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Dose Rate Calculation in the Vicinity of the Tunisian Gamma Irradiation
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作者 Elassaad Jemii Malek Mazouz Lotfi Ghedira 《World Journal of Nuclear Science and Technology》 2013年第1期28-32,共5页
Dose rates calculations, in PMMA dosimeters, placed in the vicinity of the Tunisian 60Co gamma ray irradiator, have been achieved using a pencil like model. The obtained results are in good agreement with recent exper... Dose rates calculations, in PMMA dosimeters, placed in the vicinity of the Tunisian 60Co gamma ray irradiator, have been achieved using a pencil like model. The obtained results are in good agreement with recent experimental data. Moreover, in this work we determine also the conversion factor between the dose rate deposited in a PMMA dosimeter and the one deposited in a reel medium. This factor is used to determine the dose deposited in a real irradiated medium such as foodstuff products. 展开更多
关键词 dose rate 60Co gamma Source GEANT4
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Comparison of Gamma Pass Rate between the Dose-to-Water and Dose-to-Medium Reporting Modes for Patient-Specific QA Using a Helical Diode Array Dosimeter with a Fixed Phantom Density
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作者 Hideaki Hirashima Mitsuhiro Nakamura +7 位作者 Yoshitomo Ishihara Nobutaka Mukumoto Mami Akimoto Tsuneyuki Tomita Yoshinori Hirose Kenji Kitsuda Takashi Ishigaki Takashi Mizowaki 《International Journal of Medical Physics, Clinical Engineering and Radiation Oncology》 2018年第1期74-86,共13页
Introduction: To compare the measured dose distributions to calculated ones in dose-to-water (Dw) and dose-to-medium (Dm) reporting modes for simple plans and patient-specific intensity modulated radiation therapy (IM... Introduction: To compare the measured dose distributions to calculated ones in dose-to-water (Dw) and dose-to-medium (Dm) reporting modes for simple plans and patient-specific intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) plans using ArcCHECK with a fixed phantom density. Methods: The recommended density value of 1.18 g/cm3 for Acuros XB and X-ray voxel Monte Carlo was assigned to ArcCHECK on CT images. A total of 45 simple plans, including a 1-field plan, a 3-field plan, a 4-field plan, a half-arc plan from 270° to 90°, and a full-arc plan, were assessed. Subsequently, the patient-specific 96 IMRT and VMAT plans were evaluated. Gamma analysis with a 3% normalized global dose error and a 3 mm distance-to-agreement criteria (γ3%G/3mm) was performed in the Dw and Dm. The change in γ3%G/3mm between Dw and Dm were statistically analyzed using JMPPro11 software. Results: The median values of γ3%G/3mm for all simple plans for Dw and Dm were 98.1% (range, 75.2% - 100%) and 95.5% (range, 23.7% - 100%), respectively (p 0.01). In the patient-specific IMRT and VMAT plans, the median values of γ3%G/3mm for Dw and Dm were 98.6% (range, 90.1% - 100%) and 90.5% (range, 38.5% - 97.2%), respectively (p 0.01). Conclusion: Our results showed that the calculated and measured dose distributions were in good agreement for Dw, but were not for Dm. From the viewpoint of the rationale of dosimetry, Dw shows better agreement with measured dose distribution when using the fixedphantom density recommended by the vendor. 展开更多
关键词 HELICAL Diode Array DOSIMETER dose-to-Water dose-to-Medium gamma Pass rate
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Effect of ionizing radiation on dual 8-bit analog-to-digital converters (AD9058) with various dose rates and bias conditions 被引量:1
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作者 李兴冀 刘超铭 +2 位作者 孙中亮 肖立伊 何世禹 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第9期629-633,共5页
The radiation effects on several properties (reference voltage, digital output logic voltage, and supply current) of dual 8-bit analog-to-digital (A/D) converters (AD9058) under various biased conditions are inv... The radiation effects on several properties (reference voltage, digital output logic voltage, and supply current) of dual 8-bit analog-to-digital (A/D) converters (AD9058) under various biased conditions are investigated in this paper. Gamma ray and 10-MeV proton irradiation are selected for a detailed evaluation and comparison. Based on the measurement results induced by the gamma ray with various dose rates, the devices exhibit enhanced low dose rate sensitivity (ELDRS) under zero and working bias conditions. Meanwhile, it is obvious that the ELDRS is more severe under the working bias condition than under the zero bias condition. The degradation of AD9058 does not display obvious ELDRS during 10-MeV proton irradiation with the selected flux. 展开更多
关键词 analog-to-digital converters enhanced low dose rate sensitivities (ELDRS) gamma ray and protonirradiation lower/high-dose rate
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Natural background radiation dose rate levels and incidences of reproductive abnormalities in high radiation area in Abeokuta, Southwestern Nigeria
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作者 Nnamdi Norbert Jibiri John Bamidele Famodimu 《Natural Science》 2013年第11期1145-1153,共9页
A 10 y (1999-2008) birth records from two public and most accessible maternity hospitals locally in the city of Abeokuta, Nigeria were used to investigate the possible association of high outdoor gamma radiation expos... A 10 y (1999-2008) birth records from two public and most accessible maternity hospitals locally in the city of Abeokuta, Nigeria were used to investigate the possible association of high outdoor gamma radiation exposure on reproductive abnormalities in the city. From the delivery record of 11,923 births in the period under study, a total number of 485 incidences of reproductive abnormalities were recoded. These incidences comprise 228 multiple births, 190 still births and, 67 premature births. Using the available terrestrial gamma radiation exposure data for the city and different reproductive abnormalities, regression assessment was carried out using the Pearson Product Moment (PPM) correlation statistics. The correlation showed that the incidences of reproductive abnormalities and the radiation dose levels were negatively correlated and correlation coefficient values were very low for each of the reproductive abnormalities considered. Factors such as socio-economic potentials of patients, dietary and other environmental factors may have substantial influence on the reproductive defects in the area other than radiation. However, the present study has added to the radiometric information needed in understanding the relationship between natural outdoor radiation exposure and occurrences of reproductive abnormalities in areas of high radiation in the country. 展开更多
关键词 HIGH Background RADIATION gamma RADIATION dose rates REPRODUCTIVE ABNORMALITIES Abeokuta NIGERIA
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Assessment of Natural Radioactivity Levels and Radiation Dose Rate in Some Soil Samples from Historical Area, AL-RAKKAH, Saudi Arabia
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作者 K. S. Al Mugren 《Natural Science》 2015年第5期238-247,共10页
This study aims to determine the activity concentrations of naturally occurring, technically-enhanced levels of radiation and the gamma absorbed dose rates in soil samples collected across the land scape of historical... This study aims to determine the activity concentrations of naturally occurring, technically-enhanced levels of radiation and the gamma absorbed dose rates in soil samples collected across the land scape of historical area which discovered in east of Saudi Arabia at 2009 G, Called AL- RAKKAH. By using an HPGe detector gamma-ray spectrometer, the activity concentrations of 226Ra 232Th and 40K were found in surface soil samples ranged from 17. 4 ± 1.2 Bq/kg to 28.3 ± 2.3 Bq/kg with an average value of 23 ± 1.6 Bq/kg, ranging from 1.1 ± 1.8 Bq/kg to 81.0 ± 1.7 Bq/kg with the average value 20 ± 1.4 Bq/kg and from 218 ± 11 Bq/kg to 255 ± 18 Bq/kg, with the mean value of 233 ± 12 Bq/kg respectively. The mean radium equivalent (Raeq) and outdoor radiation hazard index (Hex) for the area under study were determined as 69.52 Bq/kg and 0.16 respectively. The total absorbed dose rate due to three primordial radionuclides lies in the range of 17.74 - 72.24 nGy·h-1 with a mean of 32.69 nGy·h-1, which yields total annual effective dose of 0.37 mSv·y-1. The measured values are comparable with other global radioactivity measurements and are found to be safe for public and environment. The baseline data of this type will almost certainly be of importance in making estimations of population exposure. 展开更多
关键词 Soil gamma RAY Spectroscopy RADIOACTIVITY dose rate Alrakkah SAUDI ARABIA
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SiC探测器的中子和γ性能测试
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作者 施海宁 应红 +4 位作者 张涛 唐堂 宋金霖 龚频 汤晓斌 《核技术》 EI CAS CSCD 北大核心 2024年第3期65-70,共6页
第三代SiC半导体探测器具有体积小、响应时间快、中子/伽马(n/γ)甄别容易等优点,广泛应用于反应堆堆芯剂量监测。本文针对自研的第三代SiC半导体探测器,采用电子束蒸发真空镀膜的技术将中子转换层材料^(6)LiF(^(6)Li丰度为95%)喷镀到Si... 第三代SiC半导体探测器具有体积小、响应时间快、中子/伽马(n/γ)甄别容易等优点,广泛应用于反应堆堆芯剂量监测。本文针对自研的第三代SiC半导体探测器,采用电子束蒸发真空镀膜的技术将中子转换层材料^(6)LiF(^(6)Li丰度为95%)喷镀到SiC基底上,厚度为25μm,实现了中子转换层厚度优化。利用^(241)Amα放射源(活度9.37×10^(3)Bq)开展α粒子响应信号幅度的测量,并在^(137)Csγ放射源(活度6.23×10^(7)Bq)环境下开展γ射线的响应测试。另外,在标准辐射场系统中进行了SiC探测器的中子注量率响应线性度测量、γ剂量率响应线性度测量以及中子注量率响应线性标定。结果表明:该探测器在1×10^(3)~1×10^(6)cm^(−2)·s^(−1)中子注量率范围内线性响应拟合R^(2)=0.9969,具有良好的线性响应,n/γ剂量响应范围为0.005~20 Gy∙h^(−1),可用于核电现场反应堆中子和γ剂量的实时、精确监测。 展开更多
关键词 碳化硅探测器 中子注量率 γ剂量 线性响应
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利用地面γ总量转换为空气吸收剂量率进行环境辐射水平评价——以桂阳县潘家村和永兴县土桥村实测数据为例
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作者 刘俊峰 彭文彪 +7 位作者 陶峰 孟繁星 韦光景 刘虹 邓居智 陈辉 付宸 王培建 《物探与化探》 CAS 2024年第3期868-875,共8页
在长期的铀矿普查中,我国积累了海量的γ总量数据资料,但应用这些数据进行放射性环境评价的研究极少。本文从γ总量和空气吸收剂量率的测量原理出发,通过梳理γ总量、放射性核素含量与空气吸收剂量率之间的关系,建立起地面γ总量与空气... 在长期的铀矿普查中,我国积累了海量的γ总量数据资料,但应用这些数据进行放射性环境评价的研究极少。本文从γ总量和空气吸收剂量率的测量原理出发,通过梳理γ总量、放射性核素含量与空气吸收剂量率之间的关系,建立起地面γ总量与空气吸收剂量率之间的联系,分析了仪器参数对测量误差的影响,认为γ总量仪器bK/bU=2.287、bTh/bU=0.430时,测量的γ总量与空气吸收剂量率满足严格线性关系,因此γ总量仪器的bK/bU、bTh/bU值越接近这两个数值,测得的γ总量转换为空气吸收剂量率越准确;利用湖南省电离辐射计量站模型进行了γ总量转换为空气吸收剂量率的系数求解,并分析了误差,推测了仪器参数中钾的铀当量值、钍的铀当量值的大致范围;在郴州市桂阳县潘家村岩体和郴州市永兴县土桥村灰岩地区进行了γ总量、γ能谱、空气吸收剂量率的同点位实测,结果显示,当核素含量比CK/CU均值小于1、CTh/CU均值小于3时,利用γ总量(FD3013仪器测得)估算的空气吸收剂量率与利用Beck公式根据能谱估算的空气吸收剂量率的误差基本处于同等水平,均方根误差均小于15%。根据国内核素的CK/CU、CTh/CU均值,认为国内大部分地区可以利用由FD3013仪器(或类似性能仪器)测得的γ总量数据估算空气吸收剂量率。利用已有铀矿普查资料中的γ总量数据转换计算有效空气吸收剂量率,为快速大面积评估环境天然放射性外照射水平提供了方法参考。 展开更多
关键词 γ总量 Γ能谱 核素(铀、钍、钾)含量 空气吸收剂量率
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宫颈癌调强放射治疗三维在体剂量验证分析及最佳γ通过率阈值
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作者 王佳浩 谢洪玲 +1 位作者 陈玉凯 唐秋 《中国医学物理学杂志》 CSCD 2024年第7期803-807,共5页
目的:对宫颈癌调强放射治疗(IMRT)进行基于电子射野影像装置的三维在体剂量验证(EIVD)分析,研究测量剂量与计划剂量间的差异,并通过剂量学敏感性探讨EIVD质控中最佳γ通过率阈值。方法:回顾性分析浙江大学医学院附属妇产科医院行IMRT的4... 目的:对宫颈癌调强放射治疗(IMRT)进行基于电子射野影像装置的三维在体剂量验证(EIVD)分析,研究测量剂量与计划剂量间的差异,并通过剂量学敏感性探讨EIVD质控中最佳γ通过率阈值。方法:回顾性分析浙江大学医学院附属妇产科医院行IMRT的45例宫颈癌患者,所有患者在治疗过程中行EIVD验证,获取测量剂量。采用2mm/2%、2mm/3%、3mm/3%的全局γ指标进行通过率分析,采用剂量体积直方图参数评估测量剂量和计划剂量之间的差异。通过皮尔逊(Pearson)相关性分析研究γ通过率与剂量学差异间的相关性,绘制受试者工作特征(ROC)曲线确定最佳γ通过率阈值。结果:3类γ指标2mm/2%、2mm/3%、3mm/3%的平均通过率分别为(83.07±5.25)%、(91.69±3.52)%、(95.02±2.46)%;EIVD测量剂量与计划剂量在计划靶区(PTV)的平均剂量(Dmean)偏差为2.43%(P=0.016),膀胱、直肠、小肠的Dmean偏差分别为0.35%、0.46%、0.30%(P>0.05)。Pearson分析显示3类γ指标与PTV的剂量偏差相关性较强(r>0.7),与危及器官相关性较弱(r<0.7);ROC分析显示2mm/2%、2mm/3%、3mm/3%最佳的γ通过率阈值分别为79.06%、90.04%、94.19%。结论:EIVD能够有效保证宫颈癌IMRT过程中PTV剂量传递的精准性,利用γ通过率阈值能够为下一步宫颈癌自适应IMRT提供一定的临床依据。 展开更多
关键词 宫颈癌 在体剂量验证 剂量学 γ通过率
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最小子野宽度对原发性肝癌IMRT计划的剂量分布和实施精度的影响
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作者 季洪兵 王凯 +1 位作者 吴嘉慧 刘文晖 《中国医学物理学杂志》 CSCD 2024年第10期1211-1215,共5页
目的:通过对原发性肝癌调强放射治疗(IMRT)计划的最小子野宽度参数进行研究,评价不同最小子野宽度下治疗计划的剂量分布和实施精度,为肿瘤患者放疗计划制作提供参考。方法:选取30例原发性肝癌患者资料,保持其它优化条件不变,改变最小子... 目的:通过对原发性肝癌调强放射治疗(IMRT)计划的最小子野宽度参数进行研究,评价不同最小子野宽度下治疗计划的剂量分布和实施精度,为肿瘤患者放疗计划制作提供参考。方法:选取30例原发性肝癌患者资料,保持其它优化条件不变,改变最小子野宽度,分别为0.6、0.8、1.0、1.2、1.5 cm,对每例患者制作5个IMRT计划,比较5个计划的剂量分布、执行效率和Gamma通过率。结果:这5个计划的机器跳数和出束时间随着最小子野宽度的增加而减少;3 mm/3%、2 mm/2%阈值下的Gamma通过率则呈现增加趋势,且具有统计学差异(P<0.05)。结论:研究所用的5个计划均能够用于临床治疗,在满足临床要求的同时,合理地设置IMRT计划中的最小子野宽度,可以降低机器跳数,缩短治疗时间,又可以提高治疗精度。 展开更多
关键词 原发性肝癌 最小子野宽度 实施精度 剂量验证 gamma通过率
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基于ArcCheck模体放疗计划的验证与分析
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作者 蔡丹婷 《现代仪器与医疗》 CAS 2024年第3期29-33,共5页
目的为了保证放疗剂量输出的准确性,对放疗患者的临床放疗计划进行了验证与分析。方法选取2023年7—10月南方医科大学珠江医院放疗患者的临床放疗计划,共217例计划,其中头颈部76例,胸部82例,腹盆部59例。采用美国SunNuclear公司的ArcCh... 目的为了保证放疗剂量输出的准确性,对放疗患者的临床放疗计划进行了验证与分析。方法选取2023年7—10月南方医科大学珠江医院放疗患者的临床放疗计划,共217例计划,其中头颈部76例,胸部82例,腹盆部59例。采用美国SunNuclear公司的ArcCheck模体,比较临床放疗计划与验证计划的剂量学差异。采用T test分析在不同容许剂量差值和不同容许距离差值下的Gamma通过率,ANOVA test比较在相同条件下,不同放疗部位放疗计划的Gamma通过率。所有数据分析采用IBM公司的SPSS v27.0完成。结果在容许剂量差值为3%,容许距离差值为3.0mm和在容许剂量差值为2%,容许距离差值为2.0mm下的Gamma通过率比较,差异有统计学意义(P<0.05)。在相同容许剂量差值和容许距离差值下,不同放疗部位的Gamma通过率比较,差异无统计学意义(P>0.05)。结论在容许剂量差值为3%,容许距离差值为3.0mm的条件下,放疗计划的Gamma通过率显著高于容许剂量差值为2%,容许距离差值为2.0mm条件下的计划Gamma通过率,并且条件设置越严格,Gamma通过率越低。在相同容许剂量差值和容许距离差值下,不同放疗部位放疗计划的Gamma通过率不存在显著性差异。Gamma通过率受容许剂量差值和距离差值的影响,同时做好对直线加速器,计划系统等的日常的质量控制与保证也能提高Gamma通过率。 展开更多
关键词 调强放射治疗 ArcCheck模体 放疗计划 剂量验证 gamma通过率
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放疗计划参数对剂量验证计划γ通过率的相关性研究 被引量:1
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作者 游鸿强 《中国卫生标准管理》 2024年第4期105-109,共5页
目的 探讨头颈部放疗计划参数对剂量验证计划γ通过率的相关性。方法 选取2019年11月—2021年9月福建肿瘤医院放疗中心收治的184例放射治疗的头颈部肿瘤患者。其中85例采用调强放疗(intensity-modulated radio therapy,IMRT)计划,99例... 目的 探讨头颈部放疗计划参数对剂量验证计划γ通过率的相关性。方法 选取2019年11月—2021年9月福建肿瘤医院放疗中心收治的184例放射治疗的头颈部肿瘤患者。其中85例采用调强放疗(intensity-modulated radio therapy,IMRT)计划,99例采用容积旋转调强放疗(volumetric modulated arc therapy,VMAT)计划,通过电子射野影像装置,使用ArcCHECK分别对IMRT和VMAT计划进行计量验证,并在不同的γ分析标准(选取1%/1 mm,2%/2 mm和3%/3 mm)下验证剂量通过率。分析不同放疗计划中射野复杂度指标,并判断其射野复杂度指标与γ通过率的相关性。结果 VMAT计划在1%/1 mm标准下γ通过率低于IMRT计划,差异有统计学意义(P <0.05);VMAT计划和IMRT计划在2%/2 mm标准下γ通过率分别为(90.72±2.84)%、(90.59±5.19)%,在3%/3 mm标准下γ通过率分别为(97.02±1.71)%、(98.64±1.00)%,2种计划在3%/3 mm标准下的平均γ通过率均较高,在2%/2 mm标准下的平均γ通过率均有所下降,2种计划比较差异无统计学意义(P> 0.05)。在不同射野复杂度指标中,VMAT计划的计划标准跳数(plan normalized MU,PMU)、计划平均射野不规则性(plan averaged beam irregularity,PI)、计划平均射野调制(plan averaged beam modulation,PM)均大于IMRT计划,VMAT计划的平均调制复杂度分数(modulation complexity score,MCS)、计划平均射野面积(plan averaged beam area,PA)小于IMRT计划,差异有统计学意义(P <0.05)。Spearman相关性检验结果表明,IMRT计划中,在2%/2 mm标准下,MCS、PM和γ通过率呈弱相关性(|r|<0.4,P <0.05),PMU和γ通过率呈中度相关性(0.4≤|r|≤0.7,P <0.05),在3%/3 mm标准下,PMU、MCS、PM和γ通过率呈中度相关性(0.4≤|r|≤0.7,P <0.05);PA、PI与γ通过率均无相关性(P> 0.05);VMAT计划中,在2%/2 mm标准下,PMU、MCS、PI、PM和γ通过率呈中度相关性(0.4≤|r|≤0.7,P <0.05),在3%/3 mm标准下,PMU、MCS、PM、PI和γ通过率呈中度相关性(0.4≤|r|≤≤0.7,P <0.05),PA与γ通过率均无相关性(P> 0.05)。结论射野复杂度指标与γ通过率具有不同程度的相关性,可在剂量验证前调整射野指标辅助设计放疗计划。 展开更多
关键词 头颈部肿瘤 调强放疗 容积旋转调强放疗 剂量验证 射野指标 γ通过率
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SRS MapCHECK与EDOSE在立体定向放疗计划剂量验证中的对比 被引量:7
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作者 袁玲 刘颖 +4 位作者 徐瑶瑶 张红利 张晓鹏 王鑫 石兴源 《中国医学物理学杂志》 CSCD 2022年第1期23-27,共5页
目的:使用SRS MapCHECK和EDOSE对立体定向放疗(SRT)计划进行剂量验证,并比较它们的验证结果。方法:首先比较两种系统在不同方野(2 cm×2 cm、4 cm×4 cm、6 cm×6 cm、10 cm×10 cm)的γ通过率(3%/3 mm),然后选择29例SR... 目的:使用SRS MapCHECK和EDOSE对立体定向放疗(SRT)计划进行剂量验证,并比较它们的验证结果。方法:首先比较两种系统在不同方野(2 cm×2 cm、4 cm×4 cm、6 cm×6 cm、10 cm×10 cm)的γ通过率(3%/3 mm),然后选择29例SRT计划,分析两种系统在不同γ标准下的绝对剂量通过率,最后分析EDOSE建立的4种不同物理模型对SRT计划剂量验证的影响。结果:SRS MapCHECK在所有方野和29例SRT计划的绝对剂量γ通过率均高于EDOSE,两者的验证结果有统计学差异(P<0.05);SRS MapCHECK及EDOSE在29例SRT计划的γ通过率(2%/2 mm)分别是为98.60%±2.14%和96.53%±2.41%。基于EDOSE的不同物理模型验证结果有统计学差异,平均γ通过率(2%/2 mm)偏差为1.8%~5.1%。结论:SRS MapCHECK和EDOSE系统均满足SRT计划剂量验证的要求,且SRS MapCHECK的剂量验证通过率优于EDOSE;不同的EDOSE物理模型对SRT计划剂量验证有影响。 展开更多
关键词 立体定向放疗 SRS MapCHECK Edose γ通过率 剂量验证
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桂阳潘家庄地区地表γ辐射空气吸收剂量率估算与放射性环境评价
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作者 孟繁星 刘俊峰 +2 位作者 韦光景 郭军 黄乐清 《工程地球物理学报》 2024年第2期238-246,共9页
桂阳潘家庄地区花岗岩大面积出露,导致土壤中的放射性核素活度浓度普遍偏高。较高的γ辐射空气吸收剂量是否存在风险成为人们关心的问题。本文通过已有γ伽玛能谱测量数据估算出地表γ辐射空气吸收剂量率,根据地表γ辐射空气吸收剂量率... 桂阳潘家庄地区花岗岩大面积出露,导致土壤中的放射性核素活度浓度普遍偏高。较高的γ辐射空气吸收剂量是否存在风险成为人们关心的问题。本文通过已有γ伽玛能谱测量数据估算出地表γ辐射空气吸收剂量率,根据地表γ辐射空气吸收剂量率与人居环境适宜性的关系,从而进行人居环境适宜性分区。得出γ辐射安全区197.90 km^(2),占全区面积的98.95%;风险区1.42 km^(2),占0.71%;管制区仅0.68 km^(2);表明潘家庄地区天然放射性人居环境优良。本文可为该地区人居环境选址、合理、有效地利用潘家庄地区的国土资源提供支持,也可对加速潘家庄地区乡村健康与可持续发展提供必要的参考。 展开更多
关键词 桂阳潘家庄 Γ能谱 放射性水平 空气吸收剂量率 人居环境安全
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Measurement of Gamma-Rays Using Smartphones 被引量:3
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作者 Sandy Tith Nares Chankow 《Open Journal of Applied Sciences》 2016年第1期31-37,共7页
The CMOS (Complementary Metal Oxide Semiconductor) image sensor of a smartphone has been known for its sensitivity to gamma-rays. In this research, some smartphones were selected and tested for measurement of gamma-ra... The CMOS (Complementary Metal Oxide Semiconductor) image sensor of a smartphone has been known for its sensitivity to gamma-rays. In this research, some smartphones were selected and tested for measurement of gamma-rays emitted from Cesium-137 and Iridium-192 sources. During measurements, the phones were set in video mode while the camera lenses were covered with black adhesive tape to prevent light exposure. Interaction of gamma-rays with the CMOS appeared as flashing bright spots on the image. The bright spots were then counted by using the freely available ImageJ software. Preliminary results indicated that the number of bright spots increased linearly with increase of gamma-ray dose rate. An in-house Android application software was then developed for real-time counting of the bright spots. The application software also allowed users to input a calibration equation so that the phones could simultaneously convert the count rate to display in dose rate. This research demonstrated that, after appropriate calibration, smartphones could be used as gamma-ray measuring devices for radiation safety control involving high activity sources such as in industrial radiography, gamma-ray irradiation facility and medical treatment. 展开更多
关键词 gamma-RAY dose rate Smartphones Radiation Safety Industrial Radiography CMOS Image Sensor Cesium-137 Iridium-192 Android
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Gamma radiation levels in the ambient environment of the QNPP Base
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作者 WENG Jianqing HE Jun XIANG Yuanyi WANG Kan LI Xia HAN Zhengdong 《Nuclear Science and Techniques》 SCIE CAS CSCD 2007年第6期366-371,共6页
Monitoring results of gamma dose rate level in 1992~2004 in the ambient environment of the Qinshan Nuclear Power Plants(QNPP)Base,the northeast of Zhejiang Province,are reported in this paper.It is shown that the gam... Monitoring results of gamma dose rate level in 1992~2004 in the ambient environment of the Qinshan Nuclear Power Plants(QNPP)Base,the northeast of Zhejiang Province,are reported in this paper.It is shown that the gamma dose rate of five monitoring sites of 2.5 km to QNPP Base is 84~113 nGy/h,with an average of 96 nGy/h in the 13 years.The average value is close to the background level of 93 nGy/h prior to operation of the QNPP Base,and is lower than the monitoring result of 101 nGy/h at the reference site in Hangzhou City.Within 50 km from the QNPP Base,the cumulative dose rate of the thermoluminescent dosimeter(TLD)is 90 nGy/h,which is lower than the back- ground level of 111 nGy/h. 展开更多
关键词 Α射线 环境辐射 监测系统 辐射污染
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Micro-Tuber Production in Diploid and Tetraploid Potato after Gamma Irradiation of in Vitro Cuttings for Mutation Induction
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作者 Souleymane Bado Margit Laimer +5 位作者 Ndiogou Gueye Ndeye Fatou Deme Enoch Sapey Abdelbagi Mukhtar Ali Ghanim Vivian Carol Blok Brian Peter Forster 《American Journal of Plant Sciences》 2016年第14期1871-1887,共18页
Micro-tubers are important propagules in potato breeding and potato production, and they are also dormant and easily transported and therefore good targets for mutation induction in potato mutation breeding. A prerequ... Micro-tubers are important propagules in potato breeding and potato production, and they are also dormant and easily transported and therefore good targets for mutation induction in potato mutation breeding. A prerequisite for mutation breeding is to determine optimal mutation treatments. Therefore, radio-sensitivity tests of a tetraploid and a diploid potato to gamma irradiation were undertaken. Effects of different gamma sources on radio-activity were also studied. In vitro potato cuttings were gamma irradiated using a wide dose range (0, 3, 6, 9, 12, 15 and 20 Gy). The irradiated cuttings were then cultured to induce micro-tubers directly in vitro. Micro-tuber morphotypes were assessed after irradiation of cuttings using three gamma sources with emission activities of 1.8, 7.07 and 139 Gy/min. The diploid species (Solanum verrucosum) was more radio-sensitive than the tetraploid cultivar Desirée (Solanum tuberosum). Gamma dose rates had significant influences on subsequent micro-tuber production at various mutant generations. Effects included reductions in the number, size and weight of micro-tubers produced. Gamma dose was more lethal for the diploid potato genotype and micro-tubers produced were small compared to those produced by the tetraploid genotype after irradiation. Different treatments are recommended for diploid and tetraploid potato irradiation in producing large mutant micro-tuber populations. The mutant micro-tuber populations may then be screened for interesting mutations/trait for both genetics and plant breeding purposes. 展开更多
关键词 POTATO in Vitro Cuttings Micro-Tubers Mutation Induction gamma Irradiation Mutant Populations Recommended dose rates
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新疆伊犁盆地南缘天然放射性水平评价 被引量:1
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作者 李秋实 陈晓冬 +1 位作者 陈瑞 李炳谦 《矿产勘查》 2023年第2期223-228,共6页
本文根据新疆伊犁盆地南缘1∶2.5万地面γ能谱测量中的铀、钍、钾含量数据,对新疆伊犁盆地南缘地表介质的天然放射性进行了研究和评价。测量结果显示,该地区地表介质中放射性核素^(238)U、^(232)Th和^(40)K的比活度,分别为6.14~2584.64 ... 本文根据新疆伊犁盆地南缘1∶2.5万地面γ能谱测量中的铀、钍、钾含量数据,对新疆伊犁盆地南缘地表介质的天然放射性进行了研究和评价。测量结果显示,该地区地表介质中放射性核素^(238)U、^(232)Th和^(40)K的比活度,分别为6.14~2584.64 Bq/kg、2.86~105.63 Bq/kg、11.58~2190.83 Bq/kg。γ射线空气吸收剂量率均值为75.56 nGy/h,低于全国(81.50 nGy/h)和世界(80.00 nGy/h)的平均值;内、外照射指数和年有效剂量都在国家限量标准控制范围内。研究区局部放射性水平相对偏高,与含铀地层露头受自然动力和人类活动等作用下铀元素扩散有关;由于含铀地层露头规模有限,其对放射性环境的影响具有强度小、范围小、不均匀特征。 展开更多
关键词 Γ能谱测量 γ射线空气吸收剂量率 年有效剂量 放射性水平
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受天然放射性核素污染场地土壤放射性调查工作内容及程序研究
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作者 尹海华 吴群 +1 位作者 詹国清 胡恪 《核安全》 2023年第4期54-59,共6页
本文参考建设用地土壤污染状况调查的工作内容及程序,结合放射性核素污染特征及其在环境介质中的迁移规律等,归纳总结了一套受天然放射性核素污染场地土壤放射性调查的工作内容及程序,为土壤放射性污染调查提供参考。将土壤放射性污染... 本文参考建设用地土壤污染状况调查的工作内容及程序,结合放射性核素污染特征及其在环境介质中的迁移规律等,归纳总结了一套受天然放射性核素污染场地土壤放射性调查的工作内容及程序,为土壤放射性污染调查提供参考。将土壤放射性污染调查分为第一阶段土壤放射性污染调查和第二阶段土壤放射性污染调查,调查内容包括资料收集、现场踏勘、现场采样与监测、室内分析、报告编制等,监测项目包括地表环境γ辐射剂量率,土壤及地下水中^(238)U、^(232)Th、^(226)Ra核素浓度。根据工作内容及程序对两个可能受天然放射性核素污染的场地土壤进行调查,以评价工业过程对工矿企业场地土壤中放射性核素浓度的影响。调查结果表明该调查的工作内容及程序可行。 展开更多
关键词 天然放射性核素 土壤放射性污染调查 伴生放射性物料 环境γ辐射剂量率
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基于电子射野影像装置的肺部肿瘤立体定向体部放射治疗在体三维剂量验证模体研究及临床应用
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作者 王鹏飞 刘晓 +6 位作者 毛荣虎 李兵 郭伟 王保胜 葛红 雷宏昌 王祥 《郑州大学学报(医学版)》 CAS 北大核心 2023年第6期841-847,共7页
目的:探讨基于电子射野影像装置的肺部肿瘤立体定向体部放射治疗在体三维剂量验证模体研究及临床应用。方法:通过电子射野影像装置在体三维剂量验证系统,在静态和动态模体上测试不同立体定向体部放射治疗照射技术计划(静态调强、滑窗调... 目的:探讨基于电子射野影像装置的肺部肿瘤立体定向体部放射治疗在体三维剂量验证模体研究及临床应用。方法:通过电子射野影像装置在体三维剂量验证系统,在静态和动态模体上测试不同立体定向体部放射治疗照射技术计划(静态调强、滑窗调强、旋转调强及适形、动态适形旋转治疗),比较在体三维剂量分布5种剂量/距离一致性标准(5%/2 mm、3%/3 mm、3%/2 mm、3%/1 mm、2%/2 mm)的γ通过率,检测计划照射精度,并对临床肺立体定向体部放射治疗病例进行在体三维剂量验证靶区和危及器官剂量体积分析。结果:模体研究结果显示,在静态模体中静态调强、滑窗调强、旋转调强照射方式γ通过率差异无统计学意义(P均>0.05),在动态模体中静态调强计划γ通过率偏低,其他照射方式计划之间相近。临床应用结果显示,临床病例在体三维剂量验证3%/3 mm标准明显低于治疗前剂量验证结果,剂量体积直方图分析中体积变化大的危及器官存在较大剂量偏差。结论:基于电子射野影像装置的肺部肿瘤立体定向体部放射治疗在体三维剂量验证,能为肺部肿瘤立体定向体部放射治疗治疗期间剂量投照的准确性提供有效安全性检查,可应用于临床,为自适应治疗提供基础。 展开更多
关键词 肺部肿瘤 电子射野影像装置 立体定向体部放射治疗 在体三维剂量验证 γ通过率
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应用约束最小二乘方滤波法校正放疗3D剂量验证辐射荧光图像
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作者 杜永欢 杨悦 +2 位作者 董顺成 张佩毅 文万信 《中国医学物理学杂志》 CSCD 2023年第9期1083-1090,共8页
目的:通过约束最小二乘方滤波法对塑料闪烁体在射束辐照下的荧光图像进行校正,提高基于闪烁体辐射荧光的放疗3D剂量验证系统的准确性。方法:首先对正交三视角度拍摄的辐射荧光投影图进行去噪预处理,同时通过Zemax光学模拟软件计算出成... 目的:通过约束最小二乘方滤波法对塑料闪烁体在射束辐照下的荧光图像进行校正,提高基于闪烁体辐射荧光的放疗3D剂量验证系统的准确性。方法:首先对正交三视角度拍摄的辐射荧光投影图进行去噪预处理,同时通过Zemax光学模拟软件计算出成像系统的点扩散函数(PSF),并用洛伦兹函数对其进行拟合调整。其次使用约束最小二乘方滤波法对去噪预处理后的正交三视投影图进行去卷积处理。最后将校正前后图像进行3D剂量分布重建,并分别与Pinnacle3治疗计划系统中计算的剂量分布数据进行比较。结果:对于4 cm×4 cm、3 cm×3 cm方野照射,应用约束最小二乘方滤波法校正后的平均2D Gamma通过率(阈值10%,3%/3 mm标准)分别提高了22.95%和5.76%,中心轴上的百分深度剂量(PDD)曲线的均方根误差(RMSE)值分别降低了1.13%和0.63%。对于2 cm×2 cm方野照射,滤波校正后的平均2D Gamma通过率(阈值20%,3%/3 mm标准)提高了1.54%,PDD曲线的RMSE值降低了0.49%。结论:在3D剂量重建前对正交三视投影图进行图像校正可以有效提高基于塑闪辐射荧光3D剂量验证系统的准确性。 展开更多
关键词 剂量验证 约束最小二乘方滤波 点扩散函数 gamma通过率
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