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Radiation | Nagase (Thailand) Co.,Ltd.
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About Radiation

Basic Knowledge

What is Radiation?

Radiation is energy that travels in the form of waves or particles and is part of our everyday environment. People are exposed to radiation from cosmic rays, as well as to radioactive materials found in the soil, water, food, air and inside the body.

Human-made radiation sources are widely used in medicine, industry, and research. There are two types of radiation as ionizing and non-ionizing radiation.


Ionizing radiation is a type of energy released by atoms that travels in the form of electromagnetic waves (gamma or X-rays) or particles (neutrons, beta or alpha). Ionizing radiation can remove electrons from the atoms. In natural radiation sources, there are more than 60 different naturally occurring radioactive materials in the environment, with radon gas being the highest contributor to people’s exposure.
Artificial radiation sources are used for nuclear power generation and many other industrial and research applications, with the medical use of ionizing radiation being today the highest contributor to people’s exposure (e.g. diagnostic radiology, image-guided interventions, nuclear medicine and radiotherapy).


Non-ionizing radiation is radiation in the part of the electromagnetic spectrum where there is insufficient energy to cause ionization. It includes electric and magnetic fields, radio waves, microwaves, and optical radiation, which consists of infrared, visible, and ultraviolet radiation.

What is the radiation hazard?

Ionizing radiation has sufficient energy to affect the atoms in living cells and thereby damage their genetic material (DNA). Fortunately, the cells in our bodies are extremely efficient at repairing this damage. However, if the damage is not repaired correctly, a cell may die or eventually become cancerous. Related information in Spanish
Exposure to very high levels of radiation, such as being close to an atomic blast, can cause acute health effects such as skin burns and acute radiation syndrome (“radiation sickness"). It can also result in long-term health effects such as cancer and cardiovascular disease. Exposure to low levels of radiation encountered in the environment does not cause immediate health effects but is a minor contributor to our overall cancer risk.

What is the exposure limit?

Ionizing radiation can use in many applications in medical, industrial and research, but it also has the potential to cause harm to occupation workers, public, and environment. Throughout the years, multiple recommendations regarding occupational exposure limits have been developed by the International Commission on Radiological Protection (ICRP), national regulation body and other radiation protection groups.

What is the personal dosimetry?

Personal dosimetry is used primarily to determine doses to individuals who are exposed to radiation related to their work activities. These doses are usually measured by devices known as dosimeters. Dosimeters usually record a dose, which is the absorbed radiation energy measured in grays (Gy) or the equivalent dose measured in sieverts (Sv). A personal dosimeter is dosimeter, that is worn at the surface of the body by the person being monitored, and it records of the radiation dose received.

How many kinds of dosimeter are there?

There are two kinds of dosimeters:

  1. 01 Passive Dosimeters
    Commonly used passive dosimeters are Film badges, Thermo Luminescent Dosimeter (TLD), Optically Stimulated Luminescent Dosimeter (OSLD) and Glass dosimeter. A passive dosimeter produces a radiation-induced signal, which is stored in the device. The dosimeter is then processed, and the output is analyzed.
  2. 02 Active Dosimeters
    To get a real time value of your exposure you can instead use an active dosimeter, typically an electronic personal dosimeter (EPD). An active dosimeter produces a radiation-induced signal and displays a direct reading of the detected dose or dose rate in real time.