Digital & Film Radiography

Question 1

What x-ray receptors are used in digital film?

Answer 1

• phosphor plate
• solid-state sensor

Question 2

What x-ray receptors are used in film radiography?

Answer 2

• direct action film
• indirect action film

Question 3

What size of phosphor plate receptors should be used for anterior periapicals?

Answer 3

Size 0

Question 4

What size of phosphor plate receptors should be used for bitewings and posterior periapicals?

Answer 4

size 2

Question 5

What size of phosphor plate receptors should be used for occlusal radiographs?

Answer 5

size 4

Question 6

What do more pixels in digital radiography lead to?

Answer 6

better detail & higher resolution

Question 7

What is the format of digital images used in medical fields?

Answer 7

DICOM
- digital imaging & communications in medicine

Question 8

What software is used to manage digital radiographs?

Answer 8

PACS

Question 9

What environmental factors will improve your experience of viewing digital radiographs?

Answer 9

• subdued lighting
• avoid glare
• have a monitor which is clean, adequately displays resolution, adjustable brightness level, suitable contrast level

Question 10

What can be used to assess the resolution, contrast and brightness of monitors used to view digital radiographs?

Answer 10

SMPTE test

Question 11

What are the type of digital intra-oral receptors used in radiography?

Answer 11

• solid state sensors
• phosphor plates

Question 12

How is an image created using phosphor plates in dental radiography?

Answer 12

• receptor exposed to x-ray beam
• phosphor crystals in receptor excited by the x-ray energy resulting in creation of a latent image
• receptor scanned by a laser
• laser energy causes the excited phosphor crystals to emit visible light
• light is detected and image created

Question 13

What are the types of solid-state digital receptors?

Answer 13

• CCD (charge-coupled device)
• CMOS (complimentary metal oxide semiconductor)

Question 14

How can the orientation of radiographs be aided?

Answer 14

identification dot located in corner of receptor

Question 15

How do phosphor plates & solid-state senors differ?

Answer 15

Phosphor plates
- thinner, lighter & flexible
- wireless so more stable & comfortable
- variable room light sensitivity (BAD)
- latent image needs to be processed in scanner separately
- handling similar to film

Solid-state sensor
- bulkier & rigid
- usually wired
- smaller active area
- no issues with room light control (GOOD)
- arguably more durable
- more expensive

Question 16

What is the purpose of the black paper located in an intra-oral film packet?

Answer 16

protects film from light exposure, damage by fingers & saliva

Question 17

What is the active component in intra-oral dental film?

Answer 17

Silver halide crystals embedded in a gelatin binder

Question 18

How does the speed of the film alter the radiation dose required?

Answer 18

increased speed —> lower radiation required to achieve an image

Question 19

What are the common steps of film processing?

Answer 19

1. developing
2. washing
3. fixing
4. washing
5. drying

Question 20

What is the advantage of using self-developing film?

Answer 20

• no darkroom or processing facilities required
• faster

Question 21

What are the disadvantages of using self-developing film?

Answer 21

• poorer image quality
• image deteriorates more rapidly over time
• no lead foil
• difficult to use
• expensive

Question 22

What are potential causes for a pale image production in radiography?

Answer 22

• radiation exposure factors too low
• film removed from solution too early
• film solution too cold
• film solution too dilute/old

Question 23

What is fixing in film radiography?

Answer 23

involves a chemical reaction which removes non-sensitised crystals and hardens the remaining emulsion

Question 24

What can inadequate fixing of film radiography lead to?

Answer 24

• image greenish-yellow or milky
• image becomes brown over time

Question 25

What are the advantages of digital radiography?

Answer 25

• no need for chemical processing
• easy storage and archiving of images
• easy back-up of images
• images can be integrated into patient records
• easy transfer/sharing of images

Question 26

What are the disadvantages of digital radiography?

Answer 26

• risk of date corruption/loss
• hard copy print ours generally have poorer image quality
• image enhancement can create misleading images