曲面体层摄影受检者的X线辐射剂量研究

目的：测量颌骨牙列曲面体层摄影人体不同组织器官的X线吸收剂量,并计算当量剂量、有效剂量以及涎腺有效剂量。方法：使用仿真成年人体模测量颌骨牙列曲面体层摄影时腮腺、颌下腺、舌下腺、下颌骨表面、眼晶体、垂体、受照区皮肤、颈椎红骨髓、甲状腺、乳腺、卵巢以及睾丸等器官组织的X线吸收剂量,计算各器官组织的X线当量剂量、有效剂量以及涎腺有效剂量。结果：X线吸收剂量0μGy~730.50μGy,当量剂量0μSv~730.50μSv,有效剂量36.28μSv,涎腺有效剂量47.78μSv。结论：颌骨牙列曲面体层摄影受检者X线吸收剂量、当量剂量、有效剂量均较小,对眼晶体、甲状腺、性腺等敏感器官组织有较高安全性,从放射防护角度,使用曲面体层摄影观察上下颌牙列、牙槽骨的形态是合理的。     

俄罗斯加盟共和国各组居民照射水平的估计

俄罗斯加盟共和国1979年居民总数为135百万人,如以天然辐射的有效剂量当量(H_E)等于2mSv/年计算,则该共和国居民天然辐射源所致集体有效剂量当量(S_E)为260·10~3人·Sv/年,其内、外照射份额相应为80·10~3和180·10~3人·Sv/年。由所有来源的放射性核素所致S_E为2.9·10~3人·Sv/年,其中城市和农村相应为1.6·10~3和1.3·10~3人Sv/年。     

99Tcm-MDP全身骨显像受检者外照射剂量的研究

目的 研究99Tcm-亚甲基二膦酸盐（MDP）全身骨显像受检者对非核医学科人员的外照射剂量,以有效减少非受检者的受照辐射剂量。 方法 选取 2018年8月至2019年1月在中国科学技术大学附属第一医院行99Tcm-MDP全身骨显像的51例受检者进行回顾性研究,其中男性26例、女性25例,年龄22~91（62.23±13.36）岁。所有受检者注射925 MBq 99Tcm-MDP后,根据饮水1000 mL后0.5 h内有无排尿分为排尿组（n=39）和未排尿组（n=12）,检测注射药物后0.5、1、2、3、4、6 h时受检者腹部和头部水平距离0.5、1、2、4、6 m处的辐射剂量当量率和累积剂量当量。2组间比较采用两独立样本的Mann-Whitney U检验,多次测量的不同时间、不同距离辐射剂量当量率的比较采用重复测量方差分析,配对样本采用非参数Wilcoxon检验。 结果 排尿组受检者在腹部水平距离0.5、1、2、4、6 m处的辐射剂量当量率均低于未排尿组[（40.29±4.67）μSv/h对（77.29±10.71）μSv/h、（15.22±1.64）μSv/h对（29.48±4.56）μSv/h、（4.15±0.47）μSv/h对（7.45±1.07）μSv/h、（1.32±0.10）μSv/h对（2.63±0.31）μSv/h、（0.45±0.05）μSv/h对（0.78±0.15）μSv/h],且差异均有统计学意义（Z=5.148~5.251,均P<0.001）。排尿组受检者腹部和头部的辐射剂量当量率均随着时间和距离的增加而迅速降低,且差异有统计学意义（F=3105.426~5397.675,均P<0.001）;排尿组受检者的辐射剂量当量率随着药物注射后时间的延长而显著下降。与排尿组受检者腹部水平距离0.5 m处6 h的累积剂量当量[（148.51±13.83）μSv]相比,1 m处6 h的累积剂量当量[（55.85±5.22）μSv]显著下降,且差异有统计学意义（Z=5.610,P<0.001）;与排尿组受检者头部水平距离0.5 m处6 h的累积剂量当量[（132.74±12.95）μSv]相比,1 m处6 h的累积剂量当量[（49.88±4.72）μSv]显著下降,且差异有统计学意义（Z=5.438,P<0.001）;排尿组受检者的累积剂量当量随着照射时间的延长而增加、随着距离的增加而减少。 结论 99Tcm-MDP全身骨显像对于非核医学科人员的照射剂量远远小于国内、国际法律规定限值（个人年有效剂量当量≤1 mSv）,与注射药物后3 h的受检者距离1 m以上即可避免大部分额外辐射。     

湖北省天然本底辐射照射所致公众剂量

根据环境贯穿辐射, 大气中氡氧气和食品中天然放射性核素的测定结果, 对全省居民由天然本底辐射所致剂量当量进行了估算。结果表明, 全省居民(成人)由天然本底辐射照射所致总的人均有效剂量当量约为2030uSv/a, 集体年有效剂量当量为9.7×10⁴人·Sv; 其中宇宙射线(电离成分+中子成分), 地球Y射线、大气中氡氧气和人体内照射所致人均有效剂量当量分别为305、557、820和347uSv/a。     

安徽省医疗照射频度及剂量水平

本文报道了女徽省医疗照射频度和剂量水平.结果表明;医用诊断X线照射年频度为115.79人次/千人口,其中以胸透的年频度为最高。核医学照射的年频度为0.431人次/千人口,其中以肾图和甲状腺吸碘试验的频度为最高。放射治疗的年频度为1.98人次/千人口,其中以食管癌的照射频度为最高,由医用诊断X线照射所致年人均有效剂量当量为65.66μSv;核医学所致居民年人均有效剂量当量为5.76μSv;放射治疗因大多数为恶性肿瘤患者存活期不长,没有就其对集体剂量当量的贡献加以估算,但疗程皮肤吸收剂量平均为81.2Gy。     

山西省食品和饮水中天然放射性水平及其所致居民内照射剂量的研究

本文介绍了山西省饮用水和主要食品中天然放射性核素铀、钍、镭-226、钾-40放射性水平、估算了山西省居民上述诸核素的年摄入量及其所致待积有效剂量当量。结果表明,每年每人由饮食摄入天然铀、钍、镭-226、钾-40所致待积有效剂量当量之和为200μSv,其中钾-40贡献180μSv(占90%),镭-226贡献8μSv(占4%),钍贡献为6μSv(占3%),天然铀贡献为6μSv(占3%)。按山西膳食组成特点所得的估算表明,对总待积有效剂量当量贡献最大的是杂粮和饮水,各占31.7%和27.3%,其中不包括钾-40。     

18F-FDG PET显像中受检者周围人员的辐射剂量监测

目的　为1 8F 脱氧葡萄糖 (FDG)PET显像过程中工作和陪护人员的临床辐射防护提供参考数据。方法　用辐射剂量仪分别测量 30例工作人员在注射室、显像室的剂量当量率及受检者注射1 8F FDG后即刻、1和 2h距前胸 0 1、0 5、1 0、2 0m的剂量当量率 ,计算每例检查每一步操作的剂量当量和各工作场所工作人员的年剂量当量。结果　工作人员每例各步操作平均个人剂量当量为药品分装 :左手 (30 0± 8 0 ) μSv,右手 (6 0± 1 5 ) μSv ,全身 (0 5± 0 1) μSv;注射 :手部 (3 0 0± 0 75 )μSv,全身 (1 2 7± 0 2 0 ) μSv ;摆位和采集 ,结束采集共 (9 9± 1 4 ) μSv;密切接触的陪护人员为 (310±91) μSv。各工作场所工作人员的累计年剂量当量分别为 :药品分装及注射 :左手 (16 6 3± 4 4 1)mSv,右手 (6 4 5± 1 2 3)mSv ,全身 (1 18± 0 15 )mSv;显像采集 :全身 (4 99± 0 70 )mSv。结论　通过现有防护设施和方法 ,工作人员和陪护人员的受照剂量均未超过国家辐射安全标准 (GBSS)关于职业及公众个人年剂量限值。     

河南省食品和水中天然放射性核素水平及内剂量估算

为获得河南省食品和水中天然放射性核素含量及其所致居民的待积有效剂量当量,我们调查了12种食品和4种水样中U、Th、²²⁶Ra含量。估算了当地居民的年摄入量及所致待积有效剂量当量。我省成年男子对U、Th、²²⁶Ra三种核素的年总摄入量约为100Bq,所致总待积有效剂量当量约为27μSv。     

世界范围的医疗照射

联合国辐射效应科学委员会(UNSCEAR)估算了世界范围的医疗照射水平,年有效集体剂量当量为2×10~6～5×10~9人·Sv,其中90%～95%是医     

四川省主要食品和饮水中放射性水平及所致居民内照射剂量的评价

本文报道了四川省19个地、市、州居民的主、副食和钦用水中的铀-238、铀-234、钍-232、镭-226、钾-40、钋-210、碳-14和氢-3的放射性水平,并计算出四川省居民因膳食所致农村居民有效待积剂量当量为122μSv,城市居民为97.2μSv,全省人均有效待积剂量当量为109.6μSv,属正常天然辐射水平。     

Radiation exposure of medical staff from interventional x-ray procedures: a multicentre study

The purpose of this study was to analyse the radiation exposure of medical staff from interventional x-ray procedures. Partial-body dose measurements were performed with thermoluminescent dosimeters (TLD) in 39 physicians and nine assistants conducting 73 interventional procedures of nine different types in 14 hospitals in Germany. Fluoroscopy time and the dose–area product (DAP) were recorded too. The median (maximum) equivalent body dose per procedure was 16 (2,500) μSv for an unshielded person; the partial-body dose per procedure was 2.8 (240) μSv to the eye lens, 4.1 (730) μSv to the thyroid, 44 (1,800) μSv to one of the feet and 75 (13,000) μSv to one of the hands. A weak correlation between fluoroscopy time or DAP and the mean TLD dose was observed. Generally, the doses were within an acceptable range from a radiation hygiene point of view. However, relatively high exposures were measured to the hand in some cases and could cause a partial-body dose above the annual dose limit of 500 mSv. Thus, the use of finger dosimeters is strongly recommended.     

Activity of administered radiopharmaceutical agents and the radiation burden of the Czechoslovak population caused by nuclear medicine

The authors assessed by means of questionnaires the activities of radiopharmaceuticals administered in departments of nuclear medicine in Czechoslovakia. The mean activities of individual radiopharmaceuticals are roughly equal as in Great Britain, but lower than in the Canadian province of Manitoba. The differences of activities used in different departments are approximately equal in all compared countries. In the Czech Republic the annual collective effective dose equivalent from nuclear medicine was 433 Sv in 1983 and 609 Sv in 1987. The mean effective dose equivalent per examination was 2.23 mSv in 1983 and 2.44 mSv in 1987. The mean effective dose equivalent per inhabitant of the Czech Republic was 0.042 mSv in 1983 and 0.059 mSv in 1987. The radiation dose of the Czech population from nuclear medicine amounts approximately to one tenth of the load from radiodiagnostics.     

Ambient and personal dose assessment of a container inspection site using a mobile X-ray system

Ambient monitor and phantom studies of absorbed and effective doses by TLDs were carried out in a non-intrusive inspection station for containers, Terminal I, of Taichung harbor, Taiwan. The doses from the X-ray scan in the control room and driver waiting room, located outside of the radiation control area, were quite small and could not be distinguished from the natural background radiation. The doses in the driver cab and the inspector cab of the X-ray scan car were also within background radiation levels. The protection wall, a 40-cm thick concrete barrier, can effectively attenuate the intensity of the primary X-ray scan. The possible effective dose of a person in the container or trailer is about 3.15±0.23 μSv/scan and 2.31±0.38 μSv/scan. This dose is below the annual background dose. If someone was to be scanned by the X-ray, the effective dose would be at an acceptable level.     

Thyroid shields for radiation dose reduction during cone beam computed tomography scanning for different oral and maxillofacial regions

Aims

To evaluate the radiation dose level during cone beam computed tomography (CBCT) scanning for the different oral and maxillofacial regions with and without thyroid collar shielding.

Materials and methods

Average tissue-absorbed dose for a DCT PRO CBCT was measured using thermoluminescent dosimeter chips in a phantom with or without applying thyroid collars. Effective organ dose and total effective dose were derived using International Commission on Radiological Protection (ICRP) 2007 recommendations.

Results

The total effective doses for large, middle and small field of view (FOV) were 254.3 μSv, 249.0 μSv and 180.3 μSv, respectively, when no thyroid collar was used. Applying one thyroid collar around the front neck can reduce the total effective doses to 208.5 μSv (18.0% reduction), 149.1 μSv (40.1% reduction) and 110.5 μSv (38.7% reduction), respectively. When two thyroid collars were used around the front and back neck, the total effective doses were reduced to 219.1 μSv (13.8% reduction), 142.0 μSv (43.0% reduction) and 105.5 μSv (41.5% reduction), respectively.

Conclusions

Thyroid collar can reduce the radiation dose during CBCT scanning for the oral and maxillofacial regions. The dose reduction becomes more significant when middle or small FOV is chosen.     

Radiation Exposure of Interventional Radiologists During Computed Tomography Fluoroscopy-Guided Renal Cryoablation and Lung Radiofrequency Ablation: Direct Measurement in a Clinical Setting

Introduction

Computed tomography (CT) fluoroscopy-guided renal cryoablation and lung radiofrequency ablation (RFA) have received increasing attention as promising cancer therapies. Although radiation exposure of interventional radiologists during these procedures is an important concern, data on operator exposure are lacking.

Materials and Methods

Radiation dose to interventional radiologists during CT fluoroscopy-guided renal cryoablation (n = 20) and lung RFA (n = 20) was measured prospectively in a clinical setting. Effective dose to the operator was calculated from the 1-cm dose equivalent measured on the neck outside the lead apron, and on the left chest inside the lead apron, using electronic dosimeters. Equivalent dose to the operator’s finger skin was measured using thermoluminescent dosimeter rings.

Results

The mean (median) effective dose to the operator per procedure was 6.05 (4.52) μSv during renal cryoablation and 0.74 (0.55) μSv during lung RFA. The mean (median) equivalent dose to the operator’s finger skin per procedure was 2.1 (2.1) mSv during renal cryoablation, and 0.3 (0.3) mSv during lung RFA.

Conclusion

Radiation dose to interventional radiologists during renal cryoablation and lung RFA were at an acceptable level, and in line with recommended dose limits for occupational radiation exposure.

     

Dosimetry of two extraoral direct digital imaging devices: NewTom cone beam CT and Orthophos Plus DS panoramic unit

OBJECTIVES: This study provides effective dose measurements for two extraoral direct digital imaging devices, the NewTom 9000 cone beam CT (CBCT) unit and the Orthophos Plus DS panoramic unit. METHODS: Thermoluminescent dosemeters were placed at 20 sites throughout the layers of the head and neck of a tissue-equivalent RANDO phantom. Variations in phantom orientation and beam collimation were used to create three different CBCT examination techniques: a combined maxillary and mandibular scan (Max/Man), a maxillary scan and a mandibular scan. Ten exposures for each technique were used to ensure a reliable measure of radiation from the dosemeters. Average tissue-absorbed dose, weighted equivalent dose and effective dose were calculated for each major anatomical site. Effective doses of individual organs were summed with salivary gland exposures (E(SAL)) and without salivary gland exposures (E(ICRP60)) to calculate two measures of whole-body effective dose. RESULTS: The effective doses for CBCT were: Max/Man scan, E(ICRP60)=36.3 micro Sv, E(SAL)=77.9 micro Sv; maxillary scan, E(ICRP60)=19.9 micro Sv, E(SAL)=41.5 micro Sv; and mandibular scan, E(ICRP60)=34.7 micro Sv, E(SAL)=74.7 micro Sv. Effective doses for the panoramic examination were E(ICRP60)=6.2 micro Sv and E(SAL)=22.0 micro Sv. CONCLUSION: When viewed in the context of potential diagnostic yield, the E(ICRP60) of 36.3 micro Sv for the NewTom compares favourably with published effective doses for conventional CT (314 micro Sv) and film tomography (2-9 micro Sv per image). CBCT examinations resulted in doses that were 3-7 (E(ICRP60)) and 2-4 (E(SAL)) times the panoramic doses observed in this study.     

综合性放射防护措施在介入治疗防护中的应用

目的探讨综合性放射防护措施在介入治疗防护中的应用价值。方法在84例介入手术治疗中联合应用床下铅橡胶帘、铅玻璃防护屏、铅防护服、铅围脖、铅眼镜及距离等对介入操作人员进行综合性防护。利用FJ-2000个人剂量仪监测X射线辐射剂量,并对相关数据进行统计分析。结果床下铅橡胶帘防护效率为93.4%;铅玻璃防护屏防护效率为93.5%;铅防护服防护效率为88.4%这些放射防护器材前后X线辐射剂量差异均具有统计学意义(P<0.01)。距球管1 m处X线衰减量为58.6%,距球管3 m处的X线衰减量为86.4%。1 m与2 m之间,2 m与3 m之间的辐射剂量差异均具有统计学意义(P<0.01)。结论综合性防护措施在介入操作中可有效降低X射线辐射、减少对介入操作人员身体危害。     

Dose assessment and behavior of tritium in environmental samples around Wolsong nuclear power plant.

For the estimation of the dispersion trend of tritium discharged from the Wolsung nuclear power plant, the present level of tritium in environmental samples in the vicinity of the Wolsong site has been studied. On the basis of tritium concentrations in environmental samples, the effective dose due to tritium has been estimated for an individual and population within a 16 km radius from the Wolsong site. The annual effective dose of tritium to an inhabitant around the Wolsong site ranged from 0.15 microSv y-1 to 1.3 microSv y-1. The dose level was negligible and much lower than some applicable standards, i.e. the limit on exposure from nuclear fuel cycle to the general public as recommended by ICRP (1 mSv y-1) or US EPA's limit (0.25 mSv y-1). The collective dose to the total population within a 16 km radius from the site, 1.2 x 10(-2) man.Sv y-1 was much lower than 1 man.Sv y-1, an applicable criterion for the so-called "exemption" of radiation sources and practices from regulatory control.     

两例131I体内、体表污染人员的医学处理

目的 通过对2例¹³¹I体内、体表污染人员的事故经过、临床特点、剂量估算、临床救治及医学随访观察结果的报道,为类似病例的医学应急救治提供资料和经验。方法 采用全身测量装置进行放射性监测,通过INDO 2000软件进行估算剂量;医学处理包括问诊与体检、污染部位皮肤的去污洗消及综合治疗等;医学随访项目包括常规检查、肿瘤标志物检测、染色体畸变及微核分析等。结果 INDO 2000软件估算出2例事故受照人员的待积有效剂量分别为0.10~0.19Sv及0.023~0.046Sv,甲状腺的待积当量剂量分别为2.0~3.8Sv及0.46~0.89Sv。对他们进行去污洗消及综合治疗取得了较好的疗效,4年的医学随访观察未见明显异常。结论 成功地对2例¹³¹I体内、体表污染人员进行了剂量估算、医学处理及随访观察。