A Study on the Influence of Medical Linear Accelerator on Dosimetric Output in Non-Standard Beam State
Objective To explore the influence of non-standard beam states on the dosimetric parameters of medical linear accelerators.Methods With the Elekta Precision medical linear accelerator as the research object,the servo parameters of the 6MV beam were adjusted through maintenance mode,and the variation characteristics of conventional parameters were simulated to obtain four non-standard beam states(the unstable parameters above caused the equipment to report corresponding interlocks,but the equipment can continue to output the beam after resetting),including dose rate,2R Err(flatness and symmetry error value in y direction),2T Err(flatness and symmetry error value in x direction),and Hump Err(peak error value)interlocks.Dosimetric parameters such as absolute dose,energy radiation quality,uniform-integration and symmetry,and γ pass rate of intensity modulated dose verification under different non-standard beam states were measured by using UNIDOS dosimeter,MatriXX two-dimensional matrix and ArcCheck three-dimensional dose verification equipment.In addition,the dosimetry parameters were compared with those of the standard beam state.Results In the non-standard beam state,the dosimetric parameters of the non-standard beam state were significantly different from those of the standard beam state,except that the 2R Err interlock was consistent with the standard beam state.Conclusion The occasional 2R Err interlock of medical linear accelerator does not affect the dosimetry parameters of the device and does not affect the clinical application.However,unstable dose rates and interlocking of 2T Err and Hump Err can affect the dosimetric parameters of the equipment,requiring timely quality control.
Medical linear acceleratorNon-standardBeam stateDosimetry
NETL
NSTL
万方数据
