Chapter 8: Digital Imaging

Question 1

Define the term: sensor

Answer 1

in digital imaging, an image receptor that is used to capture an intraoral or extraoral image

Question 2

Define the term: indirect digital imaging

Answer 2

a method of obtaining a digital imaging from a sensor after exposure to x-rays by using a scanner to convert information into a digital form so that it can be viewed on a computer monitor

Question 3

What are the two methods of obtaining a digital image?

Answer 3

• direct digital imaging
• indirect digital imaging

Question 4

Define the term: digital imaging

Answer 4

a system of filmless imaging used to capture an image using a sensor, breaking it into electronic pieces, and presenting and storing the image using a computer

Question 5

When comparing digital imaging to conventional film, what is the advantage of the gray-scale resolution?

Answer 5

digital imaging has a greater gray-scale resolution with up to 256 shades of gray, in comparison to 25 shades of gray on conventional film

Question 6

Define the term: image

Answer 6

a picture or likeness of an object

Question 7

Define the term: charge-coupled device (CCD)

Answer 7

a solid-state silicon chip detector found in an intraoral digital sensor that converts light or x-ray photons into an electrical charge or signal

Question 8

Define the term: curve of Spee

Answer 8

the anterior-posterior anatomic curvature of the occlusal surfaces of the teeth

Question 9

Define the term: digital subtraction

Answer 9

a feature of digital imaging used to reverse the gray scale as an image is being viewed, causing radiolucent images (normally black) to appear white and radiopaque images (normally white) to appear black

Question 10

Define the term: digital image

Answer 10

an image composed of pixels

Question 11

Define the term: bit-depth image

Answer 11

the number of possible gray-scale combinations for each pixel

Question 12

Define the term: digitize

Answer 12

in digital imaging, to convert an image into digital form that, in turn, can be processed by a computer

Question 13

Define the term: labial mounting

Answer 13

an image mounting method in which the radiographs are placed in the mount for the dental radiographer to view the images from the labial aspect

Question 14

Define the term: analog-to-digital converter (ADC)

Answer 14

the method used to convert data elements acquired by the sensor are communicated to the computer in analog form and then converted into digital form

Question 15

What is one of the main disadvantages of digital imaging in comparison to conventional film?

Answer 15

the size and thickness of the sensor can be uncomfortable for patients or can be more common in inducing their gag reflex

Question 16

True or false: The PSP plate used in indirect digital imaging is a one-time-use product.

Answer 16

False

Question 17

Define the term: direct digital imaging

Answer 17

a method of obtaining a digital image in which an intraoral sensor is exposed to x-radiation to capture an image that can be viewed on a computer monitor

Question 18

Define the term: anatomic order

Answer 18

the order in which teeth are arranged within the dental arches

Question 19

Define the term: mount

Answer 19

to place in an appropriate setting for display or study

Question 20

Define the term: beam alignment device

Answer 20

• a device used to align the position-indicating device in relation to tooth and image receptor
• positions the intraoral image receptor in the mouth and retains the image receptor in position during exposure
• helps stabilize the image receptor in the mouth and reduces the chances of movement, thus reducing the patient’s exposure to x-radiation

Question 21

Define the term: pixel / picture element

Answer 21

in digital electronic images, digital information is contained in, and presented as, discrete units of information

Question 22

Define the term: complementary metal oxide semiconductor-active pixel sensor (CMOS-APS)

Answer 22

• silicon-based detector used in digital imaging
• differs from the charge-coupled device in the way that pixels are read

Question 23

Why does digital imaging require less radiation than conventional film?

Answer 23

the digital sensor is more sensitive to x-radiation than conventional film

Question 24

What is the difference in the percentage of exposure time for digital imaging compared to conventional film?

Answer 24

50-90% less exposure time

Question 25

Define the term: image receptor

Answer 25

a recording medium (ex: PSP plate, digital sensor)

Question 26

Define the term: storage phosphor imaging

Answer 26

an indirect method of obtaining a digital image in which the image is recorded on phosphor-coated plates and then placed into an electronic processor, where a laser scans the plate and produces an image on a computer screen

Question 27

What are the two most common types of direct digital imaging receptors?

Answer 27

• charge-coupled device (CCD)
• complementary metal oxide semiconductor-active pixel sensor (CMOS-APS)

Question 28

Define the term: lingual mounting

Answer 28

an image mounting method in which the radiographs are placed in the mount for the dental radiographer to view the images from the lingual aspect

Question 29

What can be used to help stabilize the image receptor during exposure?

Answer 29

beam alignment device

Question 30

When comparing digital imaging to conventional film, what is the advantage of the quality of diagnostic images?

Answer 30

the dimensional and geometric factors of digital imaging are greater

Question 31

Define the term: analog image

Answer 31

an image produced on conventional film that looks like the thing it represents

Question 32

What type of image receptor is common when using indirect digital imaging?

Answer 32

photo-stimulable phosphor imaging (PSP) plate

Question 33

Define the term: line pairs/millimeter (lp/mm)

Answer 33

a measurement used to evaluate the ability of the computer to capture the resolution (detail) of an image

Question 34

When comparing digital imaging to conventional film, what is the advantage of the radiation dose?

Answer 34

digital imaging requires less radiation than conventional film, thus reducing the patient’s exposure

Question 35

True or false: Digital imaging requires less radiation than conventional film.

Answer 35

True

Question 36

When comparing direct digital imaging to conventional film, what is the advantage of speed?

Answer 36

direct digital imaging produces the image instantly and does not require any processing time