x-ray films by Dr Sanjana Ravindra

X ray Film
Dr Sanjana Ravindra
Oral Medicine & Radiology
Rajarajeswari dental college, BangaloreDr Sanjana Ravindra

CONTENTS
Introduction
Historical review
Classification
Ideal Requirements
Composition
Manufacturing
Intraoral Films
Extraoral Films
Characteristics of film
Film holders
Film Identification
Film storage
Film disposal
References
DrSanjanaRavindra

Introduction
Dr Sanjana Ravindra

Introduction
Dental Radiography – art and science of making shadow pictures of the teeth
and surrounding structures.
Dental Radiograph – shadow picture of the teeth and its surrounding
structures.
X rays - electromagnetic radiation that differentially penetrates structures
within the body and creates images of these structures on a film.
X-ray Film – a medium which records the image of the object exposed with x-
rays
Image - reproduction, representation or imitation of the physical form of a
person or thing
Receptor - something that responds to the stimulus
Langland O, Langlais R P, Preece J W editors. Concepts of Radiologic Imaging. In: Principles of Dental
Imaging 2nd edition. Lippincott Williams & Wilkins. 2002. p.44-47.Dr Sanjana Ravindra

Introduction
1. The interaction of the X ray
with a suitable detection
medium to generate a
measurable response.
2. The temporary storage of this
response with a recording
device.
3. The measurement of this
stored response.
The capture of an X ray image may be divided into three stages.
Dance S, Christofides A.D, Maidment I.D, McLean K.H. Receptors for Projection Radiography. In:
Diagnostic Radiology Physics. International atomic energy agency. Austria. 2014; 145-163.Dr Sanjana Ravindra

Introduction
X-ray films are the most important material used to “decode” the information
carried by the attenuated x-ray beam, when they are made to pass through the
tissue
The x-ray films- record the information regarding the object (tissue)
through which x-rays pass and hence they greatly help in diagnosis and
treatment of the pathology.
They capture the invisible image into visible form
The x-ray film is the image receptor system used
X-rays  Films  Images
White S C, Pharoah M J editors. X-Ray Film, Intensifying Screens, and Grid. In: Oral
Radiology.Principles and Interpretation, 6th Ed. Mosby. 2006;53-64.Dr Sanjana Ravindra

HISTORICAL REVIEW
Dr Sanjana Ravindra

X-rays were discovered by Sir W.C. Roentgen 0n 8th November 1895
because of their ability to cause fluorescence
HISTORICAL REVIEW
Roentgen initially used a sheet
of Barium platinocyanide to
view the fluorescence produced
by X-ray photons
It was shortly thereafter that
photographic plates were
adapted for radiographic
purposes
The first radiograph of the human
body – Mrs. Bertha Roentgen's
hand on a photographic plate
on exposure to unknown rays
for 15 minutes
Forrai J. Culture history of dentistry. Dental Press Budapest. 2005;84-113.Dr Sanjana Ravindra

HISTORICAL REVIEW
ADVANTAGES
High resolution
Stable
Less likely to bend or
distort
Research quality
image obtained
DISADVANTAGES
High cost
Fragile, ie tends to
break easily
Difficulty to handle
Campbell DJ. A brief history of dental radiography. N Z Dent J. 1995;91(406):127-133.Dr Sanjana Ravindra

HISTORICAL REVIEW
C.EDMUND KELLS (1896) -1st practical use of
radiograph in dentistry in living persons.
First dental radiograph was
made by Otto Walkhoff on
the photo plate.
Exposure time -25 minutes
W.J.MORTAN (1896) -1ST Dental radiograph in
US using a skull.
Forrai J. Culture history of dentistry. Dental Press Budapest. 2005;84-113.Dr Sanjana Ravindra

By 1900: celluloid base film
1913: Moisture proof dental packet
1919: Kodak ‘Regular’ film
1924: Kodak ‘Radiatized’ film
1940: Kodak ‘Ultraspeed’ film
1981: Kodak ‘Ektaspeed’ film
1994: Kodak ‘Ektaspeed Plus’ film
HISTORICAL REVIEW
Peter T. Image Receptors: An update. International Journal of Innovation and Applied Studies.
2014; 7(1):211-220).
•Early 1920s, cellulose nitrate was used,
which was highly inflammable and when
burned emitted large quantities of poisonous
gases. Cellulose nitrate continued to be the
most popular base material until 1929, when a
fire in Cleveland Hospital claimed more than
100 lives. After that cellulose acetate was
used.
Dr Sanjana Ravindra

Classification
Dr Sanjana Ravindra

a) Intra-oral Films
I. Periapical Films
II. Occlusal Films
III.Bitewing Films
b) Extra-oral Films
Classification of films
ACCORDING TO THEIR USE
1. Karjodkar F R. X-ray Films and Accessories. In: Textbook of Dental and Maxillofacial Radiology,
2st Ed. Jaypee Brothers Medical Publishers (P) Ltd. 2006;111-124.Dr Sanjana Ravindra

ACCORDING TO THE COATING OF EMULSION
Single Coated
•These films have emulsion on one side
only.
•Produce better and sharper images, but
the exposure of the patient is more.
Double Coated
•These films have emulsion on the both
sides.
•Most dental films are double coated.
•These allow for less exposure to the
patient.
Screen type
• Mammographic
film
Non Screen type
•CRT film, Copying Film,
Laser film, Subtraction
film,, Dryview film
Screen type
•General radiographic film
Non Screen type
Dental film, Kidney
surgery film, radiation
monitoring film

• According to the Speed of the Film
A.Slow Films
• Have a very small grain of silver bromide.
• Emulsion is on one side only thus gives better definition.
• Exposure required is more and thus not routinely used
• Speeds are denoted by A, B, C.
B.Fast Films
• Have larger grain side and emulsion on both sides.
• Their speeds are D-ultra speed, E - ekta speed and F – ultra ekta speed
C.Hyper speed G
This is a 800 – speed film that can half the patient exposure without
blurring of the image quality.

• According to the Packing
A. Single Film Packet
B. Double Film Packet
• Two films are placed close to each other
• The second film serves as a duplicate

Peter T. Image Receptors: An update. International Journal of Innovation and Applied
Studies. 2014; 7(1):211-220).
BASED ON MODE OF
ACTION/ SENSITIVITY
Directaction/Non-screenfilms
Also called wrapped or
packet film
Sensitive primarily to x-ray
photons
Indirectaction/Screenfilms
Used in combination with
intensifying screen in a
cassette
Sensitive to light photon
which are emitted by the
adjacent intensifying screen
on exposure to x-ray
Advantage : exposure to
patient is minimized
1. Sensitive to blue light,
contains calcium
tungstate screens
2. Sensitive to green light,
contains rare earth
elements
Dr Sanjana Ravindra

CHARACTERISTICS DIRECT EXPOSURE
FILM
INDIRECT EXPOSURE
FILM
Exposed with Only by x-rays Mainly by visible light
Used Without Screen With screen
Emulsion layer Thick Thin
Image formation In deep superficialy
Processing time more less
Resolution more less
Exposure dose more less
Used in Orbit and extremities
radiography. Also in
Industrial Radiography
General radiography
Dr Sanjana Ravindra

• According to the Use of Screens
A. Screen Films
I. Sensitive to blue light, e.g. yttrium tantalite
screens
II. Sensitive to green light, e.g. rare earth screens
B. Non – screen Films
• According to Barrier Envelopes
A. With barrier envelopes
B. Without barrier envelopes

Ideal requirements of x-ray
film
Dr Sanjana Ravindra

IDEAL REQUIREMENTS OF X-RAY FILMS
Should require smallest possible
quantity of x-ray to produce
blackening
Change in intensity of X-ray must
produce clearly distinguishable
densities on finished films
Greatest possible effect must be
produced in shortest possible time
Waites E. Essentials of Dental Radiography and Radiology, 3rd Ed. Churchill Livingstone. 2003;33-52.Dr Sanjana Ravindra

Composition
Dr Sanjana Ravindra

COMPOSITION
Dr Sanjana Ravindra

ANTI HALATION
LAYER
Halation : it is a
phenomenon
characterized by
formation of a diffuse
image or halo around
the proper image.
Dr Sanjana Ravindra

base “ transparent supporting material upon which emulsion is
coated”
COMPOSITION
Clear transparent cellulose
triacetate (or) thin polyester
plastic ( polyethylene
terephthalate )
Thickness : 0.007 ” ie 0.2 mm
Dr Sanjana Ravindra

BLUISH TINT: for ease in case of viewing, and it
also prevents eyestrain
FLEXIBLE : flexible and unbreakable and allow
easy handling of the films
SUPPORT : serve as support for the very fragile
emulsion layers
DIMENSIONAL STABILITY : should maintain
its size and shape during use and processing
TRANSLUCENT: so that it does not cause any
pattern image in the resultant radiograqph
Requirements of base
WHY POLYESTER IS
PREFERRED??
 More resistant to wrapping with
age, and is stronger than triacetate
 Thinner than triacetate but are
strong as that of triacetate
 Comparatively non-inflammable
Karjodkar F R. X-ray Films and Accessories. In: Textbook of Dental and Maxillofacial Radiology, 2st Ed.
Jaypee Brothers Medical Publishers (P) Ltd. 2006;111-124.Dr Sanjana Ravindra

EMULSION
The emulsion is the component which is sensitive
to x-rays and visible light and records the
radiographic image.
If it is present both sides of the film – double
coated film – results in reduced exposure by half.
Sensitive to x-rays, static electricity and visible
light and should be having wide latitude
Sensitivity of emulsion depends – size and
thickness of emulsion
Thickness : 10 micrometer thick
Dr Sanjana Ravindra

SILVER HALIDE CRYSTALS
Halide – chemical compound that is sensitive to radiation or light
These crystals are arranged parallel to the surface
Silver bromide
90% to 99%
Silver
iodide
1% to 10%
Silver halide
crystals absorb
radiation during
exposure and
store energy from
the radiation
Presence of AgI gives more sensitivity to the emulsion than
plane AgBr thereby reducing the radiation dose
Diameter of
silver grains
0.7 to 0.75
mm
Shape: flat
triangular
HOW IS IT MADE
Dissolving metallic silver in
nitric acid to form silver
nitrate. The light sensitive
AgBr crystals are formed by
mixing the silver nitrate with
potassium bromide
EMULSION
 It also contains traces of sulfur (ALLYLTHIOUREA).
Dr Sanjana Ravindra

29
1.0 –1.5 microns
in diameter with
about 6.3 x 1010
grains per
centimeter of
emulsion.
Crystal size
might vary from
Silver halide
crystals may be
tabular, globular,
polyhedral, or
irregular in shape.
Silver halide in a
emulsion is in the
form of small
crystals.
Dr Sanjana Ravindra

Tabular Silver Bromide
Crystals in InSight
Films
Globular Silver
Halide Crystals in
Ultra High Films
EMULSION
Dr Sanjana Ravindra

Double-Emulsion Film:
•Emulsion shrinks when it dries
•Having two emulsions minimizes curling
Physical
advantage
•Faster system
•Two screens used
•DE film – 2x contrast
•Increase density  Increase speed
•Each emulsion optimally captures light produced
by “its” screen
Photographi
c advantage
double emulsion film screens
Dr Sanjana Ravindra

Double-Emulsion Film
• Why use 2 thin emulsions rather than 1 thicker one
• Light photons are easily absorbed by the emulsion, however, only the
outer layer of the emulsion is affected by light from intensifying screens.
• Light produced closer to emulsion
• less light spread
X-Ray X-Ray
Dr Sanjana Ravindra

GRAIN SIZE AND DISTRIBUTION
34
SPEED: The bigger
the average grain
size, the higher the
speed of the film.
CONTRAST:
Affected by size
distribution. The
more available in
the film, the lower
the contrast.
GRAININESS:
Graininess is the
apparent clumping
of the crystal as seen
on the radiograph.
The bigger the
crystal, the higher
the graininess o f the
film.
Dr Sanjana Ravindra

In a film the silver halide particles are suspended in
a surrounding vehicle that is applied to the both
sides of the supporting base.
It consists of gelatinous material which keep the
silver halide grains evenly dispersed.
The vehicle absorbs the processing solutions and
help them to reach the silver halide grains and react
with them properly.
Vehicle Matrix
Dr Sanjana Ravindra

WHY GELATIN AS BINDER
36
It is a medium in which SILVER NITRATE and SODIUM BROMIDE can react and the
resulting AgBr get finely and evenly dispersed and remain suspended
In warm state it can be easily spread on the film base
On cooling, it sets firmly on the base as gel.
It is flexible and does not crack easily on bending
It is optically transparent .
Gelatin does not react chemically with the silver halide .
It is porous so the processing chemicals can penetrate to the silver halide crystals.
Some of the constituents in gelatin enhances the activity of Silver bromide and some act
as antifoggant.
Dr Sanjana Ravindra

FEW ADDITIVES
37
Preservative – Phenol as bacteriocide
Silver iodide – To extend sensitivity towards blue range.
Some dyes may extend Colour sensitivity
Glycerin to make the emulsion pliable
Saponin – To make the emulsion receptive to the processing
chemicals
Alcohol – To prevent frothing during coating
Dr Sanjana Ravindra

Subcoating / substratum
Thin adhesive material on
both sides of the base
which ensures good
adhesion between the
emulsion and base
Dr Sanjana Ravindra

characteristic Photographic film Radiographic film
Mode of image
capture
By reflected light By penetrated/
transmitted light
Emulsion layer On one side Either On one side or
both
Speed Slow Fast
Grain size Small Large
Resolving power 1000 lines/mm 6-10 lines/mm
Irradiation by Light only Light as well as x-ray
Difference InB/W Photographic FilmAnd Radiographic Film
40
Dr Sanjana Ravindra

Manufacturing
Dr Sanjana Ravindra

Manufacturing
Precipitation/
crystal
production
Physical
ripening
Setting &
washing
Mixing.
Dr Sanjana Ravindra

CRYSTAL PRODUCTION
• AgNO3 + KBr AgBr + KNO3
Aqueous solution of Silver nitrate and Potassium bromide is mixed with warm solution of gelatin.
 Insoluble Silver bromide (AgBr) remains suspended in viscous gelatin.
 More rapid process of mixing results small grain size, that results narrow
grain size distribution hence there is low graininess & better resolution.
Note:
More bromide is used to increase the
negative charge barrier that helps in
development process.
Dr Sanjana Ravindra

CRYSTAL STRUCTURE
Structure permits
both free silver
atoms and free
electrons to drift
through the lattice-
key to the formation
of the latent image.
Negatively charged
surfaces
Positively charged
exteriors
Sensitivity speck:
must be present to
provide film
sensitivity
•Serve as electrodes
to attract the free
silver ions
Bromide: serve as
ion pumps to assist
in the deposition of
silver.
Dr Sanjana Ravindra

RIPENIN
G
Period during which
silver halides are
allowed to grow
Size of the crystal
determines their
total sensitivity.
At the proper time,
emulsion is cooled,
shredded, and
washed to remove
KNO3 (potassium
nitrate)
Dr Sanjana Ravindra

WASHING
After ripening,
emulsion is chilled
to form thick gel.
This gel is shredded.
It is washed with
water that remove
KNO3 and excess
KBrby diffusion
process.
Dr Sanjana Ravindra

MIXING
Colored dyes: improve the
sensitivity of the silver halides
to match the wavelengths of
photons that will be striking the
emulsions during exposure.
•Panchromatic: sensitive to al colors
•Orthochromatic: not sensitive to the
red spectrum
Hardeners: to prevent physical
trauma
Bactericides and fungicides
Antifogging agents: to decrease
sensitivity to environmental
factors, such as heat.
Dr Sanjana Ravindra

Intraoral films
Dr Sanjana Ravindra

non-screen films
Intra oral x-ray films
22x35mm
Pedo
31x41mm
Adult
Periapical
Type1
22x35mm
Pedo
31x41mm
Adult
Bitewing
Type2
57x76mm
Occlusal
Type3
Intraoralfilms
Classifiedaccording
to
useandsize
Dr Sanjana Ravindra

Intra oral x-ray films
Dr Sanjana Ravindra

PERIAPICAL FILMS
Size 0 Size 1 Size 2
22 x 35
mm
24 x 40
mm
31 x 41
mm
0.814” x
1.296”
0.888” x
1.481”
1.148” x
1.518”
Used to record the
crowns, roots and
periapical areas related
to the tooth
Availability
: film
packets are
available in
25, 100, 150
film per
container
They are packaged in
convient plastic trays or a
cardboard boxes that can
be recycled
Film packs
come in
three sizes
Dr Sanjana Ravindra

Used to record the
coronal portion of
the maxillary and
mandibular teeth in
one image.
Useful in detecting
interproximal caries
and the height of
alveolar bone.
BITEWING FILMS
Size 0 Size 1 Size 2 Size 3
22 x 35
mm
24 x 40
mm
31 x 41
mm
27 x 54
mm
0.814” x
1.296”
0.888” x
1.481”
1.148” x
1.518”
1.062” x
2.125”
Dr Sanjana Ravindra

Usually
positioned in the
occlusal plane
and patient
occludes on it,
hence the name
These are three
times larger than
size 2 film (57 X
76mm) or 2.111”
x 2.814”
These films are
used to obtain
right angle views
to the usual
periapical view.
OCCLUSAL FILMS
Dr Sanjana Ravindra

Contents of the film packet
Dr Sanjana Ravindra

Outer plastic wrapper; made of white
paper or soft vinyl which is hermetically
sealed, semistiff
protects the film from light, saliva and
mechanical damage, has two sides:
· Tube side: it is solid white
and has a raised bump in one
corner and when placed in
the mouth white side of the
film packet must face the
teeth.
· Label side: it has a flap used
to open the film packet and is
color coded.
The following information is
printed on label side:-
· Dot that corresponds with raised
identification dot on the film
· Statement “opposite side
towards tube”
· Manufacturer’s name
· Film speed
· No. of films enclosed
Raised dot; an elevation
embossed on each component
of the film,has two surfaces
Convex; indicates front of the
film (facing x-ray)
Concave; indicates back of
film (facing lead foil)
Dr Sanjana Ravindra

Lead foil sheet: thin lead foil sheet
is positioned behind the film to
shield the film :-
· From back scattered radiations
that result in film fog.
· Absorbs some of the radiations
after x-ray beam exposes and
passes through the film.
· Contributes to the rigidity of the
packet
The black paper film
wrapper inside the film
packet is a protective
sheet that covers the film
and shields it from light
Dr Sanjana Ravindra

Deep
Tissues
Behind
film
Incident x-rays
Object
(Tooth )
Film packet without a lead foil
Scattered x-rays
Back-scatter
Dr Sanjana Ravindra

Deep
Tissues
Behind
film
Film packet with a lead foil
No x-rays behind the film
Incident x-rays
Object
(Tooth )
Dr Sanjana Ravindra

COLOUR CODES
Dr Sanjana Ravindra

Extraoral films
Dr Sanjana Ravindra

These are the films that are placed
outside the mouth during exposure.
These are used to examine areas of the
skulls and jaws.
Extra-oral projections most frequently
used in dentistry are panoramic,
cephalometric and other skull views.
Lateral
oblique film
5” X 7”
Cephalometric
film
8” X 10”
Panoramic
Film
6” X 12”
5” X 12”
Skull
radiography
10” X 12”
6.5” X 8.5 “
SIZES
Dr Sanjana Ravindra

Film construction
EMULSION
The silver halide emulsion is designed sensitive primarily
to light rather than x-ray
BLUE LIGHT: Standard
silver halide emulsion
is sensitive to blue light
ULTRAVIOLET LIGHT
modified silver halide
emulsion with
ultraviolet sensitizer
sensitive to ultraviolet
light
GREEN LIGHT
(Orthochromatic
emulsion sensitive to
green light) : these are
2-3 times faster and
provide sufficient
clarity
RED LIGHT:
Panchromatic emulsion
is sensitive to red light
Different
emulsions are
manufactured
which are
sensitive to
different colours
• They do not have embossed
dot to indicate the surface
facing the x-rays
• They are used in film holder
or cassettes that have the
letter R or L made of lead on
the exposure side of the
cassette.
• The letter is radiopaque and
appears in the finished
radiograph
Dr Sanjana Ravindra

Digital x-ray films
DRYVIEW DVB, DVB+, and DVB+ Premium Laser
Imaging Films are coated on blue, 7-mil polyester base
supports.
DRYVIEW DVC Laser Imaging Film is coated on a clear,
7-mil polyester base support.
DRYVIEW Laser Imaging Films are high resolution, photothermographic, gray-
scale films suitable for continuous-tone medical imaging.
These films provide excellent diagnostic visualization of fine detail, sharp image
rendition, and a cool
image tone.
DRYVIEW Laser Imaging Film is designed
to record a full range of images from
various modalities including
computed tomography, digital subtraction
angiography, magnetic resonance imaging,
nuclear medicine, ultrasound, computed
radiography, digital radiography, and
digitized film images.
Dr Sanjana Ravindra

Digital x-ray films
Dry processing
techniques
Photo-
thermographic
printing
Thermographic
printing
Uses heat to directly cause a change in the silver behenate
within the film thus exposing and developing the film at the
same time.
Utilizes a laser to scan the image onto the film, film contains
all the processing chemicals within the emulsion. Once
through the laser the film is exposed to a thermal head that
activates the chemicals and develops the image. The chemical
remain in the film
Uses a laser to form a latent image and
heat to process the image
Dr Sanjana Ravindra

Duplicating film
“ is the type of film that is used to make an identical copy of an
intraoral and extraoral radiograph. It is only used in darkroom
setting and is not exposed to X-rays”
Use : useful when patient
is referred to the specialist,
insurance claim and as
teaching aid
EMULSION SIDE: one side
– shiny – non emulsion
side: dull – emulsion side
should contact radiography
during duplicating process.
Dr Sanjana Ravindra

Self-developing films
• The x-ray film is presented in a special sachet containing developer and
fixer.
• Following exposure, the developer tab is pulled, releasing developer
solution which is milked down towards the film and massaged around
it.
• After 15 sec. fixer tab is pulled and fixer solution is milked down and
agitates the film.
• After fixing chemicals are discarded and film is processed using
conventional processing procedures.
It eliminates the need of
dark room for
processing
Time saving.
Poor image quality
Expensive
Image deteriorates with
time
Film is very flexible and
easily bent
Difficult to use in film
holders.
Dr Sanjana Ravindra

Characteristics of
radiographic film
Dr Sanjana Ravindra

Optical density (OD)
OD = log Incident light intensity
Transmitted light intensity
“ Degree of blackness present on the film measured in terms
of light transmission on a logarithmic scale” Measured –
densitometer
Ideal diagnostic
film density : 0.25
– 2.5
Characteristic curve/ Sensitometric Curve
The characteristic curve is a graph showing the
variation in optical density (degree of blackening)
with different exposures.
Relationship between radiation exposure to the film
and resulting film density.
Dr Sanjana Ravindra

This is due to:
• The colour/density of the plastic base
• The development of some unexposed silver halide crystals.
Background fog density
This is the small degree of blackening evident
even with zero exposure.
Dr Sanjana Ravindra

Object factors
•object
density
(w/v)
•object
thickness
Exposure
factors
•kVp
•mA
•exposure
time
•tube-film
distance
Film
factors
•film speed
•lead foil
•storage
Processing
solution
* temperature.
*concentration.
* Time
DENSITY INCREASES WHEN
kVp
mA
exposure time
film speed
lead foil (If not used)
storage (at high Temp.
object density
object thickness
Exposure factors
tube-film distance
lead foil (Opposite
side)
Processing
solutions
* temperature
* concentration
* time
Dr Sanjana Ravindra

Film with high contrast
more desirable for
diagnosis
The manufacture have
increased the speed of
later generation E
speed film.
low when the
difference between the
shades is gradual
High when the
difference between the
shades is sharp
FILM CONTRAST
This is the difference in optical density between two points on a
film that have received different exposures
Dr Sanjana Ravindra

Defined as – amount of radiation required to produce the radiograph of adequate
density
It is the efficiency with which the film responds to x-ray exposure.
SLOW FILM
“Intraoral
films that
require more
exposure to
produce ideal
radiograph”
Group A,B,C
FAST FILM
“Intraoral film
that requires
very little
exposure to X-
radiation to
produce
radiograph”
Group D and E
FACTORS AFFECTING FILM SPEED
Size of crystal
•Directly proportional
Shape of grains
•Tubular shape grains –
more surface area – less
exposure – more speed
film
Thickness of
emulsion
•Directly proportional
Radiosensitive dyes
Directly proportional
Speed of film
Dr Sanjana Ravindra

SLOW SPEED FILMS – A, B, C.
Small grain, better definition, more exposure
time
FAST SPEED FILMS –D (ultra speed)
E (ekta speed)
F (ultra ekta speed)
Dr Sanjana Ravindra

This is the reciprocal of the exposure required to produce an optical
density of 1.0 above background fog.
Thus, a fast film has a high sensitivity.
Film sensitivity
Dr Sanjana Ravindra

Sharpness – is the ability
of a radiograph to define
an edge precisely.
Resolution – is the
ability of a radiograph to
record separate structures
that are close together.
SHARPNESS AND RESOLUTION
Dr Sanjana Ravindra

It is describes the subjective judgment by the clinicians of the
overall appearance of a radiograph.
It combines the features of density, contrast, latitude,
sharpness, resolution and other parameters.
Image quality
Dr Sanjana Ravindra

Film latitude
measure of the range of exposures that produces distinguishable
differences in optical density, i.e. the linear portion of the characteristic
curve
The wider the film
latitude the greater
the range of object
densities that may
be seen.
• Inversely related to contrast
• high contrast = low latitude
• low contrast = high latitude
Significance
Variation from optimal technique less
critical
higher range of subject contrasts
imaged on single film (such as chest)
Dr Sanjana Ravindra

Film gamma and average gradient
Film gamma is the
maximum gradient or
slope of the linear portion
of the characteristic curve.
Average gradient is a more useful
measurement and is usually
calculated between density 0.25 and
2.0 above background fog Thus the
film gamma or average gradient
measurement determines both film
latitude and film contrast as follows:
• If the gamma or average gradient
is high (i.e. a steep gradient), that
film will show good contrast, but
will have less latitude.
• If the film gamma or average
gradient is low (i.e. a shallow
gradient), that film will show poor
contrast but will have wider
latitude.
Dr Sanjana Ravindra

• Conversion Efficiency: High conversion efficiency results in increased image
noise.
• The factors that make rare earth screens have greater speed and use less
exposure also contribute to increased noise.
Image Noise/ Quantum mottle
Defined as the statistical fluctuation in the
quantity of x-ray photons that contribute to
image formation per square millimeter.
Noise (any unwanted information) can be speckled appearance or grainy
It occurs with fast screens and use of high kVp.
Dr Sanjana Ravindra

For the screen to work at maximum efficiency,
the light absorption characteristics of the film
must be matched to the light emitted from the
screens.
This is called spectrum matching.
Screens and films are manufactured for
compatibility; this helps to ensure good results.
Spectrum Matching
Dr Sanjana Ravindra

Spectrum Matching
• Calcium Tungstate emits light in the blue
region of visible spectrum.
• Rare earth emits a green spectrum.
Blue emitting screens should be matched with
blue sensitive fims
Green emitting screens should be matched with
green sensitive films
Dr Sanjana Ravindra

• Silver halide crystals are inherently sensitive to UV and blue light and thus are
sensitive to screens which emit UV and blue light.
• But when used with screens which emit green light, special dyes are added to
increase their sensitivity to green light.
Dr Sanjana Ravindra

Film holders and
hangers
Dr Sanjana Ravindra

Film Holders
Blade Type
• Throat stick
• Acrylic blade with
slot
• Snap–A-ray
Bite Block
• Styroform block
• Snap-A-ray
• Artery forceps with
bite block ( Fitzgerald
Hemostat)
PID
• Rinn XCP
• Precision X-ray
holder
Dr Sanjana Ravindra

Cassettes
The cassette is a rigid holder for the film and
screens.
It pushes the film in close contact with the
screens.
The front of the cassette is made of a radiolucent
material with low absorption characteristics.
The back of the cassette
may contain some form of
metal that can absorb x-
rays that are not absorbed
by the screens.
If cassettes that do not
adequately absorb the
rays, back scatter will
result from scatter
radiation from the
cassette holder or near by
wall.
Dr Sanjana Ravindra

Film Identification
Dr Sanjana Ravindra

Date of exposure
Full name of patient
Institution exposure made
Referring physician
Patient identification number
Examination ordered
Dr Sanjana Ravindra

Film storage and handling
Dr Sanjana Ravindra

Film Storage and Handling
Dr Sanjana Ravindra

Handling -
Hands must be clean, dry and free of
lotions, etc. Film should be handled
carefully by the edges to avoid
physical strains
such as pressure, creasing, or
buckling.
Dr Sanjana Ravindra

Fujifilm handbook. Fundamentals of Industrial radiographyDr Sanjana Ravindra

Film disposal
Dr Sanjana Ravindra

X-ray film
Used x-ray film may contain
sufficient amounts of silver to be
a hazardous waste (film with
large dark areas contains more
silver than film with smaller
dark areas).
The silver on film can be
reclaimed.
Lead Foil
Lead foil that shield X-ray film
or protective lead shields should
not be disposed of in the trash.
These materials are hazardous
waste (D008) unless they are
recycled for their scrap metal
content.
Film disposal
Dr Sanjana Ravindra

Manufacturers
Dr Sanjana Ravindra

http://www.dsir.gov.in/reports/techreps
/tsr160.pdf
Dr Sanjana Ravindra

References
1. White S C, Pharoah M J editors. X-Ray Film, Intensifying Screens, and
Grid. In: Oral Radiology.Principles and Interpretation, 6th Ed. Mosby.
2006;53-64.
2. Karjodkar F R. X-ray Films and Accessories. In: Textbook of Dental and
Maxillofacial Radiology, 2st Ed. Jaypee Brothers Medical Publishers (P)
Ltd. 2006;111-124.
3. Haring JI, Jansen L. Dental Radiography Principles and Techniques, 2nd
Ed. W. B. Saunders Company. 2001;12-26.
4. Langland O, Langlais R P, Preece J W editors. Concepts of Radiologic
Imaging. In: Principles of Dental Imaging 2nd edition. Lippincott
Williams & Wilkins. 2002. p.44-47.
5. Curry III TS, Dowdey JE, Murry RC. Christensen’s Physics of
Diagnostic Radiology. 4th ed. Philadelphia: Lea & Febiger; 1990.
6. Phinney DJ, Halstead JH EDITORS . Dental office management. In :
Delmar's Dental Assisting: A Comprehensive Approach. 720-754.
Dr Sanjana Ravindra

References
7. Waites E. Essentials of Dental Radiography and Radiology, 3rd Ed.
Churchill Livingstone. 2003;33-52.
8. Oakley J. Digital Imaging for Radiographers, Radiologists, Healthcare
professionals. 3rd Ed. Cambridge. 2008; 103-126.
9. Dance S, Christofides A.D, Maidment I.D, McLean K.H. Receptors for
Projection Radiography. In: Diagnostic Radiology Physics.
International atomic energy agency. Austria. 2014; 145-163.
10. Oborska-Kumaszyńska D et al – Analog and digital systems of
imaging. Pol J Radiol, 2010; 75(2): 73-81.
11. L. Lanc¸a and A. Silva, Digital Imaging Systems for Plain Radiography,
DOI 10.1007/978-1-4614-5067-2_2
12. Carestream Health, Inc., 2014. CARESTREAM and DRYVIEW are
trademarks of Carestream Health.
13. Indrajit IK, Alam A, Sahni, H, Bhatia M. Dry imaging cameras. Indian
Journal of Radiology and Imaging / May 2011 / Vol 21 / Issue 2
14. Blanton T. In Situ High-Temperature Study Of Silver Behenate
eduction To Silver Metal Using Synchrotron Radiation. International
Centre for Diffraction Data 2002, Advances in X-ray Analysis, Volume
45.
Dr Sanjana Ravindra

x-ray films by Dr Sanjana Ravindra

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x-ray films by Dr Sanjana Ravindra