Dental Radiology

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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RADIOLOGY

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

i

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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

8

' 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

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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RADIOLOGY

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


RADIOLOGY

' 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

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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RADIOLOGY

image char Rank the following from LEAST radiopaque to MOST radiopaque.

amalgam

bone

dentin

> maxillary sinus

enamel

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RADIOLOGY


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

misc.

Dental radiographs are the legal property of the:

patient

dentist

state

> none of the above


RADIOLOGY

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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RADIOLOGY

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

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.


RADIOLOGY

normal anat The coronoid process often appears on what periapical image?

maxillary incisor

maxillary molar

mandibular incisor

mandibular molar

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RADIOLOGY

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.

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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RADIOLOGY

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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RADIOLOGY

' 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


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."


Courtesy Dr. Stuart C. White, UCLA School of Dentistry."

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RADIOLOGY


"Courtesy Dr. Stuart C. White, UCLA School of Dentistry.'


RADIOLOGY

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


< answers 1 - 8 below

2. inferior nasal conchae A -radiopaque mass


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." .. _ copyright 2013-2014- Dental Decks

RADIOLOGY




answers 1 - 7 below

1. lingual cusp of 1st premolar radiopaque area


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


answers 1 - 4 below


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." 17

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RADIOLOGY


"Courtesy Dr. Stuart C. White, UCLA School of Dentistry." 1 8

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RADIOLOGY 18

answers 1 - 3 below

1. cement-enamel junction (CEJ) radiopaque line


3. submandibular gland fossa large radiolucent area


1. inferior nasal conchae radiopaque mass

answers 1 - 7 below



4. maxillary sinus radiolucent space


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


7. lingual cusp of 1st premolar radiopaque band


"Courtesy Dr. Stuart C. White, UCLA School of Dentistry." 19 copyright 2013-2014- Dental Decks

RADIOLOGY



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RADIOLOGY

answers 1 - 6 below


2. lateral wall in incisive canal ) radiopaque line

3. ala of nose 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



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." 21

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RADIOLOGY




RADIOLOGY

answers 1-3 below

1. mandibular tori radiopaque masses

2. lingual foramen radiolucent circle

3. genial tubercles donut shaped radiopacity


answers 1 - 4 below

1. alveolar crest of bone radiopaque structure





normal ant Identify the structures labeled 1- 8 on the image below.


= = _ _ _ _ ^ _ _ ^ _ _ copyright 2013-2014-Dental Decks

RADIOLOGY



RADIOLOGY

1. marrow space radiolucent space

answers 1 - 8 below


3. bony trabecular plate 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






7. alveolar crest radiopaque structure

8. enamel radiopaque band


9. pulp chamber radiolucent space

normal anat Identify the structures labeled 1-12 on the image below.


RADIOLOGY




RADIOLOGY

answers 1-12 below



3. tooth #10 maxillary lateral incisor


5. dentin radiopaque area


7. alveolar crest radiopaque structure


9. pulp chamber radiolucent space

10. enamel radiopaque band

lljraUdJiJmdot radiopaque circle

12. dentino-enameTjunction radiopaque line

%


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





normal anat Identify the structures labeled 1 -15 on the image below.

"Courtesy Dr. Stuart C. White, UCLA


RADIOLOGY 27

copyright2013-2014-Dental Decks

normal anat Identify the structures labeled 1 -13 on the image below.

"Courtesy Dr. Smart C. White, UCLA



RADIOLOGY

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


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


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


11. shadow of cervical spine diffuse opacity


12. submandibular gland fossa broad radiolucent area

13. articular eminence / articular tubercle radiopaque prominence

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.






RADIOLOGY

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


RADIOLOGY

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

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

31 copyright S> 2013-2014- Dental Decks

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

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


RADIOLOGY

Dose equivalent is expressed in terms of:

coulombs/kilogram (C/kg)

gray (Gy)

sievert (Sv)

quality factor (QF)

rad biology

RADIOLOGY 34


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>

rad biology List the following cells from most RADIORESISTANT to most RADIOSENSITIVE.

muscle

small lymphocyte

skin

thyroid gland


RADIOLOGY

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


RADIOLOGY

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

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


RADIOLOGY

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.



> the first statement is true, the second is false



RADIOLOGY

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


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^

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


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

40 copyright e 2013-2014- Dental Decks

RADIOLOGY

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

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


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


RADIOLOGY

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

rad physics Which of the following converts electrons into x-rays?

positive anode

1 negative anode

' positive cathode

negative cathode


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


RADIOLOGY

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

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

copyright O 2013-2014- Dental Decks

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.






RADIOLOGY

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

* % .


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

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


RADIOLOGY

rad protection Identify each component of inherent filtration:

insulating oil

unleaded glass window

lead lined PID

tubeheadseal


RADIOLOGY

> 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

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


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.






RADIOLOGY

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


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.






RADIOLOGY

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


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

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

51 copyright > 2013-2014- Dental Decks

RADIOLOGY 51

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


RADIOLOGY

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.

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


RADIOLOGY

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


RADIOLOGY -.

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 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.

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


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.


RADIOLOGY 58

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

tech A periapical image shows overlapped contacts. This error is cause by:

vertical angulation is excessive/too steep


incorrect horizontal angulation

beam not centered over receptor

poor receptor placement

RADIOLOGY 56


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


RADIOLOGY

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

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.


RADIOLOGY

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.

73 copyright o 2013-2014- Dental Decks

RADIOLOGY

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

tech Identify each one of the following that is an advantage of using the parallel-ing technique.

' receptor placement

i comfort

accuracy

simplicity

' duplication


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


RADIOLOGY

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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