山羊牙釉质电子自旋共振的剂量学特性

Objectlve To study the properties of goat tooth enamel electron spin resonance (ESR)dosimetry.Methods Tootll enamel samples of goats were achieved by combined mechanical and chemical treatment at the ages of l,2,3,5,and 6 years.respectively and 9 enamel samples of adult molar were obtained.These enamel samples were exposed to 137Cs γ-rays at the cumulative doses of 0,0.5,1.0,2.0,and 5.0 Gy,respectively.ESR spectra Was measured before and after exposure.Results The background signal of goat tooth samples W88 21.5,significantly lower than that of the adult molar samples(39.5).The dusimetric signal intensity of the goat enamel increased with the radiation dose in a linear manner just as that of the human molars.The average radiation sensitivity of the goat tooth samples was(34.3±1.9)/Gy,close to that of the human tooth samples.Conclusions Goat teeth can be used for retrospective radiation dose reconstruction when human teeth are unavailable,in order to previde scientific data for dose reconstruction accurately.     

日射量的估算及其对牙釉质电子自旋共振剂量学的影响

Objective To investigate solar radiation and its effects on human tooth enamel electron spin resonance (ESR) dosimetry. Methods 11 tooth enamel samples were prepared by mechanical method. The intensity of solar iUuminanee was measured with a light meter, the measured illuminance was converted to insolation using a coefficient. Summation of solar radiation was evaluated. Enamel samples were exposed to 60 Co γ rays followed by sunlight on sunny days, and ESR spectra were scanned after different exposure. Results The solar radiation to the samples was (580 ± 16) MJ/m2. Solar exposure also caused dosimetrie signal. The perpendicular component of dosimetrie signal increased linearly with the amount of solar radiation, another signal close to background tended to saturation. Conclusions The average effect of the solar radiation on the signal was be used to recognize the effect of solar radiation on the enamel, and estimate external dose accurately.     

日射量的估算及其对牙釉质电子自旋共振剂量学的影响

Objective To investigate solar radiation and its effects on human tooth enamel electron spin resonance (ESR) dosimetry. Methods 11 tooth enamel samples were prepared by mechanical method. The intensity of solar iUuminanee was measured with a light meter, the measured illuminance was converted to insolation using a coefficient. Summation of solar radiation was evaluated. Enamel samples were exposed to 60 Co γ rays followed by sunlight on sunny days, and ESR spectra were scanned after different exposure. Results The solar radiation to the samples was (580 ± 16) MJ/m2. Solar exposure also caused dosimetrie signal. The perpendicular component of dosimetrie signal increased linearly with the amount of solar radiation, another signal close to background tended to saturation. Conclusions The average effect of the solar radiation on the signal was be used to recognize the effect of solar radiation on the enamel, and estimate external dose accurately.     

日射量的估算及其对牙釉质电子自旋共振剂量学的影响

Objective To investigate solar radiation and its effects on human tooth enamel electron spin resonance (ESR) dosimetry. Methods 11 tooth enamel samples were prepared by mechanical method. The intensity of solar iUuminanee was measured with a light meter, the measured illuminance was converted to insolation using a coefficient. Summation of solar radiation was evaluated. Enamel samples were exposed to 60 Co γ rays followed by sunlight on sunny days, and ESR spectra were scanned after different exposure. Results The solar radiation to the samples was (580 ± 16) MJ/m2. Solar exposure also caused dosimetrie signal. The perpendicular component of dosimetrie signal increased linearly with the amount of solar radiation, another signal close to background tended to saturation. Conclusions The average effect of the solar radiation on the signal was be used to recognize the effect of solar radiation on the enamel, and estimate external dose accurately.     

日射量的估算及其对牙釉质电子自旋共振剂量学的影响

Objective To investigate solar radiation and its effects on human tooth enamel electron spin resonance (ESR) dosimetry. Methods 11 tooth enamel samples were prepared by mechanical method. The intensity of solar iUuminanee was measured with a light meter, the measured illuminance was converted to insolation using a coefficient. Summation of solar radiation was evaluated. Enamel samples were exposed to 60 Co γ rays followed by sunlight on sunny days, and ESR spectra were scanned after different exposure. Results The solar radiation to the samples was (580 ± 16) MJ/m2. Solar exposure also caused dosimetrie signal. The perpendicular component of dosimetrie signal increased linearly with the amount of solar radiation, another signal close to background tended to saturation. Conclusions The average effect of the solar radiation on the signal was be used to recognize the effect of solar radiation on the enamel, and estimate external dose accurately.     

日射量的估算及其对牙釉质电子自旋共振剂量学的影响

Objective To investigate solar radiation and its effects on human tooth enamel electron spin resonance (ESR) dosimetry. Methods 11 tooth enamel samples were prepared by mechanical method. The intensity of solar iUuminanee was measured with a light meter, the measured illuminance was converted to insolation using a coefficient. Summation of solar radiation was evaluated. Enamel samples were exposed to 60 Co γ rays followed by sunlight on sunny days, and ESR spectra were scanned after different exposure. Results The solar radiation to the samples was (580 ± 16) MJ/m2. Solar exposure also caused dosimetrie signal. The perpendicular component of dosimetrie signal increased linearly with the amount of solar radiation, another signal close to background tended to saturation. Conclusions The average effect of the solar radiation on the signal was be used to recognize the effect of solar radiation on the enamel, and estimate external dose accurately.     

日射量的估算及其对牙釉质电子自旋共振剂量学的影响

Objective To investigate solar radiation and its effects on human tooth enamel electron spin resonance (ESR) dosimetry. Methods 11 tooth enamel samples were prepared by mechanical method. The intensity of solar iUuminanee was measured with a light meter, the measured illuminance was converted to insolation using a coefficient. Summation of solar radiation was evaluated. Enamel samples were exposed to 60 Co γ rays followed by sunlight on sunny days, and ESR spectra were scanned after different exposure. Results The solar radiation to the samples was (580 ± 16) MJ/m2. Solar exposure also caused dosimetrie signal. The perpendicular component of dosimetrie signal increased linearly with the amount of solar radiation, another signal close to background tended to saturation. Conclusions The average effect of the solar radiation on the signal was be used to recognize the effect of solar radiation on the enamel, and estimate external dose accurately.     

日射量的估算及其对牙釉质电子自旋共振剂量学的影响

Objective To investigate solar radiation and its effects on human tooth enamel electron spin resonance (ESR) dosimetry. Methods 11 tooth enamel samples were prepared by mechanical method. The intensity of solar iUuminanee was measured with a light meter, the measured illuminance was converted to insolation using a coefficient. Summation of solar radiation was evaluated. Enamel samples were exposed to 60 Co γ rays followed by sunlight on sunny days, and ESR spectra were scanned after different exposure. Results The solar radiation to the samples was (580 ± 16) MJ/m2. Solar exposure also caused dosimetrie signal. The perpendicular component of dosimetrie signal increased linearly with the amount of solar radiation, another signal close to background tended to saturation. Conclusions The average effect of the solar radiation on the signal was be used to recognize the effect of solar radiation on the enamel, and estimate external dose accurately.     

日射量的估算及其对牙釉质电子自旋共振剂量学的影响

Objective To investigate solar radiation and its effects on human tooth enamel electron spin resonance (ESR) dosimetry. Methods 11 tooth enamel samples were prepared by mechanical method. The intensity of solar iUuminanee was measured with a light meter, the measured illuminance was converted to insolation using a coefficient. Summation of solar radiation was evaluated. Enamel samples were exposed to 60 Co γ rays followed by sunlight on sunny days, and ESR spectra were scanned after different exposure. Results The solar radiation to the samples was (580 ± 16) MJ/m2. Solar exposure also caused dosimetrie signal. The perpendicular component of dosimetrie signal increased linearly with the amount of solar radiation, another signal close to background tended to saturation. Conclusions The average effect of the solar radiation on the signal was be used to recognize the effect of solar radiation on the enamel, and estimate external dose accurately.     

日射量的估算及其对牙釉质电子自旋共振剂量学的影响

Objective To investigate solar radiation and its effects on human tooth enamel electron spin resonance (ESR) dosimetry. Methods 11 tooth enamel samples were prepared by mechanical method. The intensity of solar iUuminanee was measured with a light meter, the measured illuminance was converted to insolation using a coefficient. Summation of solar radiation was evaluated. Enamel samples were exposed to 60 Co γ rays followed by sunlight on sunny days, and ESR spectra were scanned after different exposure. Results The solar radiation to the samples was (580 ± 16) MJ/m2. Solar exposure also caused dosimetrie signal. The perpendicular component of dosimetrie signal increased linearly with the amount of solar radiation, another signal close to background tended to saturation. Conclusions The average effect of the solar radiation on the signal was be used to recognize the effect of solar radiation on the enamel, and estimate external dose accurately.     

用牙釉电子自旋共振方法估算慢性辐射损伤人员的受照剂量

目的 用于牙釉电子自旋共振对慢性辐射损伤人员的受照剂量进行估算的方法。方法 用电子自旋共振仪测定慢性辐射损伤人员牙釉电子自旋共振信号强度，用剂量－效应曲线法和附加剂量法来重建辐射损伤人员的受照剂量，探讨牙釉电子自旋共振法估算受照剂量的可行性；并比较了不同能量的射线（1.25MeV的γ射线和6MeV的X射线）对牙釉电子自旋共振信号强度的影响。结果 用两种方法估算的辐射损伤人员受照剂量基本一致；对能量1.25MeV的γ射线和6MeV的X射线进行比较，无论从剂量－效应曲线的直线系数，还是用混合照射后的剂量估算，两者差别不大。结论 慢性辐射损伤人员的受照剂量可以用于牙釉电子自旋共振方法进行估算，射线能量在1.25MeV-6MeV范围内对牙釉电子自旋共振信号强度影响不大。     

Biophysical dose measurement using electron paramagnetic resonance in rodent teeth.

Electron paramagnetic resonance (EPR) dosimetry of human tooth enamel has been widely used in measuring radiation doses in various scenarios. However, there are situations that do not involve a human victim (e.g. tests for suspected environmental overexposures, measurements of doses to experimental animals in radiation biology research, or chronology of archaeological deposits). For such cases we have developed an EPR dosimetry technique making use of enamel of teeth extracted from mice. Tooth enamel from both previously irradiated and unirradiated mice was extracted and cleaned by processing in supersaturated KOH aqueous solution. Teeth from mice with no previous irradiation history exhibited a linear EPR response to the dose in the range from 0.8 to 5.5 Gy. The EPR dose reconstruction for a preliminarily irradiated batch resulted in the radiation dose of (1.4+/-0.2) Gy, which was in a good agreement with the estimated exposure of the teeth. The sensitivity of the EPR response of mouse enamel to gamma radiation was found to be half of that of human tooth enamel. The dosimetric EPR signal of mouse enamel is stable up at least to 42 days after exposure to radiation. Dose reconstruction was only possible with the enamel extracted from molars and premolars and could not be performed with incisors. Electron micrographs showed structural variations in the incisor enamel, possibly explaining the large interfering signal in the non-molar teeth.     

不同制备方法对牙釉质样品ESR信号的影响

目的研究不同制备方法对牙釉质样品ESR信号的影响，有效地提高牙釉质样品ESR剂量学的灵敏度。方法对无放射线照射史成年人臼齿分别用化学、机械以及机械加化学方法进行处理，制备牙釉质样品。利用电子自旋共振仪测定不同制备方法处理的样品在^60Coγ射线照射不同剂量后的ESR信号。比较分析其灵敏度，从而寻求一种对牙釉质样品ESR信号影响较小的样品制备及处理方法。结果不同方法处理的牙釉质样品的ESR信号，对^60Coγ射线的响应有较明显的差异。结论利用牙釉质ESR剂量学重建受照人员剂量时，尤其是使用附加照射法进行较低剂量重建时，选择合适的样品制备方法是十分重要的。     

日射量的估算及其对牙釉质电子自旋共振剂量学的影响

目的 探讨日射量的估算方法及太阳光辐射对牙釉质电子自旋共振(ESR)剂量学的影响。方法 用机械方法获得11个牙釉质样品。用照度计测量太阳光的照度,通过比较日本气象厅在广岛市测得的瞬时日射量和相同时刻所测得的照度,计算出转换系数,然后估算出照射在牙釉质样品的累积日射量。用⁶⁰⁶⁰Co γ射线和太阳光分别照射牙釉质样品,使用ESR波谱仪测量不同辐射后牙釉质样品的ESR信号。结果 照度与瞬时日射量的转换系数为(8.67±0.22) W·m^-2klx。照射在牙釉质样品上的累积日射量为(580±16) MJm²。太阳光辐射也引起γ射线照射产生的剂量学信号,而且随累积日射量而线性增强,太阳光辐射还产生一个紧邻本底的信号,当累积日射量大于某一值时,该信号趋于饱和状态。结论 用剂量学信号对所受辐射剂量进行评价,本研究中每MJm²的太阳光辐射的影响相当于(7.7±1.4) mGy的γ射线辐射。紧邻本底的ESR信号可作为太阳光辐射的标志峰,有助于判断所收集的样品是否受到太阳光辐射,从而提高小剂量重建的准确度。     

嚼烟习俗地区的牙釉质电子自旋共振剂量学的研究

目的 研究嚼烟习俗对牙釉质电子自旋共振(ESR)剂量学的影响。方法 用机械方法获得20个孟买地区的舌侧牙釉质样品与10个混合均匀的日本人舌侧牙釉质样品。用⁶⁰Co γ射线分别照射部分牙釉质样品,使用ESR波谱仪测量辐射前和不同辐射剂量后牙釉质样品的ESR信号。结果 9个孟买牙釉质样品,其ESR的本底信号强度明显高于日本人的平均水平,为日本人水平的1.5~3.3倍。ESR本底信号强度较高的样品,γ射线照射后,剂量学信号的辐射响应略低,说明高本底可能降低了辐射剂量的灵敏度。6个样品辐射响应的平均值为(0.42±0.03)mGy,与日本牙釉质混合样品很相近。结论 嚼烟地区的部分牙釉质的ESR本底水平明显高于一般平均水平,可能是嚼烟中大量的烟碱与牙釉质相互作用的结果。进一步研究特殊生活习俗对牙釉质ESR剂量学的影响,有助于提高不同地区剂量重建的精度,为正确地评价辐射事故剂量提供科学依据。     

Retrospective radiation dosimetry using electron paramagnetic resonance in canine dental enamel.

Electron paramagnetic resonance (EPR) biodosimetry of human tooth enamel has been widely used for measuring radiation doses in various scenarios. We have now developed EPR dosimetry in tooth enamel extracted from canines. Molars and incisors from canines were cleaned by processing in supersaturated aqueous potassium hydroxide solution. The dosimetric signal in canine tooth enamel was found to increase linearly as a function of laboratory added dose from 0.44+/-0.02 to 4.42+/-0.22 Gy. The gamma radiation sensitivity of the canine molar enamel was found to be comparable to that of human tooth enamel. The dosimetric signal in canine enamel has been found to be stable up to at least 6 weeks after in vitro irradiation. A dosimetric signal variation of 10-25% was observed for canines ranging from in age 3 years to 16 year old.     

Aspects of retrospective ESR dosimetry (invited paper)

A review is given on the major technological and methodological aspects of retrospective ESR dosimetry with tooth enamel. Topics include the collection and preparation of samples, the evaluation, treatment and interpretation of the ESR signals, and the procedure of dose reconstruction. Two pathways are described to differentiate between doses from different internal and external sources. They are based on dose comparisons as evaluated from different tooth tissues or from dose vs age dependencies obtained by ESR dosimetry from populations with different exposure conditions. The concepts given are illustrated by recently achieved ESR doses that were reconstructed from teeth of radiation workers and members of the public of the Southern Urals region, Russia.     

ESR dosimetry of a deceased radiation worker

A case of overexposure of an industrial radiographer using ¹⁹²Ir sources and having a filmbadge dosimeter record of 104 mSv has been examined with ESR dosimetry of postmortem tooth and bone specimens. ESR measurements of the tooth enamel showed an intense signal of CO₂⁻ and gave the equivalent dose (ED) of 14 Gy by the additive dose method using γ-rays from a source of ⁶⁰Co. The doses for a finger bone and humerus were 14.7 and 7.0 Gy, respectively. It was concluded that he had been exposed to radiation repeatedly over 10 yr and that ESR dosimetry can give a life-long cumulative dose for personnel using radiation.     

牙釉质ESR回顾性剂量技术与剂量重建

电子自旋共振作为一种回顾性剂量测定技术在剂量重建中应用日益广泛。介绍了电子自旋共振剂量估算的基本原理和过程,包括样品的收集和准备、ESR的测量和信号处理、剂量校准、结果的解释、误差来源及新的进展。另外,还介绍了此技术在剂量重建中的一些应用实例。     

Comparison of sample preparation and signal evaluation methods for EPR analysis of tooth enamel.

In dose reconstruction by EPR dosimetry with teeth various methods are applied to prepare tooth enamel samples and to evaluate the dosimetric signal. A comparison of seven frequently used methods in EPR dosimetry with tooth enamel was performed. The participating Institutes have applied their own procedure to prepare tooth enamel samples and to evaluate the dosimetric signal. The precision of the EPR measurement and the dependence of the estimated dosimetric signal with irradiation up to 1000 mGy were compared. The obtained results are consistent among the different methods. The reproducibility of the dosimetric signal and its estimated relation with the absorbed dose was found to be very close for the applied methods with one possible exception.