Chemical elements exist the variants, which have the different relative atomic mass and radioactivity but the same physical and chemical properties, these variants should be in the same position on the periodic table, and they were called as isotopes. The radioisotope refers to the isotope elements which have radioactivity. Each element has its radioactive isotope, but not every isotope has radioactivity. Some radioisotopes are found in nature, while others are artificially created. Since the isotopes have radioactivity, it would do great harm to human beings if under the radioactive isotopes environment for a long time. However, using tungsten alloy shielding material to shield radioisotope elements can bring significant effectiveness, which is due to the high density of tungsten alloy, and the high density of material can absorb radiation highly.

 

The applications and productions of radioisotopes and radiation technology of China began in the 1950s, but with the widening of radioisotopes and radiation technology applications, the quantities of production, transportation and variety have increased year by year. Currently there are many kinds of products that been produced by isotope technique, such as radiopharmaceuticals, various labeled compounds of radiation sources, H-3, C-14 etc., radiochemical preparations and various kits, which were used for radioimmunoassay, the stable isotope and its labeled compounds and so on. This also means that shielding the radioisotopes will become an important part during the producing process.