Radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium.
This includes: electromagnetic radiation, such as radio waves, microwaves, infrared, visible light, ultraviolet, x-rays, and gamma radiation (γ)
RADIATION EFFECT ON BODY
Ionizing radiation—the kind that minerals, atom bombs and nuclear reactors emit—does one main thing to the human body: it weakens and breaks up DNA, either damaging cells enough to kill them or causing them to mutate in ways that may eventually lead to cancer.
Radiation protection is the protection of the people from harmful effects of ionized radiation which include both particle radiation and high energy electromagnetic radiation.
SOURCE OF RADIATION EXPOSURES
BIOLOGICAL EFFECT OF RADIATION
Prompt personal effect
Delayed personal effects
PROMPT PERSONAL EFFECTS
On receiving very large doses
Occurs within few hours or days
Symptoms associated are erythema, vomiting, diarrhoea.
DELAYED PERSONAL EFFECTS
Chronic low dose irradiation over a considerable period of
time or few exposures giving a high dose
- Skin cancer
- Thyroid cancer
- Cataract formation
- Bone marrow compromise leading to fatal anaemia and
- Premature ageing
- Growth and development of fetus and young children
Effect is produced in the long run and may be far more important than any purely personal injury.
Occurs mainly due to changes produced by radiation in hereditary materials..
The harmful effects of radiation are classified into stochastic effects and non-stochastic effects.
|STOCHASTIC EFFECT||NON-STOCHASTIC EFFECT|
|Is one in which the probability of occurrence increases with increasing absorbed dose.||Is one in which severity increases with increase in absorbed dose in affected individuals..|
|The severity in affected individuals dose not depend on magnitude of absorbed dose||Have definite threshold levels of radiation dose.|
|Have no threshold levels of radiation dose, all or none phenomenon.|
One of the first bodies involved in regulating radiation hazards is the ICRP (international commission on radiation protection)
In U.S the regulatory board is the NCRP (National council on radiation protection and measurements)
In India the board is the AERB (Atomic energy regulatory board)
Constituted in Nov 15,1983.
Headquarters in Mumbai.
ICRP has recommended a series of maximum permissible dose (MPD) for different body tissues.
The quoted values are maximum, and every effort should be made to keep the doses to absolute minimum.
ICRP has also recommended maximum values for amounts of different radioisotopes which can be deposited in the body without constituting radiation hazards.
OBJECTIVES OF RADIATION PROTECTION
The international commission of Radiation Protection (ICRP) Stated that “the overall objectives of radiation protection is to provide an appropriate standard of protection for man without unduly limiting the beneficial practices giving rise to radiation exposure.”
“The goal of radiation protection is to prevent the occurrence of serious radiation induced conditions in exposed persons and to reduce stochastic effects in exposed persons to a degree that is acceptable in relation to the benefits to the individuals & society from activities that generate such exposure.
ICRP was established in 1928 at the second International Congress of Radiology to respond to growing concerns about the effects of ionizing radiation being observed in the medical community.
At the time it was called the International X-ray and Radium Protection Committee, but was restructured to better take account of uses of radiation outside the medical area and given its present name in 1950.
Originally, ICRP published its recommendations and advice as papers in various scientific journals in the fields of medicine and physics.
Since 1959, ICRP has its own series of publications, since 1977 in the shape of a scientific journal, the Annals of the ICRP, which is published Elsevier Science.
The ICRP uses the following overall principles for all controllable exposure situations.
Justification: No unnecessary use of radiation is permitted, which means that the advantages must outweigh the disadvantages.
Limitation: Each individual must be protected against risks that are too great, through the application of individual radiation dose limits.
Optimization: This process is intended for application to those situations that have been deemed to be justified.
It means “the likelihood of incurring exposures, the number of people exposed, and the magnitude of their individual doses” should all be kept as Low As Reasonably Achievable (known as ALARA or ALARP).
It takes into account economic and societal factors.
AS LOW AS REASONABLY ACHIEVABLE
ALARA (As Low As Reasonably Achievable) is a safety principle designed to minimize radiation doses and releases of radioactive materials.
More than merely best practice, ALARA is predicated on legal dose limits for regulatory compliance, and is a requirement for all radiation safety programs.
The ALARA principle is an important principle for any worker, exposed to radiation, to fully understand and apply in every day use.
ALARA stands for “As Low As Reasonably Achievable”, a safety principle specifically designed to reduce radiation doses and releases of radioactive materials
It is an acronym for an important principle in exposure to radiation and other occupational health risks and stands for “As Low As Reasonably Practicable“.
The aim is to minimize the risk of radioactive exposure or other hazard while keeping in mind that some exposure may be acceptable in order to further the task at hand.
These are depend on three things:
Time– limit time in room with radiation present.
Distance– reduce amount of radiation exposure by moving as far from the source of radiation as possible.
Shielding– protect yourself by wearing lead apron, the lead will absorb most of scattered and secondary radiation.
The dosimetric quantity relevant to radiation protection is the dose equivalent.
Harmful effects of ionizing radiation are classified as stochastic and non-stochastic.
Effective dose equivalent limits for occupational and general population have been recommended by the regulatory board of that country.
The values quoted for radiation workers are such that the hazards that the doses represent to health is small compared with ordinary hazards of life.