dental radiology
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digital rad 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)
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digital rad 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
RADIOLOGY
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^>tA4S03lS ^
Digital imaging filmless imaging system method of capturing a radiographic image with a sensor, breaking the image into electronic pieces and presenting & storing the image using a computer
Direct digital image production requires x-ray source digital intraoral sensor computer high-resolution monitor software & printer
Digital intraoral sensor small intraoral detector used to capture a radiographic image when x-rays strike the sensor, an electronic charge is produced on the surface of the sensor, this electronic charge is digitized or converted to digital form may be wired or wireless sensor transmits information to computer
Pixel or picture element discrete unit of information consists of a small electron well where the x-ray or light energy is deposited upon exposure
(/digital image is composed ofpixejsh
CCD (charge-coupled device) (CCDTjHiarge-coupled device)
most common digital image receptor in the intraoral sensor, a solid-state detector that contains a silicon chip with an embedded electronic circuit sensitive to light or x-rays 640 x 480 pixels in size
CMOS/APS (complementary metal oxide semiconductor/active pixel sensor)
Jatest development in direct digital sensor tecnnSlogy externally identical to CCD
i differs in the way pixels are read advantages include lower production cost of
* the chip, lower power requirements & greater '. durability
smaUef.acjtive a r e a f r image acquisition
VCIDjJfcharge injection device) another sensor technology silicon based solid-state imaging receptor similar to CCD no computer is required to process the images system features CID x-ray sensor, cord and plug that are inserted into a light source on a camera platform
Advantages of digital imaging superior gray scale resolution 256 shades of gray used instead of the 16-25 shades used with film reduced exposure to radiation radiation exposure is 50% to 90% less than what is used to expose E-speed film increased speed of image viewing images can be viewed instantly which allows for immediate intetpretation lower equipment and film cost no need for purchase of film and related processing supplies and equipment increased efficiency allows dental professionals to be more productive; image storage and communication are easier with digital networking enhancement of diagnostic image features such as colorization and zooming allow for highlighting of conditions; the gray scale may be re-YSBjed. (digital subtraction) effective patient education tool the size of images displayed monitor are easier for the patient to see; allows for chairside education and interaction
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' 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 Disadvantages of digital imaging
sensor size some sensors are thicker and less flexible than film and may stimulate the gag reflex initial set up costs significant initial cost for purchase of digital equipment as well as maintenance and repairs resolution / image quality conventional x-ray film has a resolution of 12
n - 20 lp/mm (linepairs per millimeter); digital Mmaging using a CCD has a resolution of 10
lp/mm; because human eye can only perceive 8 N>- 10 lp/mm digital imaging performs at
least as well as traditional radiography infection control some sensors cannot withstand heat steriliza-tion; barrier protection is required wear & tear sensors are subject to damage, wear & tear and have a limited lifespan legal issues because digital images can be enhanced, there may be legal implications
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digital rad 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
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digital rad A patient is extremely concerned about radiation exposure. Which of the fol-lowing 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
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' direct digital imaging
Digital imaging filmless imaging system methods of obtaining a digital image: direct and indirect
Direct digital imaging required components - x-ray machine - intraoral sensor - computer & monitor utilizes a sensor with a fiberoptic cable that is linked to a computer sensor is placed intraorally and exposed to x-radiation images are captured via a sensor (CCD, CMOS/APS or CID) the sensor transmits the image to a computer monitor images appear on monitor within seconds of exposure software is used to enhance & store the image
Indirect digital imaging scanning of traditional films storage phosphor imaging
Scanning of traditional films required components - CCD camera - computer & monitor existing films are scanned and digitized using a CCD camera CCD camera scans radiograph, converts the image and displays it on monitor is inferior to direct digital imaging image is a "copy" not an "original"
^Steage, phosphor imaging ss P{> required components
.-phosphor- coated plate - electronic processor/scanner - computer & monitor a "wireless" digital imaging system a reusable imaging plate coated with phosphors is used instead of a sensor with a fiberoptic cable plates are similar to intraoral film in size, shape & thickness image recorded on plate after exposure, plate is placed in electronic processor where a laser scans the plate; image is transferred to the monitor within time frame nf'jQ.s.gcciridr1 to 5 minutes also referred to as photo-stimulable phosphor imaging or PSP imaging
use of digital imaging
Digital imaging requires LESS radiation than conventional films because the sensor is more sensitive to x-rays than dental film exposure time for digital imaging is approximately 5-0% less than what is required for F-speed film intraoral, panoramic and other extraoral films may all be obtained digitally
Intraoral film speed E-speed film is no longer available Only D-speed film and F-speed film are available for use with intraoral radiography F-speed film is recommended by the ADA
Q*^^Sdj!2u j r e s 6p%_qf the exposure time of D-speed
Other ways to limit exposure to x-radiation proper prescribing of dental radiographs based on individual needs of patient use of lead apron & thyroid collar use of proper dental x-ray equipment use of rectangular position-indicating device (PID) use of beam alignment devices use of proper technique proper sensor handing proper image retrieval
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image char 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 short-est object-receptor distance are used. ^He
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
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image char Rank the following from LEAST radiopaque to MOST radiopaque.
amalgam
bone
dentin
> maxillary sinus
enamel
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both statements are true
contrast the difference in degrees of blackness (densi-tjg) between adjacent areas on a dental radi-ograph.
high contrast describes an image that ap-pears mostly black & white; shades of gray are absent
low contrast describes an image with many shades of gray; few areas of black and white
scales of contrast the range of useful densities seen on a dental radiograph.
short-scale contrast describes a high contrast image with densities of black & white that results from using a .low kilovoltage. ^Mi l ium V ,
long-scale contrast describes a low contrast image with many shades of gray that results from using a highkilo-voltaee.
magnification a radiographic image that appears larger than the actual size of the object it represents; mag-nification is influenced by the target-receptor distance and the object-receptor distance.
target-receptor distance - distance between the source of x-rays and the image receptor*film / W . * ^
a longer PID results in a longer target-recep-tor distance and helps to limit magnification
object-receptor distance 's^*f- Q^* distance between the tooth and the image
receptor the closer the receptor is to the tooth, the less
magnification is seen on the image
to limit magnification use a long target-receptor distance/I target-
receptor distance use a short object-receptor distance/J, object
-receptor distance
bus cm i LOW CONTRAST LONG-SCALE CONTRAST
HV**t kvp 'image receptor=digital sensor or x-ray film
sinus bone dent in enamel fit
radiolucent structures lack density permit the passage of x-radiation absorb very little x-radiation '.a.fj.o.w more x-rays to reach the receptor* appear dark or black on an image
amalgam radiopaque structures
are dense resist the passage of x-radiation absorb the x-radiation allow few_xjay.s to reach the receptor appear light or white on an image
Examples of radiolucent structures/mate-rials BLACK or DARK
air space images soft tissue images canals foramens fossas sinuses sutures caries pulp cavities periodontal ligament space denture acrylic some composite restorations
Examples of radiopaque structures/mate-rials _ WHITE or LIGHT
enamel dentin bone lamina dura septa tubercles tuberosities ridges processes amalgams, metal restorations implants gutta percha
LUCENT means TRANSPARENT and suggests something that lacks density something that lacks density permits the pas-sage of x-rays & appears RADIOLUCENT
% ^S
OPAQUE means NOT TRANSPARENT and suggests something that is more dense something that is more dense resists the passage of the x-rays & appears RA-DIOPAQUE
*receptot=digital sensor or x-ray film
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misc.
Dental radiographs are the legal property of the:
patient
dentist
state
> none of the above
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misc. A dental hygienist in your practice has an adult recall patient without evi-dence 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
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Dental radiographs original radiographs are legally the property of the dentist even though the patient or an insurance company may have paid for them the radiographs are the property of the dentist because they are indispensable to the dentist as part of the patient record radiographs should be kept indefinitely
Patient access to radiographs patients have a right to reasonable access of their dental radiographs access includes copies of original radi-ographs (not originals) forwarded to the dentist who will be responsible for the pa-tient's dental care
dentist
Patients who refuse dental radiographs when a patient refuses to have dental ra-diographs, the dentist must decide whether diagnosis and treatment can take place without the recommended radiographs no document can be signed by the patient that releases the dentist from liability
Very important: the patient record, includ-ing radiographs, is legal documentation of a patient's condition.
Patient record must contain documentation of informed consent number & type of radiographs exposed rationale for taking radiographs diagnostic information obtained from in-terpretation
images should be taken based on patient need instead of a set time
Prescribing dental radiographs the dentist is responsible for prescribing the number, type and frequency of dental ra-diographs each patient's condition is different and therefore each patient must be evaluated for radiographs on an individual basis a radiographic examination should never include a set number and type of images at a set interval guidelines for prescribing dental radiographs are published by the American Dental Association (ADA) in conjunction with the Food & Drug Administrations (FDA) visit www.ADA.org for current guidelines patients with caries, periodontal disease, tooth mobility, pain and impacted teeth need more frequent radiographic examinations
Guidelines for radiographs in the recall patient with clinical caries or risk of caries
bite-wings at 6 - 12 month intervals with no clinical caries or risk of caries
bite wings at 24 - 36 month intervals with periodontal disease
clinical judgement for radiographs needed to evaluate periodontal disease; selected bite-wings & periapicals
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normal anat Identify the structures indicated in the images below.
Image 1 Image 2
Reprinted from Haring, Joen Iannucci and Laura Jansen: Dental Radiography: Principles and Techniques: Third Edition. 2000, with permission from Elsevier.
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normal anat The coronoid process often appears on what periapical image?
maxillary incisor
maxillary molar
mandibular incisor
mandibular molar
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Res Image 1- hamulus v
a.k.a. hamular process small, hook-like projection of bone extends ..fmm the medial Pterygoid
jg|atejof^emsjp;hjenoidjbone located posterior to the maxillary tuberosity appears radiopaque on a maxillary molar periapical image, appears as a hook-like radiopaque struc-ture varies in length, shape & density not always visible, depends on receptor placement
hamulus ' maxillary tuberosity
*b Image 2- maxillary tuberosity
rounded prominence of bone that ex-tends distal to the third molar region appears radiopaque on a maxillary molar periapical image, appears as a rounded ra-diopaque bulge distal to the third molar region varies in size, shape and density not always visible, depends on re-ceptor placement
maxillary molar
Coronoid process coronoid means "resembling the beak of a crow" large prominence of bone on anterior ramus of mandible is thin and triangular in shape serves as an attachment site for one of the muscles of mastication appears radiopaque on a maxillary molar periapical image, appears as a beak-shaped radiopacity located inferior to, or superimposed over, the maxillary tuberosity varies in shape and density not always visible, depends on receptor placement
Reprinted from Haring, Joen Iannucci and Laura Jansen Lind: Radiographic Interpretation for the Dental Hygienist. 1993, with permission from Elsevier.
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normal anat Identify the structures labeled 1 - 8 on the image below.
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry." y\
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normal anat Identify the structures labeled 1- 7 on the image below.
"Courtesy Dr. Stuart C White, UCLA School of Dentistry." 1 2
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' answers 1-8 below
1. lateral wall of the incisive (nasopalatine) canal radiopaque line
2. anterior wall of the maxillary sinus radiopaque line
3. nasopalatine fossa radiolucent space
4. floor of nasal fossa radiopaque line
5. soft tissue outline of the nose slightly radiopaque outline
6. lamina dura radiopaque line
7. border of maxillary sinus radiopaque line
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry."
8. periodontal ligament space radiolucent line
answers 1 - 7 below
1. anterior nasal spine radiopaque line
2..lateral wall of nasopalatine canal radiopaque line
3. median palatal suture radiolucent line
4. floor of nasal fossa radiopaque line
5. incisive (nasoplatine) foramen radiolucent structure
6. soft tissue outline of tip of nose slightly ra^oplique'^uTrihe
7. alveolar crest radiopaque line
"Courtesy Dr. Stuart C White, UCLA School of Dentistry."
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normal anat Identify the structures labeled 1- 5 on the image below.
Courtesy Dr. Stuart C. White, UCLA School of Dentistry."
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normal anat Identify the structures labeled 1 - 8 on the image below.
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry.'
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answers 1 -5 below
1. nutrient canal radiopaque lines
2. bony trabecular plate radiopaque line
3. inferior border of mandibular canal radiopaque line
4. submandibular gland fossa radiolucent space
5. inferior border of mandible radiopaque structure
1. anterior wall of maxillary sinus radiopaque line
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry."
< answers 1 - 8 below
2. inferior nasal conchae A -radiopaque mass
3. floor of nasal fossa radiopaque line
4. inferior border of zygomatic process of maxilla j-shaped radiopaque line C/*
5. posterior wall of zygomatic process of maxilla radiopaque line
6.jnieiifljLboxdt:.QLzygoma # ^ radiopaque line
7. floor of maxillary sinus radiopaque line
8. mucosa over alveolar bone slightly radiopaque structure
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry."
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normal anat Identify the structures labeled 1- 7 on the image below.
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry." .. _ copyright 2013-2014- Dental Decks
RADIOLOGY
normal anat Identify the structures labeled 1- 4 on the image below.
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry."
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answers 1 - 7 below
1. lingual cusp of 1st premolar radiopaque area
2. periodontal ligament space radiolucent line
3. film holder radiopaque area
4. genial tubercles donut shaped radiopacity
5. lingual foramen radiolucent circle
6. bony trabeculations radiopaque lines
7. marrow space radiolucent area
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry."
answers 1 - 4 below
1. periodontal ligament space radiolucent line
2. mental foramen ovoid radiolucency
3. submandibular gland fossa radiolucent area
4. film clip mark radiolucent artifact
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry."
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normal anat Identify the structures labeled 1 - 3 on the image below.
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry." 17
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RADIOLOGY
normal anat Identify the structures labeled 1- 7 on the image below.
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry." 1 8
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RADIOLOGY 18
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answers 1 - 3 below
1. cement-enamel junction (CEJ) radiopaque line
2. mental foramen ovoid radiolucency
3. submandibular gland fossa large radiolucent area
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry."
1. inferior nasal conchae radiopaque mass
answers 1 - 7 below
2. anterior wall of maxillary sinus radiopaque line
3. floor of nasal fossa radiopaque line
4. maxillary sinus radiolucent space
5. floor of maxillary sinus radiopaque line
6.inferior border of the zygomatic TiVl l l l l l lWWII IIIIMI ijitilllll mi I I . Nil,? ,
process of the maxilla radiopaque area
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry."
7. lingual cusp of 1st premolar radiopaque band
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normal anat Identify the structures labeled 1- 6 on the image below.
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry." 19 copyright 2013-2014- Dental Decks
RADIOLOGY
normal anat Identify the structures labeled 1 - 6 on the image below.
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry."
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answers 1 - 6 below
1. floor of nasal fossa radiopaque line
2. lateral wall in incisive canal ) radiopaque line
3. ala of nose radiopaque line
4. anterior wall of maxillary sinus radiopaque line
5. maxillary sinus radiolucent space
6. lingual cusp of 1st premolar radiopaque band "Courtesy Dr. Stuart C. White, UCLA
School of Dentistry."
1. dentino-enamel junction (DEJ) radiopaque line
' answers 1 - 6 below
2. periodontal ligament space radiolucent line
3. lamina dura radiopaque line
4. periodontal ligament space of palatal root radiolucent line
5. film holder radiopaque area
6. mucosa over alveolar bone slightly radiopaque structure
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry."
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normal anat Identify the structures labeled 1- 3 on the image below.
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry." 21
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RADIOLOGY
normal anat Identify the structures labeled 1 - 4 on the image below.
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry."
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RADIOLOGY
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answers 1-3 below
1. mandibular tori radiopaque masses
2. lingual foramen radiolucent circle
3. genial tubercles donut shaped radiopacity
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry."
answers 1 - 4 below
1. alveolar crest of bone radiopaque structure
2. lamina dura radiopaque line
3. periodontal ligament space radiolucent line
4. bony trabeculations radiopaque lines
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry."
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normal ant Identify the structures labeled 1- 8 on the image below.
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry." 2 3
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RADIOLOGY
normal anat Identify the structures labeled 1 - 9 on the image below.
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry." 24 copyright 2013-2014- Dental Decks
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1. marrow space radiolucent space
answers 1 - 8 below
2. periodontal ligament space radiolucent line
3. bony trabecular plate radiopaque line
4. lamina dura radiopaque line
5. pulp canal radiolucent space
6. alveolar crest radiopaque area
7. dentin radiopaque area "Courtesy Dr. Stuart C. White, UCLA School of Dentistry."
8. enamel radiopaque area
1. dentin radiopaque area
answers 1 - 9 below
2. bony trabeculations radiopaque lines
3. marrow space radiolucent area
4. pulp canal radiolucent space
5. periodontal ligament space radiolucent line
6. lamina dura radiopaque line
7. alveolar crest radiopaque structure
8. enamel radiopaque band
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry."
9. pulp chamber radiolucent space
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normal anat Identify the structures labeled 1-12 on the image below.
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry." 25 copyright 2013-2014- Dental Decks
RADIOLOGY
normal anat Identify the structures labeled 1 - 8 on the image below.
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry." 2 6
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answers 1-12 below
1. bony trabeculations radiopaque lines
2. marrow space radiolucent area
3. tooth #10 maxillary lateral incisor
4. lamina dura radiopaque line
5. dentin radiopaque area
6. periodontal ligament space radiolucent line
7. alveolar crest radiopaque structure
8. pulp canal radiolucent space
9. pulp chamber radiolucent space
10. enamel radiopaque band
lljraUdJiJmdot radiopaque circle
12. dentino-enameTjunction radiopaque line
%
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry."
answers 1 - 8 below
1. tooth #3 maxillary first molar
2. amalgam restoration
3. plastic bite block faint opacity
4. film dot rounajradiolucency
5. black letters - PLS indicates Kodak Ektaspeed plus film
6. lamina dura radiopaque line
7. periodontal ligament space radiolucent line
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry."
8. lamina dura radiopaque line
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normal anat Identify the structures labeled 1 -15 on the image below.
"Courtesy Dr. Stuart C. White, UCLA
School of Dentistry."
RADIOLOGY 27
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normal anat Identify the structures labeled 1 -13 on the image below.
"Courtesy Dr. Smart C. White, UCLA
School of Dentistry."
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answers 1-15 below
1. air in nasal fossa raHTolucenTspace
2. nasal septum radiopaque line
3-lateralwaU of nasal septum medial wall of maxillary sinus radiopaque lines
4. infraorbital rim radiopaque line
5- wall of infraorbital canal radiopaque line
6. pterveomaxillary fissure radiolucent space
7. pterygoid spine of sphenoid radiopaque line
8. zygomatic arch radiopaque mass
9. posterior wall of maxillary sinus radiopaque line
10. posterior wall of the zygomatic process of the maxilla radiopaque line
11. ear lobe radiopaque mass
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry."
12. inferior border of the mandibular canal radiopaque line
13. anterior nasal spine v-shaped radiopacity
14. inferior border of the mandible radiopaque band
15. hyoid bone radiopaque structure
answers 1-13 below
1. tip of nose radiopaque area
2. hard palate / floor of nasal fossa radiopaque line
3. orbit radiolucent area
4. hard palate / floor of nasal fossa radiopaque line
5. floor of maxillary sinus radiopaque line
6. soft palate radiopaque structure
7. air between soft palate & tongue radiolucent space
8.._dorsum of the tongue radiopaque line
9. ghost ima^eofop^>ositerartius ^TndTcateTrjy radiopaque dote
10. mental foramen ovoid radiolucency
11. shadow of cervical spine diffuse opacity
"Courtesy Dr. Stuart C. White, UCLA School of Dentistry."
12. submandibular gland fossa broad radiolucent area
13. articular eminence / articular tubercle radiopaque prominence
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processing 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
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processing 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
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both statements are true Film processing converts the latent image to a visible image and preserves the image on film Latent image
the film emulsion absorbs x:rays during ex-jffgnni r^ W e s the energy,within the silver halide crystals the stored energy forms a pattern and creates an invisible image the pattern of stored energy cannot be seen and is referred to as the latent image; it re-mains invisible until chemical processing
Black areas of the visible image appear radiolucent f-;y created by deposits of black metallic silver structures that permit the passage of the x-ray beam allow more x-rays to reach the film & energize more silver halide crystals more energized silver halide crystals result in more deposits of black metallic silver
White areas of the visible image appear radiopaque ^?Ci results from .unexposed silver halide crystals structures that resist the passage of the x-ray beam restrict or limit amount of x-rays that reach the film resulting in no energized silver halide crystals and no deposits of black metal-lic silver
Film processing steps 1. development - developer solution removes halide portion of exposed silver halide crystals; this reduction of exposed crystals results in pre-cipitated.Wackjnel^icjy]yer (6^FJsJheopti-mal temperature for developer) 2. rinsing - water removes developer & stops development process 3. fixing - fixer solution removes unexposed sil-ver halide crystals & hardens the film 4. washing - water removesaTTexcess chemi-cals from the emulsion 5. drying
Developer composition developing agent contains 2 chemicals hy-
Cdroquinone & cloijj hydroquinone slpjvly con-verts silver halide crystals & generates black tones ;elon-quickly converts silver halide crys-tals & generates gray tones preservative is Sodium sulfite; prevents oxi-dation of developer agents accelerator is sodium carbonate; activates the developer & softens emulsion
^ ^t^*-*******.."""-'^
restrainer ts;potassium bromide; prevents developer from deveToping unexposed crystals
Fixer composition fixing agent (a.k.a. clearing agent or hypo) is^xliu^Jhiojul&teorammonium thiosulfate; removes or clears" all un-exposed & underdeveloped silver halide crystals from emulsion; clears the film so that black image produced by the devel-oper can be seen preservative is,si{Uumjmlfite (same as in developer); prevents the deterioration of the fixing agent hardening agent is potassium alum; shrinks and hardens the gelatin in the emulsion acidifier is a c j ^ j i c id j ) r sulfuric acid; neutralizes the alkaline developer and stops development process & provides necessary acidic environment for fixer
Safelighting lighting that is required in darkroom for safe illumination while processing x-ray film
QJ^JJQdak^BXdtS^hMM?r with a 15-watt bulb at least 4 feet away from working surface
fixing agent
Film processing steps 1. development 2. rinsing 3. fixing 4. washing 5. drying
Manual film processing a.k.a. hand processing or tank processing method used to process films where all steps are performed manually equipment needed includes processing tanks with covers, thermometer, timer, film hangers and stirring rod typical processing times include: 5 minutes in developer > 30 second rinse > 10 minutes in fixer at leastdQanm-utgsjriwash as a rule, fixing time is twice as long as developing time
Automatic film processing method used to process films using where all steps of film processing are au-tomated automatic processor is required total processing time is 4-6 minutes
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processing 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
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RADIOLOGY
processing 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
RADIOLOGY 32
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' replenish the developer
Replenisher solutions a replenisher is a superconcentrated solu-tion that is added to the existing processing solutions to compensate for the loss of vol-ume and strength that occurs due to oxida-tion
' :-
r'
both the developer and fixer must be re-plenished daily to maintain adequate fresh-ness
replenishment maintains adequate con-centrations of chemicals which ensures uni-form processing failure to use replenishing solutions results in non-diagnostic radiographs
Processing solutions include developer, fixer & replenisher must follow manufacturer directions for storage, mixing & replenishing the developer and fixer must be changed at the same time every 3-4 weeks or more often with high volume of processing tanks must be scrubbed and cleaned when changing solutions
Developer solution life is affected by cleanliness of tank size of films processed number of films processed temperature evaporation
Depleted developer is weakened, lacks concentration does not fully develop the latent image produces a non-diagnostic image with red-uced density and contrast results in underdeveloped films underdeveloped films appear light
Underdeveloped film appears light causes
- time/inadequate time in developer - temperature/developer too cool - concentration/depleted developer
solutions - time/! time in developer - temperature/t temperature - concentration/replenish developer
excessive time in developer developer solution too hot concentrated developer
Time and Temperature: Problems and Solutions Example
Underdeveloped film
Overdeveloped film
Reticulation of emulsion
Appearance
Light
Dark
Cracked
Problems
- Inadequate development time - Developer solution too cool - Inaccurate timer or thermometer - Depicted or contaminated developer solution
- Excessive developing time - Developer solution too hot - Inaccurate timer or thermometer - Concentrated developer solution
Sudden temperature change between developer and water bath
Solutions
- Check development time - Check developer temperature - Replace faulty timer or thermometer - Replenish developer with fresh
solutions as needed
- Check development time - Check developer temperature - Replace faulty timer or thermometer - Replenish developer with fresh
solutions as needed
Check temperature of processing solutions and water bath; avoid drastic temperature differences
Reprinted from Iannucci, Joen M. and Laura Jansen: Dental Radiography Principles and Techniques. Fourth Edition, d from Elsevier Saunders
2012, with permission
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processing 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
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Dose equivalent is expressed in terms of:
coulombs/kilogram (C/kg)
gray (Gy)
sievert (Sv)
quality factor (QF)
rad biology
RADIOLOGY 34
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static electricity
Film Handling: Problems and Solutions
Example
Developer cut-off
Fixer cut-off Over-lapped films
Air bubbles
Fingernail artifact
Finger-print artifact
Static ,eh?ctricity
Scratched film
Appearance
Straight white border
Straight black border
White or dark areas appear on film where overlapped
White spots
Black crescent-shaped marks
Black fingerprint
Thin, black, branching lines
White lines
Problems
Underdeveloped portion of film due to low level of developer
Unfixed portion of film due to low level of fixer
Two films contacting each other during processing
Air trapped on the film surface after being placed in the processing solutions
Film emulsion damaged by the operator's fingernail during rough handling
Film touched by fingers that are contaminated with fluoride or developer
- Occurs when film packet is opened quickly - Occurs when film pack is opened before the radiographer touches a conductive object Soft emulsion removed from the film by a sharp object
Solutions
Check developer level before processing; add solution if needed
Check fixer level before pro-cessing; add solution if needed
Separate films so that no contact takes place during processing
Gently agitate film racks after placing in processing solutions
Gently handle films holding them on the edges only
Wash and dry hands thoroughly before processing
- Open film packet slowly
- Touch a conductive object before unwrapping films
Use care when handling films and film racks
Reprinted from lannucci, Joen M. and Laura Jansen: Denial Radiography Principles and Techniques. Fourth Edition. 2012, with permission from Elsevier Saunders
sievert (Sv)
Exposure measurement exposure refers to the measurement of ion-ization in air produced by x-rays roentgen (R) is a way of measuring radia-tion exposure by determining the amount of ionization that occurs in air R is limited to measurement in air there is no SI unit for exposure that is equiv-alent to the R exposure expressed in Coulombs per kilo-gram (C/kg)
Dose measurement dose refers to amount of energy absorbed by a tissue rad is a unit of absorbed dose that is equal to the deposition of 100 ergs/g of tissue the SI unit for rad is gray (Gy)
Dose equivalent rem is traditional unit of dose equivalent used to compare the biologi&.ffects_of dif-ferent Jypes of radiation on a tissue or organ is the product of Gy x QF (quality factor) specific for the radiation type for x-rays, QF=1
5Tumt for rem is sievert (Sv)
Unit Definition Convers ion
Traditional System (older system) roentgen (R)
radiation absorbed close (rad)
1 rem = rads X QF roentgen equivalent (in) man (rem) SI system (newer system)
lR = 87erg/g
1 rad = 100 erg
1R = 2.58X10 "'C/kg
1 rad = 0.01 Gy
Coulombs per kilogram (C/kg) gray (Gy) sievert (Sv)
1 Gy = 0.01 J/kg
l S v = G y X Q F | 1
1 rem = 0.01 Sv
1 C/kg = 3880 R
is*si 10 rads : Sv = 100 rerh>
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rad biology List the following cells from most RADIORESISTANT to most RADIOSENSITIVE.
muscle
small lymphocyte
skin
thyroid gland
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rad biology After the bombings of Hiroshima, there were many persons exposed to radi-ation. Symptoms such as hair loss did not occur until days following the ex-posure. The time between exposure and onset of symptoms is termed:
latent period
period of cell injury
recovery period
cumulative effects period
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muscle thyroid gland skin small lymphocyte
all ionizing radiations are harmful to living tissues radiation produces chemical changes that results in biologic damage in living tissues not all cells respond to radiation in the same manner
cells respond to radiation based on mi-totic activity, differentiation and cell metabolism cells that are dividing and immature are most susceptible to radiation
radiosensitive cells are susceptible to ra-diation exposure the most radiosensitive cell is the small lymphjaq&e radioresistant cells are resistant to radi-ation exposure the most radioresistant cells are muscle anrlnjejye radiation effects are classified as somatic (occur in person irradiated) or genetic (passed on to future generation)
Sensitivity Radiosensitive Radioresistant Cells Sensitivity high
high
high
high
fairly high
fairly high
fairly high
small lymphocyte
bone marrow
reproductive cells
intestinal mucosa
skin
lens of eye
oral mucosa
muscle tissue
nerve tissue
mature bone/cartilage
salivary gland
thyroid gland
kidney
liver
low
low
fairly low
fairly low
fairly low
fairly low
fairly low
latent period
Mechanisms of radiation injury ionization & free radical formation are re-sponsible for cell injury free radical formation is the primary mecha-nism responsible for damage
Theories of radiation injury direct theory - cell damage results when ra-diation directly hits critical areas within the cell & direct alteration of the cell occurs indirect theory - suggests that x-ray photons are absorbed within the cell and cause the for-mation free radicals & toxins which result in cell damage K- f*W+$wa - ^W, W * eeAi,
Dose-response curve a dose-response curve is used to demonstrate the response of tissues to the dose of radiation received a threshold dose does not exist & response of tissues is directly proportional to the dose injury from radiation depends on total dose,
.dose ratej^anjount of tissue affected, cgjl sen-sitivity and age
Stochastic & nonstochastic effects stochastic effects occur as a direct function of dose (cancer, genetic mutations) nonstochastic effects have a threshold and in-crease in severity with increased dose (hair loss, decreased fertility)
Radiation injury sequence latent period - period of time between exposure and onset of symptoms period of injury - follows latent period and may result in cell death, change in cell function or ab-normal mitosis period of recovery - follows injury; depending on a number of factors, cells can repair the damage caused by radiation
Radiation effects short term effects occur when large amounts are absorbed in a short period of time (not applicable to dentistry) long term effects occur when small amounts are absorbed over a long period of time; linked to in-duction of cancer, birth & genetic effects cumulative effects occur; radiation damage is ad-ditive and unrepaired damage accumulates in the tis-sues and leads to health problems (cancer, cataract formation, birth defects)
Radiation effects on cells the cell nucleus is more sensitive to radiation than cytoplasm; DNA is affected cell division is disrupted which may lead to dis-rupted cell function or cell death radiation causes cell death by damaging chromo-somes
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rad biology 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
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rad biology 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
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Definition most serious possible complication facing the oral cancer patient condition of non-vital bone in a site of radio-therapy; bone dies as a complication of radio-therapy is not an infection
Cause radiation therapy destroys cancerous cells but also destroys normal cells, damaging small ar-teries and reducing circulation insufficient blood supply to the irradiated area decreases the ability to heal, and any subse-quent infections to the jaw can pose a huge risk to the patient patients receiving high dQjt_Qf,xadiation >40 Gv) to the jaw area are at risk
Histologic features- 3 H's v* hypocellular bone v^hypovascular tissue
v""hypoxic tissue & bone
Prevention extract all hopeless teeth 3 weeks prior to ra-diotherapy if extracting after radiotherapy, use of systemic antibiotics is warranted hyperbaric oxygen treatments before and after radiotherapy may be helpful
osteoradionecrosis
Clinical features may involve the maxilla or mandible more common in the mandible most frequently occurs when an insult to the bone is sustained in the irradiated area, such as related subsequent surgery, biopsy, tooth extractions or denture irritations may also be precipitated by periodontal disease or occur spontaneously symptoms may include pain, swelling, reduced mobility, drainage, exposed bone in the involved area and destruction of bone symptoms may occur months or years after the radiotherapy
Management difficult to manage prevention is key debridement of infected bone may be required advanced cases may require radical surgery patients must be followed closely by physicians and dentist regularly
both statements are true
Radiation therapy of oral cavity used to treat radiosensitive oral malignant tu-mors, usually squamous cell carcinoma indicated when the tumor is radiosensitive, advanced, or, cannot be treated surgically be-cause it is deeply invasive fractionation
- total radiation dose is delivered in smaller multiple doses
- provides greater tumor destruction than a sin-gle large dose
- allows for increased cellular repair of nor-mal tissues
- increases mean oxygen tension resulting in tumor cells that arc more radiosensitive
W M M I M M n
Radiation effects on the teeth irradiation of developing teeth severely retards growth adult teeth are radioresistant\3^
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rad char In the dental x-ray tube, the number of electrons flowing per second is meas-ured by:
kilovoltage peak (kVp)
milliamperage (mA)
time (in seconds)
all of the above
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RADIOLOGY
rad char 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
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RADIOLOGY
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W ~ TJu^-^ milliamperage (mA) ^rrv*4
^ V t i x_ray beam intensity
time and distance
x-ray beam quality & kVp quality refers to the average energyor 7 ^ intensity is the total energy contained in penetrating power of the x-ray beam and the x-ray beam at a specific area at a given is controlled by the kilovoltage peak (kVp) time kVp controls the speed & energy of the ~ Qrfntensity is affected by kVp, mA, exposure electrons and determines the penetrating power of the beam > kVp range for dental radiography is A s^^k ^
c^iookv^i Tt
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rad char A 6'5" muscular male with a large mandible requires a complete series of den-tal 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
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RADIOLOGY
rad char Identify each of the following that influence the density of an image:
kVp
mA
exposure time
use of a 2-film packet
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Increased kVp produces x-rays with increased energy (speed) and shorter wavelength increases the penetrating power of the x-ray beam is needed for larger patients with large bones and significant amounts of soft tissue results in increased density (makes image darker) results in reduced or low contrast which is long-scale contrast
Contrast refers to how sharply dark and light areas are separated or differentiated on an image the difference in degrees of blackness be-tween adjacent areas on a dental radiograph
a more penetrating beam a reduced subject contrast long scale contrast
Long-scale contrast LONG scale = JLOW contrast = LOTS of gray
a low contrast image exhibits many shades of gray a low contrast image does not exhibit black & white
Adjustment
T (High)
4 (Low)
kVp
kVp
Contrast scale
LONG lots of gray
SHORT black & white
Contrast
LOW
HIGH
Contrast & kVp adjustment of kVp affects contrast with low kVp (65-70), a high contrast image results with high kVp (90), a low contrast image results
Patient size & kVp large patients need increased kVp; if not increased image appears LIGHT small patients need decreased kVp; if not decreased image appears DARK
Density description a visual characteristic of a radiographic image overall blackness or darkness of an image when a dental image viewed, the relative transparency of areas depends on the distri-bution of black silver particles density is the degree of.silver blackening an image of correct density allows one to view the black areas (air space images), white areas (enamel, dentin, bone) and gray areas (soft tissue)
Factors that influence density exposure factors
-kVp - mA - exposure time
thickness of subject adjustments in kVp, mA and exposure time can be made to compensate for size variations an increase in any exposure factor , sepa-rately or combined, increases the density of an image
\9
Adjustment
T 4 r 4. T 4 t
x4
kVp
kVp
mA
mA
time
time
thickness
thickness
.
kVp mA exposure time
Densitv Film
t 4 t 4 T 4 4 T
appears darker
lighter
darker
lighter
darker
lighter
lighter
darker
Size of patient thickness of subject also affects density; with a large patient (thick bones, excess soft tissue), fewer x-rays reach the receptor and as a result, the image appears lighter with increased thickness, a decreased den-sity results with decreased thickness, an increased density results
Note: the use of a 2-film packet does not affect the density of the image
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rad physics Which of the following converts electrons into x-rays?
positive anode
1 negative anode
' positive cathode
negative cathode
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RADIOLOGY
rad physics 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
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positive anode
X-ray tube heart of the x-ray generating system critical to the production of x-rays glass vacuum tube from which all the air has been removed component parts include leaded glass hous-_ing, negative cathode & positive anode
Leaded-glass housing leaded-glass vacuum tube that prevents x-rays from escaping in all directions a "window" permits the x-ray beam to exit the tube
Reprinted from Iannucci, Jocn M. and Howerton, Laura Jansen: Dental Radiography Principles and Techniques. Fourth edition 2012 with permission from Elsevier-Saun-ders.
to remember, think C A T N A P . . .
cathode is negative
| Cathode/negative electrode! supplies electrons necessary to generate x-rays consists of a tungsten wire filament in a molybdenum cup-shaped holder tungsten filament (coiled tungsten wire) produces electrons when heated molybdenum cup focuses the electrons into a narrow beam and directs the beam across the tube toward the tungsten target of the anode
A n o node/positive electrode ode isTnto x- converts electronslivto x-ray photons
consists of a wafer-thin tungsten plate em-bedded in a solid copper rod tungsten target serves as a focal spot and converts bombarding electrons into x-ray photons copper stem functions to dissipate the heat away from the tungsten target
molybdenum cup
Production of x-rays tungsten filament is heated and electrons are produced molybdenum cup focuses the electrons into a narrow beam and directs the beam to-wards the tungsten target in the anode x-rays are generated when the beam is sud-denly stopped by the tungsten target 4fafi.enigy_of motion is converted to x-ray energy (1%) and heat (99%) insulating oil that surrounds the x-ray tube absorbs the heat x-rays that are produced are emitted in all directions; leaded-glass housing of tube pre-vents the x-rays from escaping small number of x-rays exit the x-ray tube through the unleaded glass window area x-rays travel through unleaded glass win-dow, through the tubehead seal and then the aluminium disks the lead collimator restricts the size of the beam and the x-ray beam travels down the lead lined position -indicating device (PID) and exits at the opening
Reprinted from Haring, Joen Iannucci and Laura lansen: Dental Radiogra phy: Principles and Techniques: Third Edition. 2000, with permission front Elsevier.
Component functions tungsten filament of cathode produces electrons when heated molybdenum cup of cathode focuses the electrons into a narrow beam and directs the beam towards the tungsten target in the anode tungsten target in anode stops the elec-trons and converts the energy into x-rays & heat (copper stenijjserves to dissipate the heat that is createdwith the production of x-rays
|i_Metal ji housing of x-ray 1 tube-1
J a-lnsulating : oil
K. . -
Lead Unleaded glass collimator window of
x-ray tube 'osition
indicating device
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rad physics 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 45
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RADIOLOGY
rad physics Rectification is the conversion of a direct current (DC) to an alternating cur-rent (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
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Properties of x-rays
appearance invisible and cannot be detected by any of the senses mass
have no mass or weight charge have no charge speed travel at the speed of light wavelength travel in waves and have short wave-lengths with a high frequency\V"" path of travel travel in straight lines and can be de-flected, or scattered focusing capability cannot be focused to a point and al-ways diverge from a point
no weight have no charge are invisible are absorbed by matter
penetrating power can penetrate liquids, solids, and gases; the composition of the substance deter-mines whether x-rays penetrate or pass through, or are absorbed absorption absorbed by matter; the absorption de-pends on the atomic structure of mat-ter and the wavelength of the x-ray ionization capability can interact with materials they pene-trate and cause ionization fluorescence capability can cause certain substances to fluo-resce or emit radiation in longer wave-lengths (e.g., visible light and ultraviolet light) effect on film can produce an image on photographic film effect on living tissues cause biologic changes in living cells
electricity is the energy used to make x-rays; electrical energy consists of a flow of electrons through a conductor; this flow is known as the electrical current electrical current is termed direct current (DC) when the electrons flow in one direc-tion through the conductor alternating current (AC) describes an elec-trical current in which the electrons flow in two, opposite directions rectification is the conversion of AC to DC 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 amperage is the measurement of the num-ber of electrons moving through a conductor,^, c7irrentls~measured in amperes (A) or mil-liampcres (mA) voltage is the, measurement of electrical force that causes electrons to move from a negative pole to a positive one; measured in volts (V) or kilovolts (kV) circuit is a path of electrical current; two electrical circuits are used to produce x-rays: a low-voltage/filament circuit and a high-voltage circuit
* % .
both statements are false
low voltage/filament circuit uses 3 to 5 volts, regulates the flow of electrical current to the filament; controlled by mA settings high-voltage circuit uses 65,000 to 100,000 volts, provides the high voltage required to accelerate; controlled by kVp settings transformer is a device that is used to either increase or decrease the voltage in an electri-cal circuit; it alters the voltage of the incom-ing current and then routes the electrical energy to the x-ray tube; three types of trans-formers are used to adjust the electrical cir-cuits (see below) step-down transformer is used to decrease the voltage from the incoming 110- or 220-line voltage to the 3 to 5 volts used by the fil-ament circuit high-voltage circuit uses both a step-up transformer and autotransformer step-up transformer is used to increase the voltage from the incoming 110- or 220-line voltage to the 65,000 to 100,000 volts used by the high-voltage circuit autotransformer serves as a voltage com-pensator that corrects for minor fluctuations in the current
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rad physics 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
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RADIOLOGY
rad protection Identify each component of inherent filtration:
insulating oil
unleaded glass window
lead lined PID
tubeheadseal
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> characteristic radiation
Types of x-rays not all x-rays produced in the x-ray tube are the same; x-rays differ in energy and wave-length energy and wavelength varies based on how the elections interact with the tungsten in the anode kinetic energy_of electrons isconverted to x-ray photons via general (braking or Brem-sstrahlui'g) radiation or characteristic radiat-ion general/braking radiation is produced when speeding electrons slow down due to in-teractions with the nuclei of the tungsten tar-get atoms
- braking refers to the sudden stopping or slowing of high-speed electrons when they hit or come close to the tungsten target - 70% of the x-ray energy produced is gen-eral radiation
characteristic radiation is produced when a high-speed electron dislodges an inner-shell electron from the tungsten atom and causes ionization " I - the remaining electrons rearrange to fill the vacancy resulting in a loss of energy & pro-duction of x-ray photon
- only a small % of x-rays produced; occurs only at > 70 kVp
Definitions primary radiation is the penetrating x-ray beam that is produced at the target of the anode and exits the tubehead; a.k.a. primary or useful beam secondary radiation is x-radiation that is created when the primary beam interacts with matter; ig less penetrating thanprimaryradia-tion scatter radiation, a form of secondary rad-iation, is the result of an x-ray deflected from its path by the interaction with matter; deflect-ed in all directions by the patient's tissues; detrimental to tissues id Compton scatter] ionization takes place;
& \ an x-ray photon collides with an n outer-shell C^ *> > electron and gives up part of its energy to
'% eject the electron from its orbit; x-ray photon *J*Hoses energy and continues in a different dir-
% ection (scatters) at a lower energy level; ac-counts forJ>2% of the scatter that occurs coherent or unmodified scatter occurs when a low-energy x-ray photon interacts with an outer-shell electron; no change in the atom occurs; x-ray photon of scattered radiat-ion is produced; x-ray photon is scattered in a different direction from that of the incident photon; noJoss of energy and no ionization occur; accounts for 8% of the interactions
insulating oil < unleaded glass window ' tubehead seal
inherent filtration takes place when the primary beam passes through the glass window of the x-ray tube, the insulating oil, and the tubehead seal inherent filtration of the dental x-ray machine is approximately 0.5 to 1.0 milli-meter (mm) of aluminum inherent filtration alone does not meet the standards regulated by state and federal laws; added filtration is required
OvtiioKjljtJ
. i OMMUMHW
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rad protection 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
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RADIOLOGY
rad protection 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 re-ceives.
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
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-
rad protection 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
holdthe PID
hold the film if the patient cannot stabilize it
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RADIOLOGY
rad protection 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 re-ceives.
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
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Operator protection guidelines must use proper protection during exposure to avoid the primary beam, scatter radiation etc. must avoid the primary beam distance, position and shielding are all im-portant for protection
Distance recommendations must stand at least 6' away from the tube-head if distance is not possible, a protective bar-rier must be used
Primary beam
Y '
"... ' -:.,.\:.-: :.::.-:: ' $ 'l W'
Radiographer
135"
Reprinted from Iannucci, Joen M. and Howerton, Laura Jansen: Dental Radiography Principles and Techniques. Fourth edition D 2012 with permission from Elsevier-Saunders.
stand behind a barrier Position recommendations
must stand perpendicular to the primary beam, or, at a 0-135 degree angle to the beam " ' never hold a film in place for a patient dur-ing exposure never hold the PID during exposure
Shielding recommendations whenever possible, stand behind a protec-tive barrier, such as a wall
Maximum permissible dose (MPD) MPD is the dose of radiation the body can endure with little or no injury for non-occupationally exposed person limit is 0.001 Sv/year for occupationally exposed person limit is 0.05 Sv/year for occupationally exposed pregnant person limit is 0.001 Sv/year
ALARA concept As Low As Reasonably Achievable concept states that all exposure to radiation must be kept to a minimum applies to patients & operators
Patient protection before exposure proper prescribing of dental radi-ographs use of proper equipment including filtration, collimation and PID the rectangular PID (instead of round) is most effective in reducing pa-tient exposure use of a long PID is more effective than use of a short PID
Patient protection during exposure use of thyroid collar for intraoral films and lead apron for all films use of digital imaging or use fastest film available (F-speed) use of beam alignment devices use of correct exposure factors (kVp, mA & exposure time) use of proper technique
both statements are true
Patient protection after exposure proper sensor or film handling proper image retrieval or film pro-cessing
Guidelines for prescribing of dental radiographs
dentist is responsible for ordering im-ages & uses professional judgment to make decisions concerning the num-ber, type and frequency of dental radi-ographs radiographic exam should never in-clude a predetermined number of films radiographs should never be taken at predetermined time intervals radiographs should be ordered based on the individual needs of the patient guidelines for prescribing dental ra-diographs have been determined by the ADA and FDA
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rad protection 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
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tech 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
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collimation
Collimation used to restrict the size and shape of the x-ray beam & to reduce patient exposure a collimator is a lead plate with hole in the middle, is fitted over the open-ing of the machine housing where the beam exits collimator may have a round or rec-tangular opening rectangular collimator restricts the size of the beam to slightly larger than a size 2 film and significantly re-stricts patient exposure circular collimator produces a cone shaped beam & restricts the size of the beam to 2.75" in diameter when using a circular collimator, fed-eral regulations re quire that the beam be restricted to 2.75" as it exits the PID and reaches the skin of the pa-tient
Position indicating device (PID) the PID or cone is an extension of the x-ray tubehead used to direct the beam types of PID include conical, round and rectangular a conical PID is a closed plastic cone that produces scatter radiation;no longer used in dentistry a round PID is a tubular open ended lead- lined extension; no PID scatter is produced a rectangular PID is a rectangular open ended lead-lined extension; is most effective in reducing patient ex-posure; no PID scatter is produced both round and rectangular PIDs are available in two lengths: short (8") and long (16")
^"VtMJangPID is preferred because less V'uivergence of me*x-ray beam occurs
the film was reversed (placed backwards) during exposure
A reversed film is light &
exhibits a herringbone
pattern.
A double exposure appears dark & exhibits a double image.
A bent film appears stretched & distorted. With movement of the patient or PID, a blurred image results.
Images reprinted from Iannucci, Joen M. and Howerton, Laura Jansen: Dental Radiography Principles and Techniques. Fourth edition 2012 with permission from Elsevier-Saunders.
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tech 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
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tech 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
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focal spot size
Magnification enlargement of an image that results from the divergent paths of x-ray beam some degree of magnification is pres-ent in every image due to divergent paths influenced by target-receptor distance and object-receptor distance target-receptor distance (or source to receptor distance) is the distance be-tween the source of x-rays & image re-ceptor PID determines target-receptor distance shorter PID results in more magnifi-cation; longer PID results in lessjnagni-
JBcatjori object-receptor distance is the dis-tance between the tooth & image recep-tor if there is decreased distance between the tooth & receptor, less magnification occurs
if there is increased distance between the tooth & receptor, more magnification occurs
Focal spot size tungsten target in anode is focal spot size ranges from0.6 -1.0 minj^nd is de-termined by the manufacturer (cannot be controlled by operator) the size of focal spot influences the image sharpness the smaller the focal spot, the sharper the image
In dental radiography, the most accurate image:
use the smallest focal spot size use the LONGEST target-receptor dis-tance use the SHORTEST object-receptor distance direct the central ray of the x-ray beam perpendicular to the receptor and tooth keep the receptor parallel to the tooth being imaged
vertical angulation is insufficient/too flat
Vertical angulation refers to the positioning of the PID in a vertical, or up-and-down plane correct vertical angulation results in an image that is the same length as the tooth incorrect vertical angulation results in ELONGATION or FORESHORTENING an elongated image appears long & results from too flat vertical angulation a foreshortened image appears short & re-sults from too steep vertical angulation 0 degree vertical angulation = PID parallel with floor positive vertical angulation = PID pointing DOWN to floor/PID above occlusal plane negative vertical angulation = PID point-ing UP to ceiling/PID below occlusal plane H
Vortical angulation refers to the positioning of the PID in a horizontal or side-to-side plane when tire central ray is directed through the interproximal contacts of the teeth, correct horizontal angulation results and open con-tacts on seen the dental image incorrect horizontal angulation results in overlapped contacts (contacts are superim-posed over each other)
ELONGATION results when the vertical angula-tion is TOO FLAT; teeth look long & stretched
FORESHORTENING results when the vertical angulation is TOO STEEP; teeth look short
Both photos reprinted from Haring, Joen Iannucci and Laura Jansen: Dental Radiography: Principles and Techniques: Third Edition. 2000, with permission from Elsevier.
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tech Identify the cause of this panoramic image error seen below:
chin tipped too far upward chin tipped too far downward ' head tipped to one side
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RADIOLOGY
Identify the cause of this distorted periapical film seen below:
tech
film bending
film creasing
phalangioma
double exposure
movement
Reprinted from Haring, Joen Iannucci and Laura Jansen: Dental Radiography: Princi-ples and Techniques: Third Edition. 2000, with permission from Elsevier.
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chin tipped too far downward
chin tipped too far downward \ / (see image on reverse side)
mandibular incisors appear blurred loss of detail in anterior apical region condyles may not be visible results in severe interproximal over-lapping occlusal plane has excessive upward curve
exaggerated smile line is seen
chin tipped too far forward A (see image below) ' ^
hard palate & floor of nasal cavity ap-pear superimposed over maxillary teeth maxillary incisors appear blurred maxillary incisors appear magnified occlusal plane downward curve reverse smile line (frown) is seen
film bending Film bending
images appear stretched & distorted occurs due to curvature of hard palate
Film creasing crease appears as a thin black line represents where the emulsion of the film has cracked
Phalangioma the bone of the patient's finger seen on the image results when finger is in front of the receptor instead of behind it (seen with use of bisecting technique where patient holds the film not recommended)
Light film may result from underexposure too short of exposure time, too low kVp or too low mA
Dark film may result from overexposure - too long of exposure time, too high kVp or too high mA
Fogged film -s^-""" appears gray & lacks contrast occurs when film is exposed to radiation other than primary beam (e.g., scatter) may result from improper safelighting or light leaks in dark room
All three photos reprinted from Haring, Joen iannucci and Laura Jansen: Dental Radiography: Principles and Techniques: Third Edition. 2000, with permission from Elsevier.
Black film exposed to light
Clear film film is unexposed
A light film results from underexposure
a dark film results from overexposure
a fogged film ap-pears gray and lacks contrast
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tech A periapical image shows overlapped contacts. This error is cause by:
vertical angulation is excessive/too steep
vertical angulation is insufficient/too flat
incorrect horizontal angulation
beam not centered over receptor
poor receptor placement
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tech Use the two images below to determine the spatial position of the round ob-ject. Following the exposure of image #1, the x-ray tubehead was moved and the beam was directed from a mesial angulation in image #2. Given this in-formation, where is the round object located?
lingual to the first molar
buccal to the first molar
in soft tissue
in bone
< c 6>
Film #1 Film #2
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incorrect horizontal angulation Overlapped contacts
if the central ray is not directed through the interproximal contacts of the teeth, the horizontal angulation is incorrect incorrect horizontal angulation results in overlapped contacts seen on the image
Cone-cut if the beam is not centered over the recep-tor, a clear unexposed area or cone-cut is seen on the image the PID or "cone" is said to "cut" the image a cone-cut may occur with the use of a rect-angular or round PID a conecut may occur with or without the use of a beam alignment device
poor receptor placement a periapical image shows the entire tooth and root, including the apical area and must be placed to cover those areas incorrect periapical receptor placement may result in absence of apical structures or a tipped or tilted occlusal plane a bite-wing image shows the crowns of both the maxillary and mandibular teeth, the inter-proximal areas and crestal bone incorrect bite-wing receptor placement may result in absence of teeth or teeth surf-faces on an image, tipped occlusal plane
Incorrect hori-zontal angulation results in over-lapped contacts.
If the beam is not cen-tered over the recep-tor, a cone-cut results & a clear unexposed area is seen.
Improper place-ment (if entire root is not cov-ered) will result in no apices appear-ing on the image.
Images reprinted from Haring, Joen Iannucci and Laura Jansen: Dental Radiography: Principles and Techniques: Third Edition. 2000, with permission from Elsevier.
lingual to the first molar
Buccal object rule a.k.a. tube shift technique used to determine an object's spatial po-sition/buccal-lingual relationship within the jaws two images are obtained, each exposed with a different angulation used to compare the object's position with respect to a reference point (e.g., root of a tooth)
Example if the PID is moved mesially and the ob-ject in the second image appears to have moved in the same direction, the object lies to the lingual if the PID is moved mesially and the ob-ject in the second image appears to have moved in the opposite direction, the ob-ject lies to the buccal use the acronym SLOB to remember the buccal object rule
In image #1, note the location of the object in reference to the mesial root of the first molar.
In image #2, the PID was moved mesially; the ob-ject in reference to the mesial root of the first molar has also moved mesially.
L - O - B RULE
Same = Lingual
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extraoral Identify the radiopaque areas labeled 1 & 2 on the image below.
Reprinted from Iannucci, Joen M. and Howerton, Laura Jansen: Dental Radiography Principles and Techniques. Fourth edition 2012 with permission from Elsevier-Saunders.
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extraoral Based on the image below, identify the approximate age of the patient.
Reprinted from Iannucci, Joen M. and Howerton, Laura Jansen: Dental Radiography Principles and Techniques. Fourth edition 2012 with permission from Elsevier-Saunders.
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answers 1-2 below
Reprinted from Iannucci, joen M. and Howerton, Laura Jansen: Dental Radiography Principles and Techniques. Fourth edition 2012 with permission from Elsevier-Saunders.
1. Hoop earring 2. Ghost image of hoop earring
Ghost image defined as a radiopaque artifact on a panoramic image that is produced when a radiodense object is penetrated twice by the x-ray beam occurs If all metallic or radiodense ob-jects (e.g., eyeglasses, earrings, necklaces, hairpins, removable partial dentures, com-plete dentures, orthodontic retainers, hear-ing aids, napkin chains) are not removed before exposure of panoramic receptor obscures diagnostic information
Ghost image appearance resembles its real counterpart found on the opposite side of the image; appears indistinct, larger, & highepthan its actual counterpart a ghost image of a hoop earring appears on the opposite side of the image as a ra-diopacity that is larger & higher than the real hoop earring; appears blurred in both horizontal and vertical directions to avoid ghost images, instruct the pa-tient to remove all radiodense objects in the head-and-neck region prior to exposure of the panoramic receptor
' < 9 years old
Reprinted from Iannucci, Joen M. and Howerton, Laura Jansen: Dental Radiography Prin-ciples and Techniques. Fourth edition 2012 with permission from Elsevier-Saunders.
The erupted permanent teeth are highlighted in gray in the charts below. Based on this in-formation, the panoramic film appears to represent a child of < 9 years old.
Permanent teeth eruption charts
Maxillary
Central incisor
Lateral incisor
Canine
First premolar
Second premolar
First molar
Second molar
Third molar
Age at eruption
7-8
8-9
11-12
10-12
10-12
6-7
12-13
17-21
Mandibular
Central incisor
Lateral incisor
Canine
First premolar
Second premolar
First molar
Second molar
Third molar
Age at eruption
6-7
7-8
9-10
10-12
11-12
6-7
11-13
17-21
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tech Identify each one of the following that is an advantage of using the parallel-ing technique.
' receptor placement
i comfort
accuracy
simplicity
' duplication
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RADIOLOGY
tech Identify each one of the following that is a disadvantage of using the bisect-ing technique.
decreased exposure time
can be used without a beam alignment device
distortion
angulation problems
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Parelling technique based on concept of parallelism preferred technique for intraoral films
Basic principles receptor is placed parallel to the long axis of the tooth being imaged central ray is directed perpendicular to both the receptor & long axis of the tooth a beam alignment device must be used to keep the receptor parallel to the tooth the object-receptor distance must be in-creased to keep the receptor and tooth paral-lel the target-receptor distance must be in-creased to make certain the most parallel rays will be aimed at the tooth and receptor (16" target-receptor distance)
Long axis ol toolh
accuracy simplicity duplication
Advantages accuracy - image is highly representative of the actual tooth simplicity - simple & easy to learn and use duplication - easy to standardize and can be accurately duplicated when serial images are needed
Disadvantages receptor placement - it may be difficult for operator to place the beam alignment device in some patients discomfort - the beam alignment device may cause discomfort
^to Positions of the receptor, tooth and central ray in the paral->ft ^% leling technique. The receptor & long axis of the tooth are par-**
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