A method based on the cross-sectional relationship between^(10)B(n,α)^(7)Li and^(1)H(n,γ)^(2)H was proposed to detect and reconstruct the three-dimensional boron concentration/dose distribution in vivo during boron ...A method based on the cross-sectional relationship between^(10)B(n,α)^(7)Li and^(1)H(n,γ)^(2)H was proposed to detect and reconstruct the three-dimensional boron concentration/dose distribution in vivo during boron neutron capture therapy(BNCT).Factors such as the neutron energy,fluence rate,and degree of non-uniform distribution of the boron concentration in a voxel may affect the results of this method.A theoretical analysis of the accuracy of the method using a Monte Carlo simulation shows that the determining error is generally less than 1%under different tumor locations and neutron source configurations.When the voxel size is larger than 0.4 cm,the determining error might be higher for a non-uniformly distributed boron concentration in the voxel because of the changes in the neutron energy and fluence rate.In conclusion,the proposed method enables an accurate threedimensional boron determination in vivo during BNCT.展开更多
Radiochromic film is a useful tool for beam quality assurance, but accurate response assessment of the film is still a problem. In this study, the response uncertainties of HDV2 film were investigated using a flatbed ...Radiochromic film is a useful tool for beam quality assurance, but accurate response assessment of the film is still a problem. In this study, the response uncertainties of HDV2 film were investigated using a flatbed scanner from both the scanning settings and interscan variability. Scanning settings are fixed conditions for scanning, including scanning resolution and focus setting.In this study, multipeak distributions of pixel values were found under some dots-per-inch values, which should be avoided, and the optimal setting of 2000 dpi without this problem was selected. By changing the focus setting, the relative standard deviation of pixel values was reduced by 36–50%. The influence of the interscan variability induced by three factors was investigated, including the outside illumination intensity, film homogeneity, and operating temperature. Scanning the film before and after irradiation at the same position was recommended. Moreover, the suitable operating temperature range for the scanner was found to be 15–24 °C, which results in stable film responses. Regarding the studied factors, correction methods and strategies were proposed, and the accurate response assessment of HDV2 film was realized. Finally, a standard operating procedure for response assessment of films was introduced. It can help other researchers study more scanners, films, and particle types.展开更多
Objective: Evaluate the impact of antihypertensive drugs (AHD) on stroke and acute myocardial infarction (AMI) and death for 3 cohorts of patients: diabetics, high risk, and hypertensive. Methods: This was a retrospec...Objective: Evaluate the impact of antihypertensive drugs (AHD) on stroke and acute myocardial infarction (AMI) and death for 3 cohorts of patients: diabetics, high risk, and hypertensive. Methods: This was a retrospective cohort obervational study based on administrative database of 7 Italian Local Health Units. Newly treated patients with AHD were enrolled from 01/01/2004 to 06/30/2007. Drug utilization and incidence of death, stroke and AMI were measured until 12/31/2007. Results: The study enrolled 125,770 patients aged ≥ 18-year-old: 8516 diabetic, 8549 high risk, and 108,705 hypertensive. Diabetic and high risk patients were more frequently male (57.2%, 64.9% VS 46.6%) and older (66.4 ± 11.6, 67.5 ± 13.2 VS 61.6 ± 13.9) than hypertensive patients and were more treated with concomitant therapy. Drugs acting on the renin-angiotensin system were the more fre- quent choice in the three cohorts but with a dif- ferent prevalence (63.9%, 52.9%, 35.9% in dia- betic, hypertensive and high risk patients re- spectively). Adherent patients to AHD > 80% were 44.0% among diabetic patients, 48.4% among high risk, 35.2% among hypertensive. A Cox regression model showed that the risk of the combined outcome was determined by increasing age, male gender, presence of concomitant therapy, low adherence to AHD and first choice of AHD. Conclusions: An integrated analysis of prescription and hospital admission database has the great advantage that it uses routinely available data, it can be done quickly and by few staff, and it is less expensive than planned large scale survey.展开更多
基金This work was supported by the National Natural Science Foundation of China(Nos.11805100 and 11905106)the Fundamental Research Funds for the Central Universities(No.NG2020003).
文摘A method based on the cross-sectional relationship between^(10)B(n,α)^(7)Li and^(1)H(n,γ)^(2)H was proposed to detect and reconstruct the three-dimensional boron concentration/dose distribution in vivo during boron neutron capture therapy(BNCT).Factors such as the neutron energy,fluence rate,and degree of non-uniform distribution of the boron concentration in a voxel may affect the results of this method.A theoretical analysis of the accuracy of the method using a Monte Carlo simulation shows that the determining error is generally less than 1%under different tumor locations and neutron source configurations.When the voxel size is larger than 0.4 cm,the determining error might be higher for a non-uniformly distributed boron concentration in the voxel because of the changes in the neutron energy and fluence rate.In conclusion,the proposed method enables an accurate threedimensional boron determination in vivo during BNCT.
基金supported by the National Natural Science Foundation of China(No.11805100)the Natural Science Foundation of Jiangsu Province(No.BK20180415)+3 种基金the National Key Research and Development Program(No.2016YFE0103600)the National Key Research and Development Program(No.2017YFC0107700)the Foundation of Graduate Innovation Center in NUAA(No.kfjj20180614)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Radiochromic film is a useful tool for beam quality assurance, but accurate response assessment of the film is still a problem. In this study, the response uncertainties of HDV2 film were investigated using a flatbed scanner from both the scanning settings and interscan variability. Scanning settings are fixed conditions for scanning, including scanning resolution and focus setting.In this study, multipeak distributions of pixel values were found under some dots-per-inch values, which should be avoided, and the optimal setting of 2000 dpi without this problem was selected. By changing the focus setting, the relative standard deviation of pixel values was reduced by 36–50%. The influence of the interscan variability induced by three factors was investigated, including the outside illumination intensity, film homogeneity, and operating temperature. Scanning the film before and after irradiation at the same position was recommended. Moreover, the suitable operating temperature range for the scanner was found to be 15–24 °C, which results in stable film responses. Regarding the studied factors, correction methods and strategies were proposed, and the accurate response assessment of HDV2 film was realized. Finally, a standard operating procedure for response assessment of films was introduced. It can help other researchers study more scanners, films, and particle types.
文摘Objective: Evaluate the impact of antihypertensive drugs (AHD) on stroke and acute myocardial infarction (AMI) and death for 3 cohorts of patients: diabetics, high risk, and hypertensive. Methods: This was a retrospective cohort obervational study based on administrative database of 7 Italian Local Health Units. Newly treated patients with AHD were enrolled from 01/01/2004 to 06/30/2007. Drug utilization and incidence of death, stroke and AMI were measured until 12/31/2007. Results: The study enrolled 125,770 patients aged ≥ 18-year-old: 8516 diabetic, 8549 high risk, and 108,705 hypertensive. Diabetic and high risk patients were more frequently male (57.2%, 64.9% VS 46.6%) and older (66.4 ± 11.6, 67.5 ± 13.2 VS 61.6 ± 13.9) than hypertensive patients and were more treated with concomitant therapy. Drugs acting on the renin-angiotensin system were the more fre- quent choice in the three cohorts but with a dif- ferent prevalence (63.9%, 52.9%, 35.9% in dia- betic, hypertensive and high risk patients re- spectively). Adherent patients to AHD > 80% were 44.0% among diabetic patients, 48.4% among high risk, 35.2% among hypertensive. A Cox regression model showed that the risk of the combined outcome was determined by increasing age, male gender, presence of concomitant therapy, low adherence to AHD and first choice of AHD. Conclusions: An integrated analysis of prescription and hospital admission database has the great advantage that it uses routinely available data, it can be done quickly and by few staff, and it is less expensive than planned large scale survey.
