1.Establishment and application of the method for plasma concentration determination of lamotrigine,levetiracetam and perampanel in children with epilepsy
Wenlin SONG ; Ying ZHOU ; Haoran CHEN ; Ziyue LIN ; Yan LI ; Jie LIU ; Taiwei JIN ; Xuqiang ZHOU
China Pharmacy 2026;37(10):1313-1317
OBJECTIVE To establish a method for simultaneous determination of plasma concentration of lamotrigine(LTG), levetiracetam(LEV) and perampanel(PER) in children with epilepsy and apply this method in clinical practice. METHODS Plasma proteins were precipitated with acetonitrile. Using PER-D 5 as internal standard, ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was adopted. The determination was performed on ACQUITY UPLC HSS T3 C 18 column with mobile phase consisted of 0.1% formic acid with 5 mmol/L ammonium acetate-acetonitrile (gradient elution) at the flow rate of 0.3 mL/min. The column temperature was 40 ℃, and sample size was 5 μL. The analysis time was 5 min. The electrospray ionization source and multiple reaction monitoring mode were used for positive ion scanning. The ion pairs used for quantitative analysis of LTG, LEV, PER and internal standard were m / z 255.9→144.9, m / z 171.1→126.1, m / z 350.1→219.0 and m / z 354.9→220.2, respectively. The steady-state trough concentrations of the aforementioned drugs in the plasma of 14 pediatric epilepsy patients receiving combination therapy were determined using the same UPLC-MS/MS method as above. RESULTS The linear ranges of LTG, LEV and PER were 0.15-24 μg/mL ( R 2 >0.993), 0.312 5-50 μg/mL ( R 2 >0.997) and 6.25-1 000 ng/mL ( R 2 >0.997), respectively. The lower limits of quantification were 0.15 μg/mL, 0.312 5 μg/mL and 6.25 ng/mL, respectively. RSDs of intraday and interday precision tests of the three drugs were no more than 9.83%, and the accuracies (relative errors) were between -9.33% and 13.72%( n =6 or n =18); the average extraction recovery rates were 86.4%-97.9%, and the average matrix effects were 86.9%-110.0% ( n =6). The absolute values of the relative errors in the stability tests were all below 15%. The steady-state trough concentrations of LTG, LEV and PER were (5.64±4.03)μg/mL, (10.67±8.78)μg/mL and(450.20±251.27)ng/mL, respectively; the rates of achieving target trough concentrations were 71.4%, 37.5% and 84.6%, respectively. CONCLUSIONS The established UPLC-MS/MS method is specific, rapid and suitable for the plasma concentration monitoring in epileptic children receiving combination therapy.
2.Risk prediction of long working hours exposure on occupational stress and depressive symptoms among internet industry employees: Based on an interpretable machine learning framework
Xinyi LU ; Tao SONG ; Yuting ZHOU ; Qingxin MENG ; Jianlin LOU ; Hongchang ZHOU ; Jin WANG ; Shuang LI
Journal of Environmental and Occupational Medicine 2026;43(1):16-27
Background Long working hours, as a common risk factor for occupational stress, is closely related to the occurrence of depressive symptoms. Understanding how long working hours affect occupational stress and depressive symptoms will inform occupational health interventions. Objective To quantify the impact of long working hours exposure on occupational stress and depressive symptoms among Internet industry employees, translate black-box outputs into actionable insights, and demonstrate the value of interpretable machine learning for early-warning occupational-health surveillance. Methods A dataset was derived from a cross-sectional survey involving 2866 internet industry employees in China. This survey was part of the project Risk Assessment Of Long Working Hour Exposure And Its Adverse Health Effects, conducted by the National Institute for Occupational Health and Poisoning Control, Chinese Center for Disease Control and Prevention, from 2021 to 2023. Working hours, occupational stress and depressive symptoms were quantified with a set of structured questionnaires including the Core Occupational Stress Scale and the Patient Health Questionnaire. Pairwise associations were screened by Mantel tests and variance-inflation factors. Key predictors identified through feature selection were fed into six machine-learning risk-prediction models. Visual interpretation was provided by feature importance, Shapley additive explanations (SHAP) and local interpretable model-agnostic explanations (LIME), while directed causal effects and intervention impacts of prolonged working hours exposure on occupational stress and depressive symptoms were dissected with causal explanation of features techniques. Results The positive rates of occupational stress and depressive symptoms among internet employees were 12.9% and 77.8% respectively. Twelve core features for occupational stress and nine for depressive symptoms were retained after selection. After these features were supplied to six predictive algorithms and evaluated on five metrics, the Light Gradient Boosting Machine (LGBM) achieved the highest accuracy—0.89 for occupational stress and 0.79 for depressive symptoms on the hold-out test set. The feature-importance rankings converged on fatigue accumulation and life satisfaction as dominant drivers for both outcomes, whereas weekly working hours and daily overtime emerged as the principal exposure-related predictors. The SHAP summary plots revealed that longer weekly hours and daily overtime systematically elevated the probability of occupational stress. The causal feature explanation further quantified that ascending one category in weekly working hours increased the probability of occupational stress by 7.04%. Conclusion Exposure to long working hours is associated with both occupational stress and depressive symptoms among internet industry employees. Interpretable machine-learning frameworks translate these associations into transparent, defensible drivers, enabling precise identification of the pivotal factors and their interplay. This evidence base equips occupational-health practitioners with actionable insights for designing targeted prevention and intervention strategies.
3.Accuracy of Magnetic Resonance Spectroscopy–Detected Fumarate Peak for Diagnosing Fumarate Hydratase Deficiency in Uterine Leiomyomas: A Prospective Study
Guiqin LIU ; Wenxin YU ; Shihang PAN ; Yuansheng LUO ; Jingli CHEN ; Mengying ZHU ; Zaoyu WANG ; Yang SONG ; Jin ZHANG ; Jianrong XU ; Yan ZHOU ; Jun MA ; Guangyu WU
Korean Journal of Radiology 2026;27(5):440-451
Objective:
To evaluate the diagnostic performance of magnetic resonance spectroscopy (MRS) in discriminating fumarate hydratase-deficient (FH-d) uterine leiomyomas (ULs) from FH-preserved ULs.
Materials and Methods:
This study consisted of three stages, with independent cohorts recruited for each stage: 1) sample-size estimation was retrospectively performed on UL specimens (diameter ≥3 cm; age, 20–40 years) from our database with immunohistochemistry (IHC) for 2-succinocysteine (2-SC) as the reference, without genetic testing, 2) MRS sequence optimization in confirmed FH germline mutation participants with ultrasound-detected ULs (diameter ≥3 cm), without IHC analysis, and 3) prospective diagnostic test accuracy was evaluated in consecutive participants with ultrasound-detected ULs (diameter ≥3 cm;age, 20–40 years), using IHC for 2-SC for determining the FH status and subsequent genetic testing in those with positive 2-SC results to identify whether FH mutations were germline or somatic in origin. The choline and fumarate peaks in MRS were classified as positive, negative, or technical failure (TF). TFs were analyzed separately and excluded from the primary diagnostic accuracy calculations. T1-, T2-, and diffusion-weighted images were interpreted as hyperintense or hypointense. The enhancement rate and apparent diffusion coefficient were also acquired. Diagnostic performance was compared between MRS and various magnetic resonance imaging (MRI) features.
Results:
The optimal MRS parameters for the fumarate peak were echo time (TE) = 140 ms and an average of 256. Among the 360 prospective participants, 37 were confirmed to have FH-dULs. MRS showed positive fumarate peaks in 35 of 37 FH-dULs.After excluding six TFs, the positive fumarate peak on MRS showed 94.6% (35/37) sensitivity, 99.7% (316/317) specificity, and 99.2% (351/354) accuracy, all of which were significantly superior to those of other MRI features (P ≤ 0.002).
Conclusion
A positive fumarate peak on MRS may be a useful imaging biomarker for diagnosing FH-dULs.
4.Renal mucinous tubular and spindle cell carcinoma: a diagnostic and therapeutic analysis of 14 cases
Ning DONG ; Yulin ZHOU ; Wenyi HUANG ; Xiaoxu JIN ; Xiaodong ZHAO ; Jie DONG ; Song XU
Journal of Modern Urology 2026;31(5):422-427
Objective To analyze the clinical, imaging, pathological characteristics and prognosis of renal mucinous tubular and spindle cell carcinoma (MTSCC), so as to provide preference for the differential diagnosis and clinical management of this disease.Methods A retrospective analysis was conducted on the clinical and follow-up data of 14 patients diagnosed with renal MTSCC at the Eastern Theater Command General Hospital during June 2021 and Aug.2025.Relevant literature was reviewed.Results Of the 14 patients, 10 were female (71.4%) and 4 were male (28.6%), with a mean age of 56.9 years. Pathological staging included pT1a in 6 cases, pT1b in 7 cases, and pT2b in 1 case.The median tumor diameter was 4.5 (range 2.0-11.0) cm.Twelve cases (85.7%) were asymptomatic and detected incidentally.On ultrasonography, most tumors exhibited well-defined margins and regular morphology (9/10, 90%) and appeared as homogeneous hypoechoic masses (7/10, 70%).All lesions demonstrated hypovascular features on imaging studies.Ten patients (71.4%) underwent laparoscopic radical nephrectomy, and 4(28.6%) received partial nephrectomy.Histologically, a distinctive architecture composed of tubular structures, spindle-shaped cells, and mucinous stroma was exhibited.Immunohistochemically, the positive rates of PAX-8, VIMENTIN and CK7 in tumor cells were 100% (13/13), 91.7% (11/12) and 84.6% (11/13), respectively.The Ki-67 proliferation index ranged from 2.0% to 40.0%.During a median follow-up of 25.0 (range4.9-0.0) months, no local recurrence or distant metastasis was observed.Conclusion Renal MTSCC is a rare subtype of renal cell carcinoma, typically lacking specific clinical symptoms and characterized by hypovascular imaging features.The tumor generally follows an indolent course with a favorable prognosis.For localized tumors, partial nephrectomy should be the primary consideration.For cases with high-risk pathological features such as sarcomatoid changes, due attention should be paid to the potential invasiveness and follow-up should be closely conducted.
5.Preoperative short-course radiotherapy followed by chemotherapy and PD-1 inhibitor administration for locally advanced rectal cancer: the initial results of a randomized controlled clinical trial (STELLAR II)
Haoyue LI ; Haitao ZHOU ; Lichun WEI ; Yinggang CHEN ; Wenjue ZHANG ; Feiyan DENG ; Ning LI ; Zheng JIANG ; Zheng LIU ; Jianwei LIANG ; Zhaoxu ZHENG ; Xianyu MENG ; Yufei LU ; Zifa LEI ; Xiaoge SUN ; Gong LI ; Yingjie WANG ; Yongwen SONG ; Shunan QI ; Hao JING ; Yirui ZHAI ; Shulian WANG ; Yexiong LI ; Yuan TANG ; Jing JIN
Chinese Journal of Oncology 2025;47(9):913-921
Objectives:To explore whether short-course radiotherapy (SCRT)-based total neoadjuvant therapy (TNT) combined with PD-1 inhibitors could further promote tumor regression and improve the prognosis.Methods:This is a prospective, multicenter, two-arm randomized controlled, seamless phase Ⅱ/Ⅲ trial for proficient mismatch repair or microsatellite stable (pMMR/MSS) locally advanced rectal cancer (LARC). Eligible patients were randomly assigned to the iTNT (TNT+PD-1) group or the TNT group. Patients in the TNT group received SCRT (5 Gy×5) followed by 4 cycles of CAPOX or 6 cycles of mFOLFOX chemotherapy, with the iTNT group receiving SCRT followed by the same regime in combination with 4 cycles of Sintilimab. Total mesorectal excision (TME) surgery or watch and wait (W&W) was performed after neoadjuvant therapy and then 2 cycles of same regimen as before were recommended. The primary endpoints are the complete response (CR) rate for phase Ⅱ trial and 3-year disease-free survival (DFS) for phase Ⅲ trial. A total of 588 patients will be enrolled for the phase Ⅱ/Ⅲ trial. Short-term efficacy and safety data from the initial 100 treated patients were analyzed as planned.Results:From 2022-8-31 to 2023-5-24 the initial 100 patients were enrolled from 10 hospitals in China, 76.0%(76/100) patients were male, and the median age was 61 years (21-74 years). More patients had tumors located in the lower rectum (78.0%, 78/100), staged T3-4 (97.0%, 97/100) and N1-2 (93.0%, 93/100), and about half of the tumors invaded the mesorectal fascia (52.0%, 52/100) and with extramural vascular invasion (51.0%, 51/100). Analyses were performed according to the per-protocal (PP) set. All patients in the iTNT group ( n=52) and the TNT group ( n=48) completed SCRT; The 4-cycle chemotherapy±Sintilimab completion rates were 86.5% and 100.0% in the iTNT and TNT groups, respectively. In the iTNT group, 82.7% (43/52), 11.5% (6/52), and 5.8% (3/52) of the patients received 4, 3, and 2 cycles of PD-1 inhibitor. After TNT, 68 patients underwent radical surgery and 15 patients achieved cCR and adopted W&W. The pathological complete response (pCR) rates were 48.5% (16/33) and 17.1% (6/35) in the iTNT and TNT groups, with CR rates of 50.0% (25/50) and 26.1% (12/46), respectively. The incidence of treatment-related grade 3-4 adverse events was 26.9% (14/52, iTNT group) and 18.8% (9/48, TNT group), with thrombocytopenia and leukopenia being the most common. Among patients receiving immunotherapy, grade 3 immunotherapy-related adverse events occurred in 2 (3.8%, 2/52) patients: one case was pancreatitis, another case was hepatitis combined with myositis and myocarditis. Conclusion:The preliminary results show that SCRT-based TNT combined with PD-1 inhibitors could further improve the CR rate for LARC without unexpected serious adverse events.
6.Changing resistance profiles of Haemophilus influenzae and Moraxella catarrhalis isolates in hospitals across China:results from the CHINET Antimicrobial Resistance Surveillance Program,2015-2021
Hui FAN ; Chunhong SHAO ; Jia WANG ; Yang YANG ; Fupin HU ; Demei ZHU ; Yunsheng CHEN ; Qing MENG ; Hong ZHANG ; Chun WANG ; Fang DONG ; Wenqi SONG ; Kaizhen WEN ; Yirong ZHANG ; Chuanqing WANG ; Pan FU ; Chao ZHUO ; Danhong SU ; Jiangwei KE ; Shuping ZHOU ; Hua ZHANG ; Fangfang HU ; Mei KANG ; Chao HE ; Hua YU ; Xiangning HUANG ; Yingchun XU ; Xiaojiang ZHANG ; Wenen LIU ; Yanming LI ; Lei ZHU ; Jinhua MENG ; Shifu WANG ; Bin SHAN ; Yan DU ; Wei JIA ; Gang LI ; Jiao FENG ; Ping GONG ; Miao SONG ; Lianhua WEI ; Xin WANG ; Ruizhong WANG ; Hua FANG ; Sufang GUO ; Yanyan WANG ; Dawen GUO ; Jinying ZHAO ; Lixia ZHANG ; Juan MA ; Han SHEN ; Wanqing ZHOU ; Ruyi GUO ; Yan ZHU ; Jinsong WU ; Yuemei LU ; Yuxing NI ; Jingrong SUN ; Xiaobo MA ; Yanqing ZHENG ; Yunsong YU ; Jie LIN ; Ziyong SUN ; Zhongju CHEN ; Zhidong HU ; Jin LI ; Fengbo ZHANG ; Ping JI ; Yunjian HU ; Xiaoman AI ; Jinju DUAN ; Jianbang KANG ; Xuefei HU ; Xuesong XU ; Chao YAN ; Yi LI ; Shanmei WANG ; Hongqin GU ; Yuanhong XU ; Ying HUANG ; Yunzhuo CHU ; Sufei TIAN ; Jihong LI ; Bixia YU ; Cunshan KOU ; Jilu SHEN ; Wenhui HUANG ; Xiuli YANG ; Likang ZHU ; Lin JIANG ; Wen HE ; Chunlei YUE
Chinese Journal of Infection and Chemotherapy 2025;25(1):30-38
Objective To investigate the distribution and antimicrobial resistance profiles of clinically isolated Haemophilus influenzae and Moraxella catarrhalis in hospitals across China from 2015 to 2021,and provide evidence for rational use of antimicrobial agents.Methods Data of H.influenzae and M.catarrhalis strains isolated from 2015 to 2021 in CHINET program were collected for analysis,and antimicrobial susceptibility testing was performed by disc diffusion method or automated systems according to the uniform protocol of CHINET.The results were interpreted according to the CLSI breakpoints in 2022.Beta-lactamases was detected by using nitrocefin disk.Results From 2015 to 2021,a total of 43 642 strains of Haemophilus species were isolated,accounting for 2.91%of the total clinical isolates and 4.07%of Gram-negative bacteria in CHINET program.Among the 40 437 strains of H.influenzae,66.89%were isolated from children and 33.11%were isolated from adults.More than 90%of the H.influenzae strains were isolated from respiratory tract specimens.The prevalence of β-lactamase was 53.79%in H.influenzae strains.The H.influenzae strains isolated from children showed higher resistance rate than the strains isolated from adults.Overall,779 strains of H.influenzae did not produce β-lactamase but were resistant to ampicillin(BLNAR).Beta-lactamase-producing strains showed significantly higher resistance rates to these antimicrobial agents than the β-lactamase-nonproducing strains.Of the 16 191 M.catarrhalis strains,80.06%were isolated from children and 19.94%isolated from adults.M.catarrhalis strains were mostly susceptible to both amoxicillin-clavulanic acid and cefuroxime,evidenced by resistance rate lower than 2.0%.Conclusions The emergence of antibiotic-resistant H.influenzae due to β-lactamase production poses a challenge for clinical anti-infective treatment.Therefore,it is very important to implement antibiotic resistance surveillance for H.influenzae and guide rational antibiotic use.All local clinical microbiology laboratories should actively improve antibiotic susceptibility testing and strengthen antibiotic resistance surveillance for H.influenzae.
7.Influence of helical tomography radiotherapy planning parameters on threading effect
Ruo-qi CAO ; Xia-yu HANG ; Hua HUANG ; Xian-qiang SONG ; Jin-da ZHOU ; Yun-jie BAI ; Xiang-dong SUN ; Yi-kun LI
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]
8.Lymph node metastasis in the prostatic anterior fat pad and prognosis after robot-assisted radical prostatectomy
Zhou-jie YE ; Yong SONG ; Jin-peng SHAO ; Wen-zheng CHEN ; Guo-qiang YANG ; Qing-shan DU ; Kan LIU ; Jie ZHU ; Bao-jun WANG ; Jiang-ping GAO ; Wei-jun FU
National Journal of Andrology 2025;31(3):216-221
Objective:To investigate lymph node metastasis(LNM)in the prostatic anterior fat pad(PAFP)of PCa patients after robot-assisted radical prostatectomy(RARP),and analyze the clinicopathological features and prognosis of LNM in the PAFP.Methods:We retrospectively analyzed the clinicopathological data on 1 003 cases of PCa treated by RARP in the Department of Urolo-gy of PLA General Hospital from January 2017 to December 2022.All the patients underwent routine removal of the PAFP during RARP and pathological examination,with the results of all the specimens examined and reported by pathologists.Based on the pres-ence and locations of LNM,we grouped the patients for statistical analysis,compared the clinicopathological features between different groups using the Student's t,Mann-Whitney U and Chi-square tests,and conducted survival analyses using the Kaplan-Meier and Log-rank methods and survival curves generated by Rstudio.Results:Lymph nodes were detected in 77(7.7%)of the 1 003 PAFP samples,and LNM in 11(14.3%)of the 77 cases,with a positive rate of 1.1%(11/1 003).Of the 11 positive cases,9 were found in the upgraded pathological N stage,and the other 2 complicated by pelvic LNM.The patients with postoperative pathological stage≥T3 constituted a significantly higher proportion in the PAFP LNM than in the non-PAFP LNM group(81.8%[9/11]vs 36.2%[359/992],P=0.005),and so did the cases with Gleason score ≥8(87.5%[7/8]vs 35.5%[279/786],P=0.009).No statisti-cally significant differences were observed in the clinicopathological features and biochemical recurrence-free survival between the pa-tients with PAFP LNM only and those with pelvic LNM only.Conclusion:The PAFP is a potential route to LNM,and patients with LNM in the PAFP are characterized by poor pathological features.There is no statistically significant difference in biochemical recur-rence-free survival between the patients with PAFP LNM only and those with pelvic LNM only.Routine removal of the PAFP and inde-pendent pathological examination of the specimen during RARP is of great clinical significance.
9.Causal relationship between periodontal disease and prostate cancer:A two-sample bidirectional Mendelian randomization analysis in two races
Xiaoxu JIN ; Jing LIU ; Xiaodong ZHAO ; Wenyi HUANG ; Ning DONG ; Shihao WANG ; Mengfei MA ; Yulin ZHOU ; Yuhao CHEN ; Jinlu SUN ; Jie DONG ; Jun HU ; Song XU
National Journal of Andrology 2025;31(10):885-890
Objective The aim of this study is to discuss the causal relationship between periodontal disease(PD)and prostate cancer(PCa).Methods A two-sample bidirectional Mendelian randomization(MR)analysis based on publicly statistical data from genome-wide association studies(GWAS)was conducted.MR Egger,weighted medium,simple mode and weighted mode were supplemented,while inverse variance weighted analysis(IVW)was the main method of analysis.Heterogeneity testing,pleiotropy testing and leave-one-out testing were used to assess the sensitivity and stabili-ty.Results The results of MR analysis showed that PD had no significant impact on the occurrence of PCa:East Asian(IVW,PD:OR=1.07,P=0.48);European(IVW,PD:OR=1.00,P=0.37,periodontitis:OR=1.03,P=0.14,chronic gingivitis:OR=0.99,P=0.37,chronic periodontitis:OR=1.03,P=0.22).The reverse MR analysis also did not show a causal relationship between PCa and PD:East Asian(IVW,PD:OR=0.97,P=0.22);European(IVW,PD:OR=0.84,P=0.44,periodontitis:OR=1.01,P=0.75,chronic gingivitis:OR=0.93,P=0.23,chronic periodontitis:OR=0.99,P=0.80).The results of other analysis were consistent with those of IVW analysis.Conclusions The results of our two-sample bidirectional MR analysis do not support a causal relationship between PD and PCa.
10.Influence of helical tomography radiotherapy planning parameters on threading effect
Ruo-qi CAO ; Xia-yu HANG ; Hua HUANG ; Xian-qiang SONG ; Jin-da ZHOU ; Yun-jie BAI ; Xiang-dong SUN ; Yi-kun LI
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]

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