Ideal radiography

IDEAL
RADIOGRAPHY
DR. REVATH VYAS
PG II YEAR

CONTENTS
• DEFINITION
• IDEAL IMAGE CHARACTERISTICS
• FACTORS RELATED TO THE RADIATION BEAM
• FACTORS RELATED TO THE OBJECT
• FACTORS RELATED TO THE TECHNIQUE
• FACTORS RELATED TO RECORDING OF THE
ROENTGEN IMAGE OF THE OBJECT
• DARK/ LIGHT IMAGE  IDEAL IMAGE
• IDEAL QUALITY CRIETRIA
• CONCLUSION
• REFERENCES

DEFINITION
• An Ideal Radiograph is one that provides a great deal
of information, the image exhibits proper density and
contrast, have sharp outlines and are of the same
shape and size as the object being radiographed.
• In HM Worth’s words; “An Ideal Radiograph is one
which has desired density and overall blackness and
which shows the part completely without distortion
with maximum details and has the right amount of
contrast to make the details fully apparent”.

IMAGE CHARACTERISTICS
Dental radiograph appears as a black-and-white image
picture that includes varying shades of gray.
Radiolucent (Black or dark areas): A structure that
appears radiolucent on a radiograph lacks density and
permits the passage of the x-ray beam with little or no
resistance. For example, air space appears
radiolucent.
Radiopaque (White or light areas): Radiopaque
structures are dense and absorb or resist the passage of
the x-ray beam. For example, enamel, dentin, bone
etc. appears radiopaque.

The characteristics of an Ideal Radiograph are:
A. Visual characteristic:
i. Density.
ii. Contrast.
B. Geometric characteristics:
iii. Sharpness or detail, resolution or definition.
iv. Magnification.
v. Distortion.
C. Anatomical accuracy of radiographic images.
D. Adequate coverage of the anatomic region of
interest.

A diagnostic (ideal) radiograph provides a great deal
of information:
• the images exhibit proper density and contrast
• have sharp outlines and
• of the same shape and size as the object.

The major imaging characteristics of x-ray film are
1. Radiographic density
2. Radiographic contrast
3. Radiographic speed
4. Film latitude
5. Radiographic Noise
6. Radiographic blurring

1) RADIOGRAPHIC DENSITY
The overall degree of darkening of an
exposed film is referred to as radiographic density.
Measured as the optical density of an area of an x-
ray film, where,
OPTICAL DENSITY = Log 10 Io
Io - intensity of incident light (from view box)
It - intensity of light transmitted through the film.
It

The measurement of film density is also a measure of
the opacity of the film.
Optical density is 0 means 100% of the light is transmitted
Optical density is 1 means 10% of the light is transmitted
Optical density is 2 means 1% of the light is transmitted.
A film is of greatest diagnostic value when the
structures of interest are imaged on the relatively straight
portion of the graph, between 0.6 to 3.0 optical density
units.

Gross fog or base plus fog: an unexposed film,
when processed, shows some density caused by
the inherent density of the base, added tint and the
development of unexposed silver halide crystals.
The optical density of gross fog is 0.2 to 0.3
Radiographic density is influenced by
A.Exposure
B. Subject thickness and
C. Subject Density

A) Exposure:- The overall film density depends on the
number of photons absorbed by the film emulsion
 kVp  the no. of photons reaching
mA the film and thus
 exposure time  density of the radiograph
distance b/w, the
focal spot & film
B) Subject Thickness: The thicker the subject, the more
the beam is attenuated and the lighter the resultant
image
The exposure (either kVp or time) should vary
according to the patient’s size to produce radiographs of
optimal density.

C) Subject Density: The greater the density of
a structure within the subject, the greater the
attenuation of the x-ray beam.
Dense objects (which are strong absorbers)
cause the radiographic image to be light and
are radiopaque.

Less dense objects (which are weak absorbers) cause
the radiographic image to be dark and are radiolucent.
Decreasing densities – enamel, dentin, cementum,
bone, muscle, fat and air.
Metallic objects (eg. Restorations) are far denser than
enamel and hence better absorbers.

2. RADIOGRAPHIC CONTRAST
Defined as the difference in densities between light
and dark regions on a radiograph.
High contrast Shows both light areas
(short gray scale of contrast) and dark areas.
Low contrast Composed only of light gray
(long gray scale of contrast) and dark gray zones

H i g h L o w O p t i m u m
Contrast Contrast Contrast

A. Subject Contrast:
 Influenced largely by the subject’s thickness, density
and atomic number.
 Also is influenced by beam energy and intensity.
 As the kVp of the x-ray beam increases, subject
contrast decreases low kVp energies are used,
subject contrast increases.
“KVP KILLS CONTRAST”
Changing the time or mA of the exposure (KVp constant) also
influences subject contrast.
If the film is excessively light or dark, contrast of
anatomic structures is diminished.

B. Film Contrast:-
Describes the capacity of radiographic
films to display differences in subject contrast,
A high-contrast film reveals areas of
small difference in subject contrast
Properly exposed films have more
contrast than underexposed (light films)
Film processing influences film contrast.
Film contrast is maximized by optimal film
processing conditions.

Improper handling of the film, such as
a) Storage at too high a temperature,
b) Exposure to excessively bright safe, degrades film
lights contrast.
c) Light leaks in the darkroom

Fog on an x-ray film results in increase film density in
turn reduces the film contrast. Common causes of
film fog are
a) Improper safelighting
b) Storage of film at too high a temperature, and
c) Development of film at an excessive temperature or
for a prolonged period.
Film fog can be minimized by proper film
processing and storage.

C) Scattered radiation:
Scattered radiation results from photons that
have interacted with the subject by compton or
coherent interactions.
Scattered radiation causes fogging of a
radiograph.
Scattered radiation can be reduced by
a) Use a relatively low kVp
b) Collimate the beam to the size of the film, and
c) Use grids in extraoral radiography.

3) RADIOGRAPHIC SPEED:
Refers to the amount of radiation required to produce an
image of a standard density.
 A fast film requires a relatively low exposure to produce a
density of 1, whereas a slower film requires a longer exposure
 Controlled largely by the size of the silver halide grains and
their silver content.
 The films most often used are kodak ultraspeed (group D) and
kodak insight (group E or F).
 Insight film is preferred because it requires only about half
the exposure of ultra speed film and offers comparable
contrast and resolution.

F-speed film is faster than the D-speed film
because tabular crystal grains are used in the
emulsion of F-speed film.
Film speed can be increased by processing the film
at a higher temperature
Processing in depleted solutions can lower the
effective speed.
It is always preferable to use fresh processing
solutions and follow the recommended processing
time and temperature.

4) FILM LATITUDE:
Measure of the range of exposure that can be recorded as
distinguishable densities on a film.
A film with a characteristic curve that has a long
straight-line position and a shallow slope has a wide
latitude.
Wide latitude have lower contrast
Wide-latitude films are useful when both the osseous
structures of the skull and soft tissues of the facial
region must be recorded.
A high kVp produces images with a wide latitude and
low contrast. Recommended for imaging structures
with a wide range of subject densities.

5) RADIOGRAPHIC NOISE:
Is the appearance of uneven density of a uniformly exposed
radiographic film.
Seen on a small area of film as localized variations in density.
Primary causes of radiographic noise are
A) Radiographic mottle
B) Radiographic artifact
A) Radiographic Mottle:-
1. On intraoral dental film, mottle may be seen as film graininess
2. Graininess is most evident when high temperature processing
is used.
3. Mottle is also evident when the film is used with fast
intensifying screens

Two important causes of radiographic mottle in
intensifying screens are
1) Quantum mottle – caused by a fluctuation in the number
of photons per unit of the beam cross-sectional area
absorbed by the intensifying screens.
2) Screen structure mottle is graininess caused by screen
phosphors.
B) Radiographic Artifacts:
Radiographic artifacts are defects caused by
1. Errors in film handling, such as finger prints or bends in
the film, or
2. Errors in film processing, such as splashing developer or
fixer on a film or marks or scratches from rough handling.

6. RADIOGRAPHIC BLURRING
Sharpness – ability of a radiograph to define an edge precisely
(e.g., dentino enamel junction, a thin trabecular plate).
Resolution, or resolving power, is the ability of a
radiograph to record separate structures that are close together.
Usually measured by radiographing an object made up of a
series of thin lead strips with alternating radiolucent spaces of
the same thickness.
The resolving power is measured as the highest number of line
pairs per millimeter.
Panoramic film-screen combinations can resolve about five
line pairs per millimeter.
Periapical film has better resolving power, can delineate clearly
more than 20 line pairs per millimeter.

Radiograph of a resolving power
target consisting of groups of
radiopaque lines and radiolucent
spaces.
Numbers at each group indicate the
line pairs per millimeter
represented by the group.

Sharpness
A B
Distance (mm)
Density
D1
D2
0 5 10 15 20
The boundary between two areas A & B appears very sharp

Unsharpness
A
Distance (mm)
Density
D1
D2
0 .2 .4 .6 .8
The boundary between two areas A & B appears unsharp
B
The steeper the slope the more sharp the image appears. The shallower the slope the more
blurred the image

Sharpness, unsharpness & lack of
sharpness
•No image is perfectly sharp
•Every image has a certain lack of
sharpness
•Unsharpness is an objective concept
which can be measured
•Sharpness is our subjective perception of
unsharpness, and depends on contrast and
unsharpness

Contrast & perception of
unsharpness
•We judge one image boundary to be sharper
than another, even though they are both
equally unsharp, if the contrast of the first
image is greater.

Image sharpness in extraoral radiographic projections is lost
because.
a) Visible light and UV radiation emitted by the screen spread
about beyond the point of origin and expose a film area larger
than the phosphor crystal
b) Intensifying screens with large crystals are relatively fast,
c) Fast intensifying screens have a relatively thick phosphor
layer,
image sharpness maximized by ensuring as close a contact as
possible between the intensifying screens and the film.
3) The presence of image on each side of a double-emulsion film
also causes a loss of image sharpness through parallax.
In intraoral images, parallax is most apparent when wet films
are viewed.

Radiographic blur is caused by
A) Image receptor (film and screen) blurring
B) Motion blurring, and
C) Geometric blurring
A. Image receptor blurring:
1. with intraoral dental x-ray film, the size and
number of silver grains in the film emulsion
determines image sharpness.
Finer the grain size  finer the sharpness
slow-speed films have fine grains and faster
films have larger grains.
2. use of intensifying screens in extra-oral
radiography has an adverse effect on image
sharpness.

In intensifying screens parallax distortion contributes to image
unsharpness because light from one screen may cross the film base
and reach the emulsion on the opposite side. Problem can be
solved by incorporating dyes into the base
B) Motion Blurring:
Image sharpness also can be lost through movement of the
film, subject or x-ray source during exposure.
C) Geometric Blurring:
Several geometric factors influence image sharpness
Image sharpness is improved by
a) Using as small focal spot area as possible
b) Increasing the distance between the focalspot ad the object (and
film)
c) Reducing the distance between the object and the image
receptor (film)

Parallax unsharpness results when double emulsion film is
used because of the slightly greater magnification on the side
of the film away from the X-ray source.

FACTORS RELATED TO
RADIATION BEAM

IDEAL EQUIPMENT
•POINT SOURCE OF FOCAL SPOT
•IDEAL TARGET MATERIAL WITH high
atomic number a high melting point, high
thermal conductivity, and low vapor pressure
•Safe and accurate
•Capable of generating X-rays in the desired
energy range and with adequate mechanisms
for heat removal

IDEAL EQUIPMENT
•Small
•Easy to maneuver and position
•Stable, balanced and steady once the
tubehead has been positioned
•Easily folded and stored
•Simple to operate and capable of both film
and digital imaging
•Robust.

Ideal Distance from the focal spot on the target to the skin.
• The required focus to skin distances ( fsd) are:
• — 200 mm for sets operating above 60 kV
• — 100 mm for sets operating below 60 kV

Ideal X-ray beam
characteristics
The ideal X-ray beam used for imaging should be:
• Sufficiently penetrating, to pass through the patient
and react with the film emulsion or digital sensor and
produce good contrast between the different shadows
• Parallel, i.e. non-diverging, to prevent magnification
of the image
• Produced from a point source, to reduce blurring of
the edges of the image, a phenomenon known as the
penumbra effect.

exposure
button
oil
filterfilament
X-ray Machine Components

• The smaller the focal spot (target), the sharper the
image (teeth) will be.
• During x-ray production, a lot of heat is generated.
• If the target is too small, it will overheat and burn up.
Line Focus Principle

Apparent (effective) focal
spot size (looking at target
surface through PID)
Actual focal spot size
(looking perpendicular to
the target surface)
PID

Apparent (effective)
focal spot size
Actual focal
spot size
Target
Cathode
(-)
Anode
(+)
PID

FACTORS CONTROLLING THE X-RA Y BEAM
1. Exposure time
2. Tube current (mA)
3. Tube Voltage (kVp)
4. Filtration
5. Collimation
6. Inverse square law

1. Exposure time
X-ray Energy (keV)
NumberofX-rays
70
2 sec
1 sec
maximum energy
average energy
(no change)
(no change)
Exposure time is doubled, the number of photons generated is doubled, photon energies is
unchanged.

• The quantity of radiation produced by an-x-ray tube is directly
proportional to the tube current and the time the tube is operated.
Quantity of radiation = Time x Tube current
2. Tube Current (mA):

mA (milliamperes)
X-ray Energy (keV)
NumberofX-rays
70
10 mA
5 mA
maximum energy
average energy
(no change)
(no change)

mAs or mAi
milliamperes (mA) x seconds (s)
milliamperes (mA) x impulses (i)
60 impulses = 1 second
10 mA x .5 seconds = 5 mAs
20 mA x .25 seconds = 5 mAs
mAi = 60 x mAs

• Increasing the KVp results in increase in
1. The number of photons generated
2. Their mean energy, and
3. Their maximal energy.
• Higher the KVp greater the penetrability of the beam through
matter.
3. Tube Voltage (KVp)

KVP (KILOVOLT PEAK)
X-ray Energy (keV)
NumberofX-rays
70 90
90 kVp
70 kVp
maximum energy
average energy

Half Value Layer (HVL):-
• The HVL is the thickness of an absorber, required to reduce by
one half the number of x-ray photons passing through it.
• As the average energy of an X-ray beam increases, so does its
HVL.

• Only photons with sufficient energy to penetrate through anatomic
structures and reach the image receptor are useful for diagnostic
radiology.
Filtering an x-ray beam with aluminum preferentially removes low-energy photons,
thereby reducing the beam intensity while increasing the mean energy of the residual
beam.
4. Filtration:

Inherent filtration :
• a. Glass wall of the x-ray tube
• b. Insulating oil and
• c. Barrier Material
0.5 to 2mm of aluminum
External filtration:
• Aluminium Disks.
Total filtration = Inherent filtration + External filtration.
• Total Filtration 1.5mm of aluminum to 70KVp
• 2.5mm for all higher voltages.

Inherent
Glass window
of x-ray tube
Added
Aluminum filter (s)
Total 70 kVp
1.5 mm
2.5 mm
Total Filtration
Oil/Metal barrier

• To reduce the size of the x-ray beam therefore the volume of
irradiated tissue.
• Round and rectangular collimators most frequently used in
dentistry.
• Scattered radiation minimized by collimating the beam.
5. Collimation

collimated
beamcollimator
target
(x-ray source)
front views side view
Collimation
2.75 inches (7 cm) = maximum diameter of circular beam or maximum length
of long side of rectangular beam at end of PID.

• Collimators - may either have a round or rectangular opening.

Circular collimator :
a) cone shaped beam - 2.75 inches in diameter
b) considerably larger than the size of two intraoral periapical
films
c) increased skin dose to the patient.
Rectangular collimator :
a) restricts the size of the X-ray beam to an area slightly larger
than a size of 2 intraoral
b) significantly reduces the patient exposure

Collimation:
• Reduces the exposure area
• Number of scattered photons reaching the film-improves
image quality

Quality
Quantity
average energy
number of x-rays

(10) (20)
Quality vs. Quantity
kVp
mA
Time
Filtration
No change
No change

• The intensity is inversely proportional to the square of the distance
from the source.
I1/I2 =(D2)2/(D1)2
• If a dose of 1 gray (GY) is measured at a distance of 2m a dose of 4GY
will be found at 1m and 0.25 GY at 4m.
6. Inverse Square Law

 kVp  the no. of photons reaching
mA the film and thus
exposure time  density of the radiograph
distance b/w, the
focal spot & film
“KVP KILLS CONTRAST”

Subject Thickness: The thicker the subject, the
more the beam is attenuated and the lighter the
resultant image
Subject Density: The greater the density of a
structure within the subject, the greater the
attenuation of the x-ray beam.
Dense objects (which are strong absorbers)
cause the radiographic image to be light and
are radiopaque.
Subject Contrast:
Influenced largely by the subject’s thickness,
density and atomic number.

The basic principles of projection geometry
(shadow casting)
• The focal spot should be as small as possible
• Focal spot to object distance should be as long as possible.
• Object to film distance should be as small as possible.
• Long axis of object and film planes should be parallel.
• X-ray beam should strike the object and film planes at right angles.
• There should be no movement of the tube, film or patient during exposure
( given by Manson and Lincoln)

•The anatomy of the oral cavity does
not always allow all these ideal
positioning requirements to be
satisfied.
•In an attempt to overcome the
problems, two techniques for
periapical radiography have been
developed:
•The paralleling technique
•The bisected angle technique.

• Paralleling cone technique has the potential to
satisfy four of the five ideal requirements
mentioned earlier.
• However, the anatomy of the palate and the shape
of the arches mean that the tooth and the image
receptor cannot be both parallel and in contact.
• So, the image receptor has to be positioned some
distance from the tooth.

IDEAL PATIENT
POSITIONING
•For intraoral radiography the patient
should be positioned comfortably in the
dental chair, ideally with the occlusal
plane horizontal and parallel to the floor.
•For most projections the head should be
supported against the chair to minimize
unwanted movement.

• The tab or bite-platform should be
positioned on the middle of the film packet
and parallel to the upper and lower edges of
the film packet.
• The film packet should be positioned with its
long axis horizontally for a horizontal
bitewing or vertically for a vertical bitewing.
• The posterior teeth and the film packet
should be in contact or as close together as
possible.
• The posterior teeth and the film packet
should be parallel — the shape of the dental
arch may necessitate two separate film
positions to achieve this requirement for the
premolars and the molars.

• In the horizontal plane, the X-ray tube head
should be aimed so that the beam meets the
teeth and the film packet at right angles, and
passes directly through all the contact areas.
• In the vertical plane, the X-ray tubehead
should be aimed downwards (approximately
5°-8° to the horizontal) to compensate for the
upwardly rising curve of Monson.
• The positioning should be reproducible.

• Assessment of caries and
restorations — films should
be well exposed and show
good contrast to allow
differentiation between
enamel and dentine and to
allow the enamel — dentine
junction (EDJ) to be seen.
• Assessment of periodontal
status — films should be
under-exposed to avoid burn-
out of the thin alveolar crestal
bone.

IDEAL RECEPTOR
POSITIONING
•The ideal requirements for the position of
the image receptor and the X-ray beam,
relative to a tooth include:
•The tooth under investigation and the
image receptor should be in contact or, if
not feasible, as close together as possible
•The tooth and the image receptor should
be parallel to one another

•The image receptor should be positioned
with its long axis vertically for incisors
and canines, and horizontally for
premolars and molars with sufficient
receptor beyond the apices to record the
apical tissues
•The X-ray tubehead should be positioned
so that the beam meets the tooth and the
image receptor at right angles in both the
vertical and the horizontal planes
•The positioning should be reproducible.

Factors related to recording of
the roentgen image of the object.

IDEAL FILM STORAGE
Ideally films should be stored:
• In a refrigerator in cool, dry conditions
• Away from all sources of ionizing radiation
• Away from chemical fumes including
mercury and mercury-containing compounds
• With boxes placed on their edges, to prevent
pressure artefacts.

IDEAL DARK ROOM
CONDITIONS
• General cleanliness (daily), but particularly of work
surfaces and film hangers (if used).
• Light-tightness (yearly), by standing in the
darkroom in total darkness with the door closed
and safelights switched off and visually inspecting
for light leakage

1. Darkroom lamp
2. Electric fan,
3. Rack for drying films,
4. Storage rack for intraoral
hangers,
5. Bulletin board,
6. Exposure and processing
chart for dental X-ray films,
7. Drip pan,
8. Shelf,
9. Timer,
10. Utility safe lamp,
11. Goose neck faucet,
12. Loading area,
13. Processing area,
14. Splash board,
15. Hot and cold water
valves,
16. 8 × 10 dental
processing tank,
17. Utility sink,
18. Supply cabinet for
chemicals, cassettes and
other accessoriesSchematic Darkroom Layout

• Safelights (yearly), to ensure that these do not cause fogging of
films.
• Checks are required on:
Type of filter — this should be compatible with the colour
sensitivity of film used, i.e. blue, green or ultraviolet
Condition of filters — scratched filters should be replaced
Wattage of the bulb — ideally it should be no more than 25 W
Their distance from the work surface — ideally they should be
at least 1.2 m (4 ft) away
Overall safety (i.e. their fogging effect on film)
The simple quality control measure for doing this is known as
the coin test.

Chemical solutions
These should be:
• Always made up to the manufacturers‘ instructions
taking special precautions to avoid even trace amounts
of contamination of the developer by the fixer, e.g.
always fill the fixer tank first so that any splashes into
the developer tank can be washed away before pouring
in the developer
• Always at the correct temperature
• Changed or replenished regularly — ideally every 2
weeks — and records should be kept to control and
validate these changes
• Monitored for deterioration. This can be done easily
using radiographs of a step-wedge phantom:

Cassettes
• Regular cleaning of intensifying screens with a
proprietary cleaner
• Regular checks for light-tightness, as follows:
• 1. Load a cassette with an unexposed film and place the
cassette on a window sill in the daylight for a few
minutes
• 2. Process the film — any ingress of light will have
fogged (darkened) the film

Cassettes
• Regular checks for film/screen contact, as follows:
• 1. Load a cassette with an unexposed film and a similar
sized piece of graph paper
• 2. Expose the cassette to X-rays using a very short
exposure time
• 3. Process the film — any areas of poor film/screen
contact will be demonstrated by loss of definition of the
image of the graph paper.
• A simple method of identification of films taken in
similar looking cassettes, e.g. a Letraset letter on
one screen.

Digital phosphor storage
plates
• Regular cleaning
• Regular visual checks for scratches or other defects

IDEAL VIEWING CONDITIONS
• Human visual system is capable of distinguishing
only about 60 gray levels at any time under ideal
viewing conditions.
• Considering the typical viewing environment in the
dental operatory, the actual number of gray levels
that can be distinguished falls to less than 30.
• So, ideal viewing conditions are required for better
diagnosis

• An even, uniform, bright light viewing screen
(preferably of variable intensity to allow viewing of
films of different densities) (see Fig. 18.1)
• A quiet, darkened viewing room
• The area around the radiograph should be masked
by a dark surround so that light passes only through
the film
• Use of a magnifying glass to allow fine detail to be
seen more clearly on intraoral films
• The radiographs should be dry.

DARK/ LIGHT RADIOGRAPH  IDEAL RADIOGRAPH

REDUCTION
• An overexposed or grossly overdeveloped
film will be too dark for convenient
viewing, owing to the excessive deposit of
silver which obscures the image detail.
• A photographic reducer contains an
oxidizing agent, potassium ferricyanide
which oxidizes the silver to silver
ferrocyanide, which in turn is dissolved by
the solution of sodium thiosulphate.

•This is known as the Farmer’s
Reducer and consists of two solutions:
•Solution A : Potassium ferricyanide 75
grams + Water to make 1000 ml.
•Solution B : Sodium thiosulphate crystals
240 grams. + Water to make 1000 ml.

•Method: Take one part of Solution A and
four parts of Solution B, and add twenty
seven parts of water.
•Immerse the radiograph in the mixed
solution and watch carefully. When the
film has been sufficiently reduced, it
should be washed in running water for 30
minutes.

•The process of reduction should be
carried out in a weak artificial light,
as bright light causes rapid
deterioration of the solution.
•The Solution A and Solution B
should be mixed just prior to their
use.

Chemical intensification
of radiographs
• A radiograph may be too light because of,
underexposure, under development or both.
• Instead of repeating the radiograph,
chemical intensification may be done.
• Most of the intensification methods act by
converting the silver which forms the image
into a compound which is more opaque,
more colored or of a different physical
form.

• A number of commercially available intensifying
solutions are present:
• In-4 Chromium intensifier.
• In-5 Silver intensifier
• Copper iodide intensifying solution.
• XR-10 intensifying solution.
• Line Toner solution— this is made of three solutions:
• Solution A : Diglycolic acid 60 grams
• Sodium Hydroxide 36 grams
• Water 750 ml
• Solution B: Boric nitrate 14 grams
• Potassium fluoride 1 gram
• Water 100 ml
• Solution C: Potassium ferricyanide 5 grams
• Sodium nitrite 1 grams
• Water 100 ml

• The processed radiograph which is of low
density is immersed in the intensifying
solution for a period of three to eight minutes
depending upon the density increase
required.

For IOPA
•The image should have acceptable
definition with no distortion or blurring.
•The image should include the correct
anatomical area together with the apices
of the tooth/teeth under investigation with
at least 3–4 mm of surrounding bone.
•There should be no overlap of the
approximal surfaces of the teeth.

•The desired density and contrast for film
captured images will depend on the clinical
reasons for taking the radiograph, e.g.
• to assess caries, restorations and the periapical
tissues films should be well exposed and show
good contrast to allow differentiation between
enamel and dentine and between the periodontal
ligament space, the lamina dura and trabecullar
bone.
•to assess the periodontal status films should
be underexposed to avoid burnout of the thin
alveolar crestal bone

•The images should be free of coning off
or cone cutting and other film handling
errors.
•The images should be comparable with
previous periapical images both
geometrically and in density and
contrast.

For OPG
•All the upper and lower teeth and their
supporting alveolar bone should be
clearly demonstrated
•The whole of the mandible should be
included
•Magnification in the vertical and
horizontal planes should be equal
•The right and left molar teeth should be
equal in their mesiodistal dimension

•The density across the image should be
uniform with no air shadow above the
tongue creating a radiolucent (black)
band over the roots of the upper teeth
•The image of the hard palate should
appear above the apices of the upper
teeth
•Only the slightest ghost shadows of the
contralateral angle of the mandible and
the cervical spine should be evident

•There should be no evidence of
artefactual shadows due to dentures,
earrings and other jewellery
•The patient identification label should
not obscure any of the above features
•The image should be clearly labelled
with the patient’s name and date of the
examination
•The image should be clearly marked
with a Right and/or Left letter.

For Bite-wing
• The image should have acceptable definition with no
distortion or blurring.
• The image should include from the mesial surface of the
first premolar to the distal surface of the second molar — if
the third molars are erupted then the 7/8 contact should be
included.
• The occlusal plane/bite platform should be in the middle of
the image so that the crowns and coronal parts of the roots
of the maxillary teeth are shown in the upper half of the
image and the crowns and coronal parts of the roots of the
mandibular teeth are shown in the lower half of the image,
and the buccal and lingual cusps should be superimposed.

•The maxillary and mandibular alveolar
crests should be shown.
•There should be no overlap of the
approximal surfaces of the teeth.
•The desired density and contrast for film
captured images will depend on the
clinical reasons for taking the
radiograph, e.g.
• to assess caries and restorations films
should be well exposed and show good
contrast to allow differentiation between
enamel and dentine and to allow the
enamel–dentine junction (EDJ) to be seen.

• to assess the periodontal status films should be
underexposed to avoid burn-out of the thin alveolar
crestal bone
•The image should be free of coning off or
cone cutting and other film handling errors.
•The image should be comparable with
previous bitewing images both
geometrically and in density and contrast.

CONCLUSION
• AN IDEAL RADIOGRAPH IS AN END PRODUCT OF
SEVERAL FACTORS WHICH NEEDS TO BE FOLLOWED
IN DAY TO DAY RADIOGRAPHY.
• IDEAL RADIOGRAPH HELPS NOT ONLY IN PROPER
DIAGNOSIS BUT ALSO IN PROPER TREATMENT
PLANNING AND ALSO TO SEE THE TREATMENT
OUTCOME.

REFERENCES
• WHITE AND PHAROAH - 6TH EDITION
• ERIC WHAITES – 3RD EDITION
• HERRING AND HOWERTON – 3RD EDITION
• WEUHRMANN – 5TH EDITION
• KHARJODKHER – 2ND EDITION

Ideal radiography

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