Digital Radiology Week 4 Ppt Review

Front 1

What is digital radiography?

Back 1

• They are an integral part of the move to paperless documentation
• Uses an electronic sensor or a phosphor plate and computerized imaging system that produces x-ray images almost instantly on a computer monitor
• Reduces exposure to patients in most instances

Front 2

What is the purpose and use of digital imaging?

Back 2

To generate images that can be used in the diagnoses and assessment of dental disease:

• To deteck lesions, diseases and conditions of the teeth and surrounding structures
• to confirm or classify suspected disease
• to provide information during dental procedures
• to evaluate growth and development
• to illustrate changes secondary to caries, periodontal disease, or trauma
• to document the condition of the patient at a specific point in time

Front 3

What are the methods of Digital imaging?

Back 3

• Direct
• Indirect

- Existing radiographs can be converted to digital by scanning or photographing with a digital camera (also sometimes termed "indirect imaging)

- Quality is compromised compared to direct digital

Front 4

What is direct digital imaging?

What are the two sensors CCD and CMOS?

what is the difference?

Back 4

• Image is captured using a solid state sensor, breaking it into electronic pieces and presenting and storing the image using a computer

- CCD or Charge-Coupled Device

- CMOS or Complementary metal oxide semiconductor

Difference between the two is the makeup of the chip in the sensor

Front 5

What are the sensors?

Back 5

made up of a grid of x-ray or light sensitive cells

each cells

Front 6

What do the cells of a sensor represent?

Back 6

a pixel in the final image

Front 7

what is a pixal the digital equivalent to?

Back 7

Aranged (not random) - silver halide crystals (sensitivity specs)

Front 8

What are the pixels for?

Back 8

for electrons produced by the x-ray to be depositied into

Front 9

What do the x-rays do to the sensor?

Back 9

The x-ray strikes the sensor, the pixels are excited and the gray value is determined depending on the number of x-rays striking each pixel

Front 10

What is done with the information gathered by the sensor?

Back 10

it is transmitted to the computer where the image is constructed

Front 11

What equimpment is needed for direct digital?

Back 11

• Sensor

- some are wired and some are wireless

- wireless sensors are usually thicker and can be sensitive to other signals in the area

• Computer and software

- Can record image and send to monitor in 0.5-120 seconds

• Computer monitor
• X-ray machine and sensor holders
• Film holder (same as RINNs but with holder for sensor cord)
• Standard x-ray machine and tubehead

Front 12

What is indirect digital imaging and what does it use?

Back 12

• Photostimuable phosphor (PSP) also called storage phosphor system
• Sensor/plates look like regular film and are coated with a storage phosphor
• When exposed, it stores the image similar to a latent image on film
• Plate is placed into a scanning divice
• Absorbed energy is released during scanning and converted to a digital value
• Digital information is converted to the computer to construct the image.
• The sensor/plate is cleared/reset by the scanner

Front 13

What equipment is needed for indirect digital?

Back 13

• PSP plate (resimbles film packet)

- have a greater variety in size than direct

• Cassette to hold plates for processing
• Scanner
• Computer, software and monitor
• Film holders

Front 14

Why is it known as indirect digital imaging

Back 14

• Because of the extra step of scanning to produce the image

Front 15

What are the computer requirements?

Back 15

• type and size depends on the digital system being used
• must have enough memory to store images and support visual image display
• hand-held image viewers are available to store images much like a portable hard drive

- images can be transferred wirelessly to a nearby computer for storage

Front 16

What are some cool features/capabilities of the software?

Back 16

• Measurement tool can be utilized
• can view image on the computer screen
• split screen can be used to view several images of the same tooth
• image can be magnified
• density and contrast can be manipulated
• charting can be done
• digital subtraction can be used to document changes such as periodontal bone loss or healing of lesions

Front 17

How does the quality of digital images vary?

Back 17

• Number of pixels

- The more pixels, the higher the resolution and the sharper the image

• Spatial resolution

- Great spatial resolution = sharper image

• Gray scale

- Can be enhanced with digital systems and show more subtle changes to the structure than can be seen with a standard radiographic film

Front 18

What is the greatest reduction in exposure level?

Back 18

when going from a D-speed to digital

Front 19

which sensors are more sensitive and require less exposure time?

Back 19

CCD and CMOS

Front 20

When may exposure not be reduced

Back 20

When comparing to extraoral film (pano)

Front 21

How do you prepare the sensor?

Back 21

Each sensor is sealed and waterproofed

- the sensor must be covered with a disposable barrier because it can not be starilized

Front 22

How do you place the sensor?

Back 22

It is held in the mouth by bite-block attachments or devices that aim the beam and sensor accurately (similar to the RINNs)

- the paralleling technique is the preferred exposure method

Front 23

What are the advantages of digital imaging?

Back 23

• Superior gray-scale resolution
• Reduced exposure to x-radiation
• increased speed of image viewing
• lower equipment and film cost
• increased efficiency
• enhancement of diagnostic image
• effective patient education tools

Front 24

What is the downside to digital imaging?

Back 24

• Studies indicate more retakes with digital than traditional
• may be due to:

- ease of placing back in the mouth and exposing

- perceived reduction in dosage

- more exposures required due to size of sensor

- rigidity of sensor can cause discomfort resulting in placement errors

Front 25

What are disadvantages to digital imaging?

Back 25

• initial set-up costs
• image quality
• sensor size
• infection control
• legal issues

Front 26

What is DICOM?

Back 26

Digital imaging and communications in medicine

- standard to allow different digital systems to interface with eachother

- recommended that digital systems meet/adopt this standard to improve communication between providers

Front 27

What does the future hold?

Back 27

• Artificial inteligence
• predicting a computer that would make diagnostic decisions based on images acquired, such as analyzing bone support for digital implants or detecting subtle changes in enamel density to detect early caries.