Analogue and digital radiography - imul.umlub.edu.plimul.umlub.edu.pl/en/sites/default/files/Lecture_ATS_2_2_analogue_a… · through an object and interacting with the photographic

Analogue and digital radiography

Ingrid Różyło-Kalinowska

Department of Dental and Maxillofacial Radiology

Medical University of Lublin, Poland

Development of diagnostic imaging

American College of Radiology

RADIOGRAPHY

X-ray tube

Image detector

Film CCD/CMOS or PSP

X-ray images

The image is produced by X-rays passing through an object and interacting with the photographic emulsion on a film or with a digital image sensor (receptor).

This interaction results in blackening of the film or sensitization of a digital sensor.

The extent to which the emulsion is blackened or digital sensor sensitized depends on the number of X-rays reaching the receptor, which in turn depends on the density of the object.

Intraoral X-ray machine

Conventional X-ray film

Integrates three properties Image registration

Image presentation

Image archivization

Possibilities of increasing of film sensitivity are not available anymore

Higher sensitivity image noise, image quality

Film is not an efficient X-ray detector

Effective dose depends on type of X-ray film

Effective dose is several times higher in analogue radiography than in digital radiography


Inconveniences related to film processing (quality assurance, environmental protection)

No postprocessing available

Conventional archives – possible loss of radiograph, difficulties in finding previous X-rays


Periapical films

Bitewing films

Occlusal film

Contents of a film packet

The outer wrapper

The film

The protective black paper

The sheet of lead foil

The outer wrapper

Extraoral film pack and cassettes

Film processing

Automatic film processor

Automatic film processor

developer fixer water dryer

Automatic film

processor

developer

fixer water dryer

Francis Mouyen

Developed the first intra-oral

sensor for dental radiology in

1982

The first CCD sensor-system for

dental use was launched 1986

by Trophy Radiologie, France

The development of digital dental radiology:

January 11-12, 2013 BBM-K 2013

http://www.duerr.de/eng/print/50_2767.aspx

Digital X-ray image

Matrix of pixels = picture elements

Every pixel is assigned a number corresponding to grey level

Digital X-ray image

in dental radiography e.g. Digora

Values of grey levels between 0 – black and 255 - white

Human eye is capable of differentiating between up to maximum 40 levels of grey

Grey levels important in CAD (Computer Aided Diagnostics)

Digital radiography system


1. X-ray tube

2. Image receptor

3. Image presentation software

Digital X-ray system

X-ray tube

Digital radiography

system

Image detector - CCD, CMOS or SPP

CCD/CMOS system

Image detector

„Solid-state”: CCD (Charge Coupled Device)

CMOS-APS (Complementary Metal Oxide Semiconductor - Active Pixel Structure)

CCD sensor

CMOS-sensor with protection bag

BBM-K 2013

Placement of the holder

BBM-K 2013

PSP system

PSP – Photostimulable Storage Phosphor Plate

1 – protective layer

2 – storage phosphor layer

3 – conductive layer

4 – support

5 – layer protecting against external light

6 – back layer

The PSP-plate are manufactured in many sizes

BBM-K

2013

The active area of a solid state sensor compared to the size of a PSP-plate

BBM-K 2013

Schick Wireless CDR sensor-system

BBM-K 2013

The removable and rechargeable battery on the back increases the sensor´s dimensions

BBM-K 2013

Advantages of a solid state digital system

Sensor directly linked with a computer by a cable or WI-FI router

Image appears on screen directly after exposure

Digital radiograph is saved directly in the open patient’s file

Disadvantages of a solid state digital system

Inconveniences to the patient in intraoral radiography caused by thickness and stiffness of the image detector as well as the connecting cable, eg. gagging reflex

Difficulties in positioning in the mouth

Special holders mus be used

Smaller active area of the detector in relationship to its external dimensions

Image size smaller than on a conventional analogue film

Advantages of a PSP system

Active size of a PSP plate comparable with a conventional analogue film

PSP plate is quite thin and thus easier to position intraorally, patient’s discomfort is diminished

It is possible to use just one laser scanner operating with several X-ray tubes

Disadvantages of a PSP system

PSP plates are more susceptible to mechanical damage than solid state image receptors

X-ray image is acquired indirectly since it requires laser scanning thus the time from exposure to presentation of image on screen is slightly longer

PSP plates are not marked with patient’s ID thus it is possible to mix them between exposure and laser read-out


Graphical presentation of images - software

Digital radiography

Separation in time and space of image registration, presentation and archivization

Image postprocessing

Image postprocessing

options

1. Image presentation.

2. Greyscale correction.

3. Measurements.

4. Image filters.

5. Digital subtraction.

51

1. Image presentation

zoom-in/zoom-out

53

Image rotation

Image flipping

2. Change in distribution of grayscale

negative-positive image transformation

Contrast adjustment

Brightness correction

pseudocolor

tomosynthesis

3. Measurements

Linear measurments

Angle measurements

Grey scale measurements

histogram

4. Image filtering

62

Image filters

63

edge enhancement

sharpness

emboss

pseudo-3D

„unsharp mask”

Image filtering

64

Negative

65

Average

66

Median

67

Structure Enhancement

68

Conservative

69

Endodontic

70

Paradontal

71

Better Focus

72

Enhance 2

73

3D Effect

74

Implant

75

Detail

76

Emboss

77

Contour Detection

78

Pseudo Colour 1

79

Pseudo Colour 2

80

Pseudo Colour 3

81

Digital subtraction radiography

Superposition of two radiographs taken in the same projection in some period of time

Subtraction of identical areas

Result: enhancement of differing areas, ie. osteolysis or osteogenesis

Carvalho FB, Gonçalves M, Guerreiro-Tanomaru JM, Tanomaru-Filho M.: Evaluation of periapical changes following endodontic therapy: digital subtraction technique compared with computerized morphometric analysis. Dentomaxillofac. Radiol. 2009; 38(7): 438-44.

Baseline image After 2 months Subtracted image

Comparison between PAI and quantitative digital radiographic

assessment of apical healing after endodontic treatment

E.Olutayo Delano, BDS, MSa, John B. Ludlow, DDS, MSb, Dag Ørstavik, DDSc, Don Tyndall, DDS, PhDd and Martin

Trope, DMDe

Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology

Volume 92, Issue 1, Pages 108-115 (July 2001) DOI: 10.1067/moe.2001.115466

Copyright © 2001 Mosby, Inc. Terms and Conditions

http://www.ooooe.net/article/S1079-2104(01)79902-7/abstract



http://www.ooooe.net/misc/terms

Source: Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology 2001; 92:108-115 (DOI:10.1067/moe.2001.115466 )






Source: Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology 2001; 92:108-115 (DOI:10.1067/moe.2001.115466 )






Radiodiagnostics of proximal caries

EXAMPLES OF APPLICATION OF DIGITAL RADIOGRAPHY

Density measurements

of inflammatory lesions


Density profile of

a radicular cyst


Density measurements of roots related to

periapical lesions


Observation of root canal sealer

impacted in periapical bone


Diagnostics of pulp stones


Localization of third molar


Experimental studies –

detection of artificially

created bone lesions



Experimental studies – evaluation of influence of

dental bleaching on tooth structure

Experimental studies – detection of radiolucent and

poorly radiopaque foreign bones



Experimental studies on laboratory animals

Image resolution

Conventional radiography

Digital radiography

Theoretical resolution

Real resolution on screen

Human eye

12–16 line pairs per mm

27 line pairs per mm

14 line pairs per mm

4 – 9 line pairs per mm

Digital image

compression

Useful when transmission via internet

Impossible when Compuer Aided Diagnosis is used

Digital image

archives and

transmission

TIFF, BMP, JPEG, GIF, DICOM

CD-R, CD-RW, DVD, Flash Memory, MOD, hard disk, servers

Computer networks

Data transmission

Teleradiology

Fast, secured computer networks for transmission of diagnostic imaging data (radiographs, MRI, CT, CBCT, US, PET etc.)

DICOM image standard

PACS (Picture Archiving and Communication System)

HIS/RIS (Hospital/Radiology System)

Quick, cost-effective consultation

Decrease of time needed to acquire an X-ray image in relation to analogue films

Reduction of exposure dose required to obtain a radiograph

No chemical film processing required (environmental protection due to lack of chemicals, better quality assurance)

Image postprocessing available

Advantages of digital radiography over analogue radiography

Advantages of digital radiography over analogue radiography

Precise linear and angular measurements

Digital image storage and transmission

Teleradiology

High image resolution

Disadvantages of digital radiography

Higher cost in comparison to film radiography

Indispensable protection of personal data stored in computer systems

Inconveniencies in intraoral positioning of some sensors

No control of number of radiographs of inferior quality

Illegal image postprocessing resulting in frauds

Technical problems in opening CD files

New developments in digital radiography

New image sensors with higer image resolution

Better software for postprocessing

Wireless transmission of data, including mobile devices

Intelligent positioning systems in intraoral radiography reducing artifacts such as cone-cut

Analogue and digital radiography - imul.umlub.edu.plimul.umlub.edu.pl/en/sites/default/files/Lecture_ATS_2_2_analogue_a… · through an object and interacting with the photographic

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