of the aluminum discs is to ? from the x-ray beam
filter out the longer-wavelength, low-energy x-rays
• dental x-ray machines operating at , 70 kVp require a minimum total of ? mm aluminum filtration
- 5 mm
2. 5 mm
Identify each of the following that is recommended for operator protection during exposure.
• stand 3 feet away from x-ray tubehead
• stand at a 45-75 degree angle to the beam
• wear a lead apron
• stand behind a barrier
• hold the PID
• hold the film if the patient cannot stabilize it
stand behind a barrier (must stand at least 6’ away from the tubehead, if distance is not possible, a protective barrier must be used)
Prior to x-ray exposure, the proper prescribing of radiographs and the use of proper equipment can minimize the amount of radiation that a patient receives.
Radiographs must be prescribed by the dentist based on the individual needs of the patient.
• both statements are true
• both statements are false
• the first statement is true, the second is false
• the first statement is false, the second is true
both statements are true
Operator position recommendations
must stand perpendicular to the primary beam, or, at a 90-135 degree angle to the beam
most effective of PID in reducing patient exposure?
- rectangular PID (instead of round)
* a long PID is more effective than use of a short PID
Which of the following is used to restrict the size and shape of the x-ray beam and to reduce patient exposure? • aluminum discs • collimation • inherent filtration • total filtration
collimation
If a processed film appears light with herringbone or tire track pattern on it, which of the following is the likely cause?
• the film was bent during placement
• the film was reversed (placed backwards) during exposure
• the film was exposed twice
• the patient moved during exposure
the film was reversed (placed backwards) during exposure
a collimator is a ?, is fitted over the opening of the machine housing where the beam exits
lead plate with hole in the middle
Position indicating device (PID) or cone is an ? used to direct the beam
extension of the x-ray tubehead
types of PID include ?
conical, round and rectangular (rectangular most effective in reducing patient exposure)
both round and rectangular PIDs are available in two lengths: ?
short (8”) and long (16”) [the longPID is preferred because less divergence of the x-ray beam occurs]
a blurred image is resulted with?
With movement of the patient or PID
film appears stretched & distorted, why?
it is bent (occurs due to curvature of hard palate)
Of the following factors that influence the geometric characteristics of an image, which one is NOT able to be changed by the operator? • target-receptor distance • object-receptor distance • film composition • focal spot size • object-receptor alignment
focal spot size (ranges from 0.6 -1.0 mm2)
A periapical image shows stretched and elongated maxillary central incisors. Which of the following is the likely cause?
• vertical angulation is excessive/too steep
• vertical angulation is insufficient/too flat
• incorrect horizontal angulation
• any of the above
vertical angulation is insufficient/too flat [too steep vertical angulation results in foreshortened image]
? influences the image sharpness
the size of focal spot (the smaller the focal spot, the sharper the image)
incorrect horizontal angulation results in?
overlapped contacts
chin tipped too far downward, what would be the panoramic image errors?
- occlusal plane has excessive upward curve
* exaggerated smile line is seen
chin tipped too far forward, what would be the panoramic image errors?
- occlusal plane downward curve
- reverse smile line (frown) is seen
- hard palate & floor of nasal cavity appear superimposed over maxillary teeth
the bone of the patient’s finger seen on the image?
Phalangioma
- film appears gray & lacks contrast, its name?
- its cause?
- result from?
- fogged film
- occurs when film is exposed to radiation other than primary beam
- improper safelighting or lightleaks in dark room
if the beam is not centered over the receptor, a clear unexposed area or ? is seen on the image
cone-cut
- if the PID is moved mesially and the object in the second image appears to have moved in the same direction, the object lies to the ?
- if the PID is moved mesially and the object in the second image appears to have moved in the opposite direction, the object lies to the ?
- lingual (SLOB)
* buccal (SLOB)
Ghost image appearance
- resembles its real counterpart
* found on the opposite side of the image; appears indistinct, larger, & higher than its actual counterpart
Identify each one of the following that is an advantage of using the paralleling technique. • receptor placement • comfort • accuracy • simplicity • duplication
• accuracy
• simplicity
• duplication
(An increased target-receptor distance (16”) is required)
Identify each one of the following that is a disadvantage of using the bisecting technique.
• decreased exposure time
• can be used without a beam alignment device
• distortion
• angulation problems
- distortion
* angulation problems
