This document discusses radiation hazards and protections. It defines radiation as tiny particles or electromagnetic waves that can pass from one location to another. Radiation is used in medical science for diagnosing issues like bone problems and detecting thyroid gland issues, as well as for treating cancer. Exposure to radiation can cause both deterministic effects (early effects above a threshold dose) and stochastic effects (late effects where probability increases with dose). Protections aim to limit radiation exposure according to the ALARA principle of keeping doses as low as reasonably achievable.

1. RADIATION HAZARDS AND PROTECTIONS
B. PHARM
REPRESENTE
D BY
AMRITA RANI

2. DEFINITION
• Radiation refers to tiny, invisible or high speed particles or high energy
electromagnetic waves that passes from one location to another and can
have manifestation.
• Radiation :- 1) Rays of Energy: - Gamma Rays and X-rays are the two types
of energy waves often used in medicine. 2) The use of energy waves to
diagnose or treat disease.

3. RADIATIONS AND MEDICAL SCIENCE
• It is used to diagnose bone.
• Used to diagnose the heart problems.
• Radioactive iodine is used in imaging the Thyroid gland.
• Radioactive materials are used to kill cancerous tissues.
• Radioactive materials are used to shrink a tumour or reduce pain.
• It is also used for nuclear medicine.

4. RADIATION HAZARDS
•The harmful effect cause by the
penetration of radiation in the
human body is called radiation
hazard.

5. RADIOBIOLOGICAL EFFECT OF RADIATIONS
• When radiation falls on human body it produces moving electrons.
• These electrons ionise and excite other atoms and produces chemical
and molecular changes in cells or DNA – DIRECT EFFECT.
• Radiations can also produce free radicals that are chemically very
high reactive and produces changes in the atomic and molecular
structure of the cell- indirect effect.

6. TERMINOLOGY OF RADIATION HAZARDS
RADIOSENSITIVE CELLS
• The cells that are well nourished, quickly
dividing and metabolically high active, and
which are easily affected by the radiation are
called radiosensitive cells.
• Example:- RBC, WBC, lymph nodes, stem cells
etc.
RADIORESISTANT CELLS
• The cells of tissues that are less affected by
the radiations.
• Example:- Nerve cells.

7. CLASSIFICATION OF RADIOBIOLOGICAL EFFECT
1. Stochastic effect / Late effect / chronic effect.
a) Somatic effect
b) Foetal effect
c) Genetic effect
2. Deterministic effect / Early effect / Acute effect.
1. Stochastic effect:- The effect that appears after a period of time are called late or
stochastic effect.
-- In this effect the probability of occurrence increases with increase in absorbed dose.
-- At low dose less than 0.5 Gy this effect occurs.
-- There is no threshold dose for this effect.
-- Example :- carcinogenesis, skin necrosis.

8. TYPES OF STOCHASTIC EFFECT
• a) SOMATIC EFFECT :- This effect does not pass in the next generation as it
ends with the life span of any individual .
• b) GENETIC EFFECT :- This effect is quite dangerous as it leads to the
mutation due to the alters that appeared in the DNA and surely it continues to the
next generation.
• c) FOETAL EFFECT :- This effect depends upon the gestation period of the
pregnant lady.
It has 3 phases :- a) Pre-implantation period {1 to9 days}
b) Period of major organogenesis {9 to 45 days}
c) Foetal period {45 to 252 days}

9. 2. DETERMINISTIC EFFECT
• Soon after the radiation’s penetration which effect appears is called the early or
Deterministic effect.
• This effect has a minimum threshold dose.
• The severity of disease in this effect is increase with increase in absorbed dose in
affected individual.
• It is generally a high dose phenomenon appear at dose greater than 0.5 Gy.
Reason :- This effect occurs due to large killing of functional sub
unit cell which are responsible for normal functioning of the organ.

10. RADIATION PROTECTION
The radiation protection aims to prevent deterministic effect and can limit the
probability of stochastic effects to a certain level.
ALARA PRINCIPLE :- As Low As Reasonably Achievable
There are three basic methods for radiation protection in ALARA principle which are
as follows :- 1) Justification of practice
2) Optimization
3) Dose limit
CARDINAL PRINCIPLE :- 1) Time
2) Distance
3) Shielding

11. ALARA PRINCIPLE
1) Justification of practice :- Radiation exposure involving practicesshould be
justified and it produces a net positive benefit.
2) Optimization :- The every effort should be taken to reduce the patient dose as low
as considering the clinical, social and economical factors.
3) Dose limit :- The effective dose to the person should not exceed the limits
recommended by commission i.e. ICRP {International commission on radiation
protection}
BODY PART OCCUPATIONAL PUBLIC
Effective dose {whole body} 20 mSv / year 1 mSv / year
Lens of eye 150 mSv / year 15 mSv / year
Skin 500 mSv / year 50 mSv / year
Hands and feet 500 mSv / year 50 mSv / year
Pregnant women {foetus} 2 mSv in 9 months -

12. TEN DAY RULE
• This rule suggests that in females a non-urgent X-ray or any radiological application
procedure is being restricted during the first ten days of menstrual cycle and during
this period an X-ray of lower abdomen and pelvis could harm her developing follicles
inside the ovaries and the fertilized ovum to be implanted in the endometrium layer of
uterus.
• An urgent X-ray of any part of her body except the pelvic reason can be done by
shielding the pelvic region with a lead apron.
• For the initial 10 days embryo is in pre implanted stage and it contains only few cells, if
these cells are damaged then embryo is degenerated or reabsorbed.
• ALL OR NONE RULE IS APPLICABLE in this phase.
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