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Public Radiation Protection Awareness And Exposure

Public’s awareness on radiation protection and exposure are increasing. For an example, the nuclear energy are now being potentially generated as source of energy in our daily usages. In facts, the radioactive are widely used in medical treatment procedures in providing important information for diagnostic purposes.

The new government project that involved the usage of radioactive energy was brought to public attention. For an example, the Lynas Project in Kuantan, Pahang, has caused the local residents to stoods up objecting the project for their safety and security reasons. This is because they knew that these radioactive activities and wastage could affect both health of present and future generations in the surrounding areas.

Radiation accident in Fukushima, Japan on March 11, 2011, incidence that was due to earthquake, has raised the public concerned regarding controlling and protecting radiaoactive rays activities should be highly noted.

Definition and Types Of Radiation

Radiation rays is a form of energy that has the potential to ionized and thus produce an atom or molecule that is sufficient to change the cell systems in the human body. The disruption of cell systems in the human body depends on radiation exposure limits. The DNA in cells can be damage and the mutation may have an impact on future generations if the exposure limits are excessive.

There are five types of radioactive. Their effects and various forms of protection required are a below:

  1. Alpha radiation – has a positive charge particle with heavy mass. Alpha radiation cannot penetrate the skin and can be blocked by using a piece of paper or aluminium sheets. However, the ionized alpha radiation has a strong energy and it can be very sensitive to the human body, especially the lungs compared with other radiation type.
  2. Beta radiation – is a negatively charged particles. It has a stronger penetration but its ionized energy is less than alpha radiation. Beta radiation can penetrate the human body but are not able to penetrate the layers of aluminium foil.
  3. Gamma radiation- a type of electromagnetic radiation with no charged. Despite of not having ionized energy, its highly energetic gamma rays are able to penetrate through human body. However, it’s penetration can be blocked by using metal lead sheet or concrete. Metal thickness will depend on the light energy produced and the HVL value.
  4. An x-ray – a type electromagnetic radiation and high-energy photons resulting from the charged particle with the target material. X-ray energy has low penetration compared to gamma radiation. However it can be stopped by using lead sheet of few mm thickness or other metal such as lead, alumimium and alloys cerroband. Many X-rays are produced for human use such as in the field of medicine, industrial , inspection and control.
  5. Neutron Radiation rays – a type of particle that is neutral and very heavy. Usually seen in nuclear reactors. Neutron radiation is capable to penetrate the container and concrete, thus it requires a more effective hardware design.

Dose limit for public exposure

When the human body is exposed to radiation there will be some changes occurs and affect the functions of the human body, especially the cell systems. Cell damage and death will occur depending on exposure limit. Cell damaging may be improved, but in the event of continued cell death will cause shortage since body is unable to produce new cell for replacement. Therefore, it is important to make public aware of the exposure dose limit to be observed as scheduled 1.

Exposure Dose

Public exposure

*Effective dose (whole body)

1 mSv a year

*Equivalent dose (eye)

15 mSv

Equivalent dose (skin)

50 mSv

Equivalent dose (ekstrimitis : hand and leg)

50 mSv

Fetus dose

1 mSv

 

 

 

 

 

 

 

 

 

Scheduled 1: The exposure dose limit for the public

The cells in an infants and children are sensitive and are actively dividing as the body is still undergoing a process of growth. They should be prevented from being exposed to radiation regardless as planned or unplanned. The fetus cells are also very sensitive, especially during the first trimester period of formation. Disruptions in growth and cells division may cause defects to fetus. Thus pregnant mother is an inevitable to undergo radiation procedures unless with a clear justification from the medical officers.

The Effects of Radiation to the public

How do you know that you are exposed to radiation and how to find out what the exposure limits that you have received?

Exposure to excessive and unplanned radiation doses will produce different effects and risks depend on the receiving body. Sources of exposure to radiation is divided into 2 such as:

  1. Background radiation – Sources of radiation from cosmic background is from the sun, rocks and soil, radon gas out of the earth (terrestrial) and that seeps out from rocks and soil on Earth. The human body will received this daily radiation exposure and the rate is dependent on the area. As an example the residents in Ramsar (city in Northern Iran) receives annual background radiation as high as 260mSv/yearly. Although the dose received is higher than the normal background radiation received, people will not have cytogenetic symptoms. This shows that the human body is capable of adapting to continuous high radiation exposure compared to receive high exposure in an abrupt.
  2. Man-made radiation – The major sources of man-made radiation is which has been in demand, especially in the field of medicine (radiology, radiotherapy, and nuclear medicine), industrial radiography, nuclear reactors, the aviation industry and research laboratories. The public is also exposed to radiation from consumer goods such as tobacco (polonium-210), building materials, fuel indicator needle (tritium), smoke detectors (americium), fluorescent light (thorium) and many more. On a smaller public is also exposed to radiation from the nuclear fuel cycle activities obtained from uranium mining and milling.

Humans can not feel, touch or smell the presence of the radioactive radiation, but it can be measured by using radiation detection equipment, for example in the survey, personnel dosimeters, radiation isotope identification device (RIID) , radiation portal monitors, body counters, etc.

For the public to know the rate or amount of exposure received, they need to know some information about dose assessment of radiation exposure, strength or resources received radiation, and exposure factors such as time or range. Terminology used in calculations to determine the dose rate and biological effects on human body are:

  1. Absorbed dose – used to measure the quantity level of radiation absorbed by body. The unit of absorbed dose calculation is in Gray (Gy).
  2. Equivalent dose – used to measure the quantity level of radiation received by taking into account the type of radiation involved. To get a reading of equivalent dose, an absorbed dose is multiplied to the radiation weighting factor like the type and rate of radiation involved. Unit dose equivalent calculation is Sieverts (Sv).
  3. Cumulative dose – refer to the level of radiation received by a group of civilians. To obtain the cumulative dose readings, the average effective dose received multiplied to the number of individuals who have been exposed. Cumulative dose Unit is person Sievert (person – Sv).

The body will be constantly exposed to the dangers of radiation every day and will not have an impact on the next start early treatment and prevention cannot be retrieved.

Exposure to radioactive materials for long periods can lead to fatal consequences including X-rays that are used during medical examination. Inspection procedures involving X-rays is recommended only once in 6 months and examination of pregnant women is not recommended except with physician’s consent.

If the human body is exposed to radiation or excessive unplanned, the body will respond adversely to a particular sensitive organs. Figure 2 shows the sensitivity of organs to radiation exposure.


Figure 2: The sensitivity of organs to radiation exposure.

The following is the result when the body is exposed to radiation rate :

Dose

Effect

>2000  Gy

Sudden death. At doses greater than 5000 Gy , the central nervous system (brain and muscle) cannot control bodily function, including breathing and blood circulation. Usually death will occur within a few hours.

1000-2000 Gy

Possible fatalities is 100%. Cause damage to the digestive system or gastrointestinal system is called and cannot be treated.

50-150 Gy

Changes in the blood and decreased blood cell production cause fatigue and vomiting

5-50 Gy

Changes in the blood and can be detected through a medical examination.

Less than 5 Gy

Cannot be detected within a short time.

Radiation Protection

Principles and preventive measures for public awareness as follows:

  1. Limit your time in the area with radiation activity further in a space or workplace.
  2. Keep distance from the radiation source, the farer you are, the less intensity will be.
  3. Make sure that you are well protected by using a shielding barrier or lead gown if you need to be near to the source of radiation. Examples of shielding barrier are a thick concrete walls barriers or fitted with barium plaster or aluminium, lead, steel sheets etc.

Preventives measures to be observed:

  1. Avoid getting into the working area or the control area, where the x-ray machine or radioactive is operating.
  2. If you need to be in control areas such as helping to hold patient during the procedure, then make sure that you protected. Equipment’s provided such as lead gown, thyroid collars, gonad shield, lead goggle etc.
  3. Follow all instructions and guidelines given by authorities if you need to deals with radiation.
  4. If you happen to find any equipment or material that can produce radiation, accident or radiation exposure, inform the authorities immediately so that inspection can be carried out early to prevent the spread of radiation to public.
  5. Radioactive material should be stored in an environment airtight container and isolated.
  6. Special handling is required to avoid material being inhaled or touched by public or staffs.
  7. Storage room should have low pressure so that in the event of a leakage, it will not spread outside.
  8. In the event of radiation contamination in the country or from neighboring countries, make sure that all instructions from the authorities is followed from time to time, especially not to be in open spaces or being moved to a more remote area from the contaminated area. Radiation contamination from the air is difficult to control because of movement that follows the wind. Human body can receive as high as 1 Gy dose before it can cause threatens such as cancer, miscarriage in pregnant women or death in the next few months

References:

  1. Atomic Energy Licensing Act 1984
  2. Regulatory 25, Basic Safety Radiation Protection Regulation 2010
  3. http://mysaintis.blogspot.com/2009/01/bagaimana-mengetahui-had-dose-radiasi.html
  4. http://znaddini.wordpress.com/2011/04/14/jenis-sifat-sinar-radioaktif/
  5. http://ms.wikipedia.org/wiki/sinaran-pengion

 

Last Reviewd : 8 October 2014
Writer : Haizana bt. Hairuman
Translator : Adzlin Hana bt. Mohd Sari
Accreditor : Nik Mohamed Hazmi b. Nik Hussain

 

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