电子顺磁共振测量犬牙不确定性研究

Study on the uncertainty of EPR in measuring canine tooth

目的:探索使用转角器自动转动、随机手动转动、随机晃动样品和使用内标物(Marker)对犬牙电子顺磁共振(EPR)测量不确定性的影响,为辐射吸收剂量估算提供依据。方法:取3颗3岁家养犬牙为样品,通过化学手段获取犬牙牙釉质,使用EPR波谱仪检测其对方向的依赖情况,以及转角器自动转动、随机手动转动和随机晃动3种方式对犬牙EPR测量值和Q值的影响;观察分析Marker与犬牙样品间的相互影响,并对比有无Marker条件下,犬牙EPR信号强度变化。结果:对于随机手动转动和随机晃动两种方式,不同转动角度个数和不同晃动次数的测量结果均无显著性差异;而使用转角器转动方式,有Marker条件下测量不同角度个数的HP-P(RIS)和HP-P(RIS)/HP-P(Marker)以及无Marker条件下测量不同角度个数的HP-P(RIS)的结果差异有统计学意义(F=4.276,F=4.26,F=26.977;P<0.05);测量结果的离散系数转角器最小,随机手动转动次之,最后为随机晃动;样品发生物理变化或化学变化时,Marker的EPR测量值也随之变化;有Marker的情况下,样品不动测量结果与原位取放测量结果无显著性差异,无Marker情况下,测量结果差异有统计学意义(t=7.063,P<0.05)。结论:随机手动转动和使用Marker可减小犬牙测量不确定性、提高检测质量。

Objective:To explore the influences of automatic rotation by using goniometer,randomly manual rotation,random shaking sample and using internal marker on the uncertainty of electron paramagnetic resonance(EPR)measurement for canine tooth so as to provide basis for the estimation of radiation absorbed dose.Methods:In this experiment,the enamels of 3 canine teeth of dog aged 3-year-old were obtained by chemical mean,and then the EPR spectrometer was used to detect the dependence of them on direction,as well as the effects of three means(automatic rotation of goniometer,random manual rotation and random shaking)on EPR measurement values and Q value of canine teeth.The mutual effect between the internal Marker and the sample of canine teeth was observed and analyzed.And the change of EPR signal intensities of the canine teeth with or without internal Marker were further compared.Results:The differences of the measurement results of random manual rotation and random shaking among different rotation angle and among different shaking times were not significant.And in the mean of using goniometer for rotation,the differences of HPP(RIS)and HP-P(RIS)/HP-P(Marker)among different angles under Marker condition and the difference of HP-P(RIS)results among different angles without Marker condition were significant(F=4.276,F=4.26,F=26.977,P<0.05).For the coefficient of dispersion of the measurement results,the goniometer was the smallest,and the random manual rotation was the second,and the random shaking was the last.When the samples occurred physical changes or chemical changes,the EPR measurement value of the internal Marker also changes accordingly.The difference of the measurement results with internal Marker between the immobility and the picking and replacement of sample on primary place was no significant,while that without internal Marker between them was significant(t=7.063,P<0.05).Conclusion:Random manual rotation and the use of internal Marker can reduce the uncertainty of measuring canine tooth and improve the quality of detection.