digital imaging and DICOM.

1. DIGITAL IMAGE RECEPTORS
AND
DICOM
Presented by :
Dr Vishal Mehrotra
Professor & HOD
OMDR, Rama Dental College Hospital and Research Centre,
Kanpur (UP)

2. • The term ‘Digital Radiography’ refers to the
method of capturing a radiographical image
by using a sensor, breaking it into electronic
pieces and presenting and storing the image
by using a computer.

3. Definitions
• Charge coupled device (CCD): A solid state
detector used in many devices (e.g. fax machine)
in D.R. a CCD is an image receptor found in the
intraoral sensor
• Digital subtraction: it's a method of reversing the
gray scale as an image is viewed, i.e. radiolucent
images (normally black) appear white and
radiopaque images (Normally white) appear
black.
• Pixel: A discrete (smallest) unit of information
also termed (picture element).
• Sensor: it's a small detector that is placed
intraorally to capture a radiographic image.

4. Equipments:
• X – radiation (x – ray unit timer must be adapted to
allow exposures in a time frame of 1/100 of a second)
• Intraoral sensor (The sensor is a small detector, placed
in the mouth of the patient and used to capture the
radiographic image. Intraoral sensors may be wired or
wireless)
• Computer (The computer is responsible for converting
the electronic signal from the sensor into a shade of
gray that is viewed on the computer monitor)

5. Step by Step Procedure
Sensor preparation
Sensor placement

6. INDICATIONS
• To generate image used in diagnosis and assessment of
dental disease.
• To obtain information about the teeth and supporting
structures.
• To detect lesions, disease, and condition of teeth and
surrounding structures.
• to confirm or classify suspected disease.
• to provide information during dental procedures (e.g. root
canal therapy and surgical placement of implants).
• to evaluate growth and development.
• Plays an import role in Orthodontics, endodntics,
Periodontics and implant placement, TMJ disorders

7. ADVANTAGES OF DIGITAL
RADIOGRAPHY
• Chemical processing of the film is not required
• The acquired images can be modified to obtain the desirable density
and contrast and the exposure latitude is higher in digital imaging as
compared to films.
• Images can be obtained without the loss of their quality and can be
retrieved as and when required.
• They can also be transmitted via electronic media.
• Superior grey scale-Superior resolution
• Easy reproducibility, reduced exposure to radiation
• Increased speed of image viewing
• Lower equipment and film cost
• Increased efficiency
• Enhancement of the diagnostic images and its strong efficiency as a
patient education tool.
• Reduced exposure to radiation

8. DISADVANTAGES OF DENTAL
RADIOGRAPHY
• The expenditure involved in initially setting up a digital
imaging system is quite high
• The image receptors are vulnerable to the effects of rough
handling, once damaged, they are expensive to replace
• The image receptors are bulky and rigid and tolerate the
rigid sensor in the mouth as compared to the film.
• The resolution of the images which are acquired with a
digital system is inferior to the conventional film based
images.
• At a time, not more than two to three teeth can be studied
with digital image receptors.
• As for infection control , the sensor has to be covered
adequately in a disposable plastic wrapper.
• There can also be legal issues, because the original digital
image can be manipulated.

9. THREE METHODS TO OBTAIN
DIGITAL IMAGE

10. Direct digital imaging (DDI)
• Here, a sensor is placed in the patient’s mouth
and is exposed to radiation.
• The sensor captures the radiographical image
and then transmits the image to a computer
monitor, and within seconds, the image appears
on the computer screen.

11. Indirect Digital Image
• In this method, an existing x-ray film is
digitized by using a CCD camera which scans
the image and the digitizer or converts the
image and then displays it on the computer
monitor.

12. Storage Phosphor Imaging (Semi Direct)
• This is a wireless digital radiography system.
• A reusable imaging plate which is coated with
phosphor is used.
• These plates are flexible and fit into the mouth.
• The storage phosphor imaging records diagnostic
data on the plates following the exposure to the
x-ray source and uses a high speed scanner to
convert the information to electronic files which
can be displayed to electronic files, which can be
displayed on the computer screen.

13. ANALOG VERSUS DIGITAL
ANALOG VERSUS DIGITAL

14. • A digital image consists of a number of
collections of individual pixels which are
organized in a matrix of rows and columns.
• Each pixel has a row and a column coordinate
that uniquely identifies its location in the
matrix.
• The electrons that make up the electronic
detector can be visualized as being divided
into an arrangement of blocks or picture
elements known as ‘pixels’.
• A pixel is a small box or “well” into which the
electrons produced by the x-ray exposure are
deposited.

15. • A pixel is the digital equivalent of a silver
crystal which is used in conventional
radiography.
• The X-ray photons that come into contact with
the electronic device, cause electrons to be
released from the silicon and produce a
corresponding electronic charge.
• Consequently, each pixel arrangement or
electron potential well contains an electronic
charge which is proportional to the number of
electrons that react within the well.

16. • Furthermore, each electronic well corresponds to
a specific area on the linked computer screen.
• When x-rays activate the electrons and produce
such electronic charges, an electronic latent
image is then transmitted and stored in the
computer, which can be converted into a visible
image on screen or can be printed on paper.
• The formation of a digital image requires several
steps, beginning with the analog processes.
• At each pixel of an electronic detector, the
absorption of x-rays generates a small voltage.

17. • At each pixel, the voltage can fluctuate
between a minimum and maximum value and
is therefore called as an Analog signal

18. • The production of a digital image requires a
process called ‘analog to digital conversion’
(ADC).
This consists of 2 steps
• Sampling: That is a small range of voltage
values which are grouped together as a single
value
• Quantization: In which every sampled signal,
is assigned a value. The values are stored in
the computer and represent the image.

19. DIFFERENT TYPE OF SENSORS
OR
DIGITAL DETECTORS

20. • Two types of digital image receptors or
sensors.
• They include direct solid-state and indirect
photo-stimulable phosphor plates (PSP) that
are similar to flexible radiographic film.
• The solid-state technology uses different
semi-conductor-based detectors 1) CCD, 2)
CMOS, and 3) flat panel.

21. • Charged couple device (CCD): This is a solid
state detector that contains a thin wafer of
silicon chip with an electronic circuit
embedded in it. The silicon chip is sensitive to
x-rays or light.

22. • Complementary metal oxide semiconductors
(CMOS): These are silicon based
semiconductors where the pixel is isolated
from its neighboring pixels and is directly
connected to the transistor. This technology is
believed to give 25% more resolution and the
chip is less expensive and offers greater
durability than the CCD.
• Sesnsor made of Cesium Iodide
• Images have high resolution, high contrast,
low noise

23. • Charge injection device (CID): This is another
sensor tech nology. Structurally, it is very
much like the CCD, but in this case, no
computer is required to process the images.

24. • Photostimulable phosphor plates (PSP):
These absorb and store energy from x-rays
and then release this energy as light when
stimulated by other lights of radiographic
imaging is Europium doped, barium
fluorohalide.

25. • Flat panel Detectors (FPD): These provide a
relatively large matrix area with pixel sizes less
than 100 microns.
• This allows the direct digital imaging of larger
areas of the body, including the head
• Photoconductor made of selenium
• Intensifying screen consist of amporphous
silicon photodiode circuitry layer and TFT(Thin
Film Transistors)

26. The digital image display can be done
by two ways:
• 1. Cathode ray tubes which are used in
conventional computer monitors.
• 2. Thin Film Transistor (TFT) is used in laptops
and in flat panel computer displays

27. DICOM
Digital Imaging and Communication in
Medicine
This allows rapid communication
worldwide. DICOM is the international
standard language for the electronic
communication of digital images, be
they radiographs, photographs,
histopathological slides, or any other
type of “Picture images.”

28. • DICOM (Digital Imaging and Communication in
Medicine) is the standard within Medicine for
the transmission of radiologic images and
other medical information between
computers and various devices that acquire
images and also between various equipment
and software systems that are produced by
different manufacturers

29. • DICOM Conformance Statement is a ‘diagram’
of sorts that allows imaging equipment and
management software to speak to each other.

30. • A DICOM image file contains the x-ray image
or series of images (for example a multiple
slice CBCT imaging study) and other patient
related information that is selected from a
‘library’ of standardized terms (e.g. patient
name, identification number, and acquisition
modality to name a few) that can be pre-
selected.

31. • A dental digital x-ray machine, in DICOM
terminology, is called an acquisition modality.
• Each acquisition modality includes a
‘conformance statement’.
• Information contained in the Conformance
Statement details how the x-ray system should be
set up to allow communication between different
products such as the viewing monitor or the
digital record system and the acquisition device.

32. • The DICOM conformance statement contains the
information necessary for IT to use when they
connect different modalities.
• DICOM performance statements for various
acquisition and other connected machines are
typically available for download on the WEB.
• The conformance statements for acquisition
devices are standardized to allow comparison of
DICOM devices and the ability of one product to
communicate with another.
Hospital or Physi cian
Removable Media
Hospital or Physi cian
Removable Media

33. • A dental x-ray taken by a specific intra-oral
digital imaging machine can be downloaded to
a server supplied by a different vendor and
then displayed properly on a computer
monitor made by another manufacturer

34. Acquisition Devices
• An acquisition device is any instrument or
machine that produces a digitized image. This
includes CT, CBCT, MRI machines as well as
ultrasound, and digital projection radiography.
In dentistry, this also includes x-ray machines
that allow periapical, panoramic or
cephalometric imaging, 3D computerized
tomography, digital photography, and digitally-
driven CAD/CAM systems.

35. PACS (Picture Archiving and
Communications Systems)
• PACS software acts to integrate image acquisition,
storage, retrieval, and viewing. In dentistry the
use of PACS is primarily limited to academic
centers and dental clinics in large hospital
facilities where there is need for transmission of
data between departments such as Radiology
with Pathology, Oral Surgery, Oral Medicine,
Periodontics, and Restorative Dentistry. Or where
there is communication between dentists and
their physician colleagues.

36. DICOM USE IN DENTISTRY

37. Orthodontics
• Imaging of the craniofacial region is strategic
to treatment planning in orthodontics.(3D
IMAGING)
• Cone beam computed tomography (CBCT)
which provides 3-D views of the craniofacial
area.

38. Oral Surgery
• Clinical pre-surgical planning is an area where DICOM
based files may be useful as DICOM CBCT images
provide information that is useful in defining general
anatomy and determining the extent of pathology.
• DICOM CBCT images used to evaluate maxillofacial
bone grafts
• implant placement in three dimensions.
• Using DICOM imaging in this manner may improve
surgical accuracy.
• In the atrophic maxillae or where there has been a
sinus lift, the use of 3-D CBCT DICOM files may be
critical to therapeutic success

39. Oral Medicine
• With CBCT DICOM files not only can pathology be
readily identified, it can be measured in three
dimensions and assessed in terms of relative volume
and evaluated for relative bone density.
• In addition, CBCT DICOM imaging studies may help in
the assessment and management of sleep apnea,
snoring, and airway obstruction as the shape and
contours of upper airway passages can be analyzed in
three dimensions.
• All of the DICOM orthodontic software programs
mentioned above allow measurement of airway
volume, thus providing potential for a ‘virtual
endoscopy’

40. DICOM CONCERN
• In caries identification , identification of root
fractures
• File compression associated with DICOM
storage could alter a viewed image in such a
way as to hinder diagnosis

41. Innovations in DICOM
• Internet image transfer - DICOM images can
be transferred via the internet because they
are fully encrypted. This allows the
communication of information between
providers in nearly real time. It also may
reduce the possibility of error introduction
associated with compact disc transfer
• Use of mobile devices as viewers

42. Thank you