Familiar type of radiation


Artificial radiation


"Artificial radiation" is radiation made artificially as we have explained before. Here, we discuss how "artificial radiation" is used.



Medical system


X ray photography
We can photgraph the inside of an object or a human body using the transmission
effect which X-rays here.The amount of exposure from on X-rays is considered
to be 400~500 millirem.
CT(Computed tomography)
CT scans can create cross-sectional pictures (round slice etc.) of the body by using the penetrative action of radiation. These days, internal organs, blood vessels, etc. can be visualized in three dimensions and more vividly by improvement in image processing technology. This is called spiral CT.
PET(Positron emission tomography)
This is an inspection method used when carrying out cancer treatment. A radioactive isotope is administered which takes out a positron to a patient and photographs the distribution inside the body with PET equipment. It is necessary to make the radioactive isotope prescribed for the patient in a hospital because in order to use material that has a short half-life. But a patient's exposure can be lessened as much as possible.
This technology can check many things, for example, if cancer really exists in a body, whether it has metastasized, if medical treatment will be effective, and so on.

Cancer treatments
Cancer can now be treated without using a scalpel with radiotherapy, ensuring internal organs and bodies helth are maintained.
Recently heavy ion radiotherapy has attracted attention as the latest treatment because it can treat cancer by hitting cancerous cell with a heavy particle beam concentrated on the position and size of the cancer precisely.


Agricultural systems


Genetic modification
This technology is used to make new plant species for specific tasks, such as a species can grow well in which low-temperature, and so on, by althering genes intentionally, and causing mutation by radiation precise.
It is used for various agricultural products, such as rice, soybeans, pears, and chrysanthemums.
Cabbage which is genetic modificationed
Pest sterilization
This is a method of pest control to destroy pests which damage the farm's productive out put by using gamma rays emitted from cobalt 60.
After being rendered,released outdoors.

Hull coatings(Additives)
These additive agents mixed with paint to prevent shellfish and
seaweed, such as barnacles,from sticking to the bottom of ships.
The radiation emitted from the element thorium series makes ion
and neither a microbe nor seaweed to adhere. Because it was used,
the radioactive element thorium is contained in some ship hull coatings.


Industrial systems


Material processing
When processing of high molecular compounds (rubber and plastic) is carried out,the bonds between molecules will become firmer by applying radiation. That is, kinetic properties such as, heat resistance, etc.flexibility,and shtter resistance can be improved.
Many high molecular compounds, such as chemical fibers and a synthetic resins, are used in present-day industrial commodities.
For example, tires to which radiation has been applied to increase durability have been developed.

Radiography
This how to conduct a non-destructive test (inspection of quality and states without destroying an object) using radiation. The principle is the same as that of the X line inspection currently used in the hospital. The penetration action which a line of elevation has, and the character which becomes weaker gradually are used, and the situation inside objective is investigated.
For example, it is used for investigating whether a portion of welded metal has a defect etc., or measuring thickness, without touching a subject.


Other systems


Radioactive carbon 14 isotopic-(age-determination method)
Every living thing has absorbed "carbon 14" together with carbon dioxide. "carbon 14" is a radioactive material which has a half-life of 5730 years. When a living thing dies, it becomes impossible to take in carbon from outside of the body naturally and "carbon 14" is reduced over time.
The radioactive carbon 14 isotopic-(age-determination method) can determine the aye of things that perisned thousands of years before the sample was taken examining of the "carbon 14" which remains in the ruins or other sample.