新疆地区飞行人员宇宙辐射受照剂量的估算分析

目的为了宇宙辐射防护管理,计算飞行人员个人宇宙辐射年均受照有效剂量。方法根据飞行指令数据使用软件CARI6计算飞行航线的宇宙辐射有效剂量和乌鲁木齐地区地面的宇宙辐射有效剂量,由此计算个人年均受照有效剂量。结果乌鲁木齐地区地面个人年均受照有效剂量为0.420mSv·a-1,新疆地区全部航线1997至1999年年均宇宙辐射有效剂量率为2.381μSv·h-1(最大3.640μSv·h-1,最小0.330μSv·h-1),被检测飞行人员年均受照有效剂量为2.193mSv·a-1(最大4.419mSv·a-1,最小0.887mSv·a-1)。结论估算的234个受检飞行人员的年均受照有效剂量均小于国际放射防护委员会(ICRP)建议的限值20mSv·a-1。     

飞行人员宇宙辐射受照剂量计算机估算系统

目的为了保障机组人员健康和飞行安全,研究开发宇宙辐射剂量计算机估算系统.方法先通过模拟和测量数据,根据给定日期、地理坐标和海拔计算剂量率,然后按照飞行信息计算航程有效剂量.结果用该系统计算的剂量率和航线剂量的数值结果满足国际放射防护委员会60号出版物的精度要求.结论该计算机宇宙辐射剂量估算系统适用于航空公司辐射防护管理.     

大气层中民航飞行空域宇宙辐射有效剂量率估算方法研究

目的 根据国家标准<电离辐射防护与辐射源安全基本标准>(GB 18871-2002),为了保护民航飞行人员,应该对其飞行过程中受到的宇宙辐射剂量进行监测,为此本文提出一种计算大气层中宇宙辐射剂量率的方法.方法 在大量实验和计算数据的基础上,推导出计算从海平面至25 km高度地球大气层中任意位置宇宙辐射剂量率的基本计算公式.宇宙辐射剂量率是海拔、地磁截止刚度和太阳活动日心压的函数.结果 用该方法计算了10 km高度不同经度和纬度138个位置的宇宙辐射有效剂量率,并和美国联邦航空署的软件CARI-6的计算结果进行了对比,两组数据的差别在12.56%之内.结论 该方法计算精度满足民航飞行宇宙辐射防护监测的要求.     

高空宇宙辐射受照有效剂量率简便估算方法

目的 探讨一种可用于民航飞行人员宇宙辐射有效剂量率估算的简便算法。方法 在PC机Windows操作系统用Object Pascal语言,根据本文介绍的简便算法编制程序计算不同海拔、不同地理位置的宇宙辐射有效剂量率,并将计算结果与CARI-6和FLUKA的结果比较。结果 简便算法计算结果与CARl系统和FLUKA计算结果很一致,在与CARl比较的3组数据中,误差在25％之内的数据比例分别是76％,71％和100％。在与FLUKA比较的一组数据中,误差全在20％之内。结论 简便估算法可用于海拔为7000～20000m的飞行空间的宇宙辐射有效剂量率估算。     

民航飞行人员外周血淋巴细胞微核的观察

目的　观察宇宙辐射对民航飞行人员淋巴细胞微核的影响。　方法　采集 6 5名健康飞行人员和 2 1名地面对照人员的外周静脉血 ,在含 PHA的 RPMI16 40培养基中 37℃培养 72 h,经低渗、固定、涂片、染色 ,每例观察 10 0 0个转化淋巴细胞中的微核。　结果　飞行人员的 MNF(5 .5 1±0 .2 9‰ )、MNCF(4 .92± 0 .2 7‰ )与地面人员的 MNF(3.0 5± 0 .38‰ )、MNCF(2 .6 2± 0 .35‰ )相比 ,差异有非常显著性意义 (P<0 .0 1)。MNF、MNCF随飞行人员的年飞行小时、飞行工龄及飞行状况变化而变化的梯度小 ,差异无显著性意义 (P>0 .0 5 )。在性别和年龄可比条件下 ,吸烟飞行人员 MNF(6 .12± 0 .42‰ )、MNCF(5 .5 0± 0 .40‰ )略高于不吸烟飞行人员 MNF(5 .19± 0 .5 0‰ )、MNCF(4 .48± 0 .46‰ ) ,但差异无显著性意义 (P>0 .0 5 )。　结论　宇宙辐射引起民航飞行人员染色体损伤。常规培养微核法灵敏度低 ,不能反映飞行负荷的差别。吸烟没有明显加重飞行人员染色体损伤     

飞行人员宇宙辐射估算与实验测量的比较研究

目的为了保护民航飞行人员的身体健康,对其在飞行过程中受到的宇宙辐射剂量进行监测,并对估算系统和实际剂量计测定值准确性进行对比研究。方法选定11个往返航班的飞行员佩戴个人剂量计并检测辐射受照水平,同时采用美国民航局开发的宇宙辐射剂量估算系统CARI-6软件计算相同航线飞行员宇宙辐射受照水平,并对上述两种方法结果进行比较。结果 7条国际航线计算机模拟与实测数据准确度比值为1.06±0.32,2条国内航线计算机模拟与实测数据准确度比值为0.82±0.08,国际往返航班所受最大辐射剂量率为4.12μSv/h,国内往返航班所受最大辐射剂量率为2.26μSv/h。结论两种方法有较好的符合度。飞行员受到的千小时宇宙辐射有效剂量在ICRP和我国国家标准建议的限值以下,但对可能受到较高宇宙辐射的飞行员仍应采取预防措施。     

民航收音机座舱中宇宙辐射中子剂量与飞行高度和地磁纬？…

目的 为对民航机组人员飞行中所受宇宙宇宙辐射剂量进行全面评估，实测两条国际航线 中子剂量并进行分析探讨。方法 采用慢化ＢＦ３中子监测器，在北京－纽约和北京－斯德柯尔摩航线飞行的Ｂ－７４７飞行上进行了测量，起飞、郑陆阶段每２ｍｉｎ测一次，浸航阶段第３０ｍｉｎ测试一次，高度和纬度利用飞机仪表读出，地磁纬度采用人造地球卫生环境手册的公式计算。以回归法处理中了剂量与飞行高度和地磁纬度的关系，得出曲线及公式     

骨髓细胞染色体畸变在山东济宁事故受照人员剂量估算中的应用

目的对山东济宁“10．21”辐射事故受照者进行染色体畸变（CA）分析，并估算受照剂量。方法对2例患者（A和B）的外周血和骨髓样本进行常规CA分析，根据双着丝粒（dic）和环（r）畸变频率估算受照剂量。结果2例患者的外周血未见中期分裂细胞。骨髓获得了可供分析的细胞。2例患者的dic＋r畸变频率超过了剂量效应方程所能估计的上限剂量相对应的数值。用直接比较法估算2例患者受到比较均匀的大剂量照射，与用物理方法、微核法和ESR法所估剂量接近，与临床表现基本一致。结论用骨髓CA估算辐射事故患者的受照剂量在国内尚属首次。对肠型放射病患者A的剂量估算是迄今采用骨髓进行常规CA分析估计事故病人受照剂量的最高记录。     

Spatial Variation Regularities of Cosmic Radiation and Evaluation of Exposure Doses to Aircrews

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Peripheral Doses from Noncoplanar IMRT for Pediatric Radiation Therapy

The use of noncoplanar intensity-modulated radiation therapy (IMRT) might result in better sparing of some critical organs because of a higher degree of freedom in beam angle optimization. However, this can lead to a potential increase in peripheral dose compared with coplanar IMRT. The peripheral dose from noncoplanar IMRT has not been previously quantified. This study examines the peripheral dose from noncoplanar IMRT compared with coplanar IMRT for pediatric radiation therapy. Five cases with different pediatric malignancies in head and neck were planned with both coplanar and noncoplanar IMRT techniques. The plans were performed such that the tumor coverage, conformality, and dose uniformity were comparable for both techniques. To measure the peripheral doses of the 2 techniques, thermoluminescent dosimeters (TLD) were placed in 10 different organs of a 5-year-old pediatric anthropomorphic phantom. With the use of noncoplanar beams, the peripheral doses to the spinal cord, bone marrow, lung, and breast were found to be 1.8–2.5 times of those using the coplanar technique. This is mainly because of the additional internal scatter dose from the noncoplanar beams. Although the use of noncoplanar technique can result in better sparing of certain organs such as the optic nerves, lens, or inner ears depending on how the beam angles were optimized on each patient, oncologists should be alert of the possibility of significantly increasing the peripheral doses to certain radiation-sensitive organs such as bone marrow and breast. This might increase the secondary cancer risk to patients at young age.     

CT Radiation Dose Optimization and Estimation: an Update for Radiologists

In keeping with the increasing utilization of CT examinations, the greater concern about radiation hazards from examinations has been addressed. In this regard, CT radiation dose optimization has been given a great deal of attention by radiologists, referring physicians, technologists, and physicists. Dose-saving strategies are continuously evolving in terms of imaging techniques as well as dose management. Consequently, regular updates of this issue are necessary especially for radiologists who play a pivotal role in this activity. This review article will provide an update on how we can optimize CT dose in order to maximize the benefit-to-risk ratio of this clinically useful diagnostic imaging method.     

Staff Radiation Doses to the Lower Extremities in Interventional Radiology

The purpose of this study was to investigate the radiation doses to the lower extremities in interventional radiology suites and evaluate the benefit of installation of protective lead shielding. After an alarmingly increased dose to the lower extremity in a preliminary study, nine interventional radiologists wore thermoluminescent dosimeters (TLDs) just above the ankle, over a 4-week period. Two different interventional suites were used with Siemens undercouch fluoroscopy systems. A range of procedures was carried out including angiography, embolization, venous access, drainages, and biopsies. A second identical 4-week study was then performed after the installation of a 0.25-mm lead curtain on the working side of each interventional table. Equivalent doses for all nine radiologists were calculated. One radiologist exceeded the monthly dose limit for a Category B worker (12.5 mSv) for both lower extremities before lead shield placement but not afterward. The averages of both lower extremities showed a statistically significant dose reduction of 64% (p < 0.004) after shield placement. The left lower extremity received a higher dose than the right, 6.49 vs. 4.57 mSv, an increase by a factor of 1.42. Interventional radiology is here to stay but the benefits of interventional radiology should never distract us from the important issue of radiation protection. All possible measures should be taken to optimize working conditions for staff. This study showed a significant lower limb extremity dose reduction with the use of a protective lead curtain. This curtain should be used routinely on all C-arm interventional radiologic equipment.     

多层螺旋CT肺部低剂量与常规剂量检查的放射剂量评估

目的比较多层螺旋CT肺部低剂量与常规剂量检查的X线辐射剂量,为低剂量多层螺旋CT普查早期肺癌提供剂量参数. 资料与方法肺部低剂量与常规剂量多层螺旋CT扫描共54例.其中,低剂量扫描24例,扫描参数为:120 kV,20 mAs,准直器4×5 mm,重建层厚8 mm,床速30 mm/周,螺距为7,扫描时间0.5 s/周;常规剂量扫描30例,扫描参数为:120 kV,90 mAs,准直器4×5 mm,重建层厚8 mm,床速30 mm/周,螺距为7,扫描时间0.5 s/周.观察并计算两种扫描剂量的权重CT剂量指数(CTDIw),有效mAs,总mAs,剂量长度乘积(DLP)及有效辐射剂量. 结果肺部低剂量扫描的CTDIw为1.38 mGy,是常规剂量扫描(6.21 mGy)的22.2%;低剂量扫描的DLP为44 mGy*cm,明显低于常规剂量扫描的189 mGy*cm(P＜0.01);低剂量扫描的总mAs为459,是常规剂量扫描(1 308)的35.1%;低剂量扫描的X线最大有效辐射剂量为0.9 mSv,明显低于常规剂量扫描的4.2 mSv(P＜0.01). 结论多层螺旋CT肺部低剂量扫描(20 mAs)的有效辐射剂量为常规剂量扫描的21.4%,适用于高危人群普查早期肺癌.     

近地轨道卫星舱内辐射测量

在我国１９９２年１０月发射的返回式卫星舱内，测量的７ｄ累积辐射剂量为０．７４ｍＧＹ，平均日剂量为０．１１ｍＧＹ，舱内次级热中子注量为１．３×ｌ０４～２．３×ｌ０４ｎ／ｃｍ２，平均日通量为１．９×１０４～３．３×１０４ｎ／ｃｍ２，重核粒子径迹密度为１２～１５径迹／ｃｍ２．ｄ－１。研究发现，质量厚度不同的卫星头部与裙部的剂量水平无显著差异，说明３００ｋｍ左右的近地轨道飞行器舱内辐射剂量主要来自银河宇宙线。     

放射性介入操作中辐射剂量与防护措施

由放射性介入操作所导致的辐射剂量已引起人们越来越多的关注,尤其是考虑到该项操作的频率不断增加和日趋复杂化。现有研究的主要集中于三个方面:目前放射性介入操作中的剂量水平、操作人员和患者的辐射危险以及辐射防护措施。