Chapter 24

Digital Radiography

Digital Radiography

Invention of digital imaging Fundamentals of digital imaging &

equipment Radiation exposure Advantages/disadvantages Infection Control Legal Issues

Digital Radiography

In 1987, Dr. Francis Mouyen invented the first digital radiography system in Europe.

“Filmless imaging system” No Film or processing chemistry is

used Less radiation exposure ( from 50-

80% less) Electronic sensor , scanner, and

computerized imaging system

Digital Radiography Direct Digital Imaging (wired)-intraoral

sensor is exposed to x-rays to capture an image viewed immediately on computer

Wired sensors can be bulky In-Direct Digital Imaging (wireless)-

intraoral wireless plate is used to capture image, then scanned and converted to digital form

Wireless sensors are similar in size to traditional film - slightly larger

Digital Image

Analog image-radiographic image produced by conventional film (x-ray photons strike a film)

Bit-depth image- number of possible gray scale combinations for each pixel

8 bit-depth image has gray-scale combination of 2 to the 8th power

Equals 256 shades of gray

DIGITAL IMAGE

Array of picture elements called pixels Discrete gray values for each pixel Electronic charge is produced on the

sensor This electronic signal is digitized or

converted to “digital form” when scanned to the computer

Line pairs/millimeter (lp/ml)- measurement use to evaluate the ability of the computer to capture the resolution (detail) of a radiographic image

Storage Phosphor Imaging

Image is recorded on phosphor-coated plates and placed into an electronic processor

Laser then scans the plate and produces an image on computer screen

Concorde’s Digital System

“Wireless” plate or sensor Carrousel holds the

plates

Charge Coupled Devices (CCD)

Solid state detector used in many devices (video camera, fax machine)

Image receptor found in the intraoral sensor

Immediate viewing Wired sensors Must work around the wires Direct digital image

Complimentary Metal Oxide Semiconductor/Active Pixel Sensor

Another sensor technology is (CMOS/APS)

When APS was developed the CMOS became a useful sensor

Schick Technologies uses CMOS/APS instead of CCD and claims 25% better resolution

The CMOS/APS is also less expensive than CCDs

Durable

Charge Injection Device (CID) Another Sensor technology Silicon based solid state imaging receptor

similar to CCD No computer is required to process images Intraoral video camera platform CID x-ray sensor, cord, and plug inserted

into the Reveal light source on the camera platform

Digital images are seen on the system monitor in seconds and stored in computer

Digital Subtraction

Another image enhance method to produce two radiographs in the same area of the mouth at different time intervals

The first image can be subtracted from the second to identify changes during a specific time period

Minimal changes of hard tissue & bone loss can be detected

Done by reversing the gray scale as an image is viewed

Cephalostat – head stabilizing device

Advantages of Digital Images

Images viewed almost instantly (less time)

Less radiation exposure to the patient

Saving on disposable costs for film and chemicals

Environmentally friendly Ability to enhance images Data storage Communication with other Dentists

(teleradiology)

Disadvantages of Digital Images

Upfront cost of equipment & software

Upgrading equipment Cost of converting previous records

to digital Computers for each operatory Must work around wired sensors Loss or breakage of sensors/ or

plates Learning to use the software and

equipment

Infection Control

Digital sensor is a reusable device that cannot withstand the heat of the autoclave

Disposable barriers must be sealed over sensors to maintain asepsis

Barriers can be placed incorrectly, causing cross-contamination

Sensors must be tossed out if contaminated with saliva

Legal Issues

Digital images can be altered to show an apparent need for treatment that is not actually necessary

Although, there is upgraded software to protect from fraud and HIPPA regulations now on the market

Safety Continue placing lead apron with

thyroid collar on patients Handle equipment with care Careful not to accidently toss a

sensor in the garbage Approximately $47-60.00 per plate Do not trip over wired sensors

Digital Radiography 15-25% of dentists use Digital

Radiography according to the ADA Approximately, $11,700 to $15,500

per operatory for a wired system and $20,000 to $22,000 for a wireless system

Technology is continuing to improve The Latest in Digital is the X pod is

about 3000.00 (wireless handheld)

The End!

Any questions?