两台医科达直线加速器匹配后束流特性比较

Comparison of beam characteristics after beam matching in two Elekta linacs

目的:比较分析两台医科达直线加速器匹配后的束流特性,为临床上实现治疗计划在两台加速器上互换执行提供依据和参考。方法:利用IBA公司Blue Phantom2水箱采集两台加速器X射线束及电子束等相关数据并对其进行比较分析。结果:两台加速器6 MV各射野%dd(10)X偏差在±0.1%之内,10 MV%dd(10)X偏差在±0.3%之内。其相对应射野条件下两档能量束流平坦度与对称性差异均在±1.5%之内,半影的最大绝对偏差为0.5 mm。两档X射线能量60°楔形野的%dd(10)X最大差异为0.8%。电子线Rp、R50、E0方面,两台加速器中各档电子线的差异皆在±1.2%之内,dmax最大绝对偏差为0.9 mm。各能量射野输出因子之间虽有偏差,但差异均较为微小。结论:两台加速器的束流特性显示出良好的数据匹配度,将为治疗计划在两台加速器上实现互换执行提供临床依据。

Objective To compare and analyze the beam characteristics after beam matching in two Elekta linacs and provide the basis and reference for realizing the interchangeable implementation of treatment plans on two linacs.Methods The data related to X-ray and electron beams generated by two accelerators were obtained using IBA Blue Phantom2 and the obtained data were compared and analyzed.Results The%dd(10)X deviations for 6 and 10 MV between two accelerators was within±0.1%and±0.3%,respectively.The differences in flatness and symmetry between the two energy levels under the corresponding fields were within±1.5%,and the maximum absolute deviation of the penumbras was 0.5 mm.The maximum difference in%dd(10)X between the two energy levels in 60°wedge fields was 0.8%.The differences of the electron beams generated by two accelerators in the Rp,R50 and E0were within±1.2%,and the maximum dmax deviation was 0.9 mm.Although there were certain deviations in the output factors of each field for different energy levels,the deviations were trivial.Conclusion The beam characteristics of two linacs show a good matching of beam data,which will provide a solid foundation and necessary reference for the interchangeable implementation of clinical plans on two linacs.