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[en] Objective: To investigate the technique, safety and clinical value of CT-guided percutaneous interstitial brachytherapy for metastatic carcinoma of lymph nodes in mediastinum. Methods: Eight patients with metastatic carcinoma of lymph nodes in mediastinum were treated by CT-guided interstitial implant of radioactive seeds in our department. Anterior approach were performed on all cases, 125I radioactive seeds were implanted by setting CT Gantry at an oblique angle, three-dimensional reconstruction with SCT and separation the narrow gap between aortic arch and superior vena cava with flat- scalp core. Dose distributions were checked by TPS after operation. The improvement in clinical symptoms and lymph node sizes were documented in order to investigate the therapeutic effects. Results: The particle coverage rate was 93.5%±1.5%. According to the CT scans two months later, 3 patients (37.5%) had complete ablation, 4 (50%) partial ablation, and 1 (12.5%) stable disease. Overall response rate (CR + PR) for this group of patients was 87.5%. The symptoms of all patients including shortness of breath (5 patients), cough (4 patients), dysphagia (4 patients) showed varying degree of improvement. No edema of head-and-neck and upper extremity was observed. There was no major vascular, tracheal and esophageal injury. A small amount of pneumothorax was observed in one patient. Conclusions: CT-guided percutaneous interstitial brachytherapy, a minimally invasive procedure associated with favorable therapeutic results, is a promising technique for treatment of metastatic carcinoma of lymph nodes with local pressure symptoms which may not respond to conventional therapy. (authors)
[en] Based on the domestic patent information, combined with examples, this article makes an in-depth discussion on the domestic nuclear patent information. The author puts forward for the patent information research, the appropriate retrieval of patent documents is the basis,and the correct quantitative statistical analysis of patent documents is the key, and in-depth qualitative analysis of patent documents is the core. It is expected to provide information support and guarantee for the technical innovation and scientific research personnel in the nuclear field through in-depth study of domestic nuclear information. (authors)
[en] Objective: To evaluate the safety and efficacy of the CT-guided percutaneous cryoablation of osteoid osteoma in children. Methods: Nine children with osteoid osteoma proved by histopathology were treated with CT-guided cryoablation from January 2007 of January 2010. There were 6 boys and 3 girls. Their mean age was (13.0 ±1.6) years (ranging from 10.0-15.0 years). The procedures were performed under local anesthesia. Eight G bone biopsy needles for biopsy and 17 G freezing needles were used in the procedure. CT guidance was used for procedural planning, instrument guidance, and monitoring. Each cryoablation included two freezing-thawing cycles. Follow-up was performed to assess technical and clinical outcome. A visual analog scale (VAS) was used to assess severity of pain pre- and post-procedure, and mean VAS for the group was compared pre- and post-procedure with Kruskal-Wallis rank sum test. Results: Biopsy and cryoablation were successfully performed in all children. No major immediate or postponed complications were observed. Significant pain relief (P<0.01) was observed in all patients after procedure. The VAS of preoperation (8 points 1 case, 7 points 3 cases, 6 points 4 cases, 5 points 1 case) compared with that of one month after operation (1 point 4 cases, 0 point 5 cases), the difference was statistically significant (H=32.838, P<0.01). These patients were allowed to fully weight-bear and function without limitation 3 days after the procedure. Pain was obviously released. Pain recurrence was not observed in all patients. Moderate fever (37.8 ℃) was observed in a patient one day after operation and fully recovered 2 days later. Conclusion: CT-guided percutaneous cryoablation is a safe and effective minimally invasive method for the treatment of osteoid osteoma in children. (authors)
[en] Objective: To investigate the technique, safety and efficacy of percutaneous chemoablation of single and multiple confluent metastatic lymphatic nodes (LNs). Methods: Forty six patients of malignant metastatic LNs were treated with percutaneous chemoablation with CT guidance, and they were divided into two groups, including 30 patients of single isolated metastatic LN (group A) and 16 patients of multiple and/or confluent metastatic LNs (group B). A mixture of 5 ml absolute ethyl alcohol, 2 ml iodized oil and 10 mg epirubicin was injected into the lymph node(s). The average tumor diameter was (2.0 ± 0.5) cm in group A and (3.8 ± 0.6) cm in group B. The intratumoral drug coverage rate and the occurrence of reflux were recorded. Enhanced CT scans were performed to observe the therapeutic effects at the intervals of 3, 6 and 12 months. Results: The coverage rate was 100% in group A, which was significantly higher than group B (70% to 80%). The occurrence of reflux was 70% for group A versus 40% for group B. For group A, a complete response (CR) patients of 14, 21, 28 and a partial response (PR) patients of 16, 9, 2 were obtained at 3, 6 and 12 months after therapy respectively. For group B, a CR patient of 0, 0, 0 and PR patients of 3, 8, 9 were observed at 3, 6 and 12 months after therapy respectively. Standardized rate by direct method was performed and the CR rate (74. 4% ) for group A was higher than that for group B (0) (P = 0.0001). The tumor FDG uptake was lower compared with the preoperative images. No serious complications were observed. A few patients had mild pain during the procedure, which was relieved after 2.0 to 3.0 ml of 2% lidocaine injection adjacent to the tumor. No needle tract seeding or infection were observed. There was no effect on patients' overall survival. Conclusions: CT-guided chemoablation is an effective, low-cost and minimally invasive procedure, which is better for treating single metastatic LN than multiple and/or confluent ones. (authors)
[en] Objective: To investigate the preparation of biodegradable vena cava filter (BVCF) with poly-l-lactic acid (PLLA), and to evaluate its mechanical properties, delivery performance, the ability of capturing thrombus and the degradation property. Methods: Three-dimensional design software was used to design the shape of BVCF. The BVCF was prepared by using PLLA with molecular weight of 100 000 unit. Twelve minipigs were used to test the feasibility of this BVCF. They were randomly divided into four groups. At first the BVCFs were placed into the inferior vena cava of pigs in three experimental groups. The fourth group was used as a blank control group. The thrombi were injected into all pigs after 1 week, and CT examinations were performed at different time points to observe the filter locations and pulmonary artery. The animals were sacrificed according to a fixed time table for histopathological assessment. Results: The BVCF was successfully designed and produced, which could expand by stretching the center-thread. In vitro test results showed the radial force of BVCF was approximately 1.6 N and could capture the thrombus more than 5 mm in diameter, and it was easy to release. Through the animal experiment confirmed that the filter could capture the lethal thrombus and all 9 pigs of experimental groups were survived, two of those had the symptoms of respiratory frequency and heartbeat accelerated slightly in the operation. In control group, the symptoms such as accelerate of respiratory rate, shortness of breath were observed in varying degree. The pig which was injected with 8 strips of thrombus died in the same day after surgery. Postoperative CT and pathological examinations showed that 2 pigs in the experimental group developed peripheral pulmonary embolism, while the dead pig in the control group developed central pulmonary embolism. Histological findings showed that the intima covered the BVCF lateral branch partly after one week,and thoroughly after six weeks. The vessel wall structure remained normal and no signs of the obvious inflammatory cells infiltration were detected. Twelve weeks after the implantation, the vessel wall structure was normal, and the lumen was unobstructed, and the collateral of the filter was partly degradated. Conclusions: The BVCF has the advantage of good mechanical strength and good biocompatibility. It is easy to release and can capture the lethal thrombus, but its degradation performance remains to be studied. (authors)
[en] The stable isotope 56Fe was used to simulate the radioactive 56Fe, 59Fe, and 52Fe ions existing in the wastewater generated by nuclear medicine and then the removal efficiency of 56Fe2+ in water was studied using chitosan functionalized multi-walled carbon nanotubes (CS-MWNTs) as adsorbent. The influences of pH, temperature, time, and equilibrium ion concentration on the adsorption capacity were studied. The results show that in the same conditions, the adsorption capacity of CS-MWNTs is significantly increased compared to the pristine multi-walled carbon nanotubes (MWNTs). Both CS-MWNTs and MWNTs exhibit a better removal efficiency of Fe2+ in neutral solutions than in acidic solutions, while in basic solutions, the Fe2+ will precipitate and the removal of Fe2+ is no longer due to the adsorption effect. The adsorption equilibrium will be reached in about 3 h and the adsorption of Fe2+ to either CS-MWNTs or MWNTs is endothermic. At room temperature of 25℃ and pH=5, the saturate adsorption capacity of CS-MWNTs for Fe2+ is 51 mg/g, and that of pristine MWNTs is 27 mg/g. The Freundlich adsorption model can well represent the adsorption of Fe2+ to both of two kinds of adsorbent materials. (authors)
[en] To verify the influence of the functional elements particular size for the radiation attenuation coefficients and mechanical properties radiation shielding material based on epoxy resin, we prepare two WO3/E44 samples with different particular sizes of WO3 by a solidified forming approach. The linear attenuation coefficients of these samples are measured for γ-ray photo energies of 59.6, 121.8, and 344.1 keV, etc. using narrow beam transmission geometry. It is found that the linear attenuation coefficients would increase with the decreasing particle size of the WO3 in the epoxy resin based radiation shielding material. The theoretical values of the linear attenuation coefficients and mass attenuation are calculated using WinXcom, and good agreements between the experimental data and the theoretical values are observed. From the studies of the obtained results, it is reported that from the shielding point of view the nano-WO3 is more effective than micro-WO3 in the epoxy resin based radiation shielding material. (authors)
[en] We present the toroidal dipolar response in graphene-based disk metamaterials at terahertz range and find that this response has a dominant role over other multipoles as compared with that in noble metals, attributed to the atom-level ultrathin characteristic of two-dimensional graphene. Moreover, the toroidal response is tunable with the Fermi level of graphene, which is readily to be realized by applying electrostatic gating, photo-injection, etc. In addition, layers of graphene also obviously influence the toroidal response in terms of the resonant frequency and magnitude. It is believed that the actively tunable characteristic of terahertz toroidal response in graphene metamaterials, in contrast to noble-metal-based metastructures, can provide unique convenience for further exploration of toroidal dipolar response. (paper)
[en] Application of fertilizers to supply appropriate nutrients has become an essential agricultural strategy for enhancing the efficiency of phytoremediation in heavy metal contaminated soils. The present study was conducted to investigate the beneficial effects of three types of phosphate fertilizers (i.e., oxalic acid-activated phosphate rock (APR), Ca(H2PO4)2, and NaH2PO4) in the range of 0–600 mg P kg−1 soil, on castor bean growth, antioxidants [antioxidative enzymes and glutathione (GSH)], and Cu uptake. Results showed that with the addition of phosphorus fertilizers, the dry weight of castor bean and the Cu concentration in roots increased significantly, resulting in increased Cu extraction. The phosphorus concentration in both shoots and roots was increased as compared with the control, and the Ca(H2PO4)2 treatment had the greatest effect. Application of APR, NaH2PO4, and Ca(H2PO4)2 reduced the malondialdehyde (MDA) content, and the activity of the two antioxidant enzymes superoxide dismustase (SOD, EC 22.214.171.124) and catalase (CAT, EC 126.96.36.199) in the leaves of castor bean. GSH concentration in leaves increased with the increasing levels of phosphorus applied to soil as well as the accumulation of phosphorus in shoots, compared to the control. These results demonstrated that the addition of phosphorus fertilizers can enhance the resistance of castor bean to Cu and increase the Cu extraction efficiency of the plant from contaminated soils.
[en] The biogeochemical cycling of sulfur (S) in soil has an important impact on the bioavailability of heavy metals and affects the utilization of soil polluted by heavy metals. In addition, S-containing compounds are involved in heavy metal detoxification. This study investigated the effects of S on the toxicity and bioavailability of copper (Cu) in castor (Ricinus communis L.) grown in Cu-contaminated mine tailings. The results showed that the application of S reduced the accumulation of Cu in castor and promoted its growth. With the addition of S, the malondialdehyde (MDA) content of castor leaves decreased significantly compared with control plants, indicating the alleviation of oxidative stress. Superoxide dismutase (SOD) and catalase (CAT) activities and glutathione (GSH) content decreased significantly with the alleviation of oxidative stress. The sequential extraction of Cu fractions showed that the application of S significantly reduced the reducible Cu fraction, and increased the oxidizable Cu fraction. It also increased the residual Cu fraction in the soil. The transformation of chemical speciation reduced the bioavailability of Cu in soil, which then reduced the accumulation of Cu in castor. Our results demonstrated that S application was effective at promoting castor growth by reducing the bioavailability and uptake of Cu in Cu-contaminated mine tailings.