Effects of radiation on living beings
Ionizing radiation can damage living cells. Some of the
damaged cells die, some may mutate, but there are also
mechanisms in cells which can repair damages. In the natural
environment cells also constantly divide, reproduce and die.
Ionizing radiation accelerates the death of cells and increases
the number of mutations depending on the received doses:
• Low doses of ionizing radiation may have delayed effects
(after several years) due to mutations causing cancer or
hereditary effects.
• High doses (above 500 mSv) over short periods of time
cause immediate effects due to the death of many cells and
change of blood structure.,
• Very high doses (above 3500 mSv) cause radiation burns
or even death.
In general, ionizing radiation is harmful and potentially lethal
to living beings which effect depends on time when doses
were received but can have health benefits in diagnostics and
radiation therapy for the treatment of cancer.
Radiation protection
Three factors which limit the dose uptake are:
• Limit the time of exposure to ionizing radiation,
• Increase the distance to the source,
• Use the shielding to protect against ionizing radiation.
Principles of protection against ionizing radiation
Limitation of radiation exposure is prescribed by law or
regulations and doses may never be higher. The maximum
allowed dose per year for professionals is 20 mSv, for general
public 1 mSv, above background dose.
Doses received by patients in diagnostic procedures can be
very small to small, doses received locally for therapy must be
very high to destroy the cancer cells.
Only professionals with adequate training, suitable personal
protective eqiuipment and under regular medical survillance
and dosimetry are allowed to work with ionizing radiation
sources.
Basic Radiation Protection steps
• Justification: Benefits from the use of radioactive
substances and radiation must be greater than the
harmfull effects of ionizing radiation. Unnecessary
use of radiation is not permitted.
• Limitation: Each individual must be protected
against undue risks through individual radiation dose
limits.
• Optimization: Radiation doses should all be kept As
Low As Reasonably Achievable (ALARA principle). It
is not enough to remain under the radiation dose
limits.
• License holders are responsible for ensuring
application of justification, limitation and
optimization in daily operations.
• Use of dosimetry to control the received doses for all
radiation workers.
• Use of warning signs for ionizing
radiation is obligatory.
Kosovo Agency for
Radiation Protection
and Nuclear Safety
What should we know
about Ionizing Radiation
Ionizing radiation is a natural phenomenon which is
present in the nature from creation of the universe. The
ionizing radiation is coming from the soils, from the
cosmos, from food and drinks, our bodies are radiating
too. Ionizing radiation is part of the electromagnetic
spectrum which has enough energy to kick electrons out
of atoms and therefore produce ions. It can be also
produced with emission/ radiation of particles during
radioactive decay of nucleus. Ionizing radiation in our
environment can occur either naturally or can be produced
artificially, through human activity. The effects of artificial
and naturally occurring ionizing radiation are the same.
Kosovo Agency for Radiation Protection and
Nuclear Safety
Ex. "Germia" Building, 2th Floor, Office no. D-213
10000 Pristina, Kosovo
Web: akmrrsb.rks-gov.net
E-mail: [email protected]
Tel: +381 (0) 38 200 15 519
An EU funded project managed
by the European Office in Kosovo
Implemented by:
Ionizing radiation is part of the electromagnetic spectrum
What is Radiation
Radiation is a process in which the energy from the
source is spread in the forms of electromagnetic waves
or high speed particles. Radiation is therefore
transmission of waves and particles and with this energy
in the space. If it produces the ionization of atoms
(liberate electrons from atoms, thereby ionizing them) it
is called ionizing radiation.
Types of Ionizing Radiation
There are several types of ionizing radiation:
• x-rays (electromagnetic radiation with short wave
length which occur on atomic level),
• Gamma rays (electromagnetic radiation with even
shorter wave length which occurs during decay of
unstable atom nuclei).
• Emission/ radiation of particles (produced during
decay of unstable nuclei emitting alpha and beta
particles),
• Cosmic radiation (consist primarily of high energy
protons and atomic nuclei coming from universe
which causes radioactive decays when hitting atoms
on Earth),
• Neutron radiation (most-often creates a secondary
ionizing radiation through forming of unstable nuclei
that subsequently decays).
Some characteristics of ionizing radiation
Particles emissions/ radiations are having mass (e.g.,
alpha and beta particles, charged nuclei and other
particles). They can be stopped by thin shields.
Electromagnetic radiations (X-rays and gamma rays)
have no mass and no charge. They are attenuated with
distance with high density material.
Neutrons are attenuated with distance with light density
material.
Ionizing radiation cannot be detected by our senses, but
t h e r e a r e m a n y i n s t r u m e n t s d e ve l o p e d f o r
measurements.
Doses
When ionizing radiation interacts with body tissues and
organs, the radiation received depends on type of
radiation, the part of the body affected and the exposure
pathway. Radiation dose is a measure of ionizing radiation
impact on the human body. The unit is the sievert (Sv)
which is very large unit. In daily life we use milisieverts
(1Sv=1.000 mSv) or microsieverts (1Sv=1.000.000 μ Sv).
Penetration of different types of ionizing radiation
Radioactive decay
Main origin of ionizing radiation is radioactive decay of
unstable atomic nuclei. They spontaneously decay in stable
nuclei and emit particles (alpha or beta) or gamma rays. In
this way new nuclei can be formed.
During radioactive decay, energy in form of waves or
particles is released from nuclei which become stable.
Unstable nuclei are radioactive.
Sources of ionizing radiation
There are natural sources of ionizing radiation (gas radon
and gas thoron from Earth, cosmic radiation, radioactive
decay of Uranium, Thorium and Potassium from soils,
rocks and food) and man-made (nuclear power plants, use
of radioactive material, accelerators and X-rays in medicine,
industry and research, nuclear accidents). The contribution
from all sources of ionizing radiation on Earth is referred to
as background radiation.
Different dose contributions in daily life from IR
Distribution of natural and man-made ionizing
radiation sources per year
Public is exposed to different doses in their everyday
activities from natural ionizing sources, but also from manmade ionizing radiation sources in case they use medical
diagnostics and treatment. Radiation workers are besides
also exposed to doses in their work environment (for
example in nuclear power plants, in medicine, industry and
research).