Abstarct: Technetum99m radioisotope is the work horse of any nuclear medicine institute. This radioisotope is acquired by the elution of Molybdenum99-Technetum99m generator which emits 140.5 keV gamma ray and having 6.04 hour half‐life. 99Mo is the source of the radiopharmaceutical in the column is a cylindrical generator and after his decay half-life of technetium- m99 comes. Factors affect the performance of the column in the generator That makes the milk generator column and an separating, does not absorb all of molybdenum99, and Technetium-m99 solution with molybdenum99 impurities give us. In this thesis, we measurement the amount of molybdenum99 impurities in the technetiumm99 at nuclear medicine ward of shahroud imam hossein hospital with a dose calibrator and baxsed on ray spectroscopy and container type KT, that the amount of impurities is one of the essential parameters in quality control Radiopharmaceutical and The results show that the use of technetium radiopharmaceutical used in nuclear medicine department of quality control is permitted. generators with capacity of 600 mCi has more contaminated molybdenum-99 in comparison of generators with capacity of 400 mCi and in the final days of generators with a capacity of 600 mCi, the amount of impurities of molybdenum99 more than the maximum standard was defined. Since then sometimes also use generators for two weeks,The use of generators with a capacity of 600 mCi of quality and and in terms of maximum pollution control molybdenum99 over a week is not allowed, and also because Absorbent aluminum oxide ,with chemical symbol ( ), is generally used in radiopharmaceuticals generator, We Aluminium isotopes used in adsorbent alumina neutron absorption cross section diagram was drawn with MCNP code. Since Mo-99 decays to Technetium-99m in one of neutrons Mo-99 to protons turns. The results of this figure shows that the best isotopes for adsorbent alumina, is the aluminum-27. And As well as silicates also can be used as an adsorbent, of course, the cost and the price is higher than the alumina asorbent.