digital radiography in Dentistry: Direct and Indirect Technology

Role of digital direct and indirect x ray in Dentistry.

1. DIGITAL
RADIOGRAPHY.
-DIRECT AND INDIRECT
TECHNOLOGY.

3. History
1982-Trophy and Dr Francis Mouyen invented
the RVG, since then 5 generations of RVG were
launched to achieve a resolution greater than
20lp/mm.
1986–the very first commercial RVG unit the
RVG 25000 was launched.
1989-a worldwide success: RVG 32000

4. 1992-RVG meet with the PC computer
standard: the RVGS
1994–the first mobile unit the RVG Imageur
1999–the RVG ui, the first sensor to exceed the
films very high resolution>20lp/mm.

7. Two Types of Digital Systems
There are two distinct technologies. The first sensor
systems, are “Direct”, meaning that the receptor sends the
data directly to a computer via wires or wireless
transmission. The second type of digital system is
“Indirect”. With these, the receptor is inserted into a reader
or scanning device that sends the data to the computer.
Indirect systems create images using Phosphor Storage
Plates (PSP).
Introduction

8. An image is said to be digital when it is composed of
separate (distinct) elements. Each element is called a
"picture element" or pixel. If an image is displayed on the
monitor, and the pixel is smaller than the smallest detail
the viewer's eye can see, it is hard to determine that the
image is indeed a digital one. If this is not the case, that
is the individual pixels can be spotted, the eye views the
image as a mosaic of pixels.
Digital Technology?

15. Introduction
What is the RVG ?
The RVG is a digital sensor that allows the doctor to make
intraoral radiographs images without film.
What is the RVG system composed of ?
•Sensor
•An acquisition electronic device that can be integrated to a
computer (PCI acquisition board) or external (USB acquisition
device).
•A software
•A set of various holders
•A x-ray generator of at least 70Kv (conventional or high
frequency).
A timer able to deliver very short x-ray doses (from 0.02 seconds)
•A computer PC compatible

16. How does the RVG work ?
This principle is called “direct or instant imaging
system
The RVG makes processing an old story.

17. The RVG system.
The computer converts the information into digital image and displays
it on the monitor.
The timer drives the x-rays to the generator. The generator delivers a flash of
x-rays.
The x-ray beam crosses the object and reaches the sensor.
The sensor catches the information immediately and turns it into electrical
signal that is sent to the computer.

18. The basic structure of an image sensor is
represented.

19. What about hygiene with the sensor ?
The intraoral sensor must be covered with a
hygienic sheath (delivered along with the RVG
kit). A new hygienic sheath must be used for each
patient
Additionally, the sensor is waterproof so one can put it
into a cold disinfecting liquid.

20. RVG: advantages
•Eliminates image distortions due to film bending.
•The high resolution of the image (over 20 line pairs per mm)
which
is the only condition for the image to contain accurate clinical
details.
•Unparalleled diagnostic capabilities thanks to :
the ultimate imaging filter, sharpness filter, pre-programmed
modes and high light tool. These filters and tools will enhance
the global or local contrast of the image in order to focus on a
particular part of the image.

21. The RVG intraoral sensor is so sensitive that it requires
very short period of time exposures

23. Storage based system –
The DIGORA PCT from SOREDEX

24. Intraoral storage phosphor plates
Primarily made of a remanent phosphor layer that
"remembers" the image, hence the name of "storage
plates".
In order to read out the image, phosphor plates need to
be put into a phosphor plate reader. What this device
does is illuminate the plate by a tiny laser beam. When a
portion of the plate is illuminated, it emits light which is
collected by a digital imaging device.
This technology is particularly well adapted extraoral
applications such as cephalometry where large
exposure areas are required

25. DI G O R A P C T
ADVANTAGES.
Fast, easy and simple
The use of the DIGORA PCT system is extremely
convenient.
Open the door, insert the imaging plate and close the door.
Plate feed, scanning and image acquisition are fully
automatic and the imaging plate is ready to be used again
right after the image appears on the computer screen.The system on its stand is ergonomically designed so that it is at the correct
height for easy operation.
AutoErase
Unit automatically erases the imaging plate after the readout.

26. EDO (Exposure Distribution Optimiser)
EDO increases dynamic range (wide latitude).
EDO will practically eliminate under and over exposure and
enhances smaller contrast details and differences in dark and
light areas of the image.
Compared to conventional intraoral films, Digora can reduce patient
radiation exposure by as much as 90% while maintaining superior
image quality.This is achieved by using the board spectrum dynamic
range of the imaging plates and by the increased sensitivity of the Digora
laser scanner.

27. Digital Radiography systems help
more dentists achieve superior
imaging results.
.
Digital radiography delivers diagnostic, archiving and
cost control capabilities absolutely unobtainable using
film.
Conclusion….