DANB RADIOLOGY TEST QUESTIONS
AND ANSWERS
What would cause increased magnification, decreased resolution and edge sharpness -
Answer- increased focal spot size, decrease source-object distance, & increased object-
film distance
According the principles of shadow casting, preferred object-film distance - Answer- as
close as possible
According to principles of shadow casting, preferred source-object distance - Answer-
as far as practical
According to principles of shadow casting, how should the film be placed in relation to
the tooth? - Answer- parallel
According to principles of shadow casting, how should the central beam be directed -
Answer- perpendicular to the tooth and film
What periapical technique offers the best diagnostic quality? - Answer- paralleling;
meets more principles of shadow casting
What is penumbra - Answer- shadow around the tooth
How is vertical angulation established with the bisecting technique - Answer- beam is
perpendicular to the imaginary line that bisects the angle formed by the long axis and
the film
How do you determine how often to take radiographs - Answer- evidence based
selection criteria
how often should an FMS be taken on an adult with no significant medical history -
Answer- take FMS on all new patients; recall adults with no sig. med. history only
require BW and PA, if indicated
What are three types of image receptors used in digital radiography - Answer- CCD
(direct)
CMOS (direct)
PSP (indirect)
List the cells from most sensitive to least sensitive - Answer- white blood cells
,red blood cells
immature reproductive cells
epithelial cells
connective tissue cells
bone cells
nerve cells
brain cells
muscle cells
When viewing a molar BW, what should be on the distal of the film - Answer- the most
distal tooth should be captured in full as well as a few mm of bone level behind the most
distal tooth
Your film badge report shows that you have received a small amt. of radiation. what
should you do - Answer- stop taking xrays and evaluate all equipment and techniques to
ensure safety
You use an exposure time of 10 impulses. how many seconds is this - Answer- 1/6th of
a second
What is the base of dental film composed of? - Answer- blue tinted polyester acetate
What is the emulsion composed of? - Answer- gelatin and silver halide crystals
What determines the speed of dental films? - Answer- size of crystals, thickness of
emulsion, radiosensitive dyes
What is the purpose of the lead foil? - Answer- absorb scatter radiation and prevent
fogging
How does film speed correlate with definition and detail? - Answer- faster film = lower
definition and detail
What speed films are most commonly used? - Answer- D, E, F
size film used for PA's on small children - Answer- #0
size film used for BW on adults when only one film is taken on each side - Answer- #3
size film used for anterior PA's for patients with narrow arches - Answer- #1
size film used for PA's on adults - Answer- #2
size film used for BW on adults - Answer- #2
size film used for occlusals on adults - Answer- #4
, What is the purpose of the embossed dot - Answer- to distinguish b/w patient's right and
left side
What is the latent image - Answer- invisible image (remains like this until film is
processed)
What happens in the developer - Answer- reduces the exposed silver halide crystals to
black metallic silver
What happens in the fixer - Answer- removes the unexposed silver halide crystals
how long does film stay in the developer - Answer- 5 min
how long are films fixed - Answer- 10 min (dbl the development time)
how long does the first rinse last - Answer- 20 seconds
how long is the final rinse - Answer- 20 min
what is the optimum processing temp. - Answer- 68 degrees F
when can the films be exposed to white light - Answer- after 2-3 min of fixing if needed
what causes film fogging - Answer- -old or contaminated processing solutions
-exposure to chemical fumes
-faulty safelight
-scatter radiation
what would cause a film to be too light - Answer- -underexposure
-underdevelopment
-depleted developer solution
-excessive fixation (takes all crystals off)
what would cause a film to be too dark - Answer- -overexposure
-overdevelopment
-developer is too strong
-not enough fixation
-exposure to white light
-improper safelighting
What causes a HERRINGBONE effect - Answer- film placed backwards
what would happen to a film that is placed in the fixer prior to development - Answer-
blank or clear
(takes all of the crystals off)
AND ANSWERS
What would cause increased magnification, decreased resolution and edge sharpness -
Answer- increased focal spot size, decrease source-object distance, & increased object-
film distance
According the principles of shadow casting, preferred object-film distance - Answer- as
close as possible
According to principles of shadow casting, preferred source-object distance - Answer-
as far as practical
According to principles of shadow casting, how should the film be placed in relation to
the tooth? - Answer- parallel
According to principles of shadow casting, how should the central beam be directed -
Answer- perpendicular to the tooth and film
What periapical technique offers the best diagnostic quality? - Answer- paralleling;
meets more principles of shadow casting
What is penumbra - Answer- shadow around the tooth
How is vertical angulation established with the bisecting technique - Answer- beam is
perpendicular to the imaginary line that bisects the angle formed by the long axis and
the film
How do you determine how often to take radiographs - Answer- evidence based
selection criteria
how often should an FMS be taken on an adult with no significant medical history -
Answer- take FMS on all new patients; recall adults with no sig. med. history only
require BW and PA, if indicated
What are three types of image receptors used in digital radiography - Answer- CCD
(direct)
CMOS (direct)
PSP (indirect)
List the cells from most sensitive to least sensitive - Answer- white blood cells
,red blood cells
immature reproductive cells
epithelial cells
connective tissue cells
bone cells
nerve cells
brain cells
muscle cells
When viewing a molar BW, what should be on the distal of the film - Answer- the most
distal tooth should be captured in full as well as a few mm of bone level behind the most
distal tooth
Your film badge report shows that you have received a small amt. of radiation. what
should you do - Answer- stop taking xrays and evaluate all equipment and techniques to
ensure safety
You use an exposure time of 10 impulses. how many seconds is this - Answer- 1/6th of
a second
What is the base of dental film composed of? - Answer- blue tinted polyester acetate
What is the emulsion composed of? - Answer- gelatin and silver halide crystals
What determines the speed of dental films? - Answer- size of crystals, thickness of
emulsion, radiosensitive dyes
What is the purpose of the lead foil? - Answer- absorb scatter radiation and prevent
fogging
How does film speed correlate with definition and detail? - Answer- faster film = lower
definition and detail
What speed films are most commonly used? - Answer- D, E, F
size film used for PA's on small children - Answer- #0
size film used for BW on adults when only one film is taken on each side - Answer- #3
size film used for anterior PA's for patients with narrow arches - Answer- #1
size film used for PA's on adults - Answer- #2
size film used for BW on adults - Answer- #2
size film used for occlusals on adults - Answer- #4
, What is the purpose of the embossed dot - Answer- to distinguish b/w patient's right and
left side
What is the latent image - Answer- invisible image (remains like this until film is
processed)
What happens in the developer - Answer- reduces the exposed silver halide crystals to
black metallic silver
What happens in the fixer - Answer- removes the unexposed silver halide crystals
how long does film stay in the developer - Answer- 5 min
how long are films fixed - Answer- 10 min (dbl the development time)
how long does the first rinse last - Answer- 20 seconds
how long is the final rinse - Answer- 20 min
what is the optimum processing temp. - Answer- 68 degrees F
when can the films be exposed to white light - Answer- after 2-3 min of fixing if needed
what causes film fogging - Answer- -old or contaminated processing solutions
-exposure to chemical fumes
-faulty safelight
-scatter radiation
what would cause a film to be too light - Answer- -underexposure
-underdevelopment
-depleted developer solution
-excessive fixation (takes all crystals off)
what would cause a film to be too dark - Answer- -overexposure
-overdevelopment
-developer is too strong
-not enough fixation
-exposure to white light
-improper safelighting
What causes a HERRINGBONE effect - Answer- film placed backwards
what would happen to a film that is placed in the fixer prior to development - Answer-
blank or clear
(takes all of the crystals off)
