Objective To investigate the influence of helical tomographic radiotherapy plans with different combinations of lead gate width,pitch and algorithms on threading effects.Methods A target model was established with a Cheese Phantom used as the simulated human body,then three lead gate widths(1.0,2.5,and 5.0 cm),six screw pitches(0.143,0.172,0.215,0.287,0.430,and 0.500)and two computational grids(Fine algorithm and Normal algorithm)were respectively combined for designing the helical tomography radiotherapy plans.The radiotherapy plans with a pitch of 0.143,0.172,0.215,0.287 or 0.430 were enrolled into an experimental group,and the plans with a pitch of 0.500 were divided into a control group.The dosimetric parameters including maximum dose(Dmax),minimum dose(Dmin)and mean dose(Dmean)of the target area PTV1 and PTV2 were evaluated by the dose volume histogram(DVH).The dose homogeneity index(HI)of the target area was calculated,and the single rotation time and total treatment time of each plan were recorded and counted.SPSS 27.0 software was used for statistical analysis.Results No significant threading effect appeared regardless of the pitch value when the lead gate width was 1.0 cm.The threading effects in the experimental group were weaker than those in the control group when the lead gate width was 2.5 or 5.0 cm.The threading effect gradually rose with the pitch increased when the lead gate width was 5.0 cm.The most significant difference was found between the threading effect in case of the screw pitch being 0.500 and that with the screw pitch being 0.143,with the differenes being statistically obvious(P<0.05).The lead gate width had significant effects on the Dmax,Dmin,Dmean and HI of PTV1 and PTV2.When the lead gate width was 5.0 cm,high HI value and uneven dose distribution were detected and lowered screw pitch weakened the threading effect.The single rotation time first remained constant and then increased with the screw pitch was enlarged,with the changing points occurring in case of the screw pitches of 0.287 and 0.430.With a certain lead gate width,the treatment time for plans was shortened with the decrease of the pitches in case of the pritches lower than 0.287,and tended to be constant after the screw pitches reached 0.287.The changes of the computational grid had no significant effects on the results of radiotherapy plans when the lead gate width and screw pitch were kept constant.Conclusion When designing a spiral tomotherapy plan with conventional doses,a lead gate width of 1.0 or 2.5 cm and a screw pitch of 0.287 or 0.430 should be selected in order to minimize the threading effect while ensuring the efficiency of plan implementation.[Chinese Medical Equipment Journal,2025,46(8):58-66]

Objective To investigate the influence of helical tomographic radiotherapy plans with different combinations of lead gate width,pitch and algorithms on threading effects.Methods A target model was established with a Cheese Phantom used as the simulated human body,then three lead gate widths(1.0,2.5,and 5.0 cm),six screw pitches(0.143,0.172,0.215,0.287,0.430,and 0.500)and two computational grids(Fine algorithm and Normal algorithm)were respectively combined for designing the helical tomography radiotherapy plans.The radiotherapy plans with a pitch of 0.143,0.172,0.215,0.287 or 0.430 were enrolled into an experimental group,and the plans with a pitch of 0.500 were divided into a control group.The dosimetric parameters including maximum dose(Dmax),minimum dose(Dmin)and mean dose(Dmean)of the target area PTV1 and PTV2 were evaluated by the dose volume histogram(DVH).The dose homogeneity index(HI)of the target area was calculated,and the single rotation time and total treatment time of each plan were recorded and counted.SPSS 27.0 software was used for statistical analysis.Results No significant threading effect appeared regardless of the pitch value when the lead gate width was 1.0 cm.The threading effects in the experimental group were weaker than those in the control group when the lead gate width was 2.5 or 5.0 cm.The threading effect gradually rose with the pitch increased when the lead gate width was 5.0 cm.The most significant difference was found between the threading effect in case of the screw pitch being 0.500 and that with the screw pitch being 0.143,with the differenes being statistically obvious(P<0.05).The lead gate width had significant effects on the Dmax,Dmin,Dmean and HI of PTV1 and PTV2.When the lead gate width was 5.0 cm,high HI value and uneven dose distribution were detected and lowered screw pitch weakened the threading effect.The single rotation time first remained constant and then increased with the screw pitch was enlarged,with the changing points occurring in case of the screw pitches of 0.287 and 0.430.With a certain lead gate width,the treatment time for plans was shortened with the decrease of the pitches in case of the pritches lower than 0.287,and tended to be constant after the screw pitches reached 0.287.The changes of the computational grid had no significant effects on the results of radiotherapy plans when the lead gate width and screw pitch were kept constant.Conclusion When designing a spiral tomotherapy plan with conventional doses,a lead gate width of 1.0 or 2.5 cm and a screw pitch of 0.287 or 0.430 should be selected in order to minimize the threading effect while ensuring the efficiency of plan implementation.[Chinese Medical Equipment Journal,2025,46(8):58-66]

Objective To investigate the dosimetric effects of different calculation grid size(CGS)in helical tomotherapy(HT)planning system on stereotactic body radiation therapy(SBRT)for non-small cell lung cancer(NSCLC).Methods Nine NSCLC patients receiving radiation therapy for the first time at some hospital from March 2019 to December 2022 were selected as the subjects.SBRT planning was carried out through the HT system with three different CGS plans(Fine,Normal,and Coarse)and the same pitch,modulation factor(MF)and optimization conditions,and the target area indexes of the three CGS plans were compared including conformity index(CI),homogeneity index(HI),dosimetric parameters of the organ at risk(OAR),point dose verification pass rate,treatment time,number of monitor units and Sinograms.SPSS 22.0 was used for statistical analysis.Results For target area HI,there weres significant differences between CGS Fine plan and Coarse plan and between CGS Normal plan and Coarse plan(P＜0.05),while no statistical differences were found between CGS Fine plan and Normal plan(P＞0.05).For target area CI,there were significant differences between CGS Fine plan and Coarse plan(P＜0.05),while no statistical differences were found between CGS Fine plan and Normal plan and between CGS Normal plan and Coarse plan(P＞0.05).For OAR dosimetric parameters,CGS Fine plan and Coarse plan had significant differences in heart Dmax and Dmean,esophageal Dmax and Dmean,V5,V20,V30 and Dmean of the whole lung and affected lung,V5 and Dmax of the affected lung and heart V10 and V30(P＜0.05),CGS Normal plan and Coarse plan had obvious differences in esophageal Dmax(P＜0.05),and the remained dosimetric parameters were not statistically significant(P＞0.05).Fine,Normal and Coarse plans had the point dose verifica-tion pass rates being 0.96％,1.50％and 1.77％,respectively.In terms of treatment time and number of monitor units,there were significant differences between Fine plan and Coarse plan(P＜0.05)while no statistical differences were found between Fine and Normal plans and between Normal and Coarse plans(P＞0.05).Sinograms analyses showed Fine plan had evenly distributed segment color gradient,Coarse plan had areas of very dark and very light color gradients and Normal plan was somewhere in between.Conclusion Low CGS has to be used as much as possible to obtain accurate dose distribution during SBRT planning for NSCLC patients,which contributes to the execution of the radiation therapy plan and the prevention of ad-verse effects.[Chinese Medical Equipment Journal,2024,45(2):52-57]

Objective To investigate the radiotherapy dose impacts of different jaw widths on stereotactic body radiotherapy(SBRT)for hepatocellular carcinoma(HCC)with the hilical tomotherapy(HT)planning system.Methods Totally 16 HCC patients who received radiotherapy at some hospital from March 2021 to August 2023 were selected,and the planning was carried out with the same pitch,modulation factors and optimization conditions and the jaw widths being 1.0,2.5 and 5.0 cm.The dosimetric differences due to the jaw widths in planned targets and organs at risk(OAR)were compared,and the planned treatment time,monitor unit,gantry rotations and gantry period were evaluated.SPSS 22.0 was used for statistical analysis.Results Better dosimetric parameters and lower doses to OARs could be got with lower jaw widths.The widened jaw widths resulted in reduced planned treatment time,decreased monitor units and gantry rotations,shortened gantry period while enhanced treatment efficiency.Conclusion A 2.5 cm jaw width for HT planning contributes to improving treatment efficiency during HCC SBRT under the premise of ensured target dose distribution and satisfactory dose to OAR for clinical require-ments.[Chinese Medical Equipment Journal,2024,45(7):51-55]

Objective This study aimed to investigate the potential relationship between urinary metals copper (Cu), arsenic (As), strontium (Sr), barium (Ba), iron (Fe), lead (Pb) and manganese (Mn) and grip strength. Methods We used linear regression models, quantile g-computation and Bayesian kernel machine regression (BKMR) to assess the relationship between metals and grip strength.Results In the multimetal linear regression, Cu (β=-2.119), As (β=-1.318), Sr (β=-2.480), Ba (β=0.781), Fe (β= 1.130) and Mn (β=-0.404) were significantly correlated with grip strength (P < 0.05). The results of the quantile g-computation showed that the risk of occurrence of grip strength reduction was -1.007 (95％ confidence interval:-1.362, -0.652; P < 0.001) when each quartile of the mixture of the seven metals was increased. Bayesian kernel function regression model analysis showed that mixtures of the seven metals had a negative overall effect on grip strength, with Cu, As and Sr being negatively associated with grip strength levels. In the total population, potential interactions were observed between As and Mn and between Cu and Mn (Pinteractions of 0.003 and 0.018, respectively).Conclusion In summary, this study suggests that combined exposure to metal mixtures is negatively associated with grip strength. Cu, Sr and As were negatively correlated with grip strength levels, and there were potential interactions between As and Mn and between Cu and Mn.

PURPOSE: Evidence suggests that the oxytocin receptor (OXTR) gene may be involved in the psychopathology of posttraumatic stress disorder (PTSD). This study aimed to investigate the effects of OXTR rs53576 genotype on PTSD symptoms introduced in the Diagnostic and Statistical Manual, Fifth Edition (DSM-5). METHODS: This study was a cross-sectional study conducted among 1140 adults who had personally experienced the Wenchuan earthquake. PTSD symptoms were measured with the PTSD checklist for DSM-5. A custom-by-design 2 × 48-Plex SNPscan RESULTS: The results revealed that the rs53576 genotype could significantly predict PTSD symptoms (β = 0.055, p = 0.045). Further analysis showed that the rs53576 genotype was only significantly associated with dysphoric arousal symptoms of PTSD (β = 0.080, p = 0.005). The rs53576 genotype × earthquake exposure interaction had no significant effect on different symptom clusters (p > 0.05). CONCLUSION This study showed that the rs53576 genotype was only associated with the dysphoric arousal symptoms but not with other symptom clusters of PTSD. These findings support the role of the OXTR on the psychopathology of PTSD and help us to understand the genetic basis of PTSD.

OBJECTIVES: To evaluate the ability of the ForenSeq^TM DNA Signature Prep kit (ForenSeq kit) in analyzing the sequence information of STRs in Zhejiang She ethnic group and its forensic application efficacy. METHODS: A total of 50 Zhejiang She ethnic group samples were sequenced with the ForenSeq kit on the MiSeq FGx platform. The data was analyzed using ForenSeq^TM universal analysis software to obtain the motif structure and flank regions of the 58 STRs, then compared with PCR-CE typing results to test the consistency. At last, the allele frequency and population genetic parameters were calculated. RESULTS: A total of 448 sequence polymorphic alleles were detected in 50 samples of Zhejiang She ethnic group. Compared with fragment length polymorphism detected by PCR-CE, 82 alleles were increased by MPS detection based on ForenSeq kit, and 7 SNPs variation were detected in the flanking regions of 6 loci. The 22 male individuals were genotyped, and total 19 haplotypes were detected in 24 Y chromosome STRs of these 22 males. The cumulative discrimination power of the 27 autosomal STRs was 1-8.87×10^-30, the cumulative probability of exclusion of duo-testing was 0.999 999 962 640 657, the cumulative probability of exclusion of trios-testing was 0.999 999 999 999 633. CONCLUSIONS Based on MPS typing technology, using the ForenSeq kit greatly improves the detection efficiency. In addition, the 58 STRs have good genetic polymorphisms in Zhejiang She ethnic group, which are suitable for individual identification and paternity identification in forensic application.
DNA ; DNA Fingerprinting/methods* ; Ethnicity/genetics* ; Gene Frequency ; High-Throughput Nucleotide Sequencing/methods* ; Humans ; Male ; Microsatellite Repeats ; Polymorphism, Single Nucleotide ; Sequence Analysis, DNA/methods*

Objective · To investigate the micro/ nano structure of human vaginal wall acellular matrix, and provide parameters for bionic vagina.Methods · A total of 35 vaginal specimens were obtained from 35 postmenopausal patients who underwent cystocele repair and/or rectocele repair.Cells in specimens were entirely removed, and the extracellular matrix was maintained. Then the acellular matrix was observed by general observation,H-E staining, Masson staining, scanning electron microscope and Micro-CT. The external and internal structure properties were measured and analyzed.Results · All cells in 35 vaginal specimens were totally removed. The vaginal wall acellular matrix was a double-layer fibrous reticular structure composed of interlaced collagen fibers, which were further arranged into bundles. Pores were distributed among fiber bundles. Epithelial side structure of vaginal wall acellular matrix was dense and subepithelial tissue was loose. There was no significant difference in fiber diameter [(82.4±9.3) nm vs (87.5±10.2)nm, P=0.432] and fiber bundle thickness [(67.6±9.3) μm vs (65.3±5.2) μm, P=0.634] between the dense and loose layers. Fiber bundle separation [(180.1±24.5) μm vs (118.2±23.0) μm, P=0.003] and total porosity [(77.1±4.2)% vs (66.6±2.8)%, P=0.002] were higher in loose layer. There was no significant difference in the micro/nano structure parameters of the acellular matrix between the anterior vaginal wall and the posterior vaginal wall.Conclusion · There was no significant difference in the fiber diameter and the fiber bundle thickness between the dense layer and the loose layer of vaginal wall acellular matrix, but the porosity of the dense layer fiber bundle was smaller than that of the loose layer.

Objective To study the prevalence and trend of obesity among primary and middle school students in Beijing from 1985 to 2005.Methods Morphological data of students aged 7-18 from the National Physical Fitness and Health Surveillances of Chinese School Students in Beijing in 1985,1995,2000 and 2005 was analyzed with methods of cross-sectional study.The prevalence of obesity was calculated,and its secular trends was characterized.Results The prevalence of obesity among students aged 7-18 in Beijing were 0.65%,3.40%,5.23% and 8.53% respectively in the four surveillance programs with obvious rising trend which had an increase.In 2005,it was indicated that the obesity prevalence of subgroups were significantly different from each other.It was higher for males(11.11%)than females(5.98%),also for students aged 10-12(11.63%).In rural schools(6.60%)it was much 10wer than in urban(10.38%),but the areas with high SES was deemed to have a 10wer prevalence.Conclusion In the last two decades,among primary and middle school students in Beijing,obesity had changed its characteristics from sporadic to epidemic with the features of both developed and developing countries.

Objective To explore the effect of Internet addiction on adolescent's attention.Methods Neuropsychological evaluations of attention function were done separately in 18 adolescents who met the diagnostic criterion for Internet addiction and in other 18 ones without Intemet addition tendency as a control group. With auditory and visual oddball paradigms, and stimulated by standard,target and novel stimuli, EEG was recorded and analyzed to get the event-related potential P300 and compare the latency and amplitude of P3a and P3b between the 2 groups. Results Compared with the controls, the attention of Internet addiction group was decreased significantly in neuropsychological evaluations. The latency of P3a potentials induced by novel stimulus was much shorter and the amplitude of it was higher in addiction group than in control group, but the latency of P3b potentials generated by target stimulus was prolonged and the amplitude decreased obviously. Conclusions Intemet addiction can cause damage to adolescent's attention function. There is a correlation between the attention impairment and the change of P300 potentials.