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Radiology 2

Subjects : health-sciences, radiology

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. desired thickness of lead apron
Before fixing
Excessive vertical angulation
.25 mm
Only when necessary to help the dentist diagnose and treat oral diseases; elective xrays should be postponed until after delivery

2. 1/10th dosage of gen. public - What are photons
Genial tubercles - lingual foramen
Insufficient or improper washing
Image the entire dentition - surrounding alveolar bone - sinuses - and the TMJ - examine large area of face and jaws - locate impacted teeth - retain root tips - evaluate trauma - lesions - and diseases - and assess growth and development
Quantum of energy

3. How much total filtration is required of x-ray machines that operate lower than 70 kVp
Paralleling; meets more principles of shadow casting
#0
1.5 mm
Tori

4. What are common sources of background radiation
Cosmic - naturally occuring radiation from earth - radiation for radioactive materials
Lighter image - patient exposed to larger beam which will increase exposure
Negative
Roentgen

5. What is the purpose of taking radiographs of an edentulous patient
Excessive vertical angulation
Increase the exposure time
Time b/w exposure and 1st clinically observable symptoms
detect pathological lesions -establish position of mental foramen -establish position of mand canal -determine quality & quantity of alveolar bone present

6. According to principles of shadow casting - How should the film be placed in relation to the tooth?
Central ray
Doesn't matter
Parallel
Reduces the exposed silver halide crystals to black metallic silver

7. What must be done to xray fixer priod to disposal
Occlucal
Chronic low-level exposures/long term dose; causing cancer - cataracts - low birth weight - genetic mutations - and embryological defects
CCD (direct) - CMOS (direct) - PSP (indirect)
Remove silver

8. What Size film is used to take a BW on a 3 yr. old
#1
Decrease kVp by 15 and double exposure time = 10 mA 60 impules 75 kVp
#0
After 2-3 min of fixing if needed

9. What info should be recorded on the dental radiographic mount

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10. How does exposure time for children compare to that of an adult
Focal spot
Incorrect horrizontal angulation
1/3-1/2
Nasal fossa - max sinus

11. How would a film appear if submerged totally in the developer but not in the fixer
Move farther from the radiation
Top of film delineated by a straight line then dark
1/6th of a second
Images conditions of the teeth and supporting structures when a larger area than a PA is needed; provides more info. than a PA about the alveolar crest and apical areas

12. How far should the operator stand from the source of radiation
Filtration and collimation
Max. sinus - zygoma
6 ft
Movement caused by the patient - slippage of the image receptor - or vibration of the tube head

13. you change you kVp from 90 to 70 and leave all other factors the same. What is the result
B/c of its stability to produce a large volume of radiographs in a short amount of time
1.5 mm
Absorb long wavelengths / soft radiation
The wave length will be shorter - the quality and energy of the beam will be higher and the contrast will be lowe. - the image will also have a higher density

14. Explain PSP
Stop taking xrays and evaluate all equipment and techniques to ensure safety
particulate radiation: made of protons - neutrons - electrons and alpha and beta particles; has mass -electromagnetic radiation: made of photons; no mass
Photostimuable Phosphor Plate aka storage phosphor system -indirect digital imaging -captures analog data then processed in a laser scanning device -light is then converted into electrical signal that the computer uses to create the digital image
Film placed backwards

15. How does resolutiong and detial of a panoramic radiograph compare with that of PA's and BW's
Increased focal spot size - decrease source-object distance - & increased object-film distance
Not as sharp and detailed as the intraoral image
#1 or #2 - placed so the edge of the receptor lines up behind the distal of the canine before the eruption of the permanent 2nd molar; - after the eruption of the perm. 2nd molar - 2 posterior PA's should be taken per quadrant
Increase the exposure time

16. Mand molar anatomy
50 mSv (5rem)
Excessive vertical angulation
Perpendicular to the tooth and film
Mand canal - external oblique ridge - beg. of ramus

17. What causes elongation
Didn't push button completely
locate retained roots -locate unerrupted or impacted teeth -evaluate for diseases and lesions -locate foreign bodies -reveal presence of salivary stones (sialothiths) -aid in evaluating fractures -size and shape of tori -aid in examining patients wit
Insufficient vertical angulation
Cosmic - naturally occuring radiation from earth - radiation for radioactive materials

18. How long is the final rinse
nasal septum - ant. nasal spine - nasal fossa - median palatine suture - incisive foramen
20 min
Higher temp. increases film fog - so radiographer should consult a time-temp. development chart to adjust developing time appropriately; developing time will decrease
CCD (direct) - CMOS (direct) - PSP (indirect)

19. What exposure is taken to determine jaw relationships in ortho treatment planning
Occlucal
15 impulses
max teeth are longer - max molars have 3 roots - mand molars have 2 roots - most roots curve toward the distal - occlusal plane is straight or curved slight towards distal
Lateral cephalometric

20. What causes missing crowns
Short-term dose
Vertical BW
Excessive vertical angulation
Mand. foramen

21. What must a patient remove before taking a PANO
Produced by internal barriers in tube head (ex: glass and insulating oils)
Oral piercings - earings - glasses - necklaces - facial piercings - hair pins - hearing aids - dentures - and retainers
Filtration and collimation
Blue light sensitive films

22. What is the most commonly used personnel monitoring devide for dental offices
Produced by internal barriers in tube head (ex: glass and insulating oils)
2.5 mm
Film badges
Invisible image (remains like this until film is processed)

23. How does reducing exposure to the patient benefit the operator
Patient positioned too far foward in the focal trough
Zygoma will be radiopaque - max. sinus will be a large area of radiolucency
Max arch ala-tragus parallel to floor - mand arch
The less the patient is exposed - the less the operator is exposed

24. Size film used for PA's on adults
extraoral film
Copper stem - tungsten target - radiator
#2
15 impulses

25. which anatomical structures appear radiopaque
No. 0
Filters placed in PID after tubehead production
B/c of its stability to produce a large volume of radiographs in a short amount of time
Dentin - enamel - bone

26. your dentist recommends that a patient have xrays taken - bu the patient refuses. What should be done

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27. What type of x-rays have greater penetrating power - long or short wavelength?
Parallel
Short
KVp
On the back side of the tori

28. How does kVp affect patient exposure
Located on the tooth surface that contacts the adjacent tooth
Focal spot size - target-image receptor distance - object-image receptor distance - motion - screen thickness - screen-film contact - and crystal/pixel size of intraoral image receptors
Higher kVp = low exposure
Patient's dental arches; maxilla and mandile

29. With What type film are intensifying screens used?
Filters placed in PID after tubehead production
extraoral film
The wave length will be shorter - the quality and energy of the beam will be higher and the contrast will be lowe. - the image will also have a higher density
Thyroid collar - lead and lead-equivalent sprons are availaable with or without an attached thyroid collar

30. What 2 unites are used to measure absorption
20 seconds
5 min
Gray & Rad
Sterilize film holder devices or discard disposable image receptor holding devices

31. What is the optimum processing temp.
68 degrees F
Filament
Enamel - dentin - and bone
Quantum of energy

32. A patient complains of pain in the upper molar region. What radiographic exposure should be made?
Lead
Method should be compensated for bisecting or paralleling
Periapical
Patient's name - date - and other pertinent info

33. What are the long term effects of radiation exposure
Cancer - cateracts - embryologic defects - genetic mutations - low birth weight
Mental foramen - mental ridge - mand canal
MA & time
Higher temp. increases film fog - so radiographer should consult a time-temp. development chart to adjust developing time appropriately; developing time will decrease

34. What Size film is 7/8 x 1 3/8
.25 mm
No. 0
Release of electrons when a material such as tungsten is heated to incandescence - electrons are boiled off from the cathode filament in the x-ray tube when electric current is passed through it
Not centered on sensor

35. which dose of radiation is more biologically damaging
Chronic low-level exposures/long term dose; causing cancer - cataracts - low birth weight - genetic mutations - and embryological defects
68 degrees F
Sterilize film holder devices or discard disposable image receptor holding devices
Gently agitating the hanger up and down a few times

36. What causes foreshortening
Beam is perpendicular to the imaginary line that bisects the angle formed by the long axis and the film
Absorb long wavelengths / soft radiation
Excessive vertical angulation
#2

37. When viewing a periapical radiograph - you notice that the image of the tooth is extremely long and well defined; However the apices are missing. What technique was used to take the radiograph? What caused the roots to appear long?
Rectangular collimation
Rectangular collimations
Max. sinus - zygoma
bisecting was used b/c of the distortion of the elongated root - the roots appeared long b/c the vertical angulation was inadequate

38. What is penumbra
X-rays hit phosphor screen creating florescent light that exposes the film
Shadow around the tooth
Reduces the exposed silver halide crystals to black metallic silver
BW

39. How is vertical angulation established with the bisecting technique
20 seconds
underexposure-underdevelopment -depleted developer solution -excessive fixation (takes all crystals off)
Insufficient or improper washing
Beam is perpendicular to the imaginary line that bisects the angle formed by the long axis and the film

40. What is the annual MPD for pregnant dental assistant
5 mSv or .5 REM
#0
The most distal tooth should be captured in full as well as a few mm of bone level behind the most distal tooth
Part that was fixed but not developed would be clear

41. What device is used to check quality of processing chemicals
Document patient's refusal and have them sign
Patient's name - date - and other pertinent info
Step-wedge or test film
X-rays that have gone thru an object and are now a newer weaker beam

42. How often must you replenish the solutions in an automatic processor
Rectangular collimations
1/3-1/2
Insufficient or improper washing
For every 30 films processed 6-8 oz should be taken out and replaced with fresh solution

43. How are indirect exposure films exposed
Insufficient or improper washing
Genetic cells
Scatter/secondary radition
X-rays hit phosphor screen creating florescent light that exposes the film

44. How does packet placement differ b/w bisecting and paralleling
Scatter/secondary radition
bisecting - packet is as close to tooth as possible - but not parallel -parallel - packet is parallel to tooth - further away
Film placed backwards
The mental ridge

45. Proper patient positiong for paralleling

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46. Size film used for occlusals on adults
Didn't push button completely
1/5 exposure time for edentulous
#4
Extra oral

47. What causes clear film
No exposure - or fixer before developer
20 seconds
Labial
1/5 exposure time for edentulous

48. What is the main source of radiation exposure to the operator
Patient positioned too far foward in the focal trough
Scatter/secondary radition
6 ft
Insufficient or improper washing

49. In the darkroom - you unwrap a film and place a coin on top of the film for several minutes. when you process the film - you notice a slight - well-defined white circle on the film. What does this mean?
Not centered on sensor
extraoral film
Patient positioning
Failed safelight test - suggesting that the safelight conditions in the darkroom are fogging the film

50. What radiographs are used to locate a salivary stone in the submandibular duct
1.5 mm
Highest of the 2 ridges - about the level of the cervical 3rd - behind the 2nd and 3rd molars
Central ray
Mandibular occlusal