RADIOGRAPHY FOR DENTISTRY 1 DR.SAMY I AL-AGHA A PROFESSOR OF RADIOLOGY AL-AZHAR UNIVERCITY

X-RAY IMAGE RECEPTORS 1-CONVENTIONAL X-RAY FILMS 2-DIGITAL IMAGE RECEPTORS

X-RAY FILM COMPOSITION 1-Film base 2-Adhesive layer 3-Film emulsion : a-Gelatin b-Silver halide crystals 4-Protective layer

RADIOGRAPHIC FILM

FILM EMULSION SILVER HALIDES: 1-AgBr 2-Ag I 3-Agcl

LATENT IMAGE Ag Br + X-ray or light---  Ag+ Br-(latent image)

CONVENTIONAL X-RAY FILMS 1-INTRA-ORAL FILMS 2-EXTRA-ORAL FILMS

INTRA-ORAL X-RAY FILMS 1-X-Ray film 2- Two black papers 3-Lead foil sheet 4-Outer wrapping(soft packet) a-Tube side(white surface) b-Label side(colour coded)

KODAK PACKET COLOR CODES One – film packet Two-film packets Ultra-speed(D-speed) GREENGRAY Ekta-speed(E-speed) BLUEPINK

TYPES OF INTRA-ORAL FILMS 1-PERIAPICAL FILMS 2-BITEWING FILMS 3-OCCLUSAL FILMS

PERIAPICAL FILMS Size 0 :For children&adults with small mouth Size 1: For anterior teeth in adults Size 2:(standard film) For anterior&posterior teeth in adults

BITE-WING FILMS Size 0 For posterior teeth in young children Size 1 For posterior teeth in children Size 2 For posterior teeth in adults(most frequent film) Size 3 For premolar or molar region

OCCLUSAL FILMS Size 4: To show large areas of upper or lower jaw

FILM SPEED(SENSITIVITY) It is exposure time necessary to produce an image on the film Determined by 1-Size of silver halide crystals 2-Thickness of emulsion Classified from A-speed(slowest) to F-speed(fastest)

FILM SPEED(SENSITIVITY) Large crystals>>>High speed>>>less details Small crystals>>>slow speed>>>More details A-speed films>>>slowest speed &best details F-speed films>>>fastest speed &less details

EXTRA-ORAL FILMS TYPES : 1-Screen films 2-non screen films INDICATIONS: 1-PTS unable to open mouth 2-view large area of pathology 3-general view of mandible or maxilla 4-view more bones of the face(skull or sinuses) 5-impacted or unerupted teeth 6-fractures of jaws&localization of F.B 7-TM joint

INTENSIFYING SCREEN COMPOSITION OF I. S. 1-Plastic or cardboard sheet 2-Reflecting layer (Titanium oxide) 3-Phosphor layer: a-Ca Tungestate or Ba Ld sulfate(conventional screen) b-Gd or Lanthanum (rare earth screen)

INTENSIFYING SCREEN TYPES A-According to phosphor layer 1-Conventional screen>>>Emit blue light Kodak x-omatic screen 2-Rare earth screen >>> emit green light Kodak Lanex screen

INTENSIFYING SCREEN B-ACCORDING TO SPEED (Crystal size) 1-Slow : small crystals>>best image details 2-Intermediate : Larger crystals>> less details 3-Fast : Largest crystals >> Least details

CASSETTE HOLDERS 1-Cassette front :Plastic, cardboad or Alaminium 2-Two Intensifying screens 3- Film 4-Felt padding 5-Cassette back : Lead

FILM STORAGE Avoid high temperature, chemical fumes, radiation & mechanical pressure Proper storage conditions: 1-Cool,dry place (no humidity) 2-No chemical fumes 3-Lead lining of storage area 4-Standing film boxes

DIGITAL RADIOGRAPHY DISADVANTAGES OF CONVENTIONAL RADIOGRAPHY 1-Processing the films 2-Use of high radiation dose 3-The image cannot be changed 4-Sensitive to variation in exposure 5-Less sensitive to detect early osseous changes

DIGITAL RADIOGRAPHY ADVANTAGES OF DIGITAL RADIOGRAPHY 1-Low radiation dose 2-Image manipulation>>adjust contrast,resolusion &image enhancement 3-No processing 4-Teleradiology 5-Storage &archiving of patient imagings

DIGITAL RADIOGRAPHY DISADVANTAGES OF DIGITAL RADIOGRAPHY 1-Expensive 2-Needs large disc spaces 3-Electronic failure 4-Difficult in intra-oral radiography

DIGITAL RADIOGRAPHY 1-Charge coupled device(CCD) system Composed of a rare earth screen(in rigid plastic casing)>>conical optical fibers &CCD>>display processing unit(DPU) PRINSIPLE: X-ray photons strike the screen>>emits light>>transferred by optical fibers>>CCD>>Electrical signals>>digital signals by computer(A/D convertor)

DIGITAL RADIOGRAPHY 2-IMAGE PLATE (IP) SYSTEM CONSISTS OF phosphor particles embeded in a polymer and coated on a plastic base PRINCIPLE:PHOTOSTIMULABLE LUMINESCENCE Some of energy is stored in the screen>>latent image>>electrical signals(by photomultiplier tubes)>>digital signals(by A/D converter)

FACTORS AFFECTING IMAGE 1-FACTORS RELATED TO X-RAY MACHINE 2-FACTORS RELATED TO OBJECT 3-FACTORS RELATED TO X-RAY FILM

FACTORS AFFECTING IMAGE A-FACTORS RELATED TO X-RAY MACHINE 1-KV 2-MA 3-EXP TIME(S) 4-COLLIMATION 5-FILTRATION 6-SOURCE-OBJECT DISTANCE

FACTORS AFFECTING IMAGE 1-KV  KV of dental x-ray machines from 65-90kv  Increase KV(within normal range)>>X-ray high energy photons >>more penetration power>>>>GOOD CONTRAST(differentiation between black,white &gray shades  Optimal contrast is between65-90KV  KV affects the quality of X-ray beam

FACTORS AFFECTING IMAGE 2-mA  Normal mA of dental X-ray machines 8-12mA  Increase mA (within normal range)>>increase heating the filament>>increase No of X-ray photons>>increase degree of darkening of image(good or optimal DENSITY)  mA affects quantity of X-ray beam  Difference in mA can be controlled by change of exposure time(S )

FACTORS AFFECTING IMAGE 3-EXPOSURE TIME (S)  Exposure= Ma X sec  Affects quantity of X-ray beam

FACTORS AFFECTING IMAGE 4-COLLIMATION  Good collimation >> restriction of x-ray beam >>decrease tissue exposure (safety of patients)  Proper collimation >> decreases secondary radiation&increases quality & sharpness of the image

FACTORS AFFECTING IMAGE 5-FILTRATION  Filter is a thin sheets of AL which absorb weak x- ray photons  Thickness of AL sheets depends on KVp of x-ray machines  1.5mm AL for KV up to 70 KVp  2.5mm AL for KV over 70 KVp  Proper filtration improves quality of beam>>patient safety &better image quality

FACTORS AFFECTING IMAGE 6-SOURCE-OBJECT DISTANCE INVERSE SQUARE LAW

FACTORS AFFECTING IMAGE B-FACTORS RELATED TO OBJECT 1-Atomic No 2-Density 3-Thickness of object

IMAGE CLARITY SHARPNESS: It is a measure of how well the minimum details of object are seen on the radiograph RESOLUTION: It is a measure of visualization small objects on the radiograph

END