I. Introduction:
Radiation storage system for patients of thyroid cancer usually is solidly with concrete, submerged and stored by decay. These chamber have many shortcomings such as the risk of radioactive waste leakage, difficult control, large construction investment, and cannot be upgraded when the patient number increasing and must use forced pumps when handling waste. All of nuclear medicine facilities using I-131 to treat patients of thyroid cancer apply this old design to store radiation waste and have treatment method by period.
II. Objective and Method:
As recommended by IAEA in IAEA tecdoc series, No.1714, the current storage system of liquid radioactive waste includes many independent small tanks, discharging automatically according to the cycle. Research and calculation of the topic focuses on analyzing and assessing radioactive safety and feasibility of recommendations, comparing with classical exhaust tank system applied in accordance with the 22/2014/TT-BKHCN on August 25, 2014 from the Vietnamese Ministry of Science and Technology. Thereby, the study offers two issues to compare:
A. Calculation of the tank system composed with many small tanks by the method of continuous treatment .
B. Calculation of waste storage system of many small tanks, floating by the method of period treatment with 20 patients x 02 periods / 1 month.
The objects of the study is the storage system of liquid radioactive waste with parameters:
– Number of tank required.
– Tank volume (l).
– Collection period (day).
– Decay period (day).
– Release activity (Bq).
Research method: It is assumed that the prescribed dose per patients of thyroid cancer is 50 mCi/1 patient, the amount of I – 131 is excreted from excretion of patients, stored in the storage system.
III. Result:
A. The project has calculated the parameters of storage system and show the table of parameters according to the accumulated time (12 days to 60 days). This difference of the new storage system from the classic (2 compartments) storage system .
B. The project shows a table of results with parameters of storagecomposedsystem (many tanks) with treatment method: 20 patients/02 periods /1 month, according to the volume of small tanks is 2000liters
IV. Conclusion and discussion:
The calculation of the study confirmed that the new storage system of liquid radioactive waste (composedwith small tanks system) has many advantages of design, more radioactive safety, easy to repair and upgrade, low construction costs but still ensuring radioactive safety and discharge levels as Vietnamese atomic energy law.
Nuclear Medicine facilities should treat patients by continuous method so that radioactive waste is easier to control and reduce the dose of patient from other
Keyword: Radiation storage system, liquid radioactive waste, calculation of the tank system, thyroid cancer
