Radiation as a friend or foe

RADIATION as
a friend or
foe
• ASHISH RANGHANI
• PG PART 2
• GDCH, AHMEDABAD
UNDER GUIDANCE OF
DR. J.S SHAH
PROFESSOR AND HEAD
ORAL MEDICINE AND RADIOLOGY
GDCH
DATE- 10/02/2017

CONTENTS
• Introduction
• Radiation and Types of Radiation
• Sources of Radiation
• Benefits And Risks of Radiation
• Uses of Electromagnetic waves
• Uses Of Radiation In Dentistry
• Radiotherapy
• Nuclear Medicine
• Types Of Radiation Effects
• Deterministic Effects
• Stochastic Effects
• Short Term Effects
• Long Term Effects
• In-utero Effects
• Radiation Effect On Cells
• General Effect Of Radiation
• Radiation Effect On Oral Cavity

DISCOVERY OF X-RADIATION
• Wilhelm Conrad Roentgen on
November 8, 1895 discovered x-rays
One of roentgen 1st experiments in
1895 was a film of his wife Bertha's
hand with a ring on her finger

• The first use of X rays was in medical diagnosis,
within six months of their discovery in 1895
• So a benefit from the use of radiation was
established very early on, but equally some of the
potential dangers of radiation became apparent in
the doctors who overexposed themselves to X rays
in the early 1900s.

What is radiation?....1,2
• Radiation refers to the propagation of energy
through space or a medium
• Ionizing radiation includes Gamma rays, X rays and
the radiation from radioactive materials.
• Non-ionizing radiation includes ultraviolet light,
radiant heat, radio waves and microwaves

Electromagnetic Spectrum1,2
• Gamma rays
• X – rays
• Ultraviolet
• Visible light
• Infra-red
• Microwaves
• Radio waves
Highest frequency
Shortest wavelength
Lowest frequency, Longest wavelength

Electromagnetic Waves
Low HighENERGY
Radio
waves
Microwaves
Radar
Infrared
Visible
light
Ultra-violet
X-ray
Gamma-ray
Non-ionizing radiation
Ionizing radiation

Sources of ionizing radiation
Natural sources
• Cosmic rays
• Gamma rays from the
Earth
• Radon decay products
in the air
• Various radionuclides
found naturally in food
and drink
Artificial sources
• Medical X rays
• Fallout from the testing
of nuclear weapons in
the atmosphere
• Discharges of
radioactive waste from
the nuclear industry
• Industrial gamma rays
Radiation, people and environment, international atomic energy agency

source Dose (msv)
Nuclear industry
Uranium mining
Fuel fabrication
Nuclear reactors
Reprocessing
Medical uses
Radiology
Dentistry
Nuclear medicine
Radiotherapy
Industrial sources
Irradiation
Radiography
Isotope production
Luminizing
4.5
1.0
1.4
1.5
0.5
0.06
0.8
0.6
0.1
1.6
1.9
0.4
The average dose overall to
occupationally exposed workers
from artificial sources is less than
1 mSv in a year

Benefits and risks
• The discovery of ionizing radiation and radioactive
materials has led to dramatic advances in medical
diagnosis and treatment, and they are used for a
wide range of procedures in industry, agriculture,
and research.
• They can be harmful to human beings, and people
must be protected from unnecessary or excessive
exposures.

USES OF GAMMA RAYS 6
• Gamma rays kill
microbes, and are used
to sterilise food so that it
will keep fresh for longer.
This is known as
"irradiated" food
Gamma rays are also used to
sterilise medical equipment
Sterilization of plastic
syringes, hypodermic needles,
scalpels, surgical blades and
adhesive dressings & sutures
Gamma rays are the highest energy electromagnetic wave.

Gamma sterilization of human
tissue grafts
In industry, radioactive "tracer" substances can be put
into pipes and machinery, then we can detect where the
substances go
Study the nucleus in atoms

Ultraviolet Waves 6
• UV Light that is at a higher frequency and energy than violet light
• The main source of ultra-violet radiation is sunlight
• UV light can kill micro-organisms
• Ultra-violet radiation is used in hospitals to sterilize the surgical instruments and
operating theatres as it kills bacteria and viruses
• Too much exposure can cause:
• Sunburn and skin cancer
• As it damages cell DNA

Infra-red waves 6
• Infrared waves are heat waves
• Night vision goggles detect infrared
waves and allow the user to see the
movement of objects in the dark.
• Many TV remotes use infrared
• It shows a thermo-detector which is
placed outside hospitals/airport to
identify the warm and cool parts of a
person by analyzing infra-red radiation
emitted from the person’s body. And
through this we can see if someone is
having a fever
• For navigation through fog & haze as
it is less easily scattered compared to
visible light

Microwaves6
• One of their most common
uses is in microwave ovens.
• Other uses of microwaves:
• Radar communication
• Analysis of fine details of
molecular and atomic
structure
• Telephone communication
(mobile phones, etc)

Why are Radio Waves Important?6
The biggest use for radio
waves are communication,
such as phones, texts,
emails and instant
messaging.
Radio waves, that we use
every day. Such as-
• Television
• Wireless networks
• Mobile phones
• GPS systems
• Police radios
• Radio controlled toys

Dental uses of radiation
• Ionizing radiation has two very different uses in
dentistry — for diagnosis and therapy
• X-rays plays a vital role in the practice of dentistry
1. As part of routine examination,
2. Diagnostic purpose,
3. Treatment planning or for follow-up evaluation of
the patients
• Much higher doses are required to treat malignant
diseases in combination with other forms of
treatment.
• Oral Radiology-Principles and Interpretation, White and pharoh-6th Edition

Diagnostic radiology
• Radiographs are important in the routine investigation of dental
caries and its sequelae,
• Evaluation of periodontal diseases,
• Identification of osseous pathologies such as cysts and tumors
• Evaluation of traumatic injuries involving the jaws and facial
bones
• Radiographs are also useful in the evaluation of growth and
development
• From the foregoing it is very clear that radiographs are
sometimes referred to as the main diagnostic aids of the
clinician

DENTAL CARIES
• Intraoral radiography can reveal caries
lesions that otherwise might go
undetected, especially in case of proximal
lesions
• Various radiographs for caries detection:
• Bitewing: Aids in detecting caries in
interproximal areas and distal ends of
premolars and molars, and caries at CE
junction.
• Periapical: Aids in detecting gross carious
lesions, root caries and changes in the
apical and inter radicular bone due to
caries.
• OPG: Useful to examine a case with
multiple carious teeth or rampant caries.

Radiographic Assessment of Periodontal Conditions
Radiographs are especially helpful in the
evaluation of the following features:
• Amount of bone present
• Condition of the alveolar crests
• Bone loss in the furcation areas
• Width of the periodontal ligament space
• Poorly contoured or overextended
restorations
• Root length and morphology and the
crown-to-root ratio
• Open interproximal contacts, which may
be sites for food impaction

Inflammatory lesions of the jaws
• Periapical
inflammatory
lesions associated
with a mandibular
first molar
Occlusal film
demonstrates
chronic phase of
osteomyelitis
Panoramic film reveals
large sequestra (black
arrow) and a periosteal
reaction at the
inferior border of the
mandible in a case of
chronic osteomyelitis

Cysts of Jaw
Dentigerous cyst that is
expanding distally from
the involved third molar
Radicular Cyst

Benign Tumors of the Jaws
• Radiologic examination will
provide information regarding
the extent of the lesion, and
sometimes the characteristics are
so specific that a preliminary
diagnosis of the type of benign
tumor can be made

Malignant Diseases of the Jaws
• There are various diagnostic imaging modalities available to aid in
the diagnosis.
• Intraoral radiographs still provide the best image resolution and are
able to reveal malignant changes
• Panoramic radiographs provide an overall assessment of the
maxillofacial osseous structures and can reveal relevant changes such
as destruction of the boundaries of the maxillary sinus.
• Computed tomography (CT) images can provide a superior three-
dimensional analysis of the osseous structures and better determine
the position and extent of the tumor
• Positron emission tomographic (PET) scans, a technique capable of
detecting abnormal cellular metabolic activity associated with
malignant tumors, have been fused with CT images to provide an
accurate location of the tumor in preparation for radiotherapy.
• Magnetic resonance imaging (MRI) has provided three-dimensional
soft tissue images of tumors and information regarding perineural
spread and involvement of lymph nodes

• The purposes of TMJ imaging
are to evaluate the integrity
and relationships of the hard
and soft tissues, confirm the
extent or stage of progression
of known disease, and
evaluate the effects of
treatment

Trauma to Teeth and Facial Structures
• Radiologic examination is
essential for evaluating trauma
to the teeth and jaws.
• The presence, location, and
orientation of fracture planes
and fragments can be
determined, and the involvement
of nearby vital anatomic
structures can be assessed.
• Furthermore, foreign objects that
have become embedded within
the soft tissues as a result of
trauma can be detected.

SIALOGRAPHY
• Sialography is the radiographic
visualization of the salivary gland
following retrograde instillation of
soluble contrast material into the
ducts before imaging with plain
films, fluoroscopy, panoramic
radiography, CT
• Iodine which is used as a contrast
media
CONTRAST MEDIA
Two types of contrast media are presently available for contrast studies
Water soluble- Sinografin
Oil based- Ethiodol

Arthrography
• Arthrography is a technique
in which an indirect image of
the disk is obtained by
injecting a radiopaque
contrast agent into the joint
spaces under fluoroscopic
guidance.
• Magnetic resonance imaging
(MRI) has replaced
arthrography and is now the
imaging technique of choice
for the soft tissues of the
TMJ

SCINTIGRAPHY (Nuclear medicine)
• Scintigraphy with technetium (Tc) 99m is a dynamic and
minimally invasive diagnostic test to assess salivary gland
function and to determine abnormalities in gland uptake
and excretion
• Technetium is a pure gamma ray– emitting radionuclide
that is taken up by the salivary glands
• It has also been used to aid in the diagnosis of ductal
obstruction, sialolithiasis, gland aplasia and Sjögren’s
syndrome

• Salivary imaging is performed following the
injection of Tc 99m pertechnetate
• The uptake, concentration, and excretion of the
pertechnetate by the major salivary glands and
other organs is imaged with a gamma detector that
records both the number and the location of
gamma particles released in a given field during a
period of time
• A special detector called a gamma camera is used
to observe how the organs or tissue behave or how
quickly the radionuclide moves

Scintigraphy, 99m Tc-
pertechnetate
scan of the salivary glands (right
and left anterior oblique views)
demonstrates increased uptake of
radioisotope in the right parotid
gland (black arrowhead)
Scintigram taken after
administration
of a sialogog (lemon juice)
demonstrates
retention of isotope in right
parotid gland (white arrowheads).
This is a typical presentation of
salivary stasis

OBJECT LOCALIZATION
Two Dimensional Techniques
• Tube Shift Technique / Clark`s Technique
• Occlusal Radiography
• Right Angle Technique / Miller`s Technique
Three Dimensional Techniques
• Computed Tomography Scan (CT)
• CBCT ( Cone Beam Computed Tomography)
Frenny karjodkar, Text book of oral radiology. 2nd edition.
Methods Used to Localize Objects

Interpretation
When the dental structure or object seen in the second
radiograph appears to have moved in the same direction as
the shift of the position indicating device (PID), the structure
or the object in question is said to be positioned lingually.
But, if the object appears to have moved in a direction
opposite to the shift of the PID, then the object in question
is said to be positioned buccally.
SLOB rule: Same side Lingual - Opposite side Buccal.

Right angle technique
• Here two projections are taken at right angles to
each other, which helps to localize an object in the
maxilla or mandible.
Method
• A periapical radiograph is taken to show the position of
the object superio-inferiorly and anteroposteriorly.
• Next, an occlusal radiograph is taken which will show
the object’s buccolingual and anteroposterior
relationship.

A. The object appears to be located in
bone on the periapical radiograph.
B. The occlusal radiograph reveals
that the object is actually located
in the soft tissue lingual to the
mandible

Occlusal Radiography
• Locate roots and
supernumerary, unerupted,
and impacted teeth
• Stones in the ducts of
sublingual and
submandibular glands
• To determine the medial
and lateral extent of
disease
• Fractures of the mandible
and maxilla

ASSESSMENT OF FOLLOWING ANATOMIC PARAMETERS ON
RADIOGRAPHS
• Height of the alveolar bone
• Buccolingual dimension of the ridge at the implant
site
• Determine bone quality
• Determine long axis of alveolar bone
• Determine Jaw boundaries
• Pathology detection
• Position of inferior alveolar canal
Dental Implants

• periapical radiograph of
two successful dental
implants
• The close apposition of
the bone to the surface
of each implant.
Periapical radiograph of
bone loss around a root-
form dental implant (thin
radiolucent band
surrounding the implant),
indicating
failure of osseous
integration.
Periapical view of a
fractured endosseous
implant

What is Radiotherapy ?
• It is the medical use of ionizing radiation, generally
as part of cancer treatment to control or kill
malignant cells by destroying reproductive integrity
of the malignant cells.
• Radiotherapy can be given as
1. External radiotherapy (Teletherapy)
2. Internal radiotherapy (Brachytherapy)
Head and Neck Cancer Treatment, RadiologyInfo.org Reviewed: Mar-21-2016

• Head and neck cancer represents the 6th most
common malignancy & accounts for approx. 6% of
new cancer cases annually worldwide.
• The first patient was treated with radiation in 1896,
two months after the discovery of the X-ray.

• Patients with early-stage head and neck cancers are
treated with one modality—either radiation
therapy or surgery.
• Patients who have more extensive cancers are
often treated with chemotherapy and radiation
therapy.
• Sometimes, patients are treated with surgery
followed by postoperative radiation therapy and
chemotherapy

Intensity-modulated radiation therapy (IMRT)
• An advanced mode of high-precision radiotherapy
that utilizes computer-controlled x-ray accelerators
to deliver precise radiation doses to a malignant
tumor or specific areas within the tumor.
• The radiation dose is designed to confirm to the
three-dimensional (3-D) shape of the tumor by
modulating—or controlling—the intensity of the
radiation beam to focus a higher radiation dose to
the tumor while minimizing radiation exposure to
healthy cells

External beam therapy (EBT)
• A method for delivering a beam of high-energy x-rays to
the location of the tumor.
• The beam is generated outside the patient usually by a
linear accelerator targeted at the tumor site.
• These x-rays can destroy the cancer cells and careful
treatment planning allows the surrounding normal
tissues to be spared.
• No radioactive sources are placed inside the patient's
body.

Other Uses of X rays-
• Examination of Baggage in Airports :
The use of X-rays in airports to
examine for the presence of
dangerous weapons or bombs is a
routine practice
• Industrial Use
• X-rays reveal structural information
about the material
• It can therefore be used to detect
structural deficits or cracks in metal
objects that are likely to be missed
by the human eye

Study the crystal structure of
crystalline substances
Examination and analysis of paintings, where
studies can reveal such details as the age of a
painting and underlying brushstroke
techniques that help to identify or verify the
artist

Health Concerns
• The widespread use of x-rays led to serious
injuries.
• Some early experimenters did tie x-ray exposure
and skin burns together.

How do X-rays cause damage?
• Two main mechanisms are thought to be
responsible:
• Direct damage to specific targets within the cell
• Indirect damage to the cell as a result of the
ionization
of water or other molecules within the cell.
• The first warning of possible adverse effects of x-
rays came from Thomas Edison, William J Morton,
and Nikola Tesla who each reported eye irritations
from experimentation with x-rays and fluorescent
substances.

Deterministic effects
• Nonstochastic effects (deterministic effects) are somatic
effects that have a threshold and that increase in severity
with increasing absorbed dose.
• Examples of nonstochastic effects include erythema, loss of
hair, cataract formation, and decreased fertility.
• Compared with stochastic effects, deterministic effects
require larger radiation doses to cause serious impairment
of health.
Eric Whaites.Essentials of Dental Radiography and Radiology.4th edition

Stochastic effects
• Their development is random and depends on the laws of chance or
probability. Examples of somatic stochastic effects include leukaemia
and certain tumours.
• These damaging effects may be induced when the body is exposed to
any dose of radiation.
• There is no threshold dose, and that every exposure to ionizing
radiation carries with the possibility of inducing a stochastic effect.

Short-Term Effects
• Following the latent period, effects that are seen within
minutes, days, or weeks are termed short-term effects.
Short-term effects are associated with large amounts of
radiation absorbed in a short time (e.g., exposure to a
nuclear accident or the atomic bomb).
• Acute radiation syndrome (ARS) is a short-term effect and
includes nausea, vomiting, diarrhea, hair loss, and
hemorrhage.
• Short-term effects are not applicable to dentistry.

Long-term effects
• Effects that appear after years, decades, or generations are
termed long-term effects.
• Long-term effects are associated with small amounts of
radiation absorbed repeatedly over a long period.
• Repeated low levels of radiation exposure are linked to the
induction of cancer, birth abnormalities, and genetic
defects.
Eric Whaites. Essentials of Dental Radiography and Radiology.4th edition

BIOLOGICAL EFFECTS
EFFECT ON CELLS
1.DNA
2.CYTOPLASM
3.NUCLEUS
4.CHROMOSOMES
GENERAL EFFECT OF
RADIATION
1.SKIN
2.BONE MARROW
3.Testicles
4.GONADAL
5.EYE
EFFECT ON ORAL TISSUES
1.ORAL MUCOSA-MUCOSITIS
2.TASTE BUDS
3.SALVARY GLANDS-
4.TEETH
5. RADIATION CARIES
6.BONES
7. MUSCULATURE
EFFECT ON WHOLE BODY
1.ACUTE RADIATION SYNDROME

CYTOPLASM
 Increased permeability of plasma membrane to sodium
and potassium ions.
Swelling and disorganization of mitochondria.
Focal cytoplasmic necrosis.

NUCLEUS
• Nucleus is more radiosesitive than the cytoplasm
• Inhibition of cell division

Chromosome Aberrations
If radiation exposure
occurs after DNA synthesis
(I,e G2 or late s)only one
arm of the effected
chromosome is broken
If radiation occurs before
DNA synthesis (G1 or early
S) both arms are effected

The survivors of the atomic
bombings of Hiroshima and
Nagasaki have
demonstrated chromosome
aberrations in circulating
lymphocytes more than
two decades after the
radiation exposure.

SKIN
Physical foundations of radiology, Otto glasser, Third edition
Doses up to 1000 R or so given within a
few days leave little or no permanent
mark
Two or three times this amount may
leave permanent tanning and some
superficial blood vessel damage
Hair loss may be permanent and some
sweat gland destroyed
Hair loss

Skin: The reaction of the skin to radiation may be categorized as:
• Essentials of Oral and maxillofacial radiology, Freny R Karjodkar
Early or acute signs
• Increased susceptibility to
chapping
• Intolerance to surgical
scrub
• Blunting and leveling of
finger ridges
• Brittleness and ridging of
finger nails
Late or chronic signs:
• Loosening of hair and
epilation
• Dryness and atrophy of skin,
due to destruction of the
sweat glands
• Progressive pigmentation,
telangiectasis and keratosis
• Indolent type of ulcerations
• Possibility of malignant
changes in tissue

HEMATOPOIETIC
INJURY
The usual picture of blood reaction to
radiation is leukopenia, which in some cases
may progress to leukemia, anemia,
lymphopenia, and loss of specific immune
response
The primary somatic risk from dental
radiography is leukemia induction, especially
in young individuals.
This is because at birth all bones contain
only red bone marrow. younger individuals
are at a greater risk of developing leukemia.

Eyes
• Epilation of eyelashes
• Inflammation, fibrosis and decreased flexibility
of the eyelid
• Damage to the lacrimal glands, leading to
dryness
• Ulceration of the cornea
• Initiation of cataract formation from the
periphery towards the center

Testicles
• Permanent sterility may be produced by acute dose
of 500 r to the reproductive organs
• Suppression of germinal activity
• Alteration in fertility

ORAL MUCOUS MEMBRANE
• The oral mucous membrane
contains a basal layer
composed of rapidly dividing,
radiosensitive stem cells.
• Near the end of the second
week of therapy, as some of
these cells die, the mucous
membranes begin to show
areas of redness and
inflammation (mucositis).
• Oral Radiology-Principles and Interpretation, White
and pharoh-6th Edition

• As then therapy continues, the
irradiated mucous membrane begins
to separate from the underlying
connective tissue, with the formation
of a white to yellow
pseudomembrane (the desquamated
epithelial layer).
• At the end of therapy the mucositis is
usually most severe, discomfort is at
a maximum, and food intake is
difficult.
• Oral Radiology-Principles and Interpretation, White
and pharoh-6th Edition

Taste Buds
• Taste buds are sensitive to radiation.
• Patients often notice a loss of taste
acuity during the second or third
week of radiotherapy.
• Bitter and acid flavors are more
severely affected when the posterior
two thirds of the tongue is irradiated
and salt and sweet when the anterior
third of the tongue is irradiated.
• Taste loss is reversible and recovery
takes 60 to 120 days

SALIVARY GLANDS
• The parenchymal component
of the gland is sensitive to
radiation. The gland
demonstrates progressive
fibrosis adiposis, loss of fine
vasculature and simultaneous
parenchymal degeneration.
• Parotid gland is more radio
sensitive than the other glands

• There is marked decrease in the salivary flow.
• The composition of saliva is affected.
• There is increased concentration of sodium,chloride,
calcium, magnesium ions and proteins.
• The saliva loses its lubricating properties.
• The mouth becomes dry and tender due to xerostomia.
• The pH of saliva is decreased which may initiate
decalcification of enamel.
• A compensatory hypertrophy of the salivary gland may
take place and the xerostomia may subside after six to
twelve months after therapy.

Teeth
Exposure
Before calcification
completion - tooth bud may
be damaged
• At later stage of
development - may
arrest growth
Pulp shows decrease in vascular elements, with accompanying
fibrosis and atrophy
Pulpal response to infection, trauma, and various dental
procedures appears compromised

• Children receiving radiation therapy to the jaws may show
defects in the permanent dentition such as retarded root
development, dwarfed teeth, or failure to form one or
more teeth
• Eruptive mechanism of teeth is relatively radiation
resistant
• Adult teeth are resistant to the direct effects of radiation
exposure
• Radiation has no direct effect on the crystalline structure
of enamel, dentin, or cementum, and radiation does not
increase their solubility.

RADIATION CARIES
• Radiation caries is a rampant form of dental decay that may
occur in individuals who receive a course of radiotherapy
that includes exposure of the salivary glands
• Patients receiving radiation therapy to oral structures have
increases in Streptococcus mutans,Lactobacillus, and
Candida .
• Caries results from changes in the salivary glands and saliva,
including
• Reduced flow,
• Decreased pH,
• Reduced buffering capacity,
• Increased viscosity, and altered flora.

TYPES
• Clinically, three types of radiation caries exist.
• The most common is
widespread
superficial lesions
attacking buccal,
occlusal, incisal, and
palatal surfaces
• Another type
involves primarily
the cementum and
dentin in the cervical
region.
• These lesions may
progress around the
teeth
circumferentially
and result in loss of
the crown
• A final type appears
as a dark
pigmentation of the
entire crown. The
incisal edges may be
markedly worn

Radiation has a rapid effect on the
salivary glands
• In the first two weeks,
with a cumulative RT
dose of 20 Gy, around
80% of salivary function
is lost
• Above 58 Gy there was
a complete loss of
salivary gland function

Bone
Radiation acts by destroying
osteoblasts and to a lesser extent
osteoclasts
Subsequent to irradiation, Normal marrow may be
replaced with fatty marrow and fibrous connective
tissue.
The marrow tissue becomes hypo
vascular, hypoxic, and hypo cellular

• Osteoradionecrosis is the most serious clinical complication
that occurs in bone after irradiation.
• The decreased vascularity of the mandible renders it easily
infected by microorganisms from the oral cavity
• This bone infection may result from radiation-induced
breakdown of the oral mucous membrane, by tooth
extraction, a periodontal lesion, or from radiation caries
• This infection may cause a non healing wound in irradiated
bone
• It is more common in the mandible than in the maxilla,
probably because of the richer vascular supply to the
maxilla and the fact that the mandible is more frequently
irradiated
• The higher the radiation dose absorbed by the bone, the
greater the risk for osteoradionecrosis.

Musculature
• Restriction in mouth opening usually starts about 2 months after
radiotherapy is completed and progresses thereafter
• An exercise program may be helpful in increasing opening distance.
Radiation may causes inflammation and fibrosis
resulting in contracture and trismus in the
muscles of mastication
Usually the masseter or pterygoid muscles are
involved.

ACUTE RADIATION SYNDROME
 Acute Radiation Syndrome (ARS) is an acute illness caused
by irradiation of the entire body (or most of the body) by a
high dose of penetrating radiation in a very short period of
time (usually a matter of minutes)

Acute Radiation Syndrome
DOSE (Gy) MANIFESTATION
1 to 2 Prodromal symptoms
2 to 4 Mild hematopoietic symptoms
4 to 7 Severe hematopoietic symptoms
7 to 15 Gastrointestinal symptoms
>50 Cardiovascular and central nervous system symptoms

STAGES OF ARS
• Prodromal stage (N-V-D stage): The classic
symptoms for this stage are nausea, vomiting,
as well as anorexia and possibly diarrhea
(depending on dose), which occur from
minutes to days following exposure. The
symptoms may last (episodically) for minutes
up to several days
• Latent stage: In this stage, the patient looks
and feels generally healthy for a few hours or
even up to a few weeks
• Manifest illness stage: In this stage the
symptoms depend on the specific syndrome
and last from hours up to several months
• Recovery or death: Most patients who do not
recover will die within several months of
exposure. The recovery process lasts from
several weeks up to two years

Bone marrow (hemopoietic) syndrome:
• (2 to7 Gy) Here severe damage may be caused to the circulatory
system.
• The bone marrow being radiosensitive, results in fall in the
number of granulocytes, platelets and erythrocytes.
• Granulocytes, with short lives in circulation, fall off in a few days,
whereas red blood cells, with long lives in circulation, fall off
slowly
• Clinically this is manifested as lymphopenia, granulocytopenia and
hemorrhage due to thrombocytopenia and anemia due to
depletion of the erythrocytes.

GASTROINTESTINAL SYNDROME
• The gastrointestinal syndrome is caused by whole-body
exposures in the range of 7 to 15 Gy, which causes
extensive damage to the gastrointestinal system in
addition to the hematopoietic damage described
previously
• Because of the denuded mucosal surface, there is loss
of plasma and electrolytes, loss of efficient intestinal
absorption, and ulceration of the mucosal lining with
hemorrhaging into the intestines
• These changes are responsible for the diarrhea,
dehydration, and loss of weight
• Endogenous intestinal bacteria readily invade the
denuded surface, producing septicemia

• At about the time that developing damage to the
gastrointestinal system reaches a maximum, the effect of
bone marrow depression is beginning to be manifested.
• The result is a marked lowering of the body ’s defense
against bacterial infection and a decrease in effectiveness of
the clotting mechanism.
• The combined effects of damage to these hematopoietic
and gastrointestinal stem cell systems cause death within 2
weeks from fluid and electrolyte loss, infection, and possibly
nutritional impairment.
• Thirty of the firefighters at the accident site at Chernobyl,
Ukraine, died in the first few months of the hematopoietic
or gastrointestinal syndrome

Cardiovascular and central nervous system
syndrome
• (More than 50 Gy): This produces death within one or two
days.
• Individuals show incordination, disorientation and
convulsions suggestive of extensive damage to the nervous
system.

Effects on the unborn child
• Embryos and fetuses are considerably more radio-sensitive than
adults because most embryonic cells are relatively undifferentiated
and rapidly mitotic
• The developing fetus is particularly sensitive to the effects of
radiation, especially during the period of organogenesis (2–9 weeks
after conception).
• These effects are deterministic in nature
• Exposures in the range of 2 to 3 Gy during the first few days after
conception are thought to cause undetectable death of the embryo.
• The period of maximal sensitivity of the brain is 8 to 15 weeks after
conception.

• The major problems are:
1.Congenital abnormalities or death associated with
large doses of radiation
2.Mental retardation associated with low doses of
radiation.
There is also an Increased risk for childhood cancer,
(leukemia and solid tumors), after irradiation in
utero.

X-ray examination Estimated risk
of fatal cancer
Dental intraoral (x 2) 1 in 2 000 000
Dental panoramic
tomograph
1 in 2 000 000
Skull (PA) 1 in 670 000
Skull (Lat) 1 in 2 000 000
Chest (PA) 1 in 1 000 000
CT chest 1 in 2500
CT head 1 in 10000
A broad estimate of the magnitude of
the risk of developing a fatal radiation-
induced cancer, from various X-ray
examinations, was published in the
UK in 1999 by the NRPB in their
booklet
Guidelines on Patient Dose to Promote the Optimisation of Protection for Diagnostic
Medical Exposures, 1999

Chernobyl accident
• Despite all the safety
measures applied in using
radiation and radioactive
materials, accidents can
happen
• An explosion in a nuclear
reactor at the Chernobyl
nuclear power plant on 26
April 1986 caused the release
of substantial quantities of
radionuclides during a period
of ten days
• As the contaminated air
spread throughout Europe
and beyond, local weather
conditions largely determined

• The accident had a catastrophic effect locally and high
radiation exposures of emergency workers led to the
deaths of 31 people.
• The firemen received large external doses from
deposited radionuclides, between 3 and 16 Sv, and
contamination on their skin lead to severe erythema
• A further 209 people were hospitalized of whom 106
were diagnosed as having acute radiation sickness
• The most significant radionuclides were iodine-131,
caesium-134 and caesium-137

• Between 1945 and 1999 there were some 140
serious reported accidents involving excessive
radiation exposure in the nuclear industry, military
facilities, hospitals, research facilities, and general
industry. The most frequent occurrence (about 70
in total) is the mishandling or misappropriation of
sealed sources used for radiography in industry and
radiotherapy in hospitals

REFERENCES
1.White and pharoh-Oral Radiology-Principles and
Interpretation 6th
2.Essentials of Oral and maxillofacial radiology, Freny R
Karjodkar
3.Eric Whaites.Essentials of Dental Radiography and
Radiology.4th edition.
4. Physical foundations of radiology, Otto glasser, Third
edition
5. Head and Neck Cancer Treatment, RadiologyInfo.org
Reviewed: Mar-21-2016
6. Radiation, people and environment, international atomic
energy agency

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