4. Terminology
RADIATION : It is energy that comes from the source and travels
through the space and may be able to penetrate various materials or
structure
Radiation is the emission and propagation of energy through the
space or a substance in the form of waves or particles
5. RADIOLOGY
The branch of medicine concerned with X-rays, radioactive materials
and ionizing radiations & the application of the principles of science
to diagnosis and treatment of disease
ROENTGENOLOGY
Is the study and use of roentgen rays as applied to medicine and
dentistry
6. RADIOGRAPHY:
The technique of producing a photographic image of an opaque
specimen by the penetration of radiation such as gamma rays, x-
rays, neutrons
RADIOGRAPH
A Picture (visible photographic record ) on film produced by the
passage of X-RAYS through an object or body also called X-ray film
DENTAL RADIOGRAPHY
The production of radiographs of teeth and adjacent structures by
the exposure of film to X-rays
7. The term radiation should not be confused with radiotherapy, which
is the process where by certain un stable elements undergo
spontaneous degeneration and produce high-energy waves called
gamma and particulate radiations
In dental radiology, we deal with x-ray radiations, however our
patients who are undergoing cancer therapy may receive radiation
from radioactive materials
9. X-rays:
"X-rays are weightless packets of pure energy, called photons, with
no electrical charge. They travel at the speed of light in a vacuum in
straight lines and exhibit both wave-like and particle-like behavior,
with a frequency range characteristic of X-ray radiation."
• A high energy radiation was produced by the collision of beam of
electrons with a metal target In a x-ray tube
• Beam of energy that has the power to penetrate substances and
record image shadows on photographic film
10. X-rays - are invisible waves or bundles of energy
that possess certain properties that allow us, among other things, to
see differences in densities in opaque objects
The use of X-rays is an intricate and essential part of dental
diagnosis and is applied in many of the diagnostic imaging systems
in both dentistry and medicine
The images produced are seen on either film or a digital display
device and are referred to as radiographs (or) images but not as X-
RAYS
X-rays are energy waves with no mass and are part of a grouping
called electromagnetic radiation
11. Properties of x- rays:
Electromagnetic waves
Produced by conversion of electrical energy in to radiation
Invisible
Emitted with various energy and wavelengths.
Travels in a straight line from their source at the speed of light.
Can travel in vaccum
Shorter the wavelength, higher the energy
Can penetrate opaque tissues and structures
Can affect a photographic emulsion or digital sensors ,which ,when processed
produce a visible image
Can adversely affect human tissue
12. ORIGIN
PROF. WILHELM CONRAD ROENTGEN discovered
a “NEW KIND OF RAY” on Friday, November 8, 1895
When he was testing the ability of cathode rays to
penetrate a vaccum tube (Hittorf Crooke’s tube).
Then he notices a faint glow rising from a paper
coated with a barium platinocyanide crystals. A glow
that increases when he moved the paper closer to the
tube and fades completely when he turns off the tube’s
power supply.
He christens this alien energy “ THE X-RAY ” because
of its unknown nature
1845 – 1923
Father of Radiology
13. Roentgen,like many of his colleagues was interested in the cathode
ray and type of light produced across a vaccum tube when
electrical current was applied
Because he was concerned with light,he was working in a darkened
room with black cardboard covering the Hittorf- Crookes tube and
there were many fluorescent plates in his laboratory
15. Discover of X-radiation
Roentgen was searching for invisible light (cathode rays) by
experimenting with a Crookes vacuum discharge tube
16. Before the discovery of x-rays roentgen had experimented with the
production of cathode rays (streams of electrons)
He used a vacuum tube, an electrical current, special screens
covered with a material that glowed when exposed to the radiation
He made the following observations about the cathode rays
The rays appeared as streams of colored light passing from one end
of tube to the other
The rays did not travel far outside the tube
The rays caused the fluorescent screens to glow
18. While experimenting in a darkened laboratory with a vacuum tube,
Roentgen noticed a faint green glow coming from a near by table. He
discovered that the mysterious glow or flourescence was coming
from screens located several feet away from the tube
Roentgen observed that distance between the tube and screens
was much greater than the distance between cathode rays travel
20. By placing the various objects in the path of X-RAY beam he could
produce images on the screen
Roentgen went on to expose and produce images on photographic
plates
21. Discover of X-radiation
Roentgen proceeded to
make the first radiograph of
human body; he placed his
wife’s hand on a
photographic
plate & exposed it to the
unknown ray for 15 minutes
22. Discover of X-radiation
Roentgen named his discovery X-ray, the ‘’X’’ referring to the
unknown nature & properties of such ray
Roentgen was awarded the first Nobel Prize ever awarded in
Physics (1901)
After years of Roentgen discovery,
X-ray roentgen ray, radiology roentgenology, &
radiographs roentgenographs
23. HISTORY
1) OTTO WALKHOFF
OTTO WALKHOFF of Braunsweig,Germany and WILHEM KONIG of
Frankfurt, Germany took the first dental radiograph within the 14
days of the anouncement of Rontgen’s Ray.
He took an ordinary glass photographic plate wrapped in black
paper and covered it with rubber dam, put it his mouth between teeth
and tongue so that he could steady the plate with the tongue.
24. Then lay on the floor for 25 minutes to expose the plate to x-ray
beam, the image he obtained was of the crowns of the maxillary and
mandibular teeth.
This was the first bitewing image.
In 1896, OTTO WALKHOFF and FRITZ GIESEL established the
first dental roentgenologic laboratory in the world.
25. 2.CHARLES EDMOND KELL DDS (1865-1928)
The first dental radiograph made in America was by Dr.CHARLES
EDMOND KELL in april 1896 (New Orleans Dentist) which he called
it as SKIAGRAPH (Shadow picture)
He was the first advocate of the right angle or paralleling technique
in taking intraoral radiograph
To exhibit a dental x-ray apparatus at a dental meeting.
To devised a film holder made of vulcanite to hold the film.
26. 3) DR.WILLIAMS HERBERT ROLLINS
DDS,MD.(1852-1929)
He was the first to
Investigate the properties of x-rays.
Reported burns to his hand
In less than 7 months he had designed, made, used and published a
description of an intraoral camera (cassette) and oral fluoroscope
Invent x-ray arm and bracket for dental office in 1896
27. Offered three precautionary measures to dental and medical x-ray users
1. Wear Radioopaque Glasses (leaded)
2. Enclose x-ray tube in a leaded housing
3. Irradiate only the area of interest
Suggested the use of selective filtration in 1903
Developed the concept of rectangular collimation
Described the lethal effects of x-ray beam in pregnant guinea pigs
He authored more than 200 articles “ NOTES ON X-LIGHT ” between 1897
to 1908.He is called as the “DENTISTRY’S FORGOTTEN MAN”
28. 4) WILLIAM D. COOLIDGE
In 1913,he was the first to develop the HOT CATHODE X-RAY
TUBE. This was the real breakthrough in the tube design in the
golden age of radiology.
Coolidge used a coil of tungsten as the source of electrons (as a
filament cathode) and a tungsten target at the anode in the new tube
called as “ COOLIDGE’S TUBE ”
Protype of X-Ray tubes used today
29. 5) DR.HOWARD RILEY RAPER
He was the first to
Introduce dental radiology in the dental school curriculum for
undergraduate (University of Indiana)
Writen books on dental radiography
- ELEMENTARY DENTAL RADIOGRAPH in 1913
- ELECTRORADIGRAPHIC DIGNOSIS in 1921
Develop BITEWING FILM in co-operation with Kodak Company in
1925.
Redefine the original bisecting technique and introduced the
Bitewing Technique.
30. 6) FRANK HARRISON
He was the first to
Make Special Vaccum Tube
Demonstrate the pulp chambers of the teeth
Made dental radiograph with 10 minutes of exposure
He was one of the first, as early as July 1896,to report the
occurrence of radiation injuries.
31. 7) WILLIAM JAMES MORTON
MD.(1845-1920)
He was one of the first to
Record dental radiograph in America
Reveal impacted tooth on the radiograph that was otherwise
invisible.
Suggest that radiation injuries are due to long exposures and
nearness of the patient to the tube because of inefficient x-ray
apparatus, so he used Crooke’s Tube at the minimum distance of
18 inches for his x-ray work.
32. In 1913, the first American Dental X-ray machine was manufactured
In 1923, the Victor X-ray Corporation which later became General
ElECTRIC X-ray Corporation and now Gendex Corporation
introduced a dental X-ray machine with a Coolidge tube in the head
of the unit cooled by oil immersion
33. •X-RAYS were produced in Roentgens vaccum tube by the
electric current applied to the tube which caused the ionization of
gas molecules in the tube, because of difference in electric
potential, the negative particles (electrons) were attracted to the
positive side of the tube, where they collided with the tube wall, X-
RAYS were produced
•Modern dental X-ray tubes employ the same principle with the
some modifications, the most significant being a higher voltage,
difference in potential and variable source of electrons (hot
filament)
34. Importance of dental radiographs
Dental radiographs are a necessary component of comprehensive
patient care
In dentistry, radiographs enable the dental professional to identify
many conditions that may otherwise go undetected and to see
conditions that can not be identified clinically
An Oral examination without dental radiographs limits the practitioner
to what is seen clinically- teeth and soft tissue
35. With the use of dental radiographs,the dental radiographer can
obtain a wealth of information about the teeth and supporting bone
Through the use of dental radiographs the dental radiographer can
detect disease
Many diseases and conditions produce no clinical signs and
symptoms and are typically discovered only through the use of
dental radiographs
To evaluate growth and development
To illustrate changes secondary to caries, periodontal diseases,
trauma
To document the condition of a patient at a specific point of time
36. HISTORY OF DENTAL RADIOGRPAHIC TECHNIQUES
The dental practitioners who developed these techniques include
Weston Price, a Cleveland dentist who introduced the bisecting
angle technique in 1904
Howard Riley Raper who redefined the original bisecting technique
and introduced the bisecting technique in 1925
The paralleling technique was first introduced by C.Edmund Kells in
1896 and then later in 1920 used by Franklin W,McCormack in
practical dental radiography
37. F. Gordon Fitzgerald the Father of modern dental radiography
revived interest in paralleling technique with the introduction of the
long cone paralleling technique in 1947
The Extraoral radiographic technique used most often in dentistry is
panoramic radiography
In 1933, Hisatugu Numata of Japan was the first to expose a
panoramic radiograph
38. HISTORY OF DENTAL RADIOGRPAHIC
TECHNIQUES
Yrjo Patero of Finland is considered to be the Father of Panoramic
radiography
He experimented with a slit beam of radiography, intensifying
screens, and rotational techniques
39. HISTORY OF DENTAL X-RAY FILM
From 1896 to 1913 dental x-ray packets consisted of glass
photographic plates or film cut in to small pieces and hand-wrapped
in black paper and rubber
The hand wrapping of intra oral dental x-ray packets was a time
consuming procedure
In 1913 Eastman kodak company manufactured the first prewrapped
intraoral films and consequently increased the acceptance and use of
x-rays in dentistry
The first machine-made periapical film packets became available in
1920
The films – less than 2%
40. HISTORY OF DENTAL X-RAY EQUIPMENT
In 1913,William D.Coolidge, an electrical engineer developed the
first hot – cathode x-ray tube, high vacuum tube that contains a
tungsten filament, coolidges x-ray tube became the prototype for all
modern x-ray tubes and revolutionised the generation of x-rays
In 1923,miniature version of x-ray tube was placed inside the head of
an x-ray machine and immersed in oil
1923- victor X-RAY Corporation of chicago
1933-General electric
1957- variable kilovoltage
42. Uses of Dental Radiographs
To detect lesions, diseases & conditions of the teeth &
surrounding structures that cannot be identified
clinically
To confirm or classify suspected disease
To localize lesions or foreign objects
To provide information during dental procedures
To evaluate growth & development
To illustrate changes secondary to caries, periodontal
disease, & trauma
To document the condition of a patient at a specific point
in time
52. PARTS AND COMPONENTS OF THE DENTAL X-RAY
MACHINE
General. parts of the dental x-ray machine include a control panel (usually
mounted behind a protective shield); a tube head, which houses the dental x-
ray tube; and a flexible extension arm from which the tube head is
suspended.
54. The Control Panel. The components of the control panel are switches, dials,
gauges, and lights. Basically, each control panel has the same function, the
arrangement and location of these components will differ, depending upon the
make, model, and year of construction of the dental x-ray unit. An operator's
manual is issued with each unit. The operator should study it until he is familiar
with its operational capability.
The Extension Arm. The tube head is attached to the metal extension arm by
means of a yoke that can revolve 360 degrees horizontally where it is connected.
The construction of the yoke also provides vertical movement as well.
The Tube Head. Inside the metal tube housing is the x-ray tube. This tube emits
radiation in the form of photons or x-rays. X-ray photons expose the film. In
addition to exposing the film, it also exposes the patient to radiation. Unless
certain protective measures are taken, the x-ray technician may also be exposed
56. THREE STEP PROCESS OF X-RAY PRODUCTION
The First Step. The first step in x-ray production is to turn on the
machine. (If there is doubt on the part of the x-ray technician
concerning the operation of the unit, reference should be made to
the operator's manual.) When the unit is turned on, the filament of
the cathode is heated by electrical current, causing it to emit
electrons
57. THREE STEP PROCESS OF X-RAY
PRODUCTION
The Second Step. For the second step of this three-step process, high voltage is
passed across the x-ray tube. When this is done, the electrons or electron cloud
from the filament are drawn across the opening toward the anode. The anode is
made of tungsten and is sometimes called the tungsten target. Figure depicts the
electrons speeding toward the anode (tungsten target).
Electrons speeding toward
the anode (tungsten target)
58. The Third Step. The third and final step in this three-step
process is the collision of electrons with the anode (tungsten
target). This rapid deceleration of electrons produces x-rays,
also referred to as photons. Figure represents electrons striking
the anode (tungsten target) and producing x-ray photons.
59. RADIATION PROTECTION
General. Filtration and
collimation of the x-ray beam
are very important safety
measures. The filter and
collimator (diaphragm) block
the majority of the unwanted
x-ray photons. The diagram
will identify the location of
these two devices.
#15:The x-ray were produce whenever and wherever the cathode activated.
The ray penetrate substances opaque to light.
Penetrating power depend upon the density of the substances.
#42:Lesion is abnormal tissue found on or in the organism, usually damaged by disease or trauma.
