With the rapid development of generative artificial intelligence(GAI)technologies,their widespread application in academic research and writing is continuously expanding the boundaries of sci-entific inquiry.However,this trend has also raised a series of ethical and regulatory challenges,inclu-ding issues related to authorship,content authenticity,citation accuracy,and accountability.In light of the growing involvement of AI in generating academic content,establishing an open,controllable,and trustworthy ethical governance framework has become a key task for safeguarding research integrity and maintaining trust within the academic community.This expert consensus outlines ethical requirements across key stages of AI-assisted academic writing-including topic selection,data management,citation practices,and authorship attribution.It aims to clarify the boundaries and ethical obligations surrounding AI use in academic writing,ensuring that technological tools enhance efficiency without compromising in-tegrity.The goal is to provide guidance and institutional support for building a responsible and sustainable research ecosystem.

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.

Objective:To investigate the application of the conjugate gradient (CG) algorithm to treatment plan optimization for intensity-modulated brachytherapy (IMBT).Methods:The general Monte Carlo software TOPAS was utilized to simulate the 192Ir source of IMBT, and the unit dose contribution matrix was calculated. An objective function was established using the weighted least squares method and was solved using the CG algorithm to achieve optimized IMBT treatment plans. The optimization was validated using five clinical cervical cancer cases under modulation width 60°. The dose distributions of IMBT treatment plans under 45°, 60°, 90°, 120°, and 180° modulation widths were compared using the Wilcoxon test to determine the optimal IMBT treatment plan for cervical cancer treatment. Results:The CG algorithm successfully optimized IMBT treatment plans under modulation width 60° for five cases within 22.2 s on average. On the premise of sufficient target dose coverage, the average D2 cm 3 values of the bladder and rectum in IMBT treatment plans were 3.66 and 1.97 Gy, respectively, representing reductions of 0.54 and 0.69 Gy compared to traditional brachytherapy plans. For the five modulation widths, the D90% values of all IMBT treatment plans reached 6 Gy, without statistically significant differences ( P > 0.05). The average D2 cm 3 values of the bladder in IMBT treatment plans were significantly lower than those in the traditional brachytherapy plans( P<0.05), with modulation width 60° associated with the greatest reduction of 0.61 Gy. In contrast, the average D2 cm 3 values of the rectum under 45°, 60°, and 90° modulation widths decreased by 0.63, 0.54, and 0.45 Gy, respectively, compared to traditional plans, with statistically significant differences( P<0.05). Conclusions:The CG method enables rapid achievement of optimized IMBT treatment plans that meet clinical requirements, and modulation width 60° contributes to valid dosimetric optimization. This study can serve as a guide for the clinical implementation of IMBT.

Objective:To investigate the effect of physical activity on mortality risk in patients with chronic obstructive pulmonary disease (COPD) in Sichuan Province.Methods:Based on baseline data from 2004 to 2008 from the China Kadoorie Biobank project site in Pengzhou City, Sichuan Province, a total of 8 501 COPD patients aged 30-79 years were enrolled and followed up for a long period to determine mortality outcomes. Quartiles were used to group physical activity levels. The Cox proportional hazards regression model was used to analyze the effect of physical activity level on mortality outcomes.Results:As of December 31, 2017, the cumulative follow-up of the participants totaled 85 600.58 person-years (mean follow-up duration: 10.07 years). During this period, a total of 2 000 deaths were recorded, yielding a cumulative mortality rate of 23.53%. Among these deaths, 665 were attributed to COPD, corresponding to a cumulative mortality rate of 7.82%; and 1 116 were attributed to cardiovascular and cerebrovascular disease (CVD), corresponding to a cumulative mortality rate of 13.13%. The Cox proportional hazards regression model analysis revealed that, after adjusting for confounding factors, total physical activity was associated with a reduced risk of mortality from COPD, CVD, and all causes in patients with COPD. Compared with the low-level group of total physical activity, the medium-high-level group had the lowest risk of COPD mortality, with an HR of 0.39 (95% CI: 0.30-0.49). The high-level group had the lowest risk of CVD death and all-cause death, with HRs of 0.46 (95% CI: 0.37-0.56) and 0.55 (95% CI: 0.48-0.64), respectively. The lowest risk of COPD death and CVD death was found in the medium-high level of work-based physical activity group, with HRs of 0.36 (95% CI: 0.28-0.46) and 0.43 (95% CI: 0.36-0.51), respectively; the risk of all-cause mortality was lowest in the medium-high and high-level groups, with HRs values of 0.53 (95% CI: 0.46-0.61) and 0.53 (95% CI: 0.45-0.61). The risk of COPD death was lowest in the high-level transportation physical activity group, with an HR of 0.66 (95% CI: 0.53-0.83), and the risk of CVD and all-cause death was lowest in the medium-high level group, with HRs of 0.63 (95% CI: 0.53-0.76) and 0.73 (95% CI: 0.64-0.84), respectively. The risk of COPD death and CVD death was the lowest in the high-level domestic physical activity group, with HRs of 0.66 (95% CI: 0.49-0.89) and 0.76 (95% CI: 0.61-0.95), respectively, and the risk of all-cause death was the lowest in the medium-high level group, with an HR of 0.82 (95% CI: 0.72-0.94). There is no statistical association between leisure physical activity and the risk of death from three types of diseases. Conclusions:Total physical activity, including work-based, transportation-based, and domestic physical activity, reduced the risk of COPD, CVD, and all-cause mortality in patients with COPD in Sichuan Province. The magnitude of mortality risk was influenced by the type and level of physical activity.

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.

Objective To develop a deep learning-based denoising model for accelerating Monte Carlo(MC)simulation of electronic portal imaging device(EPID)transit dose images.Methods A total of 500 EPID fields were collected from 100 lung cancer patients undergoing 5-field intensity-modulated radiotherapy,with 400 fields randomly selected as training set,50 fields as validation set,and 50 fields as test set.EPID transit dose image datasets with low particle counts(1×107)and high particle counts(1×109)were simulated using the GPU-accelerated MC dose calculation engine ARCHER.A denoising network model named SUNet was constructed based on Swin Transformer and U-Net,and trained using low-particle-count images as input and high-particle-count images as output.Following training,SUNet model was used to denoise low-particle-count EPID images in the test set.Denoising performance was evaluated using structural similarity index(SSIM),peak signal-to-noise ratio(PSNR),and Gamma passing rates(3%/2 mm),and the computational efficiency of MC simulation combined with SUNet model was analyzed.Results Compared with the original low-particle-count images,the SUNet-denoised images showed significantly improved quality,reduced noise points,and smoother dose distribution.When benchmarked against high-particle-count images,the SUNet-denoised images achieved an average SSIM greater than 0.9,an average PSNR higher than 32 dB,and an average gamma passing rate exceeding 90%.The MC simulation combined with SUNet model required only 1.88 s to simulate a single EPID transit dose image,representing an approximate 40-fold improvement in computational efficiency as compared with high-particle-count MC simulation.Conclusion The deep learning-based denoising model substantially accelerates MC simulation of EPID transit dose images while preserving both image quality and dose accuracy,which provides possibilities for EPID-basedin vivodose verification.

Objective:To investigate the effect of physical activity on mortality risk in patients with chronic obstructive pulmonary disease (COPD) in Sichuan Province.Methods:Based on baseline data from 2004 to 2008 from the China Kadoorie Biobank project site in Pengzhou City, Sichuan Province, a total of 8 501 COPD patients aged 30-79 years were enrolled and followed up for a long period to determine mortality outcomes. Quartiles were used to group physical activity levels. The Cox proportional hazards regression model was used to analyze the effect of physical activity level on mortality outcomes.Results:As of December 31, 2017, the cumulative follow-up of the participants totaled 85 600.58 person-years (mean follow-up duration: 10.07 years). During this period, a total of 2 000 deaths were recorded, yielding a cumulative mortality rate of 23.53%. Among these deaths, 665 were attributed to COPD, corresponding to a cumulative mortality rate of 7.82%; and 1 116 were attributed to cardiovascular and cerebrovascular disease (CVD), corresponding to a cumulative mortality rate of 13.13%. The Cox proportional hazards regression model analysis revealed that, after adjusting for confounding factors, total physical activity was associated with a reduced risk of mortality from COPD, CVD, and all causes in patients with COPD. Compared with the low-level group of total physical activity, the medium-high-level group had the lowest risk of COPD mortality, with an HR of 0.39 (95% CI: 0.30-0.49). The high-level group had the lowest risk of CVD death and all-cause death, with HRs of 0.46 (95% CI: 0.37-0.56) and 0.55 (95% CI: 0.48-0.64), respectively. The lowest risk of COPD death and CVD death was found in the medium-high level of work-based physical activity group, with HRs of 0.36 (95% CI: 0.28-0.46) and 0.43 (95% CI: 0.36-0.51), respectively; the risk of all-cause mortality was lowest in the medium-high and high-level groups, with HRs values of 0.53 (95% CI: 0.46-0.61) and 0.53 (95% CI: 0.45-0.61). The risk of COPD death was lowest in the high-level transportation physical activity group, with an HR of 0.66 (95% CI: 0.53-0.83), and the risk of CVD and all-cause death was lowest in the medium-high level group, with HRs of 0.63 (95% CI: 0.53-0.76) and 0.73 (95% CI: 0.64-0.84), respectively. The risk of COPD death and CVD death was the lowest in the high-level domestic physical activity group, with HRs of 0.66 (95% CI: 0.49-0.89) and 0.76 (95% CI: 0.61-0.95), respectively, and the risk of all-cause death was the lowest in the medium-high level group, with an HR of 0.82 (95% CI: 0.72-0.94). There is no statistical association between leisure physical activity and the risk of death from three types of diseases. Conclusions:Total physical activity, including work-based, transportation-based, and domestic physical activity, reduced the risk of COPD, CVD, and all-cause mortality in patients with COPD in Sichuan Province. The magnitude of mortality risk was influenced by the type and level of physical activity.

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.

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.

Objective:To investigate the application of the conjugate gradient (CG) algorithm to treatment plan optimization for intensity-modulated brachytherapy (IMBT).Methods:The general Monte Carlo software TOPAS was utilized to simulate the 192Ir source of IMBT, and the unit dose contribution matrix was calculated. An objective function was established using the weighted least squares method and was solved using the CG algorithm to achieve optimized IMBT treatment plans. The optimization was validated using five clinical cervical cancer cases under modulation width 60°. The dose distributions of IMBT treatment plans under 45°, 60°, 90°, 120°, and 180° modulation widths were compared using the Wilcoxon test to determine the optimal IMBT treatment plan for cervical cancer treatment. Results:The CG algorithm successfully optimized IMBT treatment plans under modulation width 60° for five cases within 22.2 s on average. On the premise of sufficient target dose coverage, the average D2 cm 3 values of the bladder and rectum in IMBT treatment plans were 3.66 and 1.97 Gy, respectively, representing reductions of 0.54 and 0.69 Gy compared to traditional brachytherapy plans. For the five modulation widths, the D90% values of all IMBT treatment plans reached 6 Gy, without statistically significant differences ( P > 0.05). The average D2 cm 3 values of the bladder in IMBT treatment plans were significantly lower than those in the traditional brachytherapy plans( P<0.05), with modulation width 60° associated with the greatest reduction of 0.61 Gy. In contrast, the average D2 cm 3 values of the rectum under 45°, 60°, and 90° modulation widths decreased by 0.63, 0.54, and 0.45 Gy, respectively, compared to traditional plans, with statistically significant differences( P<0.05). Conclusions:The CG method enables rapid achievement of optimized IMBT treatment plans that meet clinical requirements, and modulation width 60° contributes to valid dosimetric optimization. This study can serve as a guide for the clinical implementation of IMBT.