Niclosamide is the most commonly used molluscicide. Along with a lot of application of niclosamide more and more scientists studied its toxic effects to aquatic organisms as well as the related cell toxicity mechanism. This paper summariz?es the toxicity on cell organelle enzyme cell signaling pathway and genetic material caused by niclosamide and puts for?ward the future research direction.

Objective To introduce a finger leaf design that is applied to dual layer MLCs.Methods An optimization model was firstly constructed to describe the problem of determining leaf end shapes,and the corresponding problems were then solved by the simplex search method or the simulated annealing technique.Optimal parameters for arc shapes of leaf end projections were obtained,and a comparison was done between optimized MLCs and conventional MLCs in terms of field conformity.The optimization process was based on 634 target fields selected from the patient data base of a treatment planning system.Areas of these fields ranged from 20.0 to 602.7 cm with a mean and its standard deviation of (125.7 ±0.0) cm~2.Results The optimized leaf end shapes projected to the isocenter plane were semicircles.With the finger leaf design,the total area of discrepancy regions between MLC fields and target fields was reduced by 32.3% .Conclusions The finger leaf design improves the conformity of the MLC shaped fields to the desired target fields.

Purpose: To analyze factors which influence the precision & accuracy of target positions in Alderson Head phantom and(or) patients.Materials and Methods: A target position simulator was used to determine the precision and accuracy of target localization while Alderson head phantom used to determine the overall precision and accuracy through the treatment procedure.Results: The overall precision and accuracy through the treatment procedure was found to be 1.72?0.60mm, and its contribution from CT localizing step, which was 1.4?0.3mm。Conclusion: Since there are more factors related to patients' treatment, the precision and accuracy of simulating in Alderson phantom is the best estimate for patient treatment.

Objective To investigate the molluscicidal effect of 5%niclosamide ethanolamine granules against Oncomela-nia hupensis in a marshland field. Methods The 5%niclosamide ethanolamine granules were sprayed at a dose of 40 g/m2 on 3 snail-breeding marshlands in Yangzhong City of Jiangsu Province to assess its field molluscicidal actions while 26%suspension concentrate of metaldehyde and niclosamide MNSC) at a dose of 4 g/m2 and fresh water served as controls. Results After seven days spraying, 5%niclosamide ethanolamine granules resulted in a of snail mortal85.42%ity while the mortality rates of snails were 82.35% and 2.86% in the MNSC and water control groups respectively. Conclusion 5% niclosamide ethanol-amine granules exhibit a high molluscicidal activity which is suitable to be used in the mashland.

Objective To design leaf patterns for Multileaf Collimator(MLC)routine quality assurance(OA)with a 2D diode array.Methods According to the detector distribution characteristic of the 2D diode array and basillg on the"picket fence"pattern,design the"stepwise"pattern.For each diode involving MLC QA,a calibration curve of relative output versus leaf positioning error was measured through delivering a set of patterns with different intentionally introduced positioning errors.When this proposed technique was delivered,the referenced patterns were exposed,and the calibration curves were used as a mean to quantitative determination of the leaf possible positioning errors through the detector readings.Results Compared with the"picket fence"pattern,the"stepwise"pattern not only had a high detecting efficiency,but also increased the dosimetric sensidvity to leaf positioning error.A 1 mm Ieaf positioni.error corresponds to a dose variation of 25% for the"stepwise"pattern,while for the"picket fence"pattern the same positioning error just causes a 17% dose vailation.Conclusions The new"stepwise"pattern is more efficient to be carried out,and more sensitive to sub-millimeter changes of leaf positioning.

Objective To evaluate the improvement of cone beam CT (CBCT) image quality by using bewtie filter (F_1) and water calibration. Methods First the multi-level gain calibration of the detector panel with the method of Cal_2 calibration was performed, and the CT images of CATPHAN503 with F_0 and bowtic filter were collected, respectively. Then the detector panel using water calibration kit was calibrated, and images were acquired again. Finally, the change of image quality after using F_1 and (or) water calibration method was observed. The observed indexes included low contrast visibility, spatial uniformity, ring artifact, spatial resolution and geometric accuracy. Results Comparing with the traditional combination of F_0 filter and Cal_2 calibration, the combination of bowtie filter F_1 and water calibration improves low contrast visibility by 13.71%, and spatial uniformity by 54. 42%. Water calibration removes ring artifacts effectively. However, none of them improves spatial resolution and geometric accuracy. Conclusions The combination of F_1 and water calibration improves CBCT image quality effectively. This improvement is aid to the registration of CBCT images and localization images.

Objective:Through the discussion on the purchasing mode of hospital equipment in China, fully understand the advantages and disadvantages of various procurement ways, choose reasonable acquisition method, optimize acquisition method, standardize the procurement management objective.Methods: By using the method of analogy, comparison of the four main acquisition methods. By the comparative analysis, the scope of each purchase way was confirmed. Results: Public bidding was better for more than 500000 yuan or the treasury payment items, competitive negotiation approach applies to 50000 yuan-500000 yuan purchase project. Consultation approach can be applied to 50000 yuan purchase project. Information project procurement preferred to methods of government procurement.Conclusion: Reasonable choices of purchasing and proper optimization has significant meaning for equipment purchasing and management in hospital.

Biogenic molluscicides refer to the use of plants,animals and micro?organisms or their metabolites,and synthesis biomimetic molluscicides to kill Oncomelania hupensis snails. With the rapid development of science and technology,new bio?genic molluscicides are continuously emerging and the category also continues to expand. According to the molluscicidal active ingredient and sources,at present,the biogenic molluscicides with in?depth studies include plant?derived molluscicides,micro?organism molluscicides,microbial metabolite molluscicides and animal molluscicides. This paper reviews the advances in the re?searches of biogenic molluscicides in recent years.

ObjectiveBoth kilovolt (KV) cone-beam computed tomography (CBCT) and KV radiography can determine set-up errors for patients with head-and-neck cancer.This study is to compare their performance.Methods16 patients with head and neck cancer were enrolled in this study.There were 160 sets of CBCT and corresponding orthogonal radiography images.Through registration of CBCT images with the planning CT images,and registration of radiography images with the digitally reconstructed radiographs,translational set-up errors were determined along left-right (x),super-inferior (y),and anterior-posterior (z) directions.Pearson correlation analysis was performed to evaluate the correlation of the set up errors determined by the two methods,and Bland-Altman plot analysis was used to assess the coincidence of these two methods.ResultsThe Pearson coefficient of correlation along all three directions was less than 0.01,and R2 was 0.95,0.84,0.81 on x,y,z,respectively.That means high correlation for two methods.The Bland-Altman plot analysis showed that the 95％ agreement limits of agreement were within preset 2 mm tolerance (x[ 1.3mm,- 1.2mm],y[ 1.6mm,- 1.1mm],z[0.8mm,-1.4 mm] ),which indicates an agreement exists for two methods.ConclusionsFor determination of set-up errors for patients with head and neck cancer,KV radiography is equivalent to CBCT.Considering CBCT delivers higher dose than KV radiography,but provides more soft tissue information.We suggest to use these two methods combinative in clinic.

Objective To verify the dose delivery accuracy of volumetric-modulated arc therapy plan by log-file analysis of linear accelerator that can be created when a dynamic delivery occurs.Methods Accelerator log file in binary format recorded the accelerator execution plan for each control point corresponding to the gantry angle,multi-leaf collimator leave position,cumulative machine monitor units ( MU).These information were read from the accelerator log file with Matlab7.1,then the original control points in the plan file replaced the corresponding information for the log,which generated a new plan.New plan was exported into the planning system to reculculate the dose.The volume dose histogram (DVH) and dose distribution was contrasted to determine the accuracy of the accelerator plan of implementation between two plans.Results Compared with the original plan,antry angle difference over ± 1° accounted for about 35％ of the entire arc of control points in 4 of 12 arcs and the percentage of the leave error of ±0.5 mm was about 95％.MU error of a single control point was larger,but the cumulative MU for each are was small which was located between-0.09％ to 0.11％ in the selected 12 arcs.Between the targets,the maximum dose,minimum dose,the mean dose differences were from-0.07％ to 0.42％,-0.38％ to 0.40％,0.03％ to 0.08％,respectively.The maximum dose and mean dose differences of organs at risks were located from-1.16％ to 2.51％,-1.21％ to 3.12％,respectively.Conclusions Accelerator log-file analysis to verify the VMAT plan nan be supplyed to the experimental method supplement.