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 annual MPD for pregnant dental assistant
2.5 mm
Vertical BW
5 mSv or .5 REM
Scatter/secondary radition

2. What NC agency is resposible for monitoring dental x-ray equipment
20 min
DEHNR
15 impulses
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

3. When looking at radiographs that were taken several years ago - you notice a brownish stain which makes interpretation difficult. What caused this?
On the back side of the tori
20 seconds
Insufficient or improper washing
Sv & Rem

4. What should be done prior to ordering radiographs for a patient
Large blank space is due to reversed image error or chemical contamination - missing apices is due to inadequate VA
Clinical exam
extraoral film
Labial

5. What Size film is 7/8 x 1 3/8
Original - undeflected - useful beam
D - E - F
Max sinus - zygoma - max tuberosity - coranoid process
No. 0

6. What Size film is 15/16 x 1 9/16
2.75 inches
No. 1
Periapical examination - paralleling technique
25

7. which anatomical structures appear radiolucent
Central ray
#0
Soft tissue - air space
Quantum of energy

8. What causes foreshortening
Excessive vertical angulation
#4
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
Patient positioned too far to the left

9. What control factors effect the density of a radiograph
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
Decrease kVp by 15 and double exposure time = 10 mA 60 impules 75 kVp
7 1/2 or 15 watt

10. your film badge report sHows that you have received a small amt. of radiation. What should you do
Stop taking xrays and evaluate all equipment and techniques to ensure safety
As far as practical
Dentin - enamel - bone
A form of radiation originating from an atom following removal of an electron or excitation of an atom

11. What is a large dose of radiation given over a short period of time
Short-term dose
Large blank space is due to reversed image error or chemical contamination - missing apices is due to inadequate VA
Film badges
Part that was fixed but not developed would be clear

12. What is the best method of protecting the thyroid gland from radiation?
Faster film = lower definition and detail
Density
Thyroid collar - lead and lead-equivalent sprons are availaable with or without an attached thyroid collar
Labial

13. What is the name for the part of the target that is struck by electrons
Beam is perpendicular to the imaginary line that bisects the angle formed by the long axis and the film
2.75 inches
MRI
Focal spot

14. What is penumbra
Shadow around the tooth
#4
Thyroid collar - lead and lead-equivalent sprons are availaable with or without an attached thyroid collar
Produced by internal barriers in tube head (ex: glass and insulating oils)

15. What is secondary radiation
X-rays that have gone thru an object and are now a newer weaker beam
Insufficient vertical angulation
Left side
Filtration and collimation

16. Mand lateral/canine anatomy
Positioning the arches too far foward
CCD (direct) - CMOS (direct) - PSP (indirect)
As low as reasonably achievable
Tori

17. What Size film is 1 1/4 x 1 5/8
7 1/2 or 15 watt
No. 1
As far as practical
No. 2

18. 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?
DEHNR
20 seconds
Increased focal spot size - decrease source-object distance - & increased object-film distance
Failed safelight test - suggesting that the safelight conditions in the darkroom are fogging the film

19. you change you kVp from 90 to 70 and leave all other factors the same. What is the result
#2
Erythema
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
KVp

20. 1/10th dosage of gen. public - What are photons
Premature contact w/ developing chemicals - Drops of developer or fixer that splash onto the work area and came in contact with the film.
Quantum of energy
Labial
Every 4 weeks

21. How much total filtration is required of x-ray machines that operate lower than 70 kVp
Lateral cephalometric
Only when necessary to help the dentist diagnose and treat oral diseases; elective xrays should be postponed until after delivery
1.5 mm
Faster film = lower definition and detail

22. What type PID significantly reduces exposure to the patient
Rapidly producing cells are more sensitive to radiation
Rectangular collimations
Gently agitating the hanger up and down a few times
Incorrect horrizontal angulation

23. What is done to the primary beam to make is useful
Long-term dose
Reg. replenishment and changing out expired solutiong with fresh chemicals at reg. intervals; monitor strength of chemicals on a daily basis
Filtration and collimation
#0

24. if the kVp is increased from 75-90 - What must be done to achieve a radiograph of comparible density
Old or contaminated processing solutions -exposure to chemical fumes -faulty safelight -scatter radiation
decrease mA & time
Rectangular collimation
50 mSv or 5 REM

25. What exposure would be useful in identifying salivary stones in the submandibular gland
Take FMS on all new patients; recall adults with no sig. med. history only require BW and PA - if indicated
Mand occlusal
Soft tissue - air space
Mandibular occlusal

26. What periapical technique offers the best diagnostic quality?
GBX - 2
Paralleling; meets more principles of shadow casting
Stop taking xrays and evaluate all equipment and techniques to ensure safety
Perpendicular to the tooth and film

27. when viewing a PANO - you notice that a lot of spine sHows on both side of the film - What caused this
Positioning the arches too far foward
Doesn't matter
Long-term dose
X-rays that have gone thru an object and are now a newer weaker beam

28. who discovered x-rays
Roentgen
Dentin - enamel - bone
Soft tissue - air space
Aka general radiation; stopping or slowing of the electrons of the cathode stream as they collide with the nuclei of the target atoms

29. What causes film fogging
Old or contaminated processing solutions -exposure to chemical fumes -faulty safelight -scatter radiation
Short
Clinical exam
2.5 mm

30. What causes conecut
turn on machine -adjust settings -press exposure button -filament heats up/thermoionic emmision -electron cloud is formed -electrons flow from cathode to anode -electrons strike target -energy is converted into x-rays and heat
Scatter/secondary radition
#4
Not centered on sensor

31. What is the major use of cross sectional occlusal radiograph
Sterilize film holder devices or discard disposable image receptor holding devices
Provides more info. about the location of tori - impacted and malpositioned teeth and the calcification of soft tissues
Central ray
particulate radiation: made of protons - neutrons - electrons and alpha and beta particles; has mass -electromagnetic radiation: made of photons; no mass

32. when processing - two films overlap in the developer - but not in the fixer. How would the films appear
Lead
Doesn't matter
Scatter/secondary radition
Clear/blue in the area of overlap b/c fixer will not remove all crystals

33. What happens in the fixer
Increase the area of radiation exposure
Gray & Rad
Depends on the needs of the patient - established after intraoral exam
Removes the unexposed silver halide crystals

34. What is the latent image
Maintain acidity & alkalinity & prevent oxidation -
20 seconds
Focal spot
Invisible image (remains like this until film is processed)

35. when duplicating radiographs - What side of the duplicating film is in contact with the radiograph to be duplicated
The emulsion side of the film is placed against the orginal radiograph with the nonemulsion side up
Filters placed in PID after tubehead production
particulate radiation: made of protons - neutrons - electrons and alpha and beta particles; has mass -electromagnetic radiation: made of photons; no mass
Faster film = lower definition and detail

36. Film submerged totally in fixer but not in developer
Incorrect horrizontal angulation
Part that was fixed but not developed would be clear
MRI
X-rays that have been deflected from an object and have changed paths

37. What Size film is used to take an occlusal radiograph of a 6 yr old child
#2
No. 0
Occlucal
1/4 as intense

38. What is the main source of radiation exposure to the operator
Scatter/secondary radition
.25 mm
Chronic low-level exposures/long term dose; causing cancer - cataracts - low birth weight - genetic mutations - and embryological defects
Labial

39. How does exposure time differ b/w adults and children
2.75 inches
Cut exposure time by 1/3
Max. sinus - zygoma
1/3-1/2

40. What is the collimator made out of...
Central ray
Lead
B/c of its stability to produce a large volume of radiographs in a short amount of time
20 seconds

41. According to principles of shadow casting - How should the central beam be directed
White blood cells - red blood cells - immature reproductive cells - epithelial cells - connective tissue cells - bone cells - nerve cells - brain cells - muscle cells
Gelatin and silver halide crystals
BW
Perpendicular to the tooth and film

42. What is the earliest sign of radiation exposure
Labial
Increase the area of radiation exposure
Long-term dose
Erythema

43. How are stabe film holders sterilized b/w uses
#1
Sterilize film holder devices or discard disposable image receptor holding devices
Short
Excessive vertical angulation

44. According to the principles of shadow casting - preferred object-film distance
Ala-tragus line is parallel to the floor
Every 6 mths
Erythema - vomitting - nausea - hemorrage - diarrhea - hair loss
As close as possible

45. What would cause increased magnification - decreased resolution and edge sharpness
Increased focal spot size - decrease source-object distance - & increased object-film distance
Beam is perpendicular to the imaginary line that bisects the angle formed by the long axis and the film
max molars have 3 roots - mand have 2 roots
Positioning the arches too far foward

46. How far from the work surface must the safelight be mounted
Max. sinus - zygoma
Focal spot
4 feet
No exposure to x-rays - electrical failure - malfunction of x-ray machine - or processing errors

47. How does resolutiong and detial of a panoramic radiograph compare with that of PA's and BW's
Move farther from the radiation
Not as sharp and detailed as the intraoral image
Oral piercings - earings - glasses - necklaces - facial piercings - hair pins - hearing aids - dentures - and retainers
Invisible image (remains like this until film is processed)

48. What type of angulation is used when taking radiographs of the mand. arch
Patient's dental arches; maxilla and mandile
Before fixing
Negative
1/5 exposure time for edentulous

49. if the source-object distance is cut from 16 to 8 - What must be changed to compensate
Every 6 mths
Method should be compensated for bisecting or paralleling
Nasal fossa - max sinus
Do not suggest gagging - emphasize - use power of suggestions - apply distractiong techniques - give patient breathing instructions - reduce tactile stimuli - being exposures in the ant. region - place image receptor firmly and expertly - confuse the

50. you notice that a radiograph taken several months ago is brown and spotted. What happened
1/3-1/2
Insufficient or improper washing
15 impulses
Quantum of energy