Learning More about Radiation

What is radiation like?

Radiation is always with us, like the air and water.

Radiation refers to

rapidly flying particles or a magnetic wave having a very short wavelength.

There are many examples of radiation, including α-ray, β-ray, γ-ray, and X-ray.
Their most outstanding characteristic is that they have high energy and high capability to pass through an object (penetrating power).

The high energy and penetrating power of radiation is utilized in various fields, including cancer treatment and
baggage checks.

Because the penetrating power varies depending on the types of radiation, various structures can be used to
block radiation.

How to Describe the Strength of Radiation

Sievert (Sv)

Unit describing the degree of effect to a person from radiation exposure

Sievert is a unit that represents the degree of exposure to radiation.

For natural radiation, a Sievert is a unit that is too large.
Therefore, a millisievert (mSv), which is one thousandth of one Sv, is used.

The external and internal effects of radiation are expressed in Sv.

For example, a person undergoing an X-ray in a hospital receives about 0.1 mSV of radiation.

* 1 Sv = 1000 mSV

Becquerel (Bq) and Curie (Ci)

Basic units representing the amount of radioactive substances

The amount of radiation emitted by a radioactive substance in unit time is expressed by Becquerel (Bq) and Curie (Ci).
The standard unit, Bq, is often used.

When 100 Bq of radioactive substances is included in 1 kg of food or water, the amount is expressed as 100 Bq/kg.

For example, bananas usually contain about 130 Bq/kg of potassium-40, which is a substance that emits radiation.

Being familiar with the units

The unit of Becquerel is from 'Antoine Henri Becquerel.'

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• Antoine Henri Becquerel, a French physicist, focused on optical studies of infrared rays and fluorescence in his early career.

  Learning of Röntgen's discovery of X-rays in 1895, Becquerel discovered radioactivity in the spring of the following year

  He discovered natural radioactivity, and named the radiation emitted from uranium a Becquerel ray.

  He further studied radiation and found that a part of radiation, being refracted by an electric field or a magnetic field, was different from an X-ray. He received the Nobel Prize in Physics in 1903 with the Curies.

The unit of Curie is from 'Marie Curie.'

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• Marie Curie was a Polish and naturalized-French physicist, and married to Pierre Curie, who was an experiment instructor at the School of Physics and Chemistry. They conducted radium studies together for several years.

  The Curies discovered that irradiation of cancerous tissues of an animal skin removed the cancerous tissues, and then the skin was regenerated, although the wounds remained.

  This was because the cancer cells were destroyed by radiation.
  Later, physicians started to use radium to cancer treatment for patients.

  Radium not only caused wounds but also treated cancers.

  The Curie Therapy was a ground-breaking discovery.
  Marie Curie was the first woman to win a Noble Prize.

  She shared the 1903 Nobel Prize in Physics with her husband for their radium study, and received the 1911 Nobel Prize in Chemistry alone

Natural Radiation and Artificial Radiation

Natural Radiation and Artificial Radiation

Same Radiation Made by Different Methods

Radiation is classified as natural radiation and artificial radiation.

‘Natural radiation’ comes from elements such as uranium, thorium, and radium, which have existed since the birth of
the earth.

Interestingly, a very small amount of natural radiation comes from not only our bodies but also from space and our food.

Human-made radiation is called 'artificial radiation.' An example of artificial radiation is the radiation coming from
the X-ray machine used in hospitals.

Comparison of Natural Radiation and Artificial Radiation

The effects of radiation on the human body from natural radiation and artificial radiation may be compared
as described below.

Exposure to artificial radiation at a high dose for a long time may produce a severe effect, which should be carefully avoided.

However, in medical treatment, intensive radiation is applied by focusing on cancer cells, and thus the normal cells
are little affected.

Radiation in Space, Atmosphere, and the Ground

Radiation in Daily Living

We are exposed to radiation in our everyday life.

Everyone in the world is exposed to 2.4 mSv of natural radiation annually.

On average, we receive a total of 2.4 mSv radiation, including 0.35 mSv from space, 0.4 mSv from the ground,
1.3 mSv through the air by respiration, and 0.35 mSv from food.

We cannot avoid natural radiation, but the amount is extremely small.
Therefore, the natural radiation does not cause any health problems in our lifetime.

For example, we receive radiation of 0.07 mSv during a round trip flight between Seoul and Europe,
and less than 0.0286 mSv in a year at a location near a nuclear power plant.
That amount is negligible in comparison with the annual exposure to natural radiation (2.4 mSv).

* Results from 2013 Environmental Radiation Survey (Korea Hydro & Nuclear Power)

Radiation from Food

Radioactive substances are contained in our everyday food.

Radioactive substances are also contained in our daily food, such as vegetables, meat, and fish.

'Radioactivity' is like an invisible beam.

'Radioactive substances' means substances that have the characteristic of emitting radiation,
and 'radioactivity' refers to the ability to emit radiation.

Radiation is like the light from a bulb. The light-emitting capability of a bulb is represented by the unit of Watt,
while the radiation-emitting capability of radioactive substances is called radioactivity.

Radiation Coming from Our Body

Our body also contains radioactive substances.

Our body also contains radioactive substances existing in the nature.
Natural radioactive substances are elements that are indispensable to animals and plants.

Natural food basically contains natural radioactive substances.

For example, potassium, one of the minerals existing in the nature, is indispensable to living organisms for
transmitting information through the nervous system.

Potassium is known to be about 0.2% of our body weight, and the ratio is generally regulated to stay constant.

Amount of Radiation Depending on Region

The amount of natural radiation is dependent on the regions in the world.

In some regions of the world, the amount of natural radiation is several times higher than Korea.

Many factors are involved in the high level of natural radiation in those regions.

For example, in Ramsar, Iran, the natural radiation level is high because radium, a radioactive substance,
is discharged from hot springs and accumulates.

Visualizing Radiation

Radiation is invisible and odorless, but it can be measured using instruments.

When an object is irradiated, an electric discharge or light emission may occur, or a photographic image may be obtained. An X-ray image is a good example.

A radiation instrument is an instrument used to measure the amount of radioactive substances or the amount of
radiation in the air, using these reactions.

Many types of radiation instruments are available, and they are necessary for measuring exposure dose, or to survey
the radiation level at certain places.

However, the right type of radiation instrument needs to be selected depending on the purpose, to obtain a useful measurement.

A cloud chamber is painted black and filled with ethanol vapor that is cooled down.
The ethanol vapor is kept in a state where the vapor may be turned into the liquid by a small stimulus.

Then, when the radiation penetrates the chamber, the trace of the radiation penetration appears, like the condensation trail of an airplane, showing the trajectory of the radiation.

Measuring the Amount of Radiation in Space

A Nal scintillation survey meter is used to measure the amount of radiation (intensity) in a specific place (space).
The measurement is performed several times at a height 1 m above the ground surface.

The Nal scintillation survey meter measures the radiation intensity.
The amount of external radiation may be measured in a specific place.

A personal dosimeter is worn by a radiation worker immediately before starting work, and is used to measure the exposure dose of the worker during their time at work.

The personal dosimeter is attached to the chest or other body part to measure the external radiation dose.
Types of personal dosimeters include a film badge and thermoluminescent dosimeter (TLD), which require reading
after measurement, and a pocket dosimeter and alarm meter, which allows the worker to check the dose right away.

Recently, pocket dosimeters are being replaced by electronic dosimeters.

Measurement of radiation in food and the human body

The amount of radiation can be measured for each of the radioactive substances contained in food and other materials.

A high-purity germanium semiconductor detector is used to detect the radiation analyze the amount of radiation from each of the radioactive substances included in food and other materials.

A whole body counter directly measures the radiation (gamma-ray) emitted from the radioactive substances accumulated in the human body, and shows the result in numerical values.

Radiation Is Beneficial To Us

Most people have vague fears about radiation, because the word 'radiation’ reminds them of the danger of
atomic bombs or nuclear accidents.

However, we are living with radiation at a very low level, from sunlight or in foods such as bananas and milk.

In addition, radiation is widely used in various fields including medicine, industry, and research,
and so we directly benefit from radiation.

For example, radiation is very useful in medical services, such as the diagnosis of diseases and the treatment of cancers. Radiation is also very useful in industrial areas, including the airport baggage check system and radiation sterilizers.

Because radiation is widely used in many parts of daily living, it is closely related to our life.

Radiation, Our Health Guard

Diagnosis through X-ray Radiography

• Since the discovery of X-rays, a type of radiation, they have contributed to the saving of numerous lives. X-rays allow the structure and state of the internal body to be viewed, and are used for the diagnosis of various diseases. When we have a leg fracture, get a severe cold, or have a severe abdominal pain, what the doctors recommend first is X-ray radiography.
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Diagnosis by Nuclear Medical Imaging (PET, PET-CT)

Positron Emission Tomography (PET) using radiopharmaceuticals allows viewing of parts of the body that may not be effectively inspected by X-ray radiography.

In particular, PET-CT, the combination of PET with X-ray based CT, is very helpful in the discovery and treatment of cancers.

Radiation, the Watchman for Industry

Radiotherapy, the Edge-Cutting Medical Technology

Anticancer treatment using radiation

In addition to surgery and anticancer drugs, radiation is one of the three major methods of cancer treatment.
Radiation is directed to cancer cells to treat cancer.

instruments, and local irradiation of a limited part of the body by placing a radiation generator on the body surface.

Anticancer treatment using radiopharmaceuticals

Radioisotopes can also be placed in the body to limit irradiation to a specific area for cancer treatment.

In thyroid cancer, radioactive iodine entering into the body is accumulated in the thyroid, and the radiation from
the iodine attacks the cancer cells, providing therapeutic effects.

Freeze, illegal substances!

Defect testing

A method of detecting engineering defects without destroying the material is called 'defect testing.'

A defect test performed with radiation allows internal cracks or defects to be examined without destroying or disassembling an object.

In technical terms, defect testing is referred to as 'nondestructive inspection,' and is a representative technology that utilizes the unique capacity of radiation to penetrate a material.

Security Screening

Security screening using radiation is performed at key facilities including airports and ports to prevent the entry and export of illegal substances. In the US, since the September 11th attack, X-ray security screening is performed on the entire body before aircraft boarding to protect passengers from terrorist attacks.

New Studies Using Radiation

Radiation, No. 1 Contributor to Eradication of Food Poisoning Bacteria

Sterilization Using Radiation

Radiation greatly contributes to our healthy life, and is applied to sterilization of food, drugs, and medical devices.

While preservatives and chemical sterilization are tightly regulated in the world because they may pose a hazard to the human body, the hygienic treatment of medical devices, drugs, and food using radiation is recommended by relevant international organizations including the World Health Organization (WHO) and Food and Agriculture Organization because radiation is recognized as 'safe to food and medical products.'

Particularly in the food industry, radiation treatment is recognized as a useful means of food poisoning prevention and food management, including the sterilization of microorganisms and harmful bacteria and the prevention of food spoilage.

Therefore, radiation also plays an important role in facilitating the international trade of agricultural products.

New Variety Development by Radiation

Radiation Breeding Technology

Irradiating plants allows us to change existing traits or improve a variety to have different genetic functions. Radiation mutagenesis has been used in various food and horticulture studies to develop crops that are strong to blight, have special functionalities, and replace imported crops.

Purification of Polluted Wastewater

Degradation of wastewater pollutants by radiation

Water purification technology based on radiation, especially gamma-rays, are methods for completely eliminating water pollutants by using the strong oxidizing, reducing, and disinfecting power generated by the ionization of water. In contrast to conventional treatment technologies, this technology causes no additional pollutants, requires a simple facility, and has a short treatment time. An actual system for treating dye wastewater using radiation is installed in the Daegu Dyeing Industry Complex. Instead of treating the wastewater by using a large amount of chemicals, radiation is used to remove the toxicity and degrade the pollutants biologically in the environment-friendly wastewater treatment system.

Radiation Safety Management

Radiation is like a two-edged sword, which is useful but may be dangerous if misused. So, thorough safety management is necessary.

Radiation Safety Management

Radiation safety management means various activities for 'protecting people and environment from radiation.'

Three parties play important roles in radiation safety. The workers directly handling radiation and radioisotopes (RI), the employers of the workers, and the government or the regulatory authorities should thoroughly perform what they have to do to accomplish perfect management.

Radiation Management Targets

Radiation Source Management; Environment Management; Individual Management

Radiation management targets are classified as radiation sources, environment, and individuals.

Radiation Safety Management

Radiation Source Management

To manage the sources of radiation

Natural radiation sources : : Natural radiation sources are excluded from the targets of radiation management. However, natural radiation sources that may be reduced by artificial activities is the target of radiation defense.

Example) Flight attendants on jet airplanes, miners working in mines with a high natural radioactivity level

Artificial radiation sources : Artificial radiation sources are the targets of radiation management.

Environmental Management

To manage the spaces between radiation sources and people

Self-work environment management

To verify the control of radiation; to check that the radiation dose in the working environment is below the legal standard value

General environmental management

To verify the control of radiation; to check that general conditions in the environment are safe to the public

Individual Management

To manage those who are potential targets of exposure

Vocational Exposure Defense

Regular monitoring of individual dose; Monitoring of dose in workers' groups

Radiation in daily living vs Radiation for medical purposes

Utilization of radiation is safe.

Artificial radiation is used for various purposes, including medical purposes. The annual dose limit for a common person is 1 mSv. However, high-dose radiation is used for CT imaging and cancer radiotherapy, where radiation is appropriately used in specific settings for the purposes of disease diagnosis and treatment. Particularly with radiotherapy for cancer patients, even though irradiation may be with thousands of mSv, the irradiation is kept very local so that only cancer cells will be destroyed.

How can I keep my body safe from radiation?

Safety rules depending on type of radiation exposure

(1) External exposure

The outside of the body is exposed to radioactive substances.

(2) ) Internal exposure

The inside of the body is exposed to radioactive substances (gas, liquid, particles, etc.) that have entered the body.

Safety Rules Against External Exposure

Exposure of external body to radioactive substances

Safety Rules Against Internal Exposure

Exposure of the internal body to radioactive substances