Analysis Of Key Factors For Radiation Occupational Hazards In Self-shielding Medical Electron Accelerator

BackgroundMedical electron accelerator with self-shielding device has been initially applied in clinical practice with the growth of tumor treatment demand,and medical electron accelerator has developed rapidly in recent years.However,at present,the radiation level and exposure characteristics of radioactive occupational hazards of self-shielded medical electron accelerator are poorly understood,it is unclear whether its monitoring,evaluation,and protection specifications need to be adjusted accordingly.Therefore,the structure,design parameters of protective facilities,radiation level in workplace,personal exposure of exposed workers and occupational health examination results of with and without self-shielding devices medical electronic accelerators were investigated.Through comparative analysis,the intensity,distribution characteristics of radioactive occupational hazard factors and their impact on the health of radiation workers were evaluated,so as to provide reference materials and scientific basis for further revision of the norms for the monitoring,evaluation and protection of radioactive occupational hazard factors in medical electron accelerators.Materials and Methods Two types of accelerators were selected,one domestic OMX6 i medical electron accelerator with self shielding and four medical electron accelerators without self shielding with the same performance parameters,which were COMPACT,NMSR600,PRIMUS and XHA600 D accelerator without self-shielding device.By analyzing the structure of the accelerator,according to the national standard of accelerator room shielding wall and room top thickness of theoretical calculation,comparison of five accelerator calculated values.Using the same instruments and detection methods,the performance indicators of the five types of accelerators and the radiation level in the workplace of the accelerator were tested on the spot,and the results of personal annual effective dose of the five types of accelerators who wore four cycles were investigated.Statistical analysis The Excel software was used to build the database.Software SPSS 21.0 statistical software was used for statistical analysis.The significance level α was set at 0.05.ResultsOMX6 i accelerator protection facilities do not need the main shielding structure.The calculated thickness of shielding wall and chamber top is 1000 mm less than that of COMPACT accelerator protection facilities,940 mm less than that of XHA600 D accelerator protection facilities,700 mm less than that of PRIMUS accelerator protection facilities.The radiation level of the five accelerators can meet the control level of surrounding dose equivalent rate,but the radiation level of OMX6 i accelerator is lower.The personal dose monitoring results of radiation workers exposed to two types of electron accelerators were 0.260±0.118 m Sv、0.290±0.027 m Sv、0.134±0.037 m Sv、0.278±0.033 m Sv、0.366±0.365 m Sv,there was no significant difference F =-0.509,P = 0.625).And it was far lower than the requirements of "basic standard for protection against ionizing radiation and safety of radiation sources"(GB 18871-2002),There was no dose-response relationship between occupational health examination results and personal dose monitoring results.ConclusionsThe calculated value of radiation protection for OMX6 i accelerator with self-shielding device is reduced,the radiation level in the workplace is reduced,and the absorbed dose of the contact person is not increased.The radiation protection effect is better,which can reduce the potential risk of the occurrence of radioactive occupational disease,and the requirements for the protection facilities are also significantly reduced.