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Radiology > Radiographic Exposures and Film Processing > Flashcards

Radiographic Exposures and Film Processing Flashcards

1
Q

What is the density of an X-ray described as?

A

The degree of blackness on the radiograph. A high quality radiograph has good density.

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2
Q

What are areas in the mouth that are denser, therefore absorb more X-rays? List 2.

A
  1. ) Bone

2. ) Metallic restorations

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3
Q

What do Radiopaque areas of an X-ray appear as?

A

Appears white.

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4
Q

What do Radiolucent areas on an X-ray appear as?

A

They appear black because they are less dense.

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5
Q

What are some examples of areas in the mouth that appear radiolucent on X-rays? Name 2.

A
  1. ) Pulp Chambers

2. ) Sinus Cavities

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6
Q

What is contrast?

A

The range of shades from white to black, including all gray.

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7
Q

What is the contrast of an X-ray controlled by?

A

Kilovoltage adjustment.

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8
Q

What does decreasing the contrast do?

A

Lightens the radiograph, producing more shades of gray, therefore making the X-ray more diagnostic.

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9
Q

What does increasing the Milliamperage do to the X-ray?

A

Darkens the radiograph and increases the density.

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10
Q

Increasing the exposure time ______ the density, and _____ the X-ray.

A

Increases, darkens.

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11
Q

Decreasing the exposure time ______ the density, and ______ the X-ray.

A

Decreases, lightens.

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12
Q

What does FFD stand for?

A

Focal Film Distance.

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13
Q

Why is having a lengthy FFD (Focal Film Distance) necessary?

A

For the most parallel rays to reach the object.

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14
Q

The Inverse Square Law demonstrated that large FFD’s do what?

A

They increase exposure, therefore increase radiation to the patient.

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15
Q

What are the most commonly used size FFD’s in dentistry? Name 3, in inches.

A

8, 12, 16 inches.

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16
Q

What does the Inverse Square Law do?

A

They regulate energy and distance.

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17
Q

Density of radiographs is best controlled by doing what?

A

Adjusting the mA.

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18
Q

What 3 qualities must a film packet maintain?

A
  1. ) Moisture and light resistant
  2. ) Flexible
  3. ) Easy to open in the dark room
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19
Q

What is the benefit of using a double film pakcet?

A

You can contain 2 X-rays, without exposing the patient twice.

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20
Q

What is a duplicate film composed of?

A

Silver halide emulsion, covered by gelatin, on a cellulose acetate film.

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21
Q

What determines the film speed or sensitivity in a duplicating film?

A

The size of the silver halide crystals.

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22
Q

Faster films have _____ crystals and give _____ definition, or detail on a film.

A

Larger, poorer.

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23
Q

Slower films have _____ crystals, and give ______ detail, and require more ________.

A

Smaller, better, milliamperes.

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24
Q

What does the ANSI stand for?

A

American National Standards Institute.

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25
Q

Who is film speed designated by?

A

The ANSI, or American National Standards Institute.

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26
Q

How is film speed measured according to the ANSI?

A

By letter groups A-F, with speed increasing incrementally with the alphabet.

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27
Q

What fast film, characterized by letters, are most commonly used in the dental office?

A

D-E.

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28
Q

Film size is manufactured in what sizes?

A

0-4.

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29
Q

What should dental films be stored in?

A

A lead-lined container or compartment.

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30
Q

Why are dental films stored in a lead-lined container or department? There are 5 reasons.

A

So that they are not exposed to scatter radiation, moisture contamination, heat, chemicals, or light.

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31
Q

What happens to film that is outdated, or affected by undesired radiation or light?

A

They become fogged.

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32
Q

What are periapical (PA) radiographs used to diagnose?

A

Pathologic conditions of alveolar bone and teeth, including tumors, cysts, developmental abnormalities, and infection.

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33
Q

What are Bitewing (BXW) radiographs used to determine?

A

Interproximal caries and decay, periodontal disease.

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34
Q

What are occlusal radiographs used to diagnose? There are 6 reasons.

A
  1. ) To locate SN teeth, impacted teeth, retained roots, foreign bodies, salivary gland calcifications, and other pathoses.
  2. ) To determine extent and shape or cystic, neoplastic, and infectious lesions,
  3. ) To locate and determine the type and extent of jaw fracture in tooth bearing lesions.
  4. ) For patients who are not able to open wide of other X-rays.
  5. ) Record changes in shape and size of dental arches.
  6. ) To minimize the number of radiographs taken during a periodontic survey.
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35
Q

What are the size variations of an extraoral film packet in inches? There are 3 variations.

A

5x7, 8x10, and 5x12 inches.

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36
Q

What are intensifying screens used for in a cassette?

A

To intensify the radiation and decrease exposure time,

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37
Q

What are cassettes made of? There are 2 kinds.

A

Most are metal, but lightweight plastic is used for Pans,

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38
Q

What are some reasons for obtaining a Panoramic X-ray? List 4.

A
  1. ) To evaluate facial trauma or fractures, cysts, and tumors.
  2. ) To assess maxillary and mandibular dentition development
  3. ) To evaluate the jawbones of edentulous patients.
  4. ) To evaluate the eruption or positioning of wisdom teeth.
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39
Q

What does edentulous mean?

A

Patients who lack teeth.

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40
Q

What areas of diagnostic quality does the Panoramic X-ray capture? Name 4.

A
  1. ) The condoyles
  2. ) The inferior border of the mandible
  3. ) The Maxilla including zygomatic arches
  4. ) Sinuses
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41
Q

What are 5 disadvantages of taking a Panoramic X-ray?

A
  1. ) Not as diagnostic as individual films for caries or bone height
  2. ) Images of teeth are enlarged or distorted
  3. ) There is overlapping of contacts in premolars and molars.
  4. ) Anterior teeth are difficult to see when they have pronounced inclinations
  5. ) Decreased sharpness and generalized haziness occurs
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42
Q

What are 3 common positioning errors when taking Panoramic X-rays?

A
  1. ) Improper chin tilt
  2. ) Non centered patients
  3. ) Head tilted to one side
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43
Q

What 5 things occur when the chin is tilted too far downward on a Panoramic X-ray?

A
  1. ) Mandibular symphysis is projected off the film
  2. ) Occlusal plane may exhibit an exaggerated curve
  3. ) Condoyles may not be present on the film
  4. ) Anteriors may be distorted
  5. ) Excessive overlap of interproximal contacts exists.
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44
Q

What 2 things may occur when the chin is tilted too far upward on a Panoramic X-ray?

A
  1. ) there is a reverse occlusal plane curve
  2. ) Mandibular structures may appear narrower than normal, whereas maxilla structures appear widened, the palate appears thickened, and the film lacks bilateral image symmetry.
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45
Q

What 2 thinks may occur when the head is tilted slightly upon taking a Panoramic X-ray?

A
  1. ) Images of structures on the side farther from the film appear wider and may be out of focus
  2. ) Superior portion of the condyle heads may be projected off the film
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46
Q

What 4 things to an X-ray film packet consist of?

A
  1. ) Waterproof outer covering
  2. ) Black paper
  3. ) Film
  4. ) Lead foil
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47
Q

What 2 things does lead foil in a film packet do?

A
  1. ) Prevents film fogging

2. ) Reduces background scatter radiation

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48
Q

What are 2 techniques used to take a series of radiographic films?

A
  1. ) Paralleling

2. ) Bisecting the angle

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49
Q

What does PID stand for?

A

Position Indicating Device

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50
Q

What are 3 advantages of paralleling?

A
  1. ) The image formed on the film will have dimensional accuracy
  2. ) Owing to minimum distortion, periodontal bone height can be diagnosed correctly
  3. ) on maxillary molar projection, there is little or no root superimposition
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51
Q

What are 3 disadvantages of paralelling?

A
  1. ) Intraoral film-holding devices must be used, which can be difficult to use and uncomfortable for the patient
  2. ) Some PT.’s have anatomic features such as low palatal vaults that prevent proper film placement
  3. ) The use of a long cone (PID) necessitates an increase in exposure time.
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52
Q

What are 3 advantages of bisecting the angle?

A
  1. ) Decreased exposure time
  2. ) Less cumbersome film holder
  3. ) Anatomic features usually do not interfere with film placement
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53
Q

What are 3 disadvantages of bisecting the angle?

A
  1. ) The image projected on the film is dimensionally distorted in varying degrees
  2. ) True alveolar bone height can be misinterpreted
  3. ) The use of a short cone (PID) results in divergent rays, therefore the image is not an optimum reproduction of the object
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54
Q

How many PA’s and BWX’s are taken in an FMX?

A

14-16 PA’s, and 4 BWX’s

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55
Q

What is the purpose of taking an FMX?

A

Diagnose bone and root pathologic conditions, and to provide information on tooth formation and eruption.

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56
Q

What are the 10 essential components to have in a dark room?

A
  1. ) No light leaks
  2. ) Safelight (Usually a 10 watt or 15 watt bulb with a red filter placed about 3-4 feet from the working surface)
  3. ) Developing tank with a developer, wash, and fixer
  4. ) Timing device
  5. ) Thermometer (In developing solution)
  6. ) Rack on which to place films
  7. ) Clean working surface
  8. ) Sink (For cleaning tanks)
  9. ) View box
  10. ) Storage space
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57
Q

How many watts is a safelight usually, and how many feet from the working surface should it be placed?

A

10 or 15 watts, 3-4 feet

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58
Q

Where is the developer usually placed in relation to the wash and fixer?

A

On the right

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59
Q

Where is the thermometer kept in the dark room?

A

in the developing solution

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60
Q

When does the error of elongation occur on X-rays? List 4 reasons.

A
  1. ) When there is too little vertical angulation
  2. ) When the occlusal plane is not parallel to the floor
  3. ) Film not placed against tissue
  4. ) Poor film placement
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61
Q

When does the error of foreshortening occur on X-rays? Name 2 reasons.

A
  1. ) Too much vertical angulation

2. ) Poor chair position

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62
Q

When does the error of film reversal or herringbone effect occur on X-rays?

A

Film placed in mouth backwards

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63
Q

When does the error of artifact occur on X-rays?

A

When failing to have the PT. remove sunglasses, earrings, prosthetic appliances

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64
Q

Before developing films, what should you do to the solution to ensure that they are homogeneous and temperatures are equalized?

A

Stir them

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65
Q

How often should you record solution temperatures in the dark room?

A

Daily

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66
Q

What are the 5 steps, in order, for developing X-rays?

A
  1. ) Developing
  2. ) Washing
  3. ) Fixing
  4. ) Washing
  5. ) Drying
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67
Q

What is the developing solution made up of, and what does it do?

A

It is made of a simple solution of Elon or metal hydroquinone, and it reduces the energized silver halide crystals to silver.

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68
Q

The radiograph is very sensitive to both length of time in the developer, and the temperature of the solution. What is the optimum time-temperature relationship?

A

4.5 minutes at 68 degrees Fahrenheit.

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69
Q

How many seconds is the developed film washed for in running water?

A

20-30 seconds.

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70
Q

What is the fixer made of, and what does it do?

A

It’s an acidic solution that contains sodium thiosulfate and sodium sulfite. It removes the unexposed (or unenergized) silver halide crystals from the emulsion and preserves the picture.

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71
Q

What is in the fixer solution, that shrinks and hardens the film?

A

Potassium aluminum.

72
Q

How many minutes must the radiographs be placed in the fixer for?

A

A minimum of 10 minutes.

73
Q

What will happen if the radiograph is not placed in the fixer for at least 10 minutes?

A

It will turn brown.

74
Q

How many minutes after the radiograph is placed in the fixer, can it be removed for inspection, before being replaced to complete fixation?

A

1 minute. It must immediately be placed back in the fixer for at least 10 minutes after inspection.

75
Q

How many minutes must the film be placed under running water for the final wash?

A

At least 20 minutes.

76
Q

What are the 2 methods of drying films in the dark room?

A
  1. ) Air drying

2. ) Machine drying

77
Q

What is the process of automatic processing?

A

It permits films to be carried on a series of rollers from solution to solution. The appropriate time-temperature relationship is set, and dry films emerge in approximately 5 minutes.

78
Q

How many minutes does it take approximately, for dry films to emerge when using automatic processing?

A

Approximately 5 minutes.

79
Q

Automatic Processors save time. What are 2 disadvantages of using automatic processing?

A
  1. ) They require periodic cleaning

2. ) Solutions must be changed regularly

80
Q

What are the 5 steps to duplicate X-ray films?

A
  1. ) Enter darkroom and turn on safelight
  2. ) Place films on duplicator machine glass
  3. ) Place duplicating film emulsion side down on top of radiographs
  4. ) Turn on duplicating machine light according to manufacturers recommendations
  5. ) Remove duplicating film from duplicating machine and process in wet tanks or automatic processor. The dark room safe light remains on during this process.
81
Q

What is the anode usually made of, and why?

A

Copper, because of its high heat conductivity.

82
Q

The cathode is _____charged.

A

Negatively.

83
Q

The anode is ______ charged.

A

Positively.

84
Q

One kilovolt is equal to _____ volts.

A

1000 volts.

85
Q

What does D-min stand for?

A

Minimum point.

86
Q

What does D-max stand for?

A

Maximum point.

87
Q

What is the range between the D-Min and the D-max?

A

0.2-0.5 or greater.

88
Q

What is subject contrast?

A

The result of differential attenuation of X-ray beam.

89
Q

Why do we have subject contrast?

A

If all the X-rays generated by the source were the pass directly to the film, it would appear black. If all the X-rays were absorbed before reaching the film, they would appear clear.

90
Q

A sensor=

Phosphor plates=

A
  1. ) Sensor

2. ) Radiograph

91
Q

What does CCD stand for?

A

Charge Coupled device (in a sensor)

92
Q

What does PSP stand for?

A

Phosphor storage plate.

93
Q

What is a latent image?

A

An image that has been exposed but not developed yet.

94
Q

The warmer the water bath, the _____ radiographs will develop.

95
Q

What kind of wavelengths penetrate deeper?

96
Q

What does the mA pass through?

A

The tungsten filament.

97
Q

What 4 things does the control panel consist of?

A
  1. ) The master switch
  2. ) The indicator light
  3. ) Selector buttons
  4. ) Exposure button
98
Q

What does PID stand for?

A

Position indicator device.

99
Q

Secondary radiation travels through ______?

A

Tissue, like lips or cheeks.

100
Q

When the beam is longer, the image is _______?

A

Shorter. Like our shadows in the sun.

101
Q

What do stepwedges determine?

A

The density and quality of radiographs.

102
Q

What determines the density and quality of radiographs?

A

Stepwedges.

103
Q

What is the radiators purpose?

A

Distributes the hear into the X-ray tube, and eventually into the air.

104
Q

What is the glass envelope or vacuum tube?

A

Protective layer surrounding the parts of the X-ray tube.

105
Q

Rapid Processing is the quickest way to develop radiographs. How long does it take approximately?

106
Q

What is the disadvantage of using rapid processing?

A

Lower quality (Low density and definition)

107
Q

When is the only time that rapid processing should be used?

A

During an endodontic or emergency procedure.

108
Q

Rapid processing uses the same steps as manual processing. What are the 3 things that change to help speed up the process?

A
  1. ) The temperature of the solutions are higher
  2. ) Concentrated developer or fixer solutions
  3. ) Increased agitation
  4. ) Combo of all
109
Q

How many minutes does automatic processing need to fully develop?

A

4-6 minutes.

110
Q

What is a daylight loader?

A

Light shielded compartment that allows operator to process film.

111
Q

What are the 3 things that radiographs should always be labeled with?

A
  1. ) Patient name or ID number
  2. ) The date
  3. ) Any additional info the dentist requires
112
Q

An atom that is electrically balanced is called an _____?

113
Q

What is an Ion?

A

An atom that is electrically balanced.

114
Q

The material that is most resistant to penetration of ionizing radiation is?

115
Q

What should you do to an exposed film, before processing it?

A

Dry it off to clear off any excess saliva.

116
Q

What is human tissue mainly composed of?

A

Water (H20)

117
Q

What is the optimal temperature for developer in automatic processing?

A

80-90 degrees farenheit.

118
Q

What radiographic technique is recommended for a patient with a shallow palate?

119
Q

When do we see a “ghost image”?

A

When jewelry is not removed.

120
Q

What kind of cells that are exposed to radiation may be associated with leukemia?

A

Somatic cells

121
Q

May may root resorption mimic on an intraoral radiograph?

A

Dental caries.

122
Q

What is the name of the quality control test that evaluates the safelight in a dark room?

A

A coin test.

123
Q

What is the landmark that you may see in a maxillary anterior periapical X-ray?

A

The incisive foramen

124
Q

To produce ionizing radiation, an atom must do what?

A

Add an electron

125
Q

The occlusal plane will appear ______ in a radiograph when there is inccorect film placement.

126
Q

What is the purpose of taking vertical bitwings?

A

To examine alveolar bone level

127
Q

What are 6 advantages of taking a Panoramic X-ray?

A
  1. ) Captures areas not seen on a routine FMX
  2. ) Both upper and lower teeth are shown on one film
  3. ) Less patient cooperation is needed
  4. ) Gagging is eliminated
  5. ) Less time is required
  6. ) PT. is exposed to a minimum amount of radiation
128
Q

X-rays are made up of bundles of energy called _____?

129
Q

The lead diaphragm determines the size and shape of?

A

The X-ray beam as it leaves the X-ray head.

130
Q

Film speed is determined by the size of the ______ ______ _____.

A

Silver bromide crystals.

131
Q

What is the principal that is used in Panoramic Radiography?

A

Laminagraphy

132
Q

What is laminagraphy?

A

The focusing of the X-ray beam at a point that will appear on the resulting film.

133
Q

What is the small circular radiolucency near the roots of the mandibular premolars?

A

The mental foramen

134
Q

The bisecting technique can only be performed with what size BID? Why?

A

Shorter 8 inch. It allows the film to be positioned close to the teeth to be X-rayed.

135
Q

What 5 areas of tissue types should X-rays include?

A
  1. ) Tooth enamel
  2. ) Underlying dentin or calcium-containing portion
  3. ) Sensitive central pulp w/ nerves and blood vessels
  4. ) Alveolar or jaw bone
  5. ) Surrounding soft tissue
136
Q

What length device can be used with paralleling? Why? Which length is generally the best and why?

A

Any size because its placed perpendicular to both the teeth and film. The longer tubes (Usually 16 inches) are better because the distance between focal space and object is increased and sharpness is subsequently augmented.

137
Q

What is the best type of X-ray to take on edentulous patients?

A

A panoramic X-ray. A series of 10-14 PA films can be taken if a Pan is not an option.

138
Q

What are 4 disadvantages of taking a CT scan?

A
  1. ) High cost
  2. ) Augmented radiation exposure
  3. ) Obscuration by artifacts
  4. ) General lack of image detail
139
Q

What are 2 techniques to used relax the muscles of the floor of the mouth when taking X-rays?

A
  1. ) Move the tongue to the side

2. ) Direct the beam from the distal side

140
Q

What is the best way to take a radiograph on a PT. who has a rubber dam placed?

A

Remove the frame of the dam, and arrange the film packet by using a hemostat or Snap-A-Ray holder.

141
Q

Pantomograms generated during panoramic tomography tend to have a ______ image quality than intraoral radiographs.

142
Q

What are 3 things that Pantomograms are not good at detecting?

A
  1. ) Perio disease
  2. ) Tooth decay
  3. ) Pathological conditions in the periapical region
143
Q

What do closed boxes of dental X-ray film need to b stored in?

A

A refrigerator or other cool area.

144
Q

Where should unused film be stored after opening? Name 3 places.

A
  1. ) In a lead container
  2. ) Away from the screening area (intraoral)
  3. ) Near the area but in containers that block light (screen film)
145
Q

Unused film that has been opened needs to be stored in a lead container, away from screening area, or near the area but in containers that block the light. This is because the emulsions are responsive to 5 things. What are the 5 things the emulsions are responsive to?

A

The emulsions are responsive to a number of situations including:

  1. ) Excessive heat
  2. ) Light exposure
  3. ) Other radiation
  4. ) Touching
  5. ) Gas fumes
146
Q

When feeding film into an automatic processor, what should be the time interval between insertions of different films?

A

At least 5 seconds

147
Q

What is another term for extraoral films?

A

Screen films

148
Q

Extraoral (screen films) are indirectly exposed by changing what?

A

Changing the X-ray photons to light energy by use of screens on either side of the film.

149
Q

When is an example of a time that you would use the bisecting technique?

A

When taking an occlusal film.

150
Q

What is the preferred method of taking X-rays in terms of bisecting or paralleling, and why? What is the disadvantage of using the other technique?

A

Paralleling, because there is less distortion and greater anatomical accuracy. With bisecting, the depth dimension differs for various teeth, and this can foreshorten or elongate the image.

151
Q

What does the rule of isometry state?

A

Two triangles are equivalent when they have a shared side and two equal angles.

152
Q

What is the appropriate angle for short 8-inch positioning devices, both molars and incisors?

A

+30 degrees for molars

+55 degrees for incisors

153
Q

When taking X-rays of mandibular teeth, the vertical angulation ranges from _____for molars, to _______for incisors.

A

0 degrees for molars

-20 degrees for incisors

154
Q

What is a maxillary topographic projection and what is it designed to capture?

A

It’s a type of occlusal radiograph, used to capture a large portion of the upper jaw.

155
Q

What 3 things are usually used when taking a maxillary topographic projection?

A
  1. ) Higher speed
  2. ) Large occlusal film packets
  3. ) longer 16 inch positioning devices
156
Q

What is generally the mA and kVp when taking a maxillary topographic projection?

A

15 mA and 65 kVp

157
Q

In order to achieve the proper angulation when taking a maxillary topographic projection, the positioning device should be placed ________ degrees to the film plane near to but not touching the nose.

A

+65 degrees

158
Q

What is a mandibular symphysis projection, and what is it designed to capture?

A

It’s a type of occlusal radiograph, used to capture a large area of the mandibular incisor region.

159
Q

When taking a mandibular symphysis projection, how should the patient’s head be positioned?

A

Inclined backward to form a 45 degree angle between the floor and the biting surface plane. The midline plane should be perpendicular to the ground.

160
Q

When taking a mandibular symphysis projection, the angle between the film and X-ray should be about ______ degrees, and a vertical angulation of about _______ degrees. Where is the BID placed on the patient?

A

55 degrees
-20 degrees
On the chin

161
Q

Posterior occlusal projections can be taken for both upper and lower jaws. For the Maxilla, what areas is this type of X-ray helpful in capturing?

A

The sinuses, and structural areas in the posterior region.

162
Q

What is the proper angulation in degrees, to take a posterior occlusal projection for the Maxilla?

A

55 degrees

163
Q

Panoramic X-rays expose patients to less radiation than a FMX. A pan exposes patients to about x/10 the dose compared to the FMX.

164
Q

What does CT stand for?

A

Computer tomography

165
Q

What does MRI stand for?

A

Magnetic resonance imaging

166
Q

Tomography is a radiographic procedure that records images in one plane while obscuring or getting rid of images in the other plane. What are 3 examples of Tomographic images?

A
  1. ) Panoramix
  2. ) CT
  3. ) MRI
167
Q

What is the unblurred plane called on a tomographic image? There are 2 names.

A

The focal trough or image layer.

168
Q

In a rotational panoramic X-ray, the vertical plane is angled slightly negative, about ______degrees to ______degrees.

A

-4, to -7 degrees

169
Q

Intensifying screens have several layers for backing, support, and protection, but what is the most important layer, and why?

A

The phosphor layer, because contains a substance that will fluoresce or emit visible or other light when the X-ray strikes it.

170
Q

What is a rare earth screen, and what 2 elements does it encompass?

A

A rare earth screen is an intensifying screen that incorporates elements as phosphors whose extraction from the earth is complex and costly. It contains Lanthanum (La), and Gadolinium (Gd).

171
Q

A posteroanterior Projection is an extraoral exposure of the skull, taken by directing the X-ray beam about 3 feet behind the PT. The central ray is aimed at the occipital protuberance in the ear, and the film is in front of the PT., normally with the forehead and nose positioned against the cassette. There are 3 reasons a dentist may ask an assistant to take this X-ray. What is the dentist likely looking to diagnose?

A
  1. ) Fractures
  2. ) Malignancies
  3. ) Widespread disease in the skull area
172
Q

What is the purpose of taking a Cephalometric X-ray?

A

To predict growth patterns

173
Q

What does USB stand for?

A

Universal Series Bus

174
Q

What is a disadvantage of taking a CT scan?

A

There is significantly more radiation exposure than with a regular film.

175
Q

What does CMOS/APS stand for?

A

Complementary Metal Oxide Semiconductor with an Active Pixel Sensor

176
Q

What is the difference between using a CMOS/APS and a CCD?

A

The CMOS/APS includes amplifying transistors on each of the pixels.

177
Q

What are 4 advantages of using a CMOD/APS over a CCD?

A
  1. ) Ability to put circuitry directly onto the chip
  2. ) Use of less power
  3. ) Reduction of pixel size
  4. ) Can be linked to a computer using USB

Radiology (9 decks)

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