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Objective To evaluate the impact of an external magnetic field on the dose distribution and electronic disequilibrium region around a Bebig type 60Co HDR brachytherapy source and to judge the feasibility of applying MRI scanner during brachytherapy.Methods The source model was established based on the Monte Carlo package Geant4 software.The simulated geometries consisted of the 60Co source inside a water phantom of 10.0cm× 10.0cm× 10.0cm in size.The magnetic field strength of the 0T,1.5T and 3.0T was considered,respectively.The voxels with a size of 0.2 mm,0.5 mm and 0.5 mm were established along the x-,y-and z-axis.The influence of the magnetic field on the Kerma (kinetic energy released to matter) distribution and dose distribution within the 10.0mm region from the source center was evaluated.Furthermore,the ratio of the Kerma to dose as a function of the distance to the center source was acquired.Results The 1.5T magnetic field exerted no effect on the dose distribution adjacent to 60Co HDR brachytherapy source,whereas3.0T magnetic field caused significant increase in the dose distribution within r＜6 mm from the source center.The dose distribution was increased by 40％ at r=5.4 mm from the source center.The ratio of Kerma to dose was less than 1 within the region of 1.2 mm＜r＜6.0 mm,suggesting that 3.0T magnetic field can lead to electronic disequilibrium within a larger region from the source center.Conclusions For Bebig 60Co HDR brachytherapy source,it is safe and reliable to apply1.5T external magnetic field.Nevertheless,3.0T magnetic field can cause high dose risk.Consequently,safety assessment and verification should be delivered prior to clinical application.
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Objective The objective of this study was to compare the differences between Volumetric Modulated Arc Radiotherapy(VMAT)and Fixed Field dynamic Intensity Modulated Radiotherapy(dIMRT)in dose distribution of target and organ at risk and treatment time,and to provide basis for clinical treatment.Methods Ten patients with postoperative of cervical carcinoma were selected,VMAT and seven fields dIMRT plans were designed for each patient in Monaco 5.11 planning system.We compared the differences of dose distribution of target and organ at risk,monitor units and treatment time between VMAT and 7dIMRT.Results The average dose of target for VMAT plan(46.86 Gy)was higher than that of 7dIMRT plan(46.68 Gy)(P<0.05).The percentage of the V10 and V20 of rectum and the V30 of small intestine in VMAT plan was 0.63%,3.34% and 4.14% higher than that in 7dIMRT plan,respectively(P<0.05).The conformal index(CI),homogeneity index(HI)of PTV and the other exposure dose of organ at risk for both plans were no significant differences.The average monitor units and treatment time of VMAT plan were 13.4% and 50.6% than that of 7dIMRT plan,respectively(P<0.05).Conclusion The dose distribution of VMAT plan is better or equal to that of 7dIMRT plan,but the monitor units and treatment time of VMAT plan is decreased significantly,we suggest that VMAT plan should be used for postoperative of cervical carcinoma in clinical.
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Objective We aimed to explore the difference of dosimetry among intensity modulated radia-tion therapy(IMRT),volumetric modulated arc therapy(VMAT)and helical tomotherapy(TOMO)in the radio-therapy of medulloblastoma.Methods Ten children's patients with the medulloblastoma were selected and de-signed in this study.A clinically feasible radiotherapy plan was designed for IMRT(5 fields),VMAT and TOMO. Conformality index(CI),homogeneity index(HI),V107,maximum dose(Dmax),organ at risk(OAR)dose-volume level,monitor units and treatment time were used to analyze in these groups.Results CI,HI,V107,Dmaxand OAR of target areas were significantly superior to VMAT and IMRT in the TOMO group of target PTV for whole brain full radiotherapy.The organ at risk dose-volume level in the TOMO group was lower than that in VMAT and IM-RT(5 fields)groups(P<0.05).The TOMO group also had the most monitor units and the longest treatment time (P<0.05).Hence,the patients in the TOMO group could irradiate completely the whole brain and full spinal cord without moving treatment couch to avoid the error from the man-made movement in VMAT and IMRT(5 fields)treatments.Conclusion In the radiotherapy of medulloblastoma,the dose distribution of patients in the TOMO group are superior to the VMAT and IMRT groups(5 fields).However,the number of monitor units and treatment time is significantly increased during treatment,and its clinical effect needed to be further studies.
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Objective We aimed to explore the difference of dosimetry among intensity modulated radia-tion therapy(IMRT),volumetric modulated arc therapy(VMAT)and helical tomotherapy(TOMO)in the radio-therapy of medulloblastoma.Methods Ten children's patients with the medulloblastoma were selected and de-signed in this study.A clinically feasible radiotherapy plan was designed for IMRT(5 fields),VMAT and TOMO. Conformality index(CI),homogeneity index(HI),V107,maximum dose(Dmax),organ at risk(OAR)dose-volume level,monitor units and treatment time were used to analyze in these groups.Results CI,HI,V107,Dmaxand OAR of target areas were significantly superior to VMAT and IMRT in the TOMO group of target PTV for whole brain full radiotherapy.The organ at risk dose-volume level in the TOMO group was lower than that in VMAT and IM-RT(5 fields)groups(P<0.05).The TOMO group also had the most monitor units and the longest treatment time (P<0.05).Hence,the patients in the TOMO group could irradiate completely the whole brain and full spinal cord without moving treatment couch to avoid the error from the man-made movement in VMAT and IMRT(5 fields)treatments.Conclusion In the radiotherapy of medulloblastoma,the dose distribution of patients in the TOMO group are superior to the VMAT and IMRT groups(5 fields).However,the number of monitor units and treatment time is significantly increased during treatment,and its clinical effect needed to be further studies.
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Objective To explore the relationship between angiogenin-1/2 (Ang-1/2) and clinical parameters of idiopathic pulmonary fibrosis (IPF), and to assess the value of Ang-1/2 in predicting the prognosis of patients with IPF.Methods A retrospective analysis was conducted. Ninety-one patients diagnosed as IPF by high resolution CT (HRCT) and lung biopsy admitted to Daqing Oil Field General Hospitalfrom March 2014 to January 2015 were enrolled. The general data, serum parameters and pulmonary function parameters of all patients were collected. After treatment, all of the 91 patients were followed-up to 2 years. The patients were divided into favorable prognosis group and unfavorable prognosis group according to follow-up results. The differences in all parameters between the two groups werecompared. The relationship between Ang-1, Ang-2 and lung function parameters was analyzed by Pearson correlation analysis. Cox proportional hazard regression model was used to evaluate the effect of clinical parameters on the prognosis of patients with IPF. The effect of Ang-2 in predicting prognosis of patients with IPF was analyzed by receiver operating characteristic (ROC) curve.Results During the 2-year follow-up period, 30 of 91 patients showed a favorable prognosis, and 55 showed an unfavorable prognosis with a poor prognosis rate of 64.71%, and 6 patients withdrew from the study due to loss of follow-up and death. Compared with the favorable prognosis group, Ang-2 level in the unfavorable prognosis group was significantly increased (μg/L: 2.88±1.63 vs. 1.89±1.22,t = 2.909,P= 0.005), but Ang-1 only showed a slight increase (μg/L: 28.70±14.26 vs. 25.62±11.95,t = 1.005,P = 0.318). The results of Pearson correlation analysis showed that Ang-2 level was negatively correlated with forced expiratory volume in 1 second (FVC1) and the percentage of carbon monoxide diffusing capacity accounting for the expected value (DLCO%;r value was -0.227 and -0.206, andP value was 0.147 and 0.253, respectively), but no significant correlation between the level of Ang-1 and FVC1 as well as DLCO% was found (r value was -0.153 and -0.121, andP value was 0.147 and 0.253, respectively). Cox proportional hazard regression model analysis showed that the prognosis of patients with IPF was significantly affected by smoking time and Ang-2 (bothP 0.05). Prognostic analysis showed that the area under ROC curve (AUC) of Ang-2 for predicting prognosis of patients with IPF was 0.692, and the best diagnostic point was 0.35μg/L, the sensitivity was 61.8%, the specificity was 73.3%, the positive predictive value was 69.8%, and the negative predictive value was 65.7% which indicated that Ang-2 could predict the prognosis of patients with IPF.Conclusion Ang-2 could assess the prognosis of patients with IPF, which is expected to be used as an indicator of predicting the prognosis of patients with IPF.
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Objective To investigate the current status of compliance with hand hygiene among health care work-ers (HCWs)in a comprehensive hospital in Xi’an.Methods Status of hand hygiene among HCWs in 73 clinical de-partments was observed directly.Results 404 moments for hand hygiene of 404 HCWs were observed,255 times of hand hygiene were implemented,181 times of hand hygiene were correct,the total compliance rate was 63.12%, and correct rate was 44.80%.Compliance rate and correct rate of hand hygiene of HCWs in intensive care unit were both higher than general wards (91.89% vs 60.22%,χ2 =14.485,P <0.001;81.08% vs 41.14%,χ2 =5.671,P=0.017).Among HCWs of different occupations,compliance rate and correct rate of hand hygiene of nurses were both the highest (73.76% and 60.18% respectively),while auxiliary persons were both the lowest (40.90% and 10.20% respectively);among five moments for hand hygiene,compliance rate was highest after body fluid and blood exposure (80.00%),correct rate was highest before aseptic procedure (62.96%).Conclusion There is a high compliance rate and low correct rate of hand hygiene among HCWs in this hospital.Compliance rate and correct rate of hand hygiene among HCWs in different departments,different occupations and different hand hygiene moments are varied,compliance with hand hygiene among HCWs should be paid extensive attention.
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Objective To explore the curative effect of modified closed negative pressure drainage on abnormal abdominal incision. Methods Sity-three patients with abnormal healing of abdominal incision in our hospital from January 2012 to June 2013 were selected as the observation group. Another 50 patients from January to December 2011 were assigned to the control group. The former was treated after debridement with human recombinant surface growth factor and modified closed negative pressure drainage,while the latter after debridement with anti-infection and dressings of ethacridine or gentamicinsolution as well as with infrared therapy. The two groups were compared in terms of the frequency,time and cost of changed dressings,and the healing time of the incisions.Results There was insignificant difference in the cost of changed dressings between the two groups(P>0.05). However,the differences were statistically significant in terms of the frequency and time of changed dressings and the healing time of the incisions(P<0.05). The observation group was significantly superior to the control group.Conclusions Modified closed negative pressure drainage is effective in accelerating the healing in abnormal abdominal incisions,reducing the frequency and the time of changed dressings,and easing the economic burdens of the patients,which is suggested to be popularized and applicable in the pimary hospitals.
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Objective To investigate the correlation between mental status of patients with stroke and their quality of life. Method One hundred and three stroke patients were measured by HRSD,HMAM and SS-QOL to explore the correlation between mental status and quality of life.Results Among the 103 patients,68 developed depression, taking up 66.02%,with a total score of 31.62±12.58;52 anxiety,taking up 50.49%,with a total score of 22.17±5.38.The level of depression and anxiety were negatively correlated with the life quality(P<0.01).Conclusions The occurence rate of depression and anxiety in stroke patients is higher. The higher the scores on depression and anxiety,the worse the quality of life.
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Objective To probe into the clinical effect of the sickbed management system for student nurses.Methods The student nurses at the first department of gynecology from June 2010 to April 2012 were set as the experiment group,in which the sickbed management system was used so that they completed their nursing work at fixed shifts and sickbeds under the nursing teacher’s instructions.The student nurses at the second department of gynecology during the same period were set as the control group,in which the student nurses took different tasks for unfixed sickbeds at different shifts every day.The two groups were compared in terms of the student nurses’knowledge about the patients’diseases and the degree of patients’satisfaction with their nursing work.Result The experiment group was significantly better than the control one in terms of student nurses’knowledge about the patients’diseases and the degree of patients’satisfaction with their nursing work(both P<0.05).Conclusion The sickbed management system for the student nurses may not only enhance nurses’sense of responsibility for their work,but also improve the quality of nursing teaching and patients’ satisfaction with the nursing service.
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Objective To explore the effect of straddling chair on paraplegic patients complicated with pressure sore. Methods Nineteen paraplegic patients complicated with pressure sore were set as the control group where they were managed with routine rehabilitation training and adapted negative pressure drainage at the sore.Another twenty-three paraplegic patients complicated with pressure sore were set as the experiment group where conventional rehabilitation trainings was taken and besides the patients were managed with rehabilitation training by riding on the straddling chairs.The curative effect of pressure sore and the activities of daily living(ADL)at discharge were compared between the two groups.Result The experiment group was significantly better than the control group in terms the curative effect,time for discharge and ADL(all P<0.05).Conclusion Rehabilitation training of paraplegic patients’riding on the straddling chair may be helpful for the improvement of the activities of ADL and effective prevention and curative treatment of the pressure sore.
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Objective To study the spectrum structure of X-ray and simplify the description method of it. Methods By the general program of Monte Carlo Geant4 to study X-ray spectrum structure and angular distribution of X-ray energy spectrum. Results The results of percentage depth doses and profile curves at different depths of any radiation fields in water phantom calculated by Monte Carlo Geant4 were consistent with the measurements. Conclusions In radiotherapy, X-ray with same nominal energy have very similar dosimetry characteristics, this indicates they have very similar energy spectrum and angular distribution of spectrum. the differences of dosimetric details reflect the different details of the X-ray spectrum structure and angular distribution of X-ray energy spectrum. These studies have very important significances to rapidly build precise virtual source modeling for Monte Carlo calculation based on dose curves measurements in water phantom.
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ObjectiveTo analyze the effects of high-order scattered X-ray in dose calculation in radiotherapy,to resolve the problem of correcting the dose contribution of secondary and high-order scattering X-ray to the primary scattered X ray,and to provide a support for photon fast dose calculation method of Monte Carlo.MethodsBy the theory of cross-section in interaction between X-ray with material and Monte Carlo calculating results,to analysis the relative importance of primary scattered X-ray,secondary and high-order scattered of X-ray in dose calculation.ResultsThe contribution of secondary and high-order scattered X-ray to dose calculation was very small,it can be corrected to the primary scattered X-ray with a correction factor.ConclusionsThe results show that we can obtain a precise dose calculation for radiotherapy by only to tracking the contribution of primary X-rays and primary scattering X-ray,so,to establishing the database for primary scattering X-ray by Monte Carlo methods is important for fast dose calculation of Monte Carlo method.
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ObjectiveTo study the dose distribution of the intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) inverse plans with different energy X-ray, to provide a reference of energy options for radiation therapy. MethodsEight cases with different disease were chosen, the plan for each case were finished with 1Arc (360°) VMAT, 9 fields IMRT and 5 fields IMRT.For each plan project, the energy selections were 4 MV, 6 MV, 8 MV and 15 MV. In the evaluation,homogeneity index ( HI), conformity index ( CI ) and external volume index ( EVI ) of target, the average dose ( Dmean) and 2％ volume in dose volume histogram ( D2 ) of serial organs at risk ( OARs), the average dose ( Dmean ) and a dose level volume ( Vx ) of parallel OARs were chosen and compared . Results Statistical analysis showed that: For the target, the result of HI were F=0. 13,0. 51,0. 09, P=0. 939,0.679,0.965,CI were F=0. 13,0.51,0.09,P=0.939,0.679,0.965, EVI were F=0. 15,0.31,0. 15,P =0. 930,0. 818,0. 931, respectively ; For the OARs of each patient, F ＜ 0. 20, P ＞ 0. 05. All results indicated there was little difference in option of energy for the same field p8roject. ConclusionsThe results indicate that the middle and low energy X-ray (6 MV or 8 MV) can satisfy the needs of IMRT and VMAT radiotherapy. Compared with middle and low energy, the high energy X-ray (15 MV ) showed little advantage in dose distribution.
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Objective To evaluate the precision of image guided radiotherapy (IGRT) for vertebra metastasis.Methods Cone-beam computed tomography (CBCT, ELEKTA SynergyTM) scanning was performed to 15 patients with vertebra metastasis treated with three dimensional conformal radiation therapy (3DCRT) or intensity modulated radiation therapy (IMRT).CBCT images were then compared with corresponding planning images to calculate the position errors.The isocenter was adjusted based on the errors calculated , CBCT scanning was re - performed , and the new - errors were then calculated .Results Compared to the firstly collected CBCT images, the average errors of 4 cases of cervical bone metastases in x (left-right), y (cervical-caudal), and z (anterior-posterior) directions were 1.8 mm, 0 mm and 3.6 mm respectively.After adjusting the isocenter, the new-errors were reduced to 0.1 mm, 0.4 mm and 0.3 mm.For 11 cases of thoracic and lumbar bone metastases, the average errors in x, y, and z directions were 1.9 mm, 0.1 mm, and -2.1 mm, respectively.While the new-errors were reduced to 0.9 mm, 0.5 mm and -0.3 mm.Conclusions IGRT can improve the precision of radiotherapy for vertebra metastasis to less than 2 mm, which provides a possibility of dose escalation in GTV while reduce the dose in the spinal cord.
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This paper reports the results of a study about the segregational stability of a series of pNK289-derived plasmids. The segregational stability in B. subtilis AS1. 1176 was found to be different among these same originated plasmids. The difference in segregational stability was shown not to be related to the sizes or replication patterns of the plasmids, but to have some relation to their copy numbers. As the unstable plasmid pNK219 can be miaintained stably in B. subtilis BD 224, it can be inferred that the host inheritable background could affect the segregational stability of plasmid. These results not only have laid a foundation for finding out some genes related to the stability of pNK289-derived plasmids, but also provided theoretical basis for constructing stable recombinant plasmid in Bacillus.
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Objective To improve the set up accuracy for patients by MED TEC thermoplastic sheet. Methods First, a reference positioning line was scored on the supporting board of MEC TEC. Then, lines on the patient body were marked according to the reference positioning line. After fastening MED TEC thermoplastic sheet, CT top view imagines of patients who were immobilized with MED TEC thermoplastics sheet on the CT scanner were then drawn. The results by PC graphics software were analysed. Results A total of 57 cases was studied. Deviation in 52 (91.2%) cases was less than 3?mm. The cause of the with deviation exceeding 5?mm were all found.Conclusion Using the right method is very important. Thus, results with satisfactory deviations could be obtained when the set up are repeated.
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Objective To develop a gas chromatographic (GC)method for simultaneously determination of benzyl alcohol,2-phenoxyethanol,methyl-p-hydroxy benzoate (PHBA-Me?雪,ethyl-p-hydroxybenzoate(PHBA-Et?雪,isooropyl-p-hydroxybenzoate(PHBA-iPr?雪,propyl-p-hydroxybenzoate (PHBA-Pr),isobuty-p-hydroxy benzoate(PHBA-iBu)and butyl-p-hydroxy benzoate(PHBA-Bu)in cosmetics. Methods The 8 kinds of preservatives could be separated completely using the packed column and their peaks were not interfered by the other components in cosmetics. Results The detection limits of were 0.27,0.38,0.78,0.83,0.95,1.40,1.50 and 2.1ng respectively. The linear ranges of benzyl alcohol,2-phenoxyethanol and PHBA-iPr were 25-1 000 mg/L and the linear ranges of PHBA-Me?PHBA-Et?PHBA-Pr?PHBA-iBu and PHBA-Bu were 25-500 mg/L. The recoveries were between 92.6%-101.3% and the relative standard deviations(RSD)were between 2.31%-6.44%(n=6?雪. Conclusion The method was simple,rapid,sensitive and accurate. It was suitable for the detecting of preservatives in cosmetics.