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目的用胶片剂量计测量γ-刀剂量学参数,比较不同软件对同一台γ-刀验证胶片的分析结果的差异,分析产生差异的原因及胶片剂量计检测的影响因素,为今后修订相关检测规范提供依据。方法用胶片剂量计对γ-刀照射野尺寸与标称值最大偏差、焦平面上照射野半影宽度等剂量学参数进行检测,用2套不同的胶片剂量分析软件对同一台γ-刀的验证胶片进行分析,用SPSS 11.0进行分析结果的配对t检验。结果 2种软件对玛西普SRRS型头部γ-刀照射野尺寸与标称值最大偏差的分析结果显示两者差异无统计学意义(t=0.844,P>0.05),对GMBS型体部γ-刀照射野尺寸与标称值最大偏差的分析结果显示两者差异无统计学意义(t=0.561,P>0.05);对SRRS型头部γ-刀不同尺寸准直器的照射野半影宽度的分析结果表明两者差异有统计学意义(t=-4.365,P<0.01),对GMBS型体部γ-刀不同尺寸准直器的照射野半影宽度的分析结果表明两者差异有统计学意义(t=-5.497,P<0.01)。结论胶片剂量计检测γ-刀剂量学参数的影响因素很多,剂量分析软件是很重要的影响因素。不同的胶片剂量分析软件对同一套γ-刀验证胶片的分析结果有差异。
Objective To measure γ-knife dosimetry parameters with a film dosimeter and compare the difference of the results of the same γ-knife verification film by different softwares, analyze the causes of the differences and the influencing factors of the film dosimeter detection, and to revise the relevant testing standards in the future Provide evidence. Methods The dosimeter parameters such as the maximum deviation of the size and the nominal value of γ-knife irradiation field and the penumbra width of the exposure field on the focal plane were measured with a film dosimeter. Two sets of different dosimetry softwares were used to test the dose- Verify the film for analysis and paired t-test with SPSS 11.0. Results The results showed that there was no significant difference (P> 0.05) between the two softwares and the maximal deviation between the size and the nominal value of gamma-knife irradiation field in the head of Maximap SRRS type (t = 0.844, P> The results of the maximum deviation between the size and nominal value of γ-knife irradiation field showed no significant difference (t = 0.561, P> 0.05). For the SRRS-type head γ- Analysis of the shadow width showed that there was a significant difference between the two (t = -4.365, P <0.01). Analysis of the penumbra width of the irradiation field of GMBS type body with different size collimators showed that the differences There was statistical significance (t = -5.497, P <0.01). Conclusion There are many influencing factors for the dosimeter dosimetry to detect γ-knife dosimetry parameters. Dose analysis software is a very important factor. Different film dose analysis software on the same set of γ-knife verification film analysis results are different.