Test your basic knowledge |

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. What is the major use of topographical occlusal radiographs
Incorrect horrizontal angulation
Patient positioned too far foward in the focal trough
Cosmic - naturally occuring radiation from earth - radiation for radioactive materials
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

2. How far should the operator stand from the source of radiation
Absorb long wavelengths / soft radiation
6 ft
No. 1
5 mSv or .5 REM

3. What exposure is taken to determine jaw relationships in ortho treatment planning
As low as reasonably achievable
#2
The most distal tooth should be captured in full as well as a few mm of bone level behind the most distal tooth
Lateral cephalometric

4. you change you kVp from 90 to 70 and leave all other factors the same. What is the result
Located on the tooth surface that contacts the adjacent tooth
Nasal fossa - max sinus
Air space and soft tissues
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

5. What is the x-ray at the center of the primary beam called
Patient's name - date - and other pertinent info
Patient positioning
Part that was fixed but not developed would be clear
Central ray

6. How can exposure to the operator be reduced
Dark film is from over exposure and improper packet placement for strange looking teeth and not being able to determine What film is
Absorb scatter radiation and prevent fogging
Move farther from the radiation
Density

7. The cells from most sensitive to least sensitive
No exposure - or fixer before developer
White blood cells - red blood cells - immature reproductive cells - epithelial cells - connective tissue cells - bone cells - nerve cells - brain cells - muscle cells
All of the ant. teeth will appear blurred and narrowed in width
Air space and soft tissues

8. Mand premolar anatomy
PANO
Provides more info. about the location of tori - impacted and malpositioned teeth and the calcification of soft tissues
Mental foramen - mental ridge - mand canal
Overexposure -overdevelopment -developer is too strong -not enough fixation -exposure to white light -improper safelighting

9. after processing exposed dental film - you notice dark spots on the film. What caused this
Premature contact with developer
Increase the exposure time
A form of radiation originating from an atom following removal of an electron or excitation of an atom
Blue light sensitive films

10. 3 film holding devices used for paralleling
Mand. foramen
X-ray and heat
7 1/2 or 15 watt
Dentsply rinn - XCP - XCP-DS - flow dental RAPD

11. What is formed when high speed electrons strike the target
Produced by internal barriers in tube head (ex: glass and insulating oils)
X-rays that have been deflected from an object and have changed paths
X-ray and heat
Clear/blue in the area of overlap b/c fixer will not remove all crystals

12. What controls the speed with which the electrons travel from the cathode to the anode
Filtration and collimation
20 min
KVp
Aka general radiation; stopping or slowing of the electrons of the cathode stream as they collide with the nuclei of the target atoms

13. What is penumbra
Shadow around the tooth
Cancer - cateracts - embryologic defects - genetic mutations - low birth weight
Step-wedge or test film
Patient movement

14. What is secondary radiation
Labial
15 impulses
X-rays that have gone thru an object and are now a newer weaker beam
Highest of the 2 ridges - about the level of the cervical 3rd - behind the 2nd and 3rd molars

15. What 3 types of cells are most radioresistant
The less the patient is exposed - the less the operator is exposed
Nerve - brain - muscle
5 mSv or .5 REM
Movement caused by the patient - slippage of the image receptor - or vibration of the tube head

16. What is the primary beam
Original - undeflected - useful beam
KVp
All of the ant. teeth will appear blurred and narrowed in width
Original packaging -area sheilded from radiation -50-70 degrees F

17. What causes conecut
KVp
Part that was fixed but not developed would be clear
Not centered on sensor
Tori

18. What are the 2 units used to measure exposure to radiation
Higher kVp = low exposure
Coulombs/kilogram(C/kg) & Roentgen (R)
Occlucal
D - E - F

19. What factors would decrease edge sharpness and increase magnification
Far object-image receptor distance
KVp
20 min
Eyewear - mask - and gown

20. How does exposure time for children compare to that of an adult
Excessive VA w/ PID positioned too steep enough away from zero degrees
1/3-1/2
Erythema - vomitting - nausea - hemorrage - diarrhea - hair loss
Perpendicular to the film - parallel to the bite portion of the stabe

21. How does reducing exposure to the patient benefit the operator
The less the patient is exposed - the less the operator is exposed
Short
extraoral film
6 ft

22. desired thickness of lead apron
Invisible image (remains like this until film is processed)
1/6th of a second
X-rays hit phosphor screen creating florescent light that exposes the film
.25 mm

23. What is the purpose of taking radiographs of an edentulous patient
Clear/blue in the area of overlap b/c fixer will not remove all crystals
Invisible image (remains like this until film is processed)
detect pathological lesions -establish position of mental foramen -establish position of mand canal -determine quality & quantity of alveolar bone present
Lead

24. What is the earliest sign of radiation exposure
Erythema
.25 mm
Lateral cephalometric
Rectangular collimation and fast film speed

25. What is the annual MPD for radiation workers
Large blank space is due to reversed image error or chemical contamination - missing apices is due to inadequate VA
68 degrees F
50 mSv or 5 REM
Labial

26. What is the optimum processing temp.
Didn't push button completely
For every 30 films processed 6-8 oz should be taken out and replaced with fresh solution
68 degrees F
Beam is perpendicular to the imaginary line that bisects the angle formed by the long axis and the film

27. How many impulses are in .25 seconds
Patient's name - date - and other pertinent info
All of the ant. teeth will appear blurred and narrowed in width
15 impulses
Premature contact w/ developing chemicals - Drops of developer or fixer that splash onto the work area and came in contact with the film.

28. How is vertical angulation established with the paralleling technique
Perpendicular to the film - parallel to the bite portion of the stabe
Document patient's refusal and have them sign
.25 mm
Patient positioning

29. when should radiographs be taken on a pregnant patient
Every 6 mths
Only when necessary to help the dentist diagnose and treat oral diseases; elective xrays should be postponed until after delivery
B/c of its stability to produce a large volume of radiographs in a short amount of time
Large blank space is due to reversed image error or chemical contamination - missing apices is due to inadequate VA

30. What is the purpose of collimation
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
Reduce size and shape of beam
8-16 inches
Premature contact w/ developing chemicals - Drops of developer or fixer that splash onto the work area and came in contact with the film.

31. Mand lateral/canine anatomy
Tori
10 min (dbl the development time)
Positioning the arches too far foward
Excessive VA w/ PID positioned too steep enough away from zero degrees

32. What film is used to diagnose interproximal decay
The less the patient is exposed - the less the operator is exposed
Only when necessary to help the dentist diagnose and treat oral diseases; elective xrays should be postponed until after delivery
Beam is perpendicular to the imaginary line that bisects the angle formed by the long axis and the film
BW

33. What are three types of image receptors used in digital radiography
CCD (direct) - CMOS (direct) - PSP (indirect)
Time b/w exposure and 1st clinically observable symptoms
Insufficient or improper washing
Duplicate - which will go to the insurance comp.; office keeps best copy

34. when viewing a PANO - you notice that a lot of spine sHows on both side of the film - What caused this
Chronic low-level exposures/long term dose; causing cancer - cataracts - low birth weight - genetic mutations - and embryological defects
Positioning the arches too far foward
The emulsion side of the film is placed against the orginal radiograph with the nonemulsion side up
2.5 mm

35. when taking a PANO radiograph - the patient is placed too far into the machine. How will the radiograph appear
8-16 inches
No. 4
All of the ant. teeth will appear blurred and narrowed in width
Removes the unexposed silver halide crystals

36. A properly exposed film appears completely black. when was is exposed to white light
Before fixing
KVp
Vertical BW
No. 4

37. How does exposure time differ b/w adults and children
5 mSv or .5 REM
Provides more info. about the location of tori - impacted and malpositioned teeth and the calcification of soft tissues
Cancer - cateracts - embryologic defects - genetic mutations - low birth weight
Cut exposure time by 1/3

38. in which pericapical projection will the mental ridge be visible
Check the processing chemical - particularly the developer
Mandibular lateral/central
Zygoma will be radiopaque - max. sinus will be a large area of radiolucency
Cracking of the emulsion caused by excessive temp diff. b/w any darkroom solutions

39. What would cause increased magnification - decreased resolution and edge sharpness
Eyewear - mask - and gown
Gray & Rad
Max arch ala-tragus parallel to floor - mand arch
Increased focal spot size - decrease source-object distance - & increased object-film distance

40. What part of the x-ray machine helps remove heat
Positioning the arches too far foward
Overdevelopment -temp. too high -time too long -developer concentration too high -inadequate fixation -accidental exposure to light -improper safelighting
Copper stem - radiator and air space
Reduce size and shape of beam

41. What is the base of dental film composed of?
Blue tinted polyester acetate
Paralleling; meets more principles of shadow casting
Dentin - enamel - bone
invisible -travel in straight lines -no mass/weight -travel and speed of light -no charge -interact w/ matter causing ionization -can penetrate opaque tissues and structures -can effect photographic film emulsion -can effect biologic tissue

42. According to the principles of shadow casting - preferred object-film distance
Perpendicular to the tooth and film
As close as possible
1/5 exposure time for edentulous
Clinical exam

43. How can you differentiate the zygoma from the max sinus in a max posterior PA
Shadow around the tooth
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
MA & time
Zygoma will be radiopaque - max. sinus will be a large area of radiolucency

44. Size film used for BW on adults when only one film is taken on each side
Size of crystals - thickness of emulsion - radiosensitive dyes
WBC - RBC - immature reproductive cells
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
#3

45. In which area of the tooth is interproximal caries often seen
Located on the tooth surface that contacts the adjacent tooth
Periodically examining cassettes and intensifying screens; extra oral cassettes should be checked for warping and light leaks
2.75 inch
Size of crystals - thickness of emulsion - radiosensitive dyes

46. What control factors effect contrast
Enamel - dentin - and bone
X-rays that have been deflected from an object and have changed paths
Step-wedge or test film
KVp

47. What causes overlapping
Before fixing
Max sinus - zygoma - max tuberosity - coranoid process
Incorrect horrizontal angulation
Highest of the 2 ridges - about the level of the cervical 3rd - behind the 2nd and 3rd molars

48. What Size film is used to take an occlusal radiograph of a 6 yr old child
Cathode - filament - focusing cup
BW
#2
#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

49. When mounting a FMS - you notice that one film is blank. another film is dark - the teeth look strange - and it is difficult to determine What film it is. What do you think happened?
Document patient's refusal and have them sign
Dark film is from over exposure and improper packet placement for strange looking teeth and not being able to determine What film is
Oral piercings - earings - glasses - necklaces - facial piercings - hair pins - hearing aids - dentures - and retainers
Lead

50. What radiographs are used to determine if a foreign object is located facially or lingually
Reg. replenishment and changing out expired solutiong with fresh chemicals at reg. intervals; monitor strength of chemicals on a daily basis
Removes the unexposed silver halide crystals
Long-term dose
Occlusal