Objective:To evaluate the application of visual feedback coaching method, which is embedded in an optical surface monitoring system, in deep inspiration breath holding during the radiotherapy in left breast cancer patients after breast-conserving surgery.Methods:Thirty patients with left breast cancer, who were scheduled to receive the whole breast radiotherapy after breast-conserving surgery, met the requirements of deep inspiration breath holding after respiratory coaching with the visual feedback coaching module in the optical surface monitoring system. Active breathing control equipment was used to control breath-holding state and CT simulation was performed. During treatment, optical surface monitoring system was used to guide radiotherapy. All patients were randomly divided into two groups. In group A ( n=15), visual feedback respiratory training method was utilized and not employed in group B ( n=15). In group A, the visual feedback coaching bar of the optical surface monitoring system was implemented, while audio interactive method was employed to guide patients to hold their breath. Real-time data of optical body surface monitoring were used to compare the interfraction reproducibility and intrafraction stability of breath holding fraction between two groups. Besides, the number of breath holding and treatment time per fraction were also compared. GraphPad prism 6.0 software was used for data processing and mapping, and SPSS 21.0 software was used for analyzing mean value and normality testing. Results:Compared with the control group, the reproducibility in the experiment group was reduced from 1.5 mm to 0.7 mm, the stability was reduced from 1.1 mm to 0.8 mm, the mean number of breath holding required per fraction was decreased from 4.6 to 2.4, the mean beam-on time per fraction from 336 s to 235 s, and the treatment time per fraction was shortened from 847 s to 602 s (all P<0.05), respectively. Conclusions:The application of visual feedback coaching method can improve the reproducibility and stability of breath holding during radiotherapy for left breast cancer, and it can also effectively reduce the number of breath holding and shorten the treatment time per fraction.

Background Printing and copying equipment is likely to release a large amount of particulate matter, thereby endangering human health. However, there is insufficient research on the level of particulate matter released by printers in offices and its influencing factors. Objective This study is designed to investigate the usage of printing equipment in college teachers' offices and the level of indoor particulate matter during printing, and to explore the influence of printer location and indoor ventilation on the particulate matter pollution level released during printer operation. Methods From 9:00 to 16:00 on January 4 to 6, 2021, 20 faculty offices in a university in Beijing were selected by convenient sampling to measure the indoor particulate matter level during printing, and to investigate the printing equipment usage of 31 users in the offices. Besides, experiments were designed to explore the influence of position and distance from a printer, ventilation, and the distance between a printer and a nearby window during ventilation on the number concentration of particulate matter released by the printers. Results Except one printer being placed on the ground, the other 30 printers were placed on office desks (0.71±0.16) m above the ground. Among them, 65% of the printers (n=20) were less than 1 m away from the users horizontally, and 74% of the users (n=23) accessed the printers 1-5 times a week, printing (7.03±4.07) pages per time. The peak mass concentrations in users' offices during printing of PM₁₀, PM_2.5, and PM₁ were (21.96±12.96), (7.92±5.54), and (5.77±5.00) μg·m⁻³, respectively, and the peak number concentration of PM_0.25−0.28 was (40941±36926) P·L⁻¹. The experiments showed that when the particle sizer was located in the front, side, and back of the printers, the peak values of PM_0.25−0.28 number concentration during printing were (24257±551), (12588±1354), and (11192±249) P·L⁻¹, respectively, and the difference among them was statistically significant (F=214.9, P<0.01); when the particle sizer was placed 0.1, 0.2, and 0.3 m away from the printers, the peak values of PM_0.25−0.28 number concentration during printing were (24257±551), (19847±1426), and (16480±878) P·L⁻¹, respectively, and the difference among them was statistically significant (F=44.66, P<0.01); when the experiment room was ventilated or not, the peak values of PM_0.25−0.28 number concentration during printing were (18595±488) and (24257±551) P·L⁻¹, respectively, and the difference between them was statistically significant (F=192.6, P<0.01); when the distance between the printer and the window was 1, 2, 3 m, the peak values of PM_0.25-0.28 number concentration during printing were (16780±823), (18347±348), and (18595±488) P·L⁻¹, respectively, and the difference among them was statistically significant (F=8.407, P<0.05). Conclusion The overall printer workload is small and the concentration of particulate matter in the faculty offices is low when the printers are working. Printer position, distance, ventilation, and the distance from a nearby window under ventilation conditions are factors affecting the concentration of particulate matter released by the printers.

Objective To investigate the relationship between gentamicin sulfate mediated gut microbi-ota in affecting glucolipid metabolism and inflammation with hypertension improvement.Methods Sprague-Dawley rats (8-weeks-old) were divided into the normal diet group (ND,n=11),high fat diet group (HFD,n=13) and HFD combined with gentamicin sulfate gavage group (GS,n=13).Blood pressure was monitored weekly during 5-13 weeks,and the levels of insulin,IL-1β,IL-6,TNF-α,LPS,TC,TG,LDL-C,HDL-C and homeostasis model assessment of insulin resistance index (HOMA-IR) were assessed at 13 weeks.The met-agenomic analyses were performed on DNA samples from rat colonic feces.Results The blood pressure in 13 weeks had no statistical difference among the three groups (P>0.05).The blood pressure during 5-10 weeks in the GS group was higher than that in the ND group with statistical difference (P<0.05).The blood pressure during 5-13 weeks in the HFD group was higher than that in the ND group,and the blood pressure during 10-13 weeks in the GS group was lower than that in the HFD with statistical difference (P<0.05). Compared with the group ND,the levels of TC,TG,LDL-C and HOMA-IR in the HFD group were higher,the HDL-C level was lower,and the differences were statistically significant (P<0.05).Compared with the HFD group,the levels of TG,LDL-C and HOMA-IR in the GS group were lower,the HDL-C level was higher,and the differences were statistically significant (P<0.05).The levels of LPS,IL-1β,IL-6 and TNF-α in the HFD group were higher than those in the ND group,while the GS group was lower than the HFD group (P<0.05).The partial least squares discriminant analysis showed that the intestinal microbiota in the HFD group and GS group was different in structure from that in the ND group.The family level results showed that the structure of the gut microbiota changed in three groups,including 24 microbiotas with significant changes.The hierarchical analysis showed that the proportion of f-desulphovibrio in the HFD group was higher than that in the ND group,while the GS group was lower the HFD group,and the differences were statistically significant (P<0.05).Conclusion Oral antibiotic gentamicin sulfate could improve the glucose and lipid metabolism ab-normalities and inflammation caused by HFD and its mechanism may be to relieve hypertension by regulating intestinal flora structure,abundance and LPS level.

Objective To evaluate the effects of the multiple factors especially image geometric accuracy of the imaging system on the segmentations of target areas and organs-at-risk.Methods The study used phantoms to test the imaging performance of the 1.5T magnetic resonance(MR)linear accelerator system,including the assessments of MR image geometric distortion and the segmentation errors caused by factors such as image geometric distortion.Model 604-GS large field MR image distortion phantom was used to explore the geometric distortion of the MR images for MR-guided radiotherapy;and CIRS Model 008z upper abdominal phantom was used to analyze the segmentation errors of target areas and organs-at-risk.Results The average geometric distortion and maximum distortion of 3D T1WI-FFE images vs 3D T2WI-TSE images were 0.54 mm vs 0.53 mm and 1.96 mm vs 1.68 mm,respectively;and the control points of the large distortions were distributed at the edges of the phantom,which was consistent with the MR imaging characteristics previously reported.Compared with CT-based segmentation contour,the MDA was 1.17 mm and DSC was 0.91 for 3D T1WI-FFE,while MDA was 0.86 mm and DSC was 0.94 for 3D T2WI-TSE.Conclusion The study quantitatively assesses the geometric accuracy of the imaging system for MR-guided radiotherapy.The phantom-based contour analysis reveals that with CT image as gold standard,the segmentation error in MRI images meets the clinical requirements,and that 3D T2WI-TSE image is advantageous over 3D T1WI-FFE image in segmentation accuracy.