CHP 08

Purpose of X-rays

To generate images that can be used in the diagnosis and assessment of dental disease (Caries, Disease, Cancer)

Digital imaging

A method of capturing an image using a sensor, braking it into electronic pieces, and presenting and storing the image using a computer

Digital imaging radiation exposure

Requires less x-radiation exposure than film-based imaging, sensor or more sensitive to x-rays than conventional , 50% to 90% less exposure for conventional radiography

X-ray Unit

Most digital imaging systems use a conventional dental x-ray unit as the x-radiation source. Unit time must be adapted to allow exposure in a time of 1/100 of a second

Sensor

A small detector that is placed in the mouth of the patient and used to capture the dental image.

Wired & Wireless

Sensor types

Direct sensor technologies

Charge -coupled device (CCD)

Complementary metal oxide semiconductor/active pixel sensor

Charge-Coupled Device (CCD)

Most common used dental digital imaging, A solid-state detector that contains a silicone chip with an electronic circuit embedded in it

Pixel

A small box of “well” into which the electrons produced by the x-ray exposure are deposited

How CCD works

The s-ray photos that come into contact with the CCD cause electrons to be released from the silicone and produce a corresponding electronic charge

Complementary Metal Oxide Semiconductor/Active Pixel Sensor (CMOS/APS)

One manufacturers uses a CMOS/APS sensor instead of a CCD, chip is less expensive to procure and offers greater durability than the CCD

Computer

Stores incoming electronic signal, conversion signal form the sensor into a shade of grey

Computer Use

Digitizes, processes, and stores information received from the sensor, image is recorded on computer monitor in 0.5 to 120 sec

Direct Digital Imaging

Components include an intraoral dental x-ray unit, a sensor, and a computer with imaging software

Indirect Digital Imaging

Components include a CCD camera and a computer

Storage Phosphor Imaging

A wireless digital imaging system, reusable imaging plate opted with phosphors (flexible)

Intraoral Sensor Placement

XCP, The sensor is held in the mouth by bite-block attachments or devices that aim the beam and señor accurately, preferred paralleling technique

Advantages of Digital Imaging

Super gray-scale resolution

Reduced exposure to x-radiation

Increased speed of image viewing

Disadvantages of Digital Imaging

Initial set-up costs

Image quality

Sensor size and thickness