ABSTRACT
Objective To explore the method for measurement of tritium in nuclear power plant liquid effluent purified by a mixed ion-exchange resin, to verify the feasibility of the method by experiments, and to provide technical support for the development of standard methods for the measurement of tritium in liquid effluent of nuclear power plants. Methods The purification effect of the mixed ion-exchange resin was determined by measuring the quenching factor, conductivity, and β-nuclide adsorption efficiency of the samples purified using the resin. A comparison was made between the ion-exchange resin method and the atmospheric distillation method for tritium determination. The precision and accuracy of the method were verified by calculating the relative standard deviation and the recovery in repeated measurement of samples with different activity concentrations and spiked samples. Results There were no significant differences in quenching factor, conductivity, and tritium activity concentration between the two methods. The adsorption efficiencies of EC20MB resin for common β-nuclides such as carbon, iron, nickel, strontium, yttrium, and cesium ranged from 99.28% to 99.88%. Repeated measurement of the same sample showed relative standard deviations of 5.2%-9.4% and recoveries of 86.8%-107%. Conclusion There were no significant differences between the results of the ion-exchange resin purification method and the atmospheric distillation method. The precision and accuracy of the method met the requirements of the ecological and environmental management authorities for monitoring tritium in liquid effluent from nuclear power plants. This method can be widely used in daily monitoring work.
ABSTRACT
Objective To compare the clinical efficacy between bone cement-augmented pedicle screw fixation and bone filling vertebroplasty for stable osteoporotic thoracolumbar burst fracture (TBF).Methods From August 2014 to August 2017,48 patients with stable osteoporotic TBF but no neurological symptoms were treated at Department of Orthopedics,The First Affiliated Hospital to Chongqing Medical University.Those undergoing bone cement-augmented pedicle screw fixation were assigned into Group A while those undergoing bone filling vertebroplasty into Group B.The clinical efficacy was evaluated by comparing visual analogue scale (VAS) for pain assessment,Oswestry disability index (ODI),compression ratio of anterior vertebral height,and cobb kyphotic angle between preoperation and postoperation.The 2 groups were compared in terms of operation time,bone cement consumption,blood loss,hospital stay and relative medical costs.Results Of the 48 patients included in this study,27 were in Group A and 21 in Group B.The 2 groups were comparable as their baseline characteristics were insignificantly different (P ＞ 0.05).At 3 days after operation,the VAS (2.8 ± 1.0) and ODI (26.0 ±3.5) scores for group B were significantly lower than those for group A (4.6 ± 1.3 and 34.3 ± 2.9) (P ＜ 0.05).In group A at 3 months after operation and final follow-up,the VAS (2.9 ±0.9 and 2.3 ±0.7) and ODI (24.7 ±3.1 and 23.1 ±4.6) scores were significantly lower than those at 3 days after operation (4.6 ± 1.3 and 34.3 ± 2.9) (P ＜ 0.05).In group B at 3 months after operation and final follow-up,the VAS (2.8 ±0.9 and 2.3 ± 1.0) and ODI (23.8 ±3.7 and 22.8 ± 5.6) scores were insignificantly better than those at 3 days after operation (2.8 ± 1.0 and 26.0 ± 3.5) (P ＞ 0.05).At 3 days and 3 months after operation and final follow-up,group B had significantly smaller compression ratios of anterior vertebral height (81.1％ ± 3.7％,81.1％ ± 3.4％ and 75.6％ ± 5.8％) than group A did (91.4％ ±4.4％,90.1％ ±2.9％ and 83.5％ ±4.4％) but significantly larger cobb kyphotic angles (17.0° ± 4.0°,18.0° ± 3.5 ° and 22.1 ° ± 3.6°) than group A (14.0° ± 3.2°,14.3° ± 5.5° and 19.2° ± 3.2°) (P ＜ 0.05).The compression ratio of anterior vertebral height and cobb kyphotic angle at the final follow-up in all the patients were significantly improved compared with those at 3 days and 3 months after operation (P ＜ 0.05).Group B had significantly less operation time (51.5 ±7.3 min),blood loss (16.0 ± 8.2 mL),hospital stay (3.4 ±0.9 d) and medical costs per person (34,000 ±4,000 RMB yuan) than group A (91.5 ± 9.8 min,77.4 ± 16.5 mL,8.7 ± 2.2 d and 55,000 ± 9,000 RMB yuan),but significantly larger bone cement consumption (5.1 ± 0.7 mL) than group A (1.9 ± 0.7 mL) (P ＜ 0.05).Conclusion For patients with stable osteoporotic TBF,both bone cement-augmented pedicle screw fixation and bone filling vertebroplasty can lead to similar clinical outcomes,but the latter may have advantages of less invasion,faster recovery and lower medical costs.