某设备所致脉冲X射线辐射场测量与防护评价

目的 了解某设备实验条件下不同位置脉冲X射线电离辐射水平，提出适当的防护建议。方法 采用热释光测量方法，分别在设备舱周围不同方向不同距离布放热释光剂量计，累积一定数量脉冲辐射后进行测量；采用电离室型X、γ剂量率仪（FJ-347A）实时测量工作状态下不同距离处电离辐射剂量率水平。依据《电离辐射防护与辐射源安全基本标准》（GB18871—2002）规定的职业照射人员和公众个人剂量限值提出不同工作位辐射防护建议。结果 热释光剂量计累计接收3 000个脉冲辐射，设备舱外壁0.01～8.98 mGy，顶部0.01～15.67 mGy，距外壁1～12 m之间0.01～2.18 mGy，工作位0 mGy。工作状态下，X射线剂量率仪测得距设备舱外侧壁1～20 m之间空气比释动能率范围0.26～16 mGy/h。结论 热释光剂量计、电离室型剂量率仪测量结果基本一致，说明两种方法均可用于脉冲X射线测量；工作状态下设备舱外近距离处辐射剂量率较高，可通过采取防护措施或者限制人员工作量以满足辐射防护要求。     

周围剂量当量仪的研制

周围剂量当量仪研制是根据国际辐射单位和测量委员会（ＩＣＲＵ）３９号报告推荐的周围剂量当量而设计的一种数字化智能型辐射防护仪。方法采用能量补偿对探测器进行能响校正。结果补偿结果使得探测器在４７～２３０ｋｅＶ与ＩＳＯ推荐的Ｈ＊（１０）／Ｋａ值误差在５％以内。本文重点描述了周围剂量当量仪探测器部分的工艺结构和剂量学性能以及电子学测量部分的主要功能。结论通过实际应用我们初步获得的结论是由于该仪器可直接测量周围剂量当量，稳定性好且具有自动取平均值特点，它可做为实验室校准用测量仪器，又由于该仪器体积小，电池供电，读数面板又有背光功能，它也可以做为现场仪器用于辐射防护实践的现场测量     

Environmental conditions and variation in levels of sun exposure among children in child care

Sun exposure in childhood is 1 of the risk factors for developing skin cancer, yet little is known about levels of exposure at this age. This is particularly important in countries with high levels of ultraviolet radiation (UVR) such as Australia. Among 49 children 3 to 5 years of age attending child care centers, UVR exposure was studied under 4 conditions in a repeated measures design; sunny days, cloudy days, teacher’s instruction to stay in the shade, and a health professionals instruction to apply sunscreen. Three different data collection methods were employed: (a) completion of questionnaire or diary by parents and researcher, (b) polysulphone dosimeter readings, and (c) observational audits (video recording). Results of this study indicated that more than half the children had been sunburnt (pink or red) and more than a third had experienced painful sunburn (sore or tender) in the last summer. Most wore short sleeve shirts, short skirts or shorts and cap, that do not provide optimal levels of skin protection. However, sunscreen was applied to all exposed parts before the children went out to the playground. Over the period of 1 hr (9–10 a.m.) the average amount of time children spent in full sun was 22 min. On sunny days there was more variation across children in the amount of sun exposure received. While the potential amount of UVR exposure for young children during the hour they were outside on a sunny day was 1.45 MED (Minimum Erythemal Dose), they received on average 0.35 MED, which is an insufficient amount to result in an erythemal response on fair skin even without the use of sunscreen.     

热释光剂量计在核电厂环境监测中的应用

目的 研究岭澳核电站运营后大亚湾核电基地6台机组气态流出物排放对周围陆地环境辐射水平的影响。方法 利用热释光剂量计（TLD）监测广东大亚湾核电基地外围环境辐射水平,在大亚湾核电周围陆地环境布设25个TLD监测点,每3个月左右回收热释光剂量计并测量,长期观测核电周围环境辐射水平变化。结果 2011—2020年大亚湾核电基地外围环境用热释光剂量计测量得到的γ辐射剂量率年均值范围为76.7～207.1 nGy/h、均值为（123.3 ± 5.7） nGy/h,年均值变化相对偏差范围为2%～12%,TLD监测结果、剂量率瞬时测量结果与20世纪国家环保总局组织的调查结果、核电运营前的本底水平一致。结论 不同TLD监测点环境天然辐射水平差异较大,核电站周围50 km范围内的总体环境γ辐射水平没有变化,核电运行气态流出物的释放未对外围环境辐射水平产生累积影响。     

GR-100T/GR-200A双元件热释光剂量计的实用性探讨

目的探讨GR-100T/GR-200A双元件热释光剂量计(TLD)在个人剂量监测中的实用性.方法使用RGD-3B和UD-512A热释光剂量仪、GR-100T和GR-200A元件等进行相关实验分析.结果 GR-100T/GR-200A双元件TLD能鉴别出30～1250keV的光子能量,并可测量出几μGy的低水平剂量;有0.1mmCu过滤时,该TLD中GR-100T/GR-200A相对能量响应比值几乎呈线性下降,在30～40keV能量范围内由19.5降低到13.5,对低能范围光子能量的估算非常灵敏.结论该TLD能实现能量鉴别和低水平Hp(d)测量的双重目的,其成本低、组合方便,在个人剂量监测中有一定的实用性.     

LiSr4(BO3)3:Ce3+ phosphor as a new material for ESR dosimetry

LiSr₄(BO₃)₃:0.01Ce³⁺ phosphor was investigated to assess its potential as a material for measurements of radiotherapeutic doses with electron spin resonance (ESR). The ESR spectrum of the phosphor irradiated with ⁶⁰Co features five ESR signals. An isochronal annealing experiment has shown that the strongest of these signals is associated with the same trap center as the 473 K peak on the TL glow curve of this material. The dose–response is linear in the studied range from 0.89 to 90.30 Gy. Fading of the signal was also investigated.     

Measurement of the average radiation dose to the local skin and thyroid gland during intracranial aneurysm coil embolization

IntroductionIntracranial aneurysm coil embolisation is a fluoroscopically guided procedure associated with high radiation dose. The increase in the number of coil embolisation procedures raises concern for the amount of radiation and the associated radiation risks to the patients. This research study was conducted to determine the average radiation dose to patients’ thyroid glands and local skin during intracranial aneurysm coil embolisation and to establish preliminary local diagnostic reference levels for this procedure. In this paper, local skin dose refers to the absorbed radiation dose on the areas of the skin exposed to radiation during intracranial aneurysm coil embolisation, namely neck, face and scalp.MethodsThis study employed air-kerma area product meters to determine the local skin dose and diagnostic reference levels during intracranial aneurysm coil embolisation. In addition, thyroid radiation doses were measured using thermo-luminescent dosimeters on a phantom during simulation of embolisation procedures.ResultsThe local skin doses as determined by air-kerma area product ranged between 33 and 125 Gy.cm2. The mean thyroid dose was 9.87 mGy. The established local diagnostic reference level was 52.1 Gy cm², 17.8 min’ fluoroscopy time and 503 image frames.ConclusionThe average air-kerma area product values and the proposed diagnostic reference levels were lower than most published values for intracranial aneurysm coil embolisation.Implications for practiceThe established local diagnostic reference levels are recommended for use as radiation dose optimisation tool at the research site. The findings of this study cannot be generalised or applied to other hospitals. The complexity of the embolisation procedures was not classified for this study. Further research on diagnostic reference levels for intracranial aneurysm coil embolisation, taking into account the complexity of the procedures, is recommended.     

广西医用电子加速器验收检测泄漏辐射水平分析

目的：验收、检测广西地区医用电子加速器,分析其泄漏辐射水平,为估算放射职业人员、患者辐射防护剂量水平和制定放射防护控制策略提供依据,为医院的放射治疗质量控制提供指导。方法：对广西29台医用电子加速器进行验收、检测。使用热释光剂量计（TLD）测量加速器的泄漏辐射水平;使用中子测量仪测量中子的泄漏辐射水平,结合国家标准对其进行分析与评价。结果：加速器透过限束装置的辐射泄漏率最大值≤1.2%,平均值≤0.65%;距电子轨道1 m处辐射泄漏率最大值≤0.46%,有用线束中心轴2 m圆平面内辐射泄漏率最大值≤0.19%,平均值≤0.09%;标称能量≥10 MV的加速器,其电子轨道1 m处中子的辐射泄漏率最大值≤0.032%,有用线束中心轴2 m圆平面内中子的辐射泄漏率最大值≤0.028%,平均值≤0.014%。结论：所检测设备的泄漏辐射水平均在国家标准控制范围内,医用加速器的泄漏辐射水平是设备防护性能的重要指标,在其投入使用前必须通过验收,以确保医疗质量和安全。