Volume 15, Issue 47 (Jun 2005)
J Mazandaran Univ Med Sci 2005, 15(47): 90-97 |
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Abstract: (12067 Views)
Background and purpose : Instalation of protective barrier against diagnostic x-ray is generally done based on the recommendations of NCRP49. There are analytic methods for designing protective barriers howerer, they lack sufficient efficiency and considering the NCRP49 reports, designing mechanical protective barrier in order to protect the initial x-ray radiation and absorption of the ray quality of such radiation is different.
Therefore, the protective barrier for each radiation is measured separately. In this study, a computer software was designed to calculate the needed barrier with high accuracy.
Materials and methods: Calculation of required protective barrier particularly when two or more generators are in use at diagnostic x-ray units and or installed diagnostic equipments do not have proper room space and the limitations for other clanges in parameters which are time- consuming and impossible to be manually calculated. For proper determination of thichness of the protective barrier, relevant information about curves of radiation weakness, dose limit etc should be entered. This program was done in windows and designed in such a way that the operator works easily, flexibility of the program is acceptable and its accuracy and sensitivity is high.
Results : Results of this program indicate that, in most cases, in x-ray units required protective barrier was not used. Meanwhile sometimes shielding is more than what required which lacks technical standards and cost effectiveness. When the application index is contrasting zero, thichness of NCRP49 calculation is about 20% less than the calculated rate done by the method of this study. When the applied index is equal to zero (that is the only situation where the second barrier is considered), thickness of requined barrier is about 15% less than the lead barrier and concrete barrier calculated in this project is 8% less than that calculated by McGuire method.
Conclusion : In this study proper determination of required protective thickness for weakening of radiation to the permitable level is proposed. The multi radiation sources in a single room are considered and non garanteed radiation of NCRP49 hypothesis are removed. Difference between the the oritical and calculated rates this of method is X2=10-5 which indicates accuracy and high efficiency of this software.
Materials and methods: Calculation of required protective barrier particularly when two or more generators are in use at diagnostic x-ray units and or installed diagnostic equipments do not have proper room space and the limitations for other clanges in parameters which are time- consuming and impossible to be manually calculated. For proper determination of thichness of the protective barrier, relevant information about curves of radiation weakness, dose limit etc should be entered. This program was done in windows and designed in such a way that the operator works easily, flexibility of the program is acceptable and its accuracy and sensitivity is high.
Results : Results of this program indicate that, in most cases, in x-ray units required protective barrier was not used. Meanwhile sometimes shielding is more than what required which lacks technical standards and cost effectiveness. When the application index is contrasting zero, thichness of NCRP49 calculation is about 20% less than the calculated rate done by the method of this study. When the applied index is equal to zero (that is the only situation where the second barrier is considered), thickness of requined barrier is about 15% less than the lead barrier and concrete barrier calculated in this project is 8% less than that calculated by McGuire method.
Conclusion : In this study proper determination of required protective thickness for weakening of radiation to the permitable level is proposed. The multi radiation sources in a single room are considered and non garanteed radiation of NCRP49 hypothesis are removed. Difference between the the oritical and calculated rates this of method is X2=10-5 which indicates accuracy and high efficiency of this software.
Type of Study: Research(Original) |
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