Safety evo
Life saving tips
What does ALARA stand for when talking about radiation?
This expression is widely used in radiation field.
Radiation is one of the hidden hazards that we have to deal with during our entire life.
It is not only used in destruction as many people are expecting
The beneficial uses of radiation nowadays cannot be counted
For sure, we will mention many of these uses in our future posts.
But for now our task is to answer this widely used question:
What is the meaning of ALARA
What does ALARA stand for
ALARA stands for As Low As Reasonably Achievable.
Aims to minimize the radiation exposure.
Or in other words, you need only to be exposed to that dose of radiation that you need.
giving an example may help you getting the point.
If you are suffering a minor bone trauma.
If this trauma can be diagnosed using X-ray, There is no need to go for CT.
This concept can be achieved by 3 main controls called ( the 3 cardinal principles of ALARA )
But before explaining these principles, we have to answer another question.
Is there any place on the earth without radiation
The answer is no.
There is no spot on the entire planet without radiation.
This is because of the natural radiation sources which include the cosmic rays from the sun
And also the Terrestrial radiations due to the decay of natural radioactive material in the earth.
By the way, if you remember what we mentioned about the radon gas in one of our posts,
Radon gas is one these decay products for ground radioactive materials.
These radiation levels are called the background radiation and are low levels causing no harm.
What are the main 3 principles for radiation protection
Now after we answered the first question
What does ALARA stand for ?
This leads us to ask another related question,
how can we achieve the ALARA concept ?
There are 3 main controls to achieve this ALARA
These 3 cardinal principles of ALARA are:
The time of exposure, The distance between the exposed person and the radiation source,
and finally the shield that can be used to protect against radiation.
We shall give short explanation for each one of them.
Radiation exposure time
There is a relation between the time of exposure to a radioactive source and the absorbed and effective dose.
The longer the exposure time, the higher dose absorbed.
So, the first control is to minimize the exposure time as we can.
This is because the effect of radiation on human body is related to the accumulated dose.
For this reason, we advice any one who is dealing with radioactive sources to
leave the area after finishing his job.
Relation between distance and radiation intensity
Increasing the distance has a great effect on lowering the radiation doses.
if you are able to double the distance between you and the source,
your body will absorb only quarter of the original dose.
It is a very effective control for radiation protection.
Radiation shielding
This principle means that we need to wear a proper barrier that works as a shield
This shield is related to the type of radiation.
For example, if we are dealing with Alpha particles, which have high molecular weight,
and its effect is limited to few centimeters,
it is enough to use a piece of paper to stop Alpha particles.
While for Beta particles, an aluminum sheet or plastic layer can be good.
The Gamma radiation has the most penetration power, it cannot be stopped with these shields,
We need to use lead shield to stop Gamma.
This means that we need first to know the nature of radiation we are dealing with.
And also, the intensity of radiation will determine the thickness of the used shield.
This can be calculated using some specific well known equations for the radiation professionals.
I hope this is a good answers for our questions :
What does ALARA stand for in radiation ?
what are the 3 cardinal principles of ALARA in radiation ?