Calculation of retention fractions in main source organs following acute americium inhalation based on ICRP biokinetic models / 中国辐射卫生

Objective To provide a reference for avoiding the harm to critical target organs following considerable inhalation exposure to the transuranium element americium (Am) as well as post-accident decorporation or other radiation protection measures. Methods We established calculation programs based on the generic criteria for internal radiation emergency preparedness and response in the IAEA Safety Guide No.GSG-2 and current new ICRP biokinetic models and parameters, taking an inhalation of 241Am (activity mean aerodynamic diameter of 5 μm, σ = 2.5) by an adult worker as an example; and determined that the critical target organs were the lung AI region, red bone marrow, and the main source organs leading to acute doses to the critical target organs were the lung AI region, blood, and trabecular bone surface. Results The retention fractions in the main source organs over time after 241Am inhalation were calculated. Conclusion After being absorbed into blood, Am moves quickly to other parts, and Am of different absorption types shows similar early changes in retention fractions in blood: the retention fractions of Am of S, M, and F types in blood peak around 0.03 d, and then halve around 1.7 d. Inhaled Am shows different changes over time in retention fractions in the lung AI region and trabecular bone surface in the early stage: the retention fractions of S- and M-type Am in the lung AI region change little with time, while F-type Am transfers quickly from the lung to blood; In trabecular bone surface, S-type Am increases quickly in the first 7 d, M-type Am gradually increases mainly in the first 2 weeks, and F-type Am increases quickly in the first 2 d.

Measurement of 239Pu in fecal samples based on inductively coupled plasma-mass spectrometry / 中国辐射卫生

Objective To establish a method for measurement of 239Pu in fecal samples based on inductively coupled plasma-mass spectrometry (ICP-MS), and to provide a novel method for assessing the internal exposure of workers. Methods Fecal samples were collected from workers and labeled. The samples were pretreated with carbonization ashing and microwave digestion devices, purified on TEVA resin, and measured using ICP-MS. Results The detection limit of 239Pu in fecal samples based on ICP-MS was 1.91 × 10−4 Bq. Conclusion In the routine monitoring of class S substances characterized by a 5 μm aerodynamic diameter during 12 months, the committed effective dose corresponding to the detection limit is 0.17 mSv. This value meets the requirements of relevant national standards and ICP-MS can be used as a novel means for accurate evaluation of internal exposure for workers.

Development of a simplified phantom for calibration of whole-body counter / 中国辐射卫生

Objective To develop a simplified phantom for the calibration of whole-body counters. Methods A simplified phantom design method for the calibration of whole-body counters was established based on the process and method of calibrating whole-body counters. By using the established method and Monte Carlo method, a simplified phantom including the total body, thyroid, lungs, and gastrointestinal tract was designed to calibrate the ORTEC-Stand FAST II whole-body counter. The simplified phantom was compared with the BOMAB phantom through experimental measurements. Results Within the range of 50 keV to 2 MeV, for rays of the same energy in the same organ of the simplified phantom and BOMAB phantom, the simulated data of detection efficiency by whole-body counting showed an error within 5%, and the experimental measurements showed an error within 10%. Conclusion We developed a simplified phantom for the calibration of the whole-body counter, demonstrating the feasibility of using the simplified phantom instead of a physical body phantom for whole-body counter calibration, which can greatly facilitate whole-body counter calibration for internal radiation monitoring.

Exploration of ²⁴¹Am measurement in fecal samples / 中国辐射卫生

@#<b>Objective</b> To preliminarily study and establish a method for measurement of the transuranic nuclide ²⁴¹Am in fecal samples, and to provide technical support for internal radiation monitoring of staff. <b>Methods</b> Fecal samples were collected with a self-made stool sampler and treated with a self-made carbonization and ashing furnace. DGA resin was used to separate and purify ²⁴¹Am from fecal samples. With ²⁴³Am as the tracer, the orthogonal method was used for condition optimization. <b>Results</b> The optimum conditions for separation and purification were: the acidity of HNO₃ added into the column, 6 mol/L; column flow rate, 0.6 mL/min; and the volume of analytical solution,12 mL. The method based on inductively coupled plasma mass spectrometry showed a detection limit of 9.79×10⁻⁴ Bq for ²⁴¹Am in fecal samples, which was satisfactory and feasible. <b>Conclusion</b> This method fills the vacancy of ²⁴¹Am measurement in fecal samples to some extent, which is of practical significance for internal radiation monitoring and protection for analysts.

Study on the distribution characteristics of aerosol produced by powder dumping in glove box / 中国辐射卫生

Objective To investigate the effects of particle size, wind speed and dumping velocity on aerosol concentration distribution during powder dumping in a reprocessing plant. Methods CeO2 powder was selected as the substitute material of PuO2. FLUENT software was used to calculate the pouring process of CeO2 powder under different operation conditions. Then the aerosol concentration distribution under different dumping speeds was measured by particle size spectrometer to verify the accuracy of simulation results. Results The particles with small particle size are more likely to be separated from the mainstream area by the drag force of the surrounding gas, and the radius of the diffusion range also increases with the decrease of the particle size. 2) When the ventilation speed is less than 1 m/s, the dust lifting can be reduced and the concentration of dust particles in the chamber can be reduced to a certain extent. 3) In the process of powder dumping, the spoon is rotated anticlockwise at a speed of 100° in 2～3 s, and less dust aerosol is produced on the right side of the tray. Conclusion When operating the powder particles with smaller particle size, more attention should be paid to the monitoring of aerosol at different positions; the change of air inlet velocity makes the flow field in glove box more complex, and the volume fraction of dust particles is related to the size and location of vortex formed by airflow. The greater the wind speed, the greater the impact on the powder dumping process. The experimental results are basically consistent with the simulation results, and the results show that the lower the dumping speed, the smaller the aerosol concentration near the tray.

210Po distribution after high temperature processes in coal-fired power plants.

In this paper, the distribution of 210Po after high temperature processes in six units of coal-fired power plants (CFPs) were evaluated. The coal, bottom ashes, fly ashes from electrostatic precipitators (ESP), and flue gases from stacks were sampled from four CFPs and analyzed for 210Po contents. The results showed that 210Po was mainly captured by the ESP, with little left in the bottom ash, and a small fraction of 210Po was directly discharged into the environment through the stacks, accounting for 0.06%-0.6%, which was consistent with the reported data. It was also found that part of the 210Po could not be accounted for in the mass balance analysis for the whole combustion process in CFPs, which was also in line with the reported data. The results obtained in this study provided essential basic data for environmental radiological risk analysis for CFPs.

Therapeutic Observation of Twirling Manipulations at Quchi (LI 11) for Primary Hypertension / 上海针灸杂志

Objective To observe the clinical efficacy of acupuncture in treating primary hypertension and the effect of twirling reinforcing-reducing manipulations on the treatment of primary hypertension. Methods Totally 126 patients with primary hypertension were randomized into treatment group 1 of 40 cases, treatment group 2 of 44 cases, and a control group of 42 cases. The treatment groups were both intervened by acupuncture at Quchi (LI 11), while twirling reinforcing-reducing manipulations (twirling towards left) were applied in treatment group 1, while the manipulations (twirling towards right) were applied in treatment group 2;the control group was intervened by medication. The change of blood pressure after 10 min treatment was observed, and the clinical efficacies were compared. Results The total effective rate was 85.0%in treatment group 1, versus 88.6%in treatment group 2 and 61.9% in the control group, and the total effective rates in the two treatment groups were significantly different from that in the control group (P0.05). Conclusions Acupuncture at Quchi (LI 11) is an effective approach in treating primary hypertension, and the reinforcing manipulation and reducing manipulation are both effective.

Effect of low stress environment on repairing of children necrotic femoral head / 中国矫形外科杂志

[Objective]To observe the change of children necrotic femoral head repairing under low stress environment and to explore the effect of low stress environment on Perthes disease.[Method]The sick coxa was supported by Coxa Multi-functional External Fixation Shoring Fixator,which decreased femoral head stress and creates a low-stress environment for the sick coxa.Meanwhile,the affected extremity was kept abduction and internal rotation in order to increase femoral head containment.The coxa could flex and extend partly on sagittal plane.Twenty-eight patients(32 hips) were followed up with mean follow-up time of 3 years and 5 months(2~7 years).The radiological characteristics of pre-and post-operation was analyzed.[Result]At 3 months postoperatively,joint space was broadened,high density necrosis shadow became little and little,the femoral head became full,height of the femoral head epiphysis increased.If epiphyseal nucleus fragmentation vaded epiphyseal plate,the big head and pachy-neck and the subluxation of coxa would finally result.[Conclusion]Under low stress environment,child necrotic femoral head could be repaired.The prognosis is related to Catterall stage of Perthes disease.On Catterall Ⅱ and Ⅲ stage,the curative effect is fairly good.But on Catterall Ⅳ stage,the curative effect is not evident.

Treatment of hyperplastic nonunion of the tibia with interlocking intramedullary nailing,fascia pedicled callus flap and bone grafting / 中国矫形外科杂志

[Objective]To observe the clinical effect of the treatment of hyperplastic nonunion of the tibia with interlocking intramedullary nailing,fascia pedicled callus flap and bone grafting.[Method]Twelve cases of nonunion of the tibia were treated with intramedullary interlocking nailing,fascia pedicled callus flap and bone grafting,and there were 8 males and 4 females.The patients age ranged from 26 to 64 years,with an average of 45 years.[Result]All cases were followed-up for an average of 48 months and achieved a solid union within 4～6 months.[Conclusion]Intramedullary interlocking nailing,fascia pedicled callus flap and bone grafting have the design of the reasonable biomechanics,the function of untispinning and unticurtailing,less partial blood decompose.The fascia pedicled callus flap and iliac bone grafting could result in solid union and it is a recomment method for promoting bone-healing up after grafting and forming.