1.Monte Carlo simulation study of the effect of filter on radiotherapy dosimetry in superficial X-ray therapy apparatus
Li TAO ; Hui ZHANG ; Yikai WU ; Junyi LIU ; Miao QI ; Ning GAO ; Yankui CHANG ; Xi PEI ; Zhi CHEN ; Xie XU
Chinese Journal of Radiological Medicine and Protection 2025;45(3):194-201
Objective:To explore the dosimetry optimization strategy based on filter thickness and shape selection for the bulb superficial X-ray radiotherapy unit.Methods:Monte Carlo code TOPAS was used to model tubular equipment, and the dose distribution from six X-ray energies (50-150 kV) and five conventional aluminum filters (0.5-3.0 mm) with different thickness were simulated in the water model. The percentage depth dose (PDD) curve along the central axis, the center-axis profile dose at different depths, and the lateral dose distribution were analyzed. The dose distribution of three different designs of aluminum filters (conventional cylindrical, conical and oblique cylindrical filters) was compared to evaluate the effect of dosimetric optimization of different filter shapes.Results:Under the same energy, increasing the thickness of the filter can optimize the superficial skin dose, and the optimization effect of depth dose uniformity can be increased by 26% at a depth of 5.5 mm at 70 kV energy. The raised, flat and inclined dose distribution modes can be achieved by using conventional cylindrical, conical and inclined aluminum filters.Conclusions:By selecting the appropriate X-ray energy and filter thickness, an ideal dose distribution matching the tumor depth can be achieved. The application of personalized filters is also of great significance for diverse target areas.
2.Monte Carlo study of transmission X-ray tubes in kilovoltage radiotherapy
Yikai WU ; Zhongyu QI ; Li TAO ; Hui ZHANG ; Zeeshan MUHAMMAD ; Zirui YE ; Yankui CHANG ; Xi PEI ; Xu GEORGE
Chinese Journal of Medical Physics 2025;42(7):863-871
Transmission X-ray tubes are relatively new devices characterized by portability,suitability for miniaturization,and low requirements for shielding,making them ideal radiation sources for kilovoltage X-ray therapy.However,their application in radiotherapy remains underexplored.An electron target model of a transmission X-ray tube is developed using the Monte Carlo toolkit TOPAS 3.8.1.The study investigates the effect of tungsten target thickness on X-ray output efficiency,finding that a tube voltage of 50 kV and a tungsten thickness of 1.4 μm yields the highest emission efficiency.Based on the energy spectrum at this optimal efficiency,polynomial fitting approach is applied to determine the corresponding aluminum filter thickness for mean energies ranging from 20 keV to 35 keV,achieving a mean fitting error of 0.91%.Next,the study simulates dose deposition in a water phantom for spectra with different mean energies and various source-to-surface distances,and plots percent-depth-dose curves,relative normalized dose-depth curves,and relative normalized dose histograms under each treatment condition.Finally,the simulated results are compared with experimental data from the intraoperative radiotherapy system Intrabeam and the superficial X-ray therapy unit SRT-100,obtaining average relative errors of 3.71%and 4.38%,respectively.These findings provide a theoretical foundation for further optimization of transmission X-ray tubes in kilovoltage radiotherapy.
3.Pathological mechanisms, risk factors, and preventive strategies of cardiac surgery-associated acute kidney injury
Yikai HE ; Shuyue SHEN ; Huipeng GE ; Linlin ZHANG ; Xiangcheng XIAO
Journal of Chinese Physician 2025;27(9):1430-1436
Acute Kidney Injury (AKI) is a common and severe complication after cardiac surgery. The pathogenesis of cardiac surgery-associated AKI (CSA-AKI) is complex, and it is associated with increased patient mortality and poor renal prognosis. To identify high-risk patients as early as possible, numerous clinical studies have explored perioperative risk factors and developed a variety of biomarkers with good diagnostic capabilities. Currently, multiple prediction models for AKI after cardiac surgery have been developed internationally; however, there is no effective treatment for CSA-AKI. Therefore, implementing reasonable and comprehensive preventive strategies is crucial. In addition, the clinical application of some interventions is controversial, which means more research and exploration are needed to make more informed decisions regarding the prevention and treatment of CSA-AKI.
4.Monte Carlo study of transmission X-ray tubes in kilovoltage radiotherapy
Yikai WU ; Zhongyu QI ; Li TAO ; Hui ZHANG ; Zeeshan MUHAMMAD ; Zirui YE ; Yankui CHANG ; Xi PEI ; Xu GEORGE
Chinese Journal of Medical Physics 2025;42(7):863-871
Transmission X-ray tubes are relatively new devices characterized by portability,suitability for miniaturization,and low requirements for shielding,making them ideal radiation sources for kilovoltage X-ray therapy.However,their application in radiotherapy remains underexplored.An electron target model of a transmission X-ray tube is developed using the Monte Carlo toolkit TOPAS 3.8.1.The study investigates the effect of tungsten target thickness on X-ray output efficiency,finding that a tube voltage of 50 kV and a tungsten thickness of 1.4 μm yields the highest emission efficiency.Based on the energy spectrum at this optimal efficiency,polynomial fitting approach is applied to determine the corresponding aluminum filter thickness for mean energies ranging from 20 keV to 35 keV,achieving a mean fitting error of 0.91%.Next,the study simulates dose deposition in a water phantom for spectra with different mean energies and various source-to-surface distances,and plots percent-depth-dose curves,relative normalized dose-depth curves,and relative normalized dose histograms under each treatment condition.Finally,the simulated results are compared with experimental data from the intraoperative radiotherapy system Intrabeam and the superficial X-ray therapy unit SRT-100,obtaining average relative errors of 3.71%and 4.38%,respectively.These findings provide a theoretical foundation for further optimization of transmission X-ray tubes in kilovoltage radiotherapy.
5.Monte Carlo simulation study of the effect of filter on radiotherapy dosimetry in superficial X-ray therapy apparatus
Li TAO ; Hui ZHANG ; Yikai WU ; Junyi LIU ; Miao QI ; Ning GAO ; Yankui CHANG ; Xi PEI ; Zhi CHEN ; Xie XU
Chinese Journal of Radiological Medicine and Protection 2025;45(3):194-201
Objective:To explore the dosimetry optimization strategy based on filter thickness and shape selection for the bulb superficial X-ray radiotherapy unit.Methods:Monte Carlo code TOPAS was used to model tubular equipment, and the dose distribution from six X-ray energies (50-150 kV) and five conventional aluminum filters (0.5-3.0 mm) with different thickness were simulated in the water model. The percentage depth dose (PDD) curve along the central axis, the center-axis profile dose at different depths, and the lateral dose distribution were analyzed. The dose distribution of three different designs of aluminum filters (conventional cylindrical, conical and oblique cylindrical filters) was compared to evaluate the effect of dosimetric optimization of different filter shapes.Results:Under the same energy, increasing the thickness of the filter can optimize the superficial skin dose, and the optimization effect of depth dose uniformity can be increased by 26% at a depth of 5.5 mm at 70 kV energy. The raised, flat and inclined dose distribution modes can be achieved by using conventional cylindrical, conical and inclined aluminum filters.Conclusions:By selecting the appropriate X-ray energy and filter thickness, an ideal dose distribution matching the tumor depth can be achieved. The application of personalized filters is also of great significance for diverse target areas.
6.Research progress of modalities and initiation timing of renal replacement therapy for acute kidney injury
Linlin ZHANG ; Yikai HE ; Huipeng GE ; Enhui LI ; Rong TANG ; Xiangcheng XIAO
Journal of Chinese Physician 2025;27(4):631-636
Acute kidney injury (AKI) usually requires renal replacement therapy (RRT). Common RRT modes include peritoneal dialysis, continuous renal replacement therapy, intermittent hemodialysis and continuous low-efficiency hemodialysis. In clinical practice, there is still controversy over how to select the appropriate RRT mode for AKI patients and when initiating RRT is more beneficial for AKI patients. This article summarizes previous studies on the impact of RRT mode and initiation timing on the prognosis of AKI patients, with the aim of providing assistance for clinical decision-making.
7.Research progress of modalities and initiation timing of renal replacement therapy for acute kidney injury
Linlin ZHANG ; Yikai HE ; Huipeng GE ; Enhui LI ; Rong TANG ; Xiangcheng XIAO
Journal of Chinese Physician 2025;27(4):631-636
Acute kidney injury (AKI) usually requires renal replacement therapy (RRT). Common RRT modes include peritoneal dialysis, continuous renal replacement therapy, intermittent hemodialysis and continuous low-efficiency hemodialysis. In clinical practice, there is still controversy over how to select the appropriate RRT mode for AKI patients and when initiating RRT is more beneficial for AKI patients. This article summarizes previous studies on the impact of RRT mode and initiation timing on the prognosis of AKI patients, with the aim of providing assistance for clinical decision-making.
8.Pathological mechanisms, risk factors, and preventive strategies of cardiac surgery-associated acute kidney injury
Yikai HE ; Shuyue SHEN ; Huipeng GE ; Linlin ZHANG ; Xiangcheng XIAO
Journal of Chinese Physician 2025;27(9):1430-1436
Acute Kidney Injury (AKI) is a common and severe complication after cardiac surgery. The pathogenesis of cardiac surgery-associated AKI (CSA-AKI) is complex, and it is associated with increased patient mortality and poor renal prognosis. To identify high-risk patients as early as possible, numerous clinical studies have explored perioperative risk factors and developed a variety of biomarkers with good diagnostic capabilities. Currently, multiple prediction models for AKI after cardiac surgery have been developed internationally; however, there is no effective treatment for CSA-AKI. Therefore, implementing reasonable and comprehensive preventive strategies is crucial. In addition, the clinical application of some interventions is controversial, which means more research and exploration are needed to make more informed decisions regarding the prevention and treatment of CSA-AKI.
9.Dynamic change and significance of Mindin protein in chronic hepatitis B treated with PEG-IFNα-2b
Yikai WANG ; Fengping WU ; Chenrui LIU ; Miao HAO ; Shasha LYU ; Miaomiao ZHANG ; Shuangsuo DANG ; Xin ZHANG
Journal of Clinical Hepatology 2024;40(1):52-57
ObjectiveTo investigate the change and potential role of Mindin protein in the treatment of chronic hepatitis B (CHB) with PEG-IFNα-2b. MethodsA total of 29 CHB patients who received the treatment with PEG-IFNα-2b in The Second Affiliated Hospital of Xi’an Jiaotong University from January 2018 to December 2019 were enrolled, and according to their clinical outcome, they were divided into cured group with 17 patients and uncured group with 12 patients. Peripheral blood samples were collected from both groups at baseline, 12 weeks, and 24 weeks to measure blood routine indices, liver function parameters, hepatitis B markers, and Mindin protein. HBsAg, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and Mindin protein at different time points were compared between the two groups. The independent-samples t test was used for comparison of normally distributed continuous data between two groups, and the Mann-Whitney U test was used for comparison of non-normally distributed continuous data between two groups; a Spearman correlation analysis was used to investigate correlation; a multiple linear regression analysis was used to investigate the influence of HBsAg and ALT on the content of Mindin protein. ResultsThe analysis of baseline data showed that there were significant differences in the levels of HBsAg, HBeAb, albumin, and albumin/globulin ratio between the cured group and the uncured group (all P<0.05). The cured group tended to have a gradual increase in the level of Mindin, and the level of Mindin at 24 weeks was significantly higher than that at baseline (P<0.05). The cured group had a significantly higher level of Mindin protein than the uncured group at 24 weeks (P=0.019). The cured group had a significantly lower level of HBsAg than the uncured group (P<0.05), with a significant change from baseline to each time point within the cured group (P<0.05). In addition, the levels of ALT and AST in the cured group tended to first increase and then decrease, and the expression levels at 12 weeks were significantly higher than those at baseline (P<0.05). At 12 weeks, there was a strong linear correlation between Mindin protein levels and ALT in the untreated group (r=0.760 8, P<0.05), and further multiple linear regression analysis also demonstrated a linear relationship between the two (b=1.571, P=0.019). ConclusionThere is a significant difference in the level of Mindin protein between the cured group and the non-cured group after 24 weeks of PEG-IFNα-2b antiviral treatment, and therefore, detecting the dynamic changes of Mindin protein can better predict the treatment outcome of CHB, which provides a reference for clinical practice.
10.Prediction and Prognosis for Immunotherapy of Intra-tumoral Interleukins Expression Patterns in Non-small Cell Lung Cancer
Simin ZHONG ; Dongdong ZHANG ; Shuyue GUO ; Yikai ZHANG ; Siyang LIU ; Zhenyi JIN
Journal of Sun Yat-sen University(Medical Sciences) 2024;45(4):557-566
[Objective]To identify the relationship between tumor tissue interleukins(ILs)and non-small cell lung cancer(NSCLC)patients with poor response to immune checkpoint blockade(ICB)therapy,and to investigate the differ-ential expression of ILs in tumor of NSCLC patients as well as its effect on ICB response and prognosis.[Methods]A total of 61 patients diagnosed with NSCLC and treated with ICB were retrospectively collected from the data of a previous study.We obtained transcriptome sequencing data from tumor tissues and survival data of the patients before ICB treatment.Us-ing bioinformatics methods,we screened for ILs that significantly affected the efficacy and prognosis of ICB treatment.We evaluated the efficacy of ICB treatment using progressive-free survival(PFS)and assessed the prognosis using overall sur-vival(OS).The Kaplan-Meier survival curve and ROC curve were used to analyze the predictive effect and efficacy of ILs on the efficacy and prognosis of ICB in NSCLC patients.[Results]The results of the univariate Cox regression analysis in our study showed that nine ILs were found to be associated with OS of NSCLC patients treated with ICB at a significance level of P<0.1.Further multivariate analysis revealed that high expression of IL-11,IL-17D,and IL-36A was significant-ly associated with poor prognosis in these patients(P<0.05).The results from the Kaplan-Meier survival curve analysis revealed a significant negative correlation between the high expression of IL-17D and both PFS and OS in NSCLC patients.Specifically,patients with IL-17D high expression had a median PFS of 3.1 months compared with 6.5 months in low ex-pression patients[95%confidence interval(CI)(1.178,3.655),P=0.009].Similarly,the median OS was 9.8 months in the high expression group versus 21.8 months in the low expression group[95%CI(1.116,4.392),P=0.018].ROC curve showed that the prediction performance was favorable[AUCPFS=0.702,95%CI(0.562,0.842),P=0.027;AU-COS=0.684,95%CI(0.550,0.818),P=0.014].Although IL-11 and IL-36A alone were not significant predictors of PFS and OS in NSCLC patients,the median PFS and OS were notably shortened to 2.2 months(P=0.003)and 3.0 months(P<0.001),respectively,when high expression of IL-11 and IL-36A was combined with high expression of IL-17D.The ROC curve analysis demonstrated an improvement in prediction efficiency for both PFS and OS in NSCLC patients[AUCPFS=0.748,95%CI(0.615,0.880),P=0.007;AUCOS=0.703,95%CI(0.573,0.833),P=0.007].[Conclu-sion]The results suggest that high expression of IL-11,IL-17D,and IL-36A is associated with a higher risk of disease progression which correlates to poor PFS and OS in NSCLC patients.

Result Analysis
Print
Save
E-mail