Digital Imaging

Question 1

Analog image

Answer 1

radiographic image produced by conventional film

Question 2

Digital image

Answer 2

image composed of pixels that can be stored in a computer

Question 3

Pixel

Answer 3

a distinct unit of information; short for picture element

Question 4

Direct digital imaging

Answer 4

intraoral sensor is exposed to x-radiation to capture a radiograph that can then be viewed on a computer monitor

Question 5

Indirect digital imaging

Answer 5

a type of sensor is scanned AFTER exposure to x-radiation and then converted into a digital form that can be viewed on a computer
*IMAGING PLATES

Question 6

Charge-coupled device (CCD)

Answer 6

solid state silicon chip detector found in the sensor; converts light/x-ray photons into an electrical charge or signal
-most common image receptor

Question 7

Digital subtraction

Answer 7

reversing the gray scale so that radiolucent images appear white and radiopaque images appear black

Question 8

Storage phosphor imaging

Answer 8

image is recorded on a phosphor coated plate and placed into electronic processor where laser scans plate and produces the image on a computer
*indirect digital imaging

Question 9

Bit-depth image

Answer 9

number of possible gray-scale combinations for each pixel

Question 10

True or False: Digital sensors are less sensitive to x-rays than film.

Answer 10

FALSE; sensor are more sensitive to x-radiation than film
-50-90% less exposure time
-film: 12 impulses
-sensor: 3 impulses

Question 11

Complementary metal oxide semiconductor active pixel sensor (CMOS-APS)

Answer 11

-another silicon based sensor
-pixels can be smaller and are read differently
-less power requirements
-lower production cost
-connected to computer with low-power external USB

Question 12

Advantages of digital imaging

Answer 12

-better gray scale resolution
-less radiation exposure
-increased speed of image viewing
-lower equipment and film cost
-increased efficiency
-enhancement of diagnostic image
-digital subtraction
-effective patient education tool

Question 13

Disadvantages of digital imaging

Answer 13

-initial set up costs
-image quality (debated when 1st introduced)
-sensor size & thickness
-infection control (sensors cannot be sterilized)
-wear and tear
-legal issues (due to ability enhance original image)

Question 14

What is the name of the scanner we commonly use in clinic for imaging plates?

Answer 14

Gendex GX-PS 500 Scanner