18F-FDG不同分装方式下操作人员受照剂量的比较

目的 比较临床常用的手工分装、全自动分装和PET药物分装注射系统三种方式分装氟代脱氧葡萄糖（fluorine-18-fluorodeoxyglucose,¹⁸F-FDG）的分装时间、分装准确性和分装人员手部及眼部受照剂量。方法 分装的目标活度为296 MBq,在分装人员双手食指根部、双手腕外侧以及铅防护眼镜固定位置佩戴热释光剂量计,同一分装人员分别用三种方式进行30例次¹⁸F-FDG分装,每次分装活度在296 MBq ±10%以内为达标,记录每例次的分装次数、每次分装活度和分装时间。结果 完成30例次分装,三种分装方式的分装次数分别为43、47和30次,首次分装成功率分别为76.67%、73.33%和100%,平均每次目标分装的次数分别为1.43、1.56和1例次,平均每例次分装时间分别为（39.15 ±32.80）s、（203.60 ±203.11）s和（82.29 ±26.11）s。计算三种分装方式所测个人剂量当量,手部剂量当量最高的位置为左右双手食指底部,左手和右手手工分装分别为（1231.48 ±29.40） μSv/GBq和（1281.24 ±121.00） μSv/GBq、全自动分装分别（862.49 ±30.50） μSv/GBq和（678.64 ±51.68） μSv/GBq,PET药物分装注射系统分别为（4.50 ±2.25） μSv/GBq和（7.88 ±1.13） μSv/GBq。三种分装方式左右眼晶体剂量当量分别为3.39 μSv/GBq和4.5 μSv/GBq、1.69 μSv/GBq和2.5 μSv/GBq、1.69 μSv/GBq 和0。按国家标准年剂量限值估算三种分装方式下分装人员年度分装例次分别为1319、1964和214364例次。结论 PET药物分装注射系统的分装成功率、准确性和稳定性最高,辐射防护最好,可减少分装人员配置。     

Nuclear Medicine Staff Exposure To Ionising Radiation in 18F-FDG PET/CT Practice: a Preliminary Retrospective Study

This retrospective study provides an insight into the levels of radiation exposure of six nuclear medicine (NM) staff (four technologists and two nurses) performing routine diagnostic ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography-computed tomography (PET/CT) at the University Clinical Centre of the Republic of Srpska, Department of Nuclear Medicine and Thyroid Disorders, Banja Luka, Bosnia and Herzegovina. Data analysis included monthly staff exposure measured with personal thermoluminescent dosimeters (TLD) between June and December 2018, quantified in terms of normalised dose for the whole body [Hp(10)] and dominant hand [Hp(0.07)] and their comparison between each staff member and between the two groups (technologists and nurses). The study goal was to establish how our Department compared with reports from other PET/CT centres worldwide in terms of annual number of procedures and exposure limits and whether there could be room for further improvements in radiation protection. The number of procedures rose considerably from 208 in 2016 to 876 in 2019 and was 423 in the observed seven-month period. Mean individual whole-body exposure dose per GBq of injected ¹⁸F-FDG activity, [Hp(10)/A] was 18.55 μSv/GBq for the four technologists and 15.61 μSv/GBq for the two nurses. Mean dominant-hand exposure dose per GBq of injected ¹⁸F-FDG activity [Hp(0.07)/A] was 16.99 μSv/GBq and 25.44 μSv/GBq for the two groups, respectively. The average annual cumulative dose for all staff was (1.06±0.29) mSv for Hp(10) and (1.15±0.32) mSv for Hp(0.07). These results are comparable with those of similar studies. Staff doses were well below the annual limits. Nurses received slightly higher extremity doses than technologists. In view of the increasing trends in the number of PET/CT procedures, dose monitoring should be continued to identify exposure hotspots and maintain doses as low as possible.Key words: ¹⁸F-fluorodeoxyglucose, ALARA principle, automated dispensing systems, occupational dose, positron emission tomography-computed tomography, thermoluminescent dosimeters, TLD     

137Caesium, 40Potassium and potassium in raw and deep-oil stir-fried mushroom meals from Yunnan in China

A number of wild, edible mushroom species (Baorangia bicolor, Boletus calopus, Boletus obsclereumbrinus, Butyriboletus roseoflavus, Rubroboletus sinicus, Rugiboletus extremiorientalis and Xerocomus sp.) were collected in 2017, from Yunnan (Yuxi prefecture) in SW China. Samples of raw and stir-fried pools of these specimens were analysed for radioisotopes ¹³⁷Cs (caesium) and ⁴⁰K (potassium), and for total K concentrations. On a whole (wet) weight (ww) basis, ¹³⁷Cs activity ranged from < 0.10 to 0.75 Bq kg⁻¹ for raw, and from 0.5 to 4.4 Bq kg^-1 in stir-fried mushrooms. Radiopotassium (⁴⁰K) activity ranged from 57 to 96 Bq kg⁻¹ ww for raw, and 170 to 370 Bq kg⁻¹ ww for stir-fried mushrooms, while the corresponding concentration ranges for total K were 2100–3400 mg kg⁻¹ ww (mean: 2800 ± 3900 mg kg⁻¹ ww), and 6000–13000 mg kg⁻¹ ww-(mean: 8700 ± 2100 mg kg⁻¹ ww), respectively. This data indicates that mushrooms from this region show negligible ¹³⁷Cs contamination with evidently higher activity levels of ⁴⁰K. The deep oil stir-frying process results in enrichment in the resulting meals for all three determinants. 100 g meal portions showed ¹³⁷Cs activity in the range < 0.08 to 0.44 Bq 100 g⁻¹ ww (mean 0.15 ± 0.12 Bq 100 g⁻¹ ww), and ⁴⁰K activity from 16 to 37 Bq 100 g⁻¹ ww (mean 24 ± 6 Bq 100 g⁻¹ ww). The consequent exposure from ⁴⁰K contained in a single 100 g serving and weekly (100 g x7) servings was equivalent to radiation doses in the range of 0.099 to 0.23 μSv and 0.68–1.6 μSv per capita (means 0.15 ± 0.04 and 1.1 ± 0.3 μSv). This is equivalent to doses in the range of 0.0017 to 0.0038 μSv kg^-1 bm day^-1 and 0.011 to 0.027 μSv kg^-1 bm week^-1 respectively (mean values of 0.0025 ± 0.006 μSv kg^-1 bm day^-1and 0.018 ± 0.004 μSv kg^-1 bm week^-1). Analogically to the annual ¹³⁷Cs radiation exposure resulting from high rates of annual consumption (20–24 kg per capita), the estimated annual dose of radiation from ⁴⁰K would range from 0.34 up to 0.92 μSv kg^-1 bm (mean 0.60 μSv kg^-1 bm). Thus in practice, high annual consumption rates of wild, stir-fried mushrooms as seen in Yunnan, would result in negligible internal doses from decay of artificial ¹³⁷Cs, relative to that from natural ⁴⁰K. The 100 g servings also contained between 590–1300 mg K making this local food one of the top dietary sources of nutritionally important potassium for local consumers.     

Studying of <Superscript>210</Superscript>Po and <Superscript>210</Superscript>Pb Deposition in Some Lichen Species in Manisa,Turkey

Lichens are very useful for monitoring of the radionuclide deposition because having a high efficiency capturing the radionuclides from the atmospheric fallout. In the present work, ²¹⁰Po and ²¹⁰Pb deposition in some lichen species were determined using an alpha spectrometer. Different lichens were collected around Demirci-Manisa and investigated their uses as biomonitor for ²¹⁰Po and ²¹⁰Pb deposition. The highest activity concentrations for ²¹⁰Po and ²¹⁰Pb were detected in Neofuscelia pulla (898 Bq kg^?1 and 1207 Bq kg^?1, respectively). The mean activities in the lichen species ranged from 164 to 584 Bq kg^?1 for ²¹⁰Po and from 175 to 671 Bq kg^?1 for ²¹⁰Pb. The activity ratios for ²¹⁰Po/²¹⁰Pb ranged from 0.75 to 1.57.     

Monte Carlo dosimetry of the IRAsource high dose rate <Superscript>192</Superscript>Ir brachytherapy source

High-dose-rate (HDR) brachytherapy is a common method for cancer treatment in clinical brachytherapy. Because of the different source designs, there is a need for specific dosimetry data set for each HDR model. The purpose of this study is to obtain detailed dose rate distributions in water phantom for a first prototype HDR ¹⁹²Ir brachytherapy source model, IRAsource, and compare with the other published works. In this study, Monte Carlo N-particle (MCNP version 4C) code was used to simulate the dose rate distributions around the HDR source. A full set of dosimetry parameters reported by the American Association of Physicists in Medicine Task Group No. 43U1 was evaluated. Also, the absorbed dose rate distributions in water, were obtained in an along-away look-up table. The dose rate constant, Λ, of the IRAsource was evaluated to be equal to 1.112 ± 0.005 cGy h^?1 U^?1. The results of dosimetry parameters are presented in tabulated and graphical formats and compared with those reported from other commercially available HDR ¹⁹²Ir sources, which are in good agreement. This justifies the use of specific data sets for this new source. The results obtained in this study can be used as input data in the conventional treatment planning systems.     

上海市医疗机构正电子发射断层显像／X线计算机体层成像仪（PET／CT）工作人员受照剂量调查

[目的]掌握目前上海市从事正电子发射断层显像／）（线计算机体层成像仪（PET／CT）工作的人员受照情况。[方法]普查上海市PET／CT工作人员基本情况,监测PET／CT工作场所γ辐射空气吸收剂量率和放射工作人员外照射个人累积剂量。[结果]截至2011年,上海市共有PET／CT13台,工作人员153名。采用不同放射性药物分装形式和注射方式,工作人员身体同一部位所受剂量有较大差别：非通风橱分装情况下（不考虑手部）,眼部丫辐射空气吸收剂量率最高,其最大值达到613．6gSv／h,是通风橱内操作的62倍;注射操作时,移动式防护车方式所受剂量最高,胸部最大值为391．8μSv／h;全身各部位均以手部受照剂量最大,分别达到4407．0μSv／h和2211．3μSv／h。不同工作岗位放射工作人员外照射个人累积剂量也存在较大差别,依次为护士〉技师〉医师,护士的双月最大剂量达到3946．6μSv。[结论]上海市PET／CT整体防护达到国家标准要求,但在受照剂量尽可能低的原则下,工作人员防护仍需要改进完善。     

The effect of work system on the hand exposure of workers in <Superscript>18</Superscript>F-FDG production centres

The production of the ¹⁸F isotope—the marker of deoxyglucose (¹⁸F-FDG)—the radiopharmaceutical most commonly used in the oncological diagnostic technique of positron emission tomography, requires a cyclotron device. At present, there are nine facilities working in Poland that are equipped with cyclotrons used for producing the short-lived isotopes. The aim of the paper is to determine the hand exposure of workers employed in the two ¹⁸F-FDG production centres taking in to account the production procedures and work system in those facilities. Measurements, which included all professional workers exposed to ionizing radiation that were employed in two facilities, were performed by using high-sensitivity thermoluminescent detectors during the routine activities of the personnel. The work system used at the production centre has an impact on the level of the recorded doses. Among the production procedures performed by the staff, the highest ionizing radiation doses have been received by the staff during the ¹⁸F-FDG quality control. The maximum estimated annual Hp(0.07) for chemists from the quality control department can exceed the annual skin limit dose (500 mSv). The source of lowest doses on the hands are the cyclotron operating procedure and the ¹⁸F-FDG production, provided that these procedures can’t be combined with other production procedures.     

Laboratory Degradation Studies of <Superscript>14</Superscript>C-Atrazine and -Isoproturon in Soil from Sugarcane Cultivated Fields Under Kenyan Tropical Conditions

A study to compare the degradation rates of atrazine (6-chloro-N ²-ethyl-N ⁴-isopropyl-1,3,5-triazine-2,4-diammine) and isoproturon [3-(4-isopropylphenyl)-1,1-dimethylurea] in soils from sugarcane fields with different practices of herbicides application was carried out. ¹⁴C-atrazine was poorly mineralized to ¹⁴CO₂ (1.10% ± 0.22%) after 139 days of incubation in soil without previous exposure to atrazine. In the same soil also with no previous isoproturon exposure isoproturon was mineralized to ¹⁴CO₂ by 7.70% ± 0.94%. Atrazine mineralization after 98 days was 13.4% ± 0.30% in soil which discontinued the use of atrazine in 1997 while it was 89.9% ± 1.23% in soil in which atrazine is currently being used. The isoproturon mineralization values were 7.24% ± 0.85% and 22.97% ± 0.96% in soil which discontinued atrazine and soil currently using atrazine, respectively.     

Effect of Two Herbicides on <Emphasis Type="Italic">Xenylla Welchi</Emphasis> (Hexapoda:Collembola) Under Laboratory Conditions

Xenylla welchi was used to evaluate toxicity of two herbicide formulations, pretilachlor (50 EC) and pendimethalin (30 EC) under laboratory conditions. Twenty four hours LC₅₀ value of pretilachlor and pendimethalin formulations on Xenylla welchi were 72.7 and 190.0 g a.i/ha respectively which were less than their corresponding recommended agricultural doses. Again pretilachlor attained fastest LT₅₀ (110 min) followed by pendimethalin (140 min). Significant reductions in hatching success were noted with the application of both the herbicide formulations at all doses excepting 1/₈ and ¹/₁₀th of LC₅₀ (9.1, 7.3 and 23.8, 19.0 g a.i/ha for pretilachlor and pendimethalin, respectively). Hatching success of the test specimens recorded 44.1 and 63.3% reduction from control for the highest applied dose (½ of LC₅₀) of pretilachlor and pendimethalin, respectively. Juveniles of Xenylla welchi exposed to ¹/₆, ¹/₈ and ¹/₁₀th LC₅₀ for pretilachlor (12.1, 9.1, 7.3 g a.i/ha) and ¹/₈ and ¹/₁₀th LC₅₀ for pendimethalin (23.8, 19.0 g ai/ha) survived and exhibited increased moulting frequency (7 moultings in 28 days in both the herbicide treatments) in comparison to control (8 moulting in 42 days). Test specimens required 26.0 ± 1.2 and 28.1 ± 2.1 days to attain sexual maturity exposed to pretilachlor and pendamethalin respectively which was significantly less than control (42 ± 2.6 days).     

Optimization of a shorter variable-acquisition time for legs to achieve true whole-body PET/CT images

The present study aimed to qualitatively and quantitatively evaluate PET images as a function of acquisition time for various leg sizes, and to optimize a shorter variable-acquisition time protocol for legs to achieve better qualitative and quantitative accuracy of true whole-body PET/CT images. The diameters of legs to be modeled as phantoms were defined based on data derived from 53 patients. This study analyzed PET images of a NEMA phantom and three plastic bottle phantoms (diameter, 5.68, 8.54 and 10.7 cm) that simulated the human body and legs, respectively. The phantoms comprised two spheres (diameters, 10 and 17 mm) containing fluorine-18 fluorodeoxyglucose solution with sphere-to-background ratios of 4 at a background radioactivity level of 2.65 kBq/mL. All PET data were reconstructed with acquisition times ranging from 10 to 180, and 1200 s. We visually evaluated image quality and determined the coefficient of variance (CV) of the background, contrast and the quantitative %error of the hot spheres, and then determined two shorter variable-acquisition protocols for legs. Lesion detectability and quantitative accuracy determined based on maximum standardized uptake values (SUV_max) in PET images of a patient using the proposed protocols were also evaluated. A larger phantom and a shorter acquisition time resulted in increased background noise on images and decreased the contrast in hot spheres. A visual score of ≥?1.5 was obtained when the acquisition time was ≥?30 s for three leg phantoms, and ≥?120 s for the NEMA phantom. The quantitative %errors of the 10- and 17-mm spheres in the leg phantoms were ±?15 and ±?10%, respectively, in PET images with a high CV (scan < 30 s). The mean SUV_max of three lesions using the current fixed-acquisition and two proposed variable-acquisition time protocols in the clinical study were 3.1, 3.1 and 3.2, respectively, which did not significantly differ. Leg acquisition time per bed position of even 30–90 s allows axial equalization, uniform image noise and a maximum?±?15% quantitative accuracy for the smallest lesion. The overall acquisition time was reduced by 23–42% using the proposed shorter variable than the current fixed-acquisition time for imaging legs, indicating that this is a useful and practical protocol for routine qualitative and quantitative PET/CT assessment in the clinical setting.     

Evaluating the effect of various intracavitary applicators on dosimetric parameters of <Superscript>192</Superscript>Ir, <Superscript>137</Superscript>Cs,and <Superscript>60</Superscript>Co sources

The purpose of this research is to study the effect of various applicator compositions on dosimetric parameters and dose distribution of ¹⁹²Ir, ¹³⁷Cs, and ⁶⁰Co sources, using Monte Carlo simulation techniques. To study the effect of applicators on source dosimetry, the dose rate constant, and radial dose function and isodose curves for the above noted sources were calculated in the presence and absence of plastic, titanium, and a stainless steel applicators. The effects of the applicators on the dosimetric parameters and isodose curves of these sources were dependent of the source type and materials of the applicator. The ¹⁹²Ir source with the stainless steel applicator has the maximum difference of dose rate (4.2 %) relative to the without applicator case. The ⁶⁰Co source with plastic applicator has the minimum dose variation. Moreover, this effect is higher for lower energy sources. Ignoring the effect of applicator composition and geometry on dose distribution may cause discrepancies in treatment planning. Plastic applicators have the least radiation attenuation compared to the other applicators, therefore, they are recommended for use in brachytherapy. A table of correction factors has been introduced for different sources and applicators with different materials for the clinical applications.     

18F-FDG PET/CT心肌代谢显像受检者的周围辐射剂量水平

目的 探索PET/CT心肌代谢显像受检者周围辐射剂量水平,为保证周围人员辐射安全提供数据支持。方法 选取33例行¹⁸F-FDG PET/CT心肌代谢显像患者,在受检者胸部等高位置按照不同体位方向、时间和距离处对其周围剂量当量率进行测量,探索受检者周围剂量当量率的分布规律。结果 在相同测量时间和距离下,受检者身体两侧的周围剂量当量率相比正、背面更低。受检者注射¹⁸F-FDG显像剂后,距离体表1 m处正面的周围剂量当量率为13～21 μSv/h,检查结束后降至5～14 μSv/h,平均降低46%。受检者周围剂量当量率随距离（10～300 cm）的增加呈幂函数趋势降低,其幂指数均值为−1.2。结论 心肌代谢显像受检者注射药物后周围辐射水平较高,周围剂量当量率随时间和距离增加快速降低,建议心肌代谢显像受检者检查当天避免与他人长时间、近距离接触。     

Atmospheric CO<Subscript>2</Subscript> Level and Temperature Affect Degradation of Pretilachlor and Butachlor in Indian Soil

This study was conducted at ambient (398?±?10 µmol mol^?1), elevated (450?±?10 µmol mol^?1) and elevated (550?±?10 µmol mol^?1) atmospheric CO₂ under three moisture regime and also three level of temperature (4, 25, and 40°C) to assess the degradation of pretilachlor and butachlor. Under dry condition at 398?±?10 µmol mol^?1, T_1/2 was 28.5 and 59.4 days for pretilachlor and butachlor, respectively; slowly decreased to 18.2 and 44.5 days at 550?±?10 µmol mol^?1 indicated that elevated condition enhanced degradation than ambient condition. Under field capacity with increasing CO₂ levels from ambient to elevated, T_1/2 decreased from 18.9 to 11.6 days and 39.4 to 16.2 days for of pretilachlor and butachlor, respectively. Similarly, under submerged conditions with increasing CO₂ levels T_1/2 decreased 14.7–7.1 and 26.3–11.8 days for pretilachlor and butachlor, respectively. Study also revealed that both pretilachlor and butachlor dissipated faster at 40°C (T_1/2, 9.7 and 19.4 days) than 25°C (T_1/2, 16.2 and 36.7 days). Slower dissipation was recorded at 4°C (T_1/2, 87.6 and 182.4 days).     

PET/CT性能检测中18F用量分析

目的探讨正电子发射计算机断层显像/计算机体层扫描仪(PET/CT)性能检测过程中18F的放射性活度及活度浓度准确使用量。方法按照NEMANU2-2001标准,采用其相关模体,结合飞利浦Gemini系列,GE Discovery系列和西门子Biograph系列PET/CT性能检测项目所使用18F的放射性活度或放射性活度浓度进行分析。结果①空间分辨率:飞利浦1.48～2.22GBq/ml;GE>185MBq/ml;西门子1.11GBq/ml);②散射因子、计数丢失和随机符合测量及精确性(计数丢失和随机符合校正):飞利浦481～555MBq;GE900MBq;西门子1.07GBq;③灵敏度:飞利浦7.4MBq;GE10MBq;西门子4.6MBq。结论各厂商提供的放射性活度及活度浓度可用于NEMA标准检测。     

广东阳江高本底地区γ辐射水平调查

目的 调查阳江高本底地区和对照地区地表γ辐射水平。方法 采用多阶段抽样的方法,选择阳江高本底地区112所房屋,恩平对照地区147所房屋,使用便携式X、γ剂量率仪（FH40G+FHZ672E-10）测量屋内和门口的γ辐射水平,同时测量选定管区的室外γ辐射水平。结果 高本底地区室内外γ辐射水平分别为（0.36±0.06）μSv/h和（0.16±0.06）μSv/h,对照地区分别为（0.13±0.05）μSv/h和（0.09±0.03）μSv/h,高本底地区室内外γ辐射水平约为对照地区的3倍和2倍,差异均具有统计学意义。高本底地区新房屋室内γ辐射水平为（0.34±0.05）μSv/h,低于老房屋室内γ辐射水平（0.38±0.05）μSv/h;对照地区的新房屋室内γ辐射水平为（0.18±0.02）μSv/h,高于老房屋室内γ辐射水平（0.09±0.03）μSv/h,两者的差异均有统计学意义。结论 阳江高本底地区γ辐射水平显著高于对照地区,但两地区差异较上世纪有所减小。     

Measurements of occupational exposure for a technologist performing 18F FDG PET scans

Radiation doses to one PET technologist performing 100 18F FDG (18F fluorodeoxyglucose) imaging procedures were measured in a clinical setting using two types of thermoluminescent dosimeter (TLD) badges, one finger-ring TLD and one electronic pocket dosimeter (EPD). 18F FDG was handled either with unshielded or with viewing window tungsten shielded syringes. The resulting doses using unshielded syringes were 13.8 +/- 0.8 microSv/370 MBq and 14.3 +/- 0.4 microSv/370 MBq, measured with TLD 100 and with TLD 700H/600H, respectively. For the same series of measurements, the doses obtained using shielded syringes were 10.7 +/- 0.4 microSv/370 MBq and 7.2 +/- 2.1 microSv/370 MBq with TLD700H/600H and with EPD, respectively. The dose to the right hand from shielded syringes was 69.3 +/- 5.5 microSv/370 MBq. All these values are within the ICRP recommended dose limits. Extrapolated to 725 examinations per year, the resulting effective dose measured with TLD would be 10 mSv with unshielded and 7.5 mSv with shielded syringes, respectively (25% dose reduction). The doses measured by TLD were consistently higher than those measured by EPD, suggesting that EPD measurements might underestimate occupational doses.     

Associations with intraocular pressure across Europe: The European Eye Epidemiology (E<Superscript>3</Superscript>) Consortium

Raised intraocular pressure (IOP) is the most important risk factor for developing glaucoma, the second commonest cause of blindness globally. Understanding associations with IOP and variations in IOP between countries may teach us about mechanisms underlying glaucoma. We examined cross-sectional associations with IOP in 43,500 European adults from 12 cohort studies belonging to the European Eye Epidemiology (E³) consortium. Each study conducted multivariable linear regression with IOP as the outcome variable and results were pooled using random effects meta-analysis. The association of standardized study IOP with latitude was tested using meta-regression. Higher IOP was observed in men (0.18 mmHg; 95 % CI 0.06, 0.31; P = 0.004) and with higher body mass index (0.21 mmHg per 5 kg/m²; 95 % CI 0.14, 0.28; P < 0.001), shorter height (?0.17 mmHg per 10 cm; 95 % CI –0.25, ?0.08; P < 0.001), higher systolic blood pressure (0.17 mmHg per 10 mmHg; 95 % CI 0.12, 0.22; P < 0.001) and more myopic refraction (0.06 mmHg per Dioptre; 95 % CI 0.03, 0.09; P < 0.001). An inverted U-shaped trend was observed between age and IOP, with IOP increasing up to the age of 60 and decreasing in participants older than 70 years. We found no significant association between standardized IOP and study location latitude (P = 0.76). Novel findings of our study include the association of lower IOP in taller people and an inverted-U shaped association of IOP with age. We found no evidence of significant variation in IOP across Europe. Despite the limited range of latitude amongst included studies, this finding is in favour of collaborative pooling of data from studies examining environmental and genetic determinants of IOP in Europeans.     

Performance of silver,zinc, and iron nanoparticles-doped cotton filters against airborne <Emphasis Type="Italic">E. coli</Emphasis> to minimize bioaerosol exposure

To overcome limitations of existing air-cleaning filters in capturing and deactivating aerosolized microorganisms, this study was embarked to evaluate novel Ag, Zn, and Fe nanoparticle-doped cotton filters (AgCt, ZnCt, FeCt), as biocidal filters for bioaerosol attenuation. To evaluate the biocidal activity of the nanocomposite filters, the survival of lab-generated E. coli after collection on each filter material was compared to collection on an undoped cotton control filter and in a BioSampler. Relative humidity (RH) affected the survival of bacteria on the filters, and the optimal RH was found to be 50?±?5%. The physical removal efficiency (PRE) determined by an optical particle counter was 99.9?±?0.7% for ZnCt, 97.4?±?1.2% for AgCt, and 97.3?±?0.6% for FeCt, where the control showed only 77.4?±?6.3% for particles >?500 nm. The doped filters showed 100% viable removal efficiency (VRE). Importantly, the VRE of the nanocomposite filters after four cycles remained nearly 99% and was greater than the cotton control filter at 76.6?±?3.2%. Adding to its benefits, the AgCt filters had a lower pressure drop than the FeCt and ZnCt filters and the cotton control. The permeability for the cotton control filter was 3.38?×?10^?11 m² while that for the AgCt filter was slightly higher (3.64?×?10^?11 m²) than the other filters as well. Overall, these results suggest that nanocomposite-doped filter media, particularly AgCt, can provide effective protection against airborne pathogens with a lower pressure drop, elevated collection efficiency, and better disinfection capability as compared to untreated cotton filters, which are all important features for practical biocidal applications.

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Graphical abstract

     

河北省部分核医学工作场所的放射防护现状调查与分析

目的 掌握河北省部分核医学放射工作场所防护现状和放射工作人员防护现状,为加强放射卫生监督和制定核医学相关标准提供数据支持。方法 对河北省内16个核医学工作场所用X、γ辐射剂量仪测量周围剂量当量率,用α、β表面污染仪测量工作场所及工作人员体表的β表面污染;以热释光剂量法监测77名核医学工作人员的深部个人剂量当量H_p(10),并查阅这77名核医学工作人员最近两年内的职业健康检测报告。结果 SPECT(/CT)工作场所内各检测点之间辐射水平具有统计学差异（F = 32.02,P < 0.05）,其中给药窗口（护士操作位）的周围剂量当量率最高,为11.92～37.77 μSv/h,平均（19.19 ±8.78 ）μSv/h;PET/CT工作场所内各检测点之间辐射水平具有统计学差异（F = 56.72,P < 0.05）,给药窗口（护士操作位）的周围剂量当量率为14.28～21.55 μSv/h,平均（16.55 ±3.87） μSv/h;16个核医学工作场所的β表面污染水平均符合标准要求,工作人员的工作服表面污染水平超过标准的有2个（占12.50%）,工作人员手部皮肤表面污染水平超过标准的有8个（占50.00%）;77名核医学工作人员的外照射个人剂量水平为（1.11 ±0.65） mSv;77名放射工作人员均未发现有皮肤表观异常,但有12人（占15.58%）在对电离辐射较为敏感的组织器官存在一些异常,核医学接触时间＞20年的放射工作人员眼晶体异常和染色体异常的发生率与其他核医学接触时间组相比,未发现统计学差异。结论 本次调查的核医学工作场所放射防护情况良好,但工作人员的自身防护有待加强;核医学工作人员的职业健康管理还需引起进一步的重视。     

<Superscript>153</Superscript>Sm-HM for arthritic knee pain. Estimated dosimetry

Osteoarthritis is the most common type of arthropathy and after cardiovascular diseases is the most disabling disease in developing countries. The dosimetry for the clinical application of 153-samarium-hydroxymacroaggregates (¹⁵³Sm-HM) for radiation synovectomy (RSV) and palliative treatment for arthritic pain, as far as we know, has not been reported. The aim of this research was to estimate the radiation dose necessary for synovial ablation and pain palliation with minimum risk to the patient. ¹⁵³Sm-HM (370 MBq) was administered intra-articularly in a patient with severe knee pain and hindered motility. Regions of interest drawn on sequential, conjugated, anterior and posterior scintigraphy images were used to obtain the respective activity. The data was entered into a knee joint histological-geometric model designed with micrometric dimensions to represent the synovial cell layers. The Monte Carlo code was used to calculate the absorbed dose in each of the 12 model-cells representing the distance from the synovial liquid to the cartilage or bone. The absorbed dose in the synovial cavity was 114 Gy which is sufficient energy for RSV. The treated patient referred little pain and higher motility with no adverse reactions. ¹⁵³Sm-HM is a potentially valid radiopharmaceutical for RSV, which effectively palliates knee pain.