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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.
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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.
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@#<b>Objective</b> To preliminarily study and establish a method for measurement of the transuranic nuclide <sup>241</sup>Am 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 <sup>241</sup>Am from fecal samples. With <sup>243</sup>Am 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 HNO<sub>3</sub> 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<sup>−4</sup> Bq for <sup>241</sup>Am in fecal samples, which was satisfactory and feasible. <b>Conclusion</b> This method fills the vacancy of <sup>241</sup>Am measurement in fecal samples to some extent, which is of practical significance for internal radiation monitoring and protection for analysts.
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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.
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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.
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[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.
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[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.