1. •Radiation injury causes changes in the
living tissues causing radiation sickness
•Somatic effects -harmful to the person
•genetic effects - reflected in the offspring.
2. 1. Radiation decomposition i.e. splitting of
water into H+ and OH- and also splitting
of other solvents of the body.
2. kinetic energy of the incident photons
heats up the molecules of the living
tissues
3. Incident radiation when traveling
through the body tissues knock out the
bound electrons free from their parent
atoms or molecules. These free electrons
are highly unstable and interact with
other atoms and molecules within the
irradiated system.
3. Ionization is another process where the radiations
interact with matter to form ions;
High-energy electromagnetic radiation and particle
radiation are capable of producing ions in their
passage through matter.
Types of ionizing radiation include alpha and beta
particles, X-Rays, gamma rays, etc. X-Ray machines
and Radioisotopes are the two important and potential
sources of ionizing radiation.
4. Indirect effects:
Since 80% of the biological tissue is water
Most of the incident radiation Energy is absorbed by the water
molecules and these are broken into very unstable and reactive
components. These then react with body molecules and cause
the cell damage.
Due to generation of H and OH radicals , subsequent to many
series of reactions hydrogen peroxide is formed which is highly
reactive oxidizing compound and break chemical bonds in
macromolecules of the body such as proteins, lipids and other
nucleic acids etc causing cellular damage, cell death and
mutations.
The biological effects are enhanced by the presence of oxygen
which is always present in the cells.
5. Lymphoid cells, Epithelial cells of the small
intestine, Haemopoietic cells, Germinal
cells, Epithelial cells of the skin, Connective tissue
cells, Cartilage and growing bone cells, Cells of the
brain and spinal cord, Cells of the skeletal muscles
and mature bone
•The early effect of radiation is a result of direct
injury to the tissues. Simultaneous and considerable
destruction to the radiosensitive cells lead to
radiation sickness. These effects appear within
days or weeks after exposure and include
nausea, vomitions, malaise, diarrhea, fever;
hemorrhage, loss of appetite, fall of hair and death
etc are the dangerous effects of radiation.
•The delayed effects of radiation includes
Shortening of life span, leukemia, malignant tumors
and cataract. These appear after months or even
many years of exposure.
6. Type of Radiation
Source
Health Effects
Ultraviolet radiation
UV tanning equipment (sun lamps, beds and tanning booths)
short term - sunburn
Infra-red radiation
infra-red heat lamps used in deep heat treatments
infra-red hair dryers
, conjunctivitis
long term - premature skin aging, skin cancer and cataracts
burns to skin and eye tissue
Lasers
beauty industry treatments such as skin exfoliation and hair removal
skin damage
eye damage, including blindness
Ultrasound
beauty industry heat treatment and skin exfoliation
overheating and burning of body tissue
7. The unit Rad (radiation absorbed dose) is used as the
unit of absorbed dose following exposure to any type
of ionizing radiation. One rad is equal to the radiation
necessary to deposit energy of 100 ergs in 1 g of
irradiated material (100ergs/g).
The radiation dose is measured in terms of Roentgen, -
It is the quantity of X-Rays or gamma radiation
which produces one electrostatic unit in one C.C. of
dry air after its ionization at 0 degree centigrade and
760 mm Hg pressure..
8. •The soft tissues exposed to X-Rays or gamma
rays, rad and R are nearly equivalent. The
biological effects of various types of radiations
differ a lot.
•To equate all types of radiation in terms of
biological effects, the unit Rem (roentgen
equivalent man) was evolved. One rem = radx
quality factor. Quality factor relates to the
biological effectiveness of the given radiation.
The quality factor for X-Rays and gamma rays is
one and for alpha particles 20.
•Maximum Permissible dose: It is a level at
which appreciable injury is unlikely to be
manifested in the lifetime of an individual. For
the veterinarians and radiographic staff it is
9. Body part One week One year
Whole body, gonads, bone
marrow , lens
100m rem 5000 m rem
Body part One week One year Body part One week
Whole body,
gonads, bone
marrow , lens
100m rem 5000 m rem Whole body,
gonads, bone
marrow , lens
100m rem
Hand,
forearm and
feet
1500m rem 75000m rem Hand,
forearm and
feet
1500m rem
10. Principles of radiation safety:
The distance between the radiation source and
personnel exposed should be increased. Usually
doubling the distance from the source will reduce
the radiation exposure by a factor of four.
11. Allow only the operator in the x- ray room when
exposures are made
Always try to restraint the animal or subject by
anaesthesia
Always use a cassette holding device especially in large
animal radiography.
Behind the Shielding screen or atleast 6 feet away from
the source the exposure should be made.
Fluoroscopy should never be used as a substitute for a
non motion radiographic procedure as amount of
radiations is extremely large in fluoroscopy.
12. Use of protective barriers
The lead shielding material in the gloves and aprons reduces the dose
of scatter radiation well below 1/12th of the scatter radiation dose.
Aprons should have a minimum of 0.25 mm lead equivalent for
voltages upto 100 KV. Check the shielding material periodically for
cracks etc. Never fold the protective aprons.
Gloves and goggles should be used during exposure
X-Ray room should be located away from the traffic and public places
to prevent the inadvertent exposure of the public.
Make sure workers display signs warning other persons that radiation-
emitting equipment is in use
Check the equipment periodically for possible leakage.
Display warning signs near the location of X-Ray unit regarding
potential hazards. The wall of the X-Ray room should be atleast 22 cm
thick and should be of concrete in to which iron may be introduced .
13. and reduction of unnecessary
radiography
Use of intensifying screens minimizes the factors.
Provide workers with instruction and training on the
health effects associated with radiation exposure and
the safe use of equipment.
14. Use of the radiation monitoring
devices
Users may receive a dosimeter badge or ring to monitor
radiation exposure.
Two film badges should be used one at the belt level to
monitor whole body exposure and the other above the
protective apparel, at the neckline, to estimate exposure to
the skin of the head, neck and eyes.
Film badges or thermo luminescent dosimeters can be
obtained from BARC, Division of Radiation
Safety, Mumbai, India, and at periodic intervals these
monitoring devices should be sent back to this research
institute for calculating radiation dose.
Regular testing for radioactive contamination must be
conducted.
15. Pregnant woman and persons
under 18 years of age
Pregnant woman and persons under 18 years of age
should not be involved in radiographic work as it
may adversely affect the growing fetus and the
gonads of the persons exposed which may cause
sterility or infertility.
Following with great precaution with all the safety
procedures we can reduce a significant amount of
radiation in a large number of individuals.
