1.Application of 3D-printed auxiliary guides in adolescent scoliosis surgery.
Dong HOU ; Jian-Tao WEN ; Chen ZHANG ; Jin HUANG ; Chang-Quan DAI ; Kai LI ; Han LENG ; Jing ZHANG ; Shao-Bo YANG ; Xiao-Juan CUI ; Juan WANG ; Xiao-Yun YUAN
China Journal of Orthopaedics and Traumatology 2025;38(11):1119-1125
OBJECTIVE:
To investigate the accuracy and safety of pedicle screw placement using 3D-printed auxiliary guides in scoliosis correction surgery for adolescents.
METHODS:
A retrospective analysis was conducted on the clinical data of 51 patients who underwent posterior scoliosis correction surgery from January 2020 to March 2023. Among them, there were 35 cases of adolescent idiopathic scoliosis and 16 cases of congenital scoliosis. The patients were divided into two groups based on the auxiliary tool used:the 3D-printed auxiliary guide screw placement group (3D printing group) and the free-hand screw placement group (free-hand group, without auxiliary tools). The 3D printing group included 32 patients (12 males and 20 females) with an average age of (12.59±2.60) years;the free-hand group included 19 patients (7 males and 12 females) with an average age of (14.58±3.53) years. The two groups were compared in terms of screw placement accuracy and safety, spinal correction rate, intraoperative blood loss, number of intraoperative fluoroscopies, operation time, hospital stay, and preoperative and last follow-up scores of the Scoliosis Research Society-22 (SRS-22) questionnaire.
RESULTS:
A total of 707 pedicle screws were placed in the two groups, with 441 screws in the 3D printing group and 266 screws in the free-hand group. All patients in both groups successfully completed the surgery. There was a statistically significant difference in operation time between the two groups (P<0.05). The screw placement accuracy rate of the 3D printing group was 95.46% (421/441), among which the Grade A placement rate was 89.34% (394/441);the screw placement accuracy rate of the free-hand group was 86.47% (230/266), with a Grade A placement rate of 73.31% (195/266). There were statistically significant differences in the accuracy of Grade A, B, and C screw placements between the two groups (P<0.05), while no statistically significant differences were observed in intraoperative blood loss, number of fluoroscopies, correction rate, or hospital stay (P>0.05). In the SRS-22 questionnaire scores, the scores of functional status and activity ability, self-image, mental status, and pain of patients in each group at the last follow-up were significantly improved compared with those before surgery (P<0.05), but there were no statistically significant differences in all scores between the two groups (P>0.05).
CONCLUSION
In scoliosis correction surgery, compared with traditional free-hand screw placement, the use of 3D-printed auxiliary guides for screw placement significantly improves the accuracy and safety of screw placement and shortens the operation time.
Humans
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Male
;
Scoliosis/surgery*
;
Female
;
Adolescent
;
Printing, Three-Dimensional
;
Retrospective Studies
;
Pedicle Screws
;
Child
2.Characteristics of Gut Microbiota Changes and Their Relationship with Infectious Complications During Induction Chemotherapy in AML Patients.
Quan-Lei ZHANG ; Li-Li DONG ; Lin-Lin ZHANG ; Yu-Juan WU ; Meng LI ; Jian BO ; Li-Li WANG ; Yu JING ; Li-Ping DOU ; Dai-Hong LIU ; Zhen-Yang GU ; Chun-Ji GAO
Journal of Experimental Hematology 2025;33(3):738-744
OBJECTIVE:
To investigate the characteristics of gut microbiota changes in patients with acute myeloid leukemia (AML) undergoing induction chemotherapy and to explore the relationship between infectious complications and gut microbiota.
METHODS:
Fecal samples were collected from 37 newly diagnosed AML patients at four time points: before induction chemotherapy, during chemotherapy, during the neutropenic phase, and during the recovery phase. Metagenomic sequencing was used to analyze the dynamic changes in gut microbiota. Correlation analyses were conducted to assess the relationship between changes in gut microbiota and the occurrence of infectious complications.
RESULTS:
During chemotherapy, the gut microbiota α-diversity (Shannon index) of AML patients exhibited significant fluctuations. Specifically, the diversity decreased significantly during induction chemotherapy, further declined during the neutropenic phase (P < 0.05, compared to baseline), and gradually recovered during the recovery phase, though not fully returning to baseline levels.The abundances of beneficial bacteria, such as Firmicutes and Bacteroidetes, gradually decreased during chemotherapy, whereas the abundances of opportunistic pathogens, including Enterococcus, Klebsiella, and Escherichia coli, progressively increased.Analysis of the dynamic changes in gut microbiota of seven patients with bloodstream infections revealed that the bloodstream infection pathogens could be detected in the gut microbiota of the corresponding patients, with their abundance gradually increasing during the course of infection. This finding suggests that bloodstream infections may be associated with opportunistic pathogens originating from the gut microbiota.Compared to non-infected patients, the baseline samples of infected patients showed a significantly lower relative abundance of Bacteroidetes (P < 0.05). Regression analysis indicated that Bacteroidetes abundance is an independent predictive factor for infectious complications (P < 0.05, OR =13.143).
CONCLUSION
During induction chemotherapy in AML patients, gut microbiota α-diversity fluctuates significantly, and the abundance of opportunistic pathogens increase, which may be associated with bloodstream infections. Patients with lower baseline Bacteroidetes abundance are more prone to infections, and its abundance can serve as an independent predictor of infectious complications.
Humans
;
Gastrointestinal Microbiome
;
Leukemia, Myeloid, Acute/microbiology*
;
Induction Chemotherapy
;
Feces/microbiology*
;
Male
;
Female
;
Middle Aged
3.Co-Circulation of Respiratory Pathogens that Cause Severe Acute Respiratory Infections during the Autumn and Winter of 2023 in Beijing, China.
Jing Zhi LI ; Da HUO ; Dai Tao ZHANG ; Jia Chen ZHAO ; Chun Na MA ; Dan WU ; Peng YANG ; Quan Yi WANG ; Zhao Min FENG
Biomedical and Environmental Sciences 2025;38(5):644-648
4.National bloodstream infection bacterial resistance surveillance report (2022) : Gram-negative bacteria
Zhiying LIU ; Yunbo CHEN ; Jinru JI ; Chaoqun YING ; Qing YANG ; Haishen KONG ; Haifeng MAO ; Hui DING ; Pengpeng TIAN ; Jiangqin SONG ; Yongyun LIU ; Jiliang WANG ; Yan JIN ; Yuanyuan DAI ; Yizheng ZHOU ; Yan GENG ; Fenghong CHEN ; Lu WANG ; Yanyan LI ; Dan LIU ; Peng ZHANG ; Junmin CAO ; Xiaoyan LI ; Dijing SONG ; Xinhua QIANG ; Yanhong LI ; Qiuying ZHANG ; Guolin LIAO ; Ying HUANG ; Baohua ZHANG ; Liang GUO ; Aiyun LI ; Haiquan KANG ; Donghong HUANG ; Sijin MAN ; Zhuo LI ; Youdong YIN ; Kunpeng LIANG ; Haixin DONG ; Donghua LIU ; Hongyun XU ; Yinqiao DONG ; Rong XU ; Lin ZHENG ; Shuyan HU ; Jian LI ; Qiang LIU ; Liang LUAN ; Jilu SHEN ; Lixia ZHANG ; Bo QUAN ; Xiaoping YAN ; Xiaoyan QI ; Dengyan QIAO ; Weiping LIU ; Xiusan XIA ; Ling MENG ; Jinhua LIANG ; Ping SHEN ; Yonghong XIAO
Chinese Journal of Clinical Infectious Diseases 2024;17(1):42-57
Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of national bloodstream infection Bacterial Resistant Investigation Collaborative System(BRICS)were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute(CLSI). WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:During the study period,9 035 strains of Gram-negative bacteria were collected from 51 hospitals,of which 7 895(87.4%)were Enterobacteriaceae and 1 140(12.6%)were non-fermenting bacteria. The top 5 bacterial species were Escherichia coli( n=4 510,49.9%), Klebsiella pneumoniae( n=2 340,25.9%), Pseudomonas aeruginosa( n=534,5.9%), Acinetobacter baumannii complex( n=405,4.5%)and Enterobacter cloacae( n=327,3.6%). The ESBLs-producing rates in Escherichia coli, Klebsiella pneumoniae and Proteus spp. were 47.1%(2 095/4 452),21.0%(427/2 033)and 41.1%(58/141),respectively. The prevalence of carbapenem-resistant Escherichia coli(CREC)and carbapenem-resistant Klebsiella pneumoniae(CRKP)were 1.3%(58/4 510)and 13.1%(307/2 340);62.1%(36/58)and 9.8%(30/307)of CREC and CRKP were resistant to ceftazidime/avibactam combination,respectively. The prevalence of carbapenem-resistant Acinetobacter baumannii(CRAB)complex was 59.5%(241/405),while less than 5% of Acinetobacter baumannii complex was resistant to tigecycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa(CRPA)was 18.4%(98/534). There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of main Gram-negative bacteria resistance among different regions,with statistically significant differences in the prevalence of CRKP and CRPA( χ2=20.489 and 20.252, P<0.001). The prevalence of CREC,CRKP,CRPA,CRAB,ESBLs-producing Escherichia coli and Klebsiella pneumoniae were higher in provinicial hospitals than those in municipal hospitals( χ2=11.953,81.183,10.404,5.915,12.415 and 6.459, P<0.01 or <0.05),while the prevalence of CRPA was higher in economically developed regions(per capita GDP ≥ 92 059 Yuan)than that in economically less-developed regions(per capita GDP <92 059 Yuan)( χ2=6.240, P=0.012). Conclusions:The proportion of Gram-negative bacteria in bloodstream infections shows an increasing trend,and Escherichia coli is ranked in the top,while the trend of CRKP decreases continuously with time. Decreasing trends are noted in ESBLs-producing Escherichia coli and Klebsiella pneumoniae. Low prevalence of carbapenem resistance in Escherichia coli and high prevalence in CRAB complex have been observed. The composition ratio and antibacterial spectrum of bloodstream infections in different regions of China are slightly different,and the proportion of main drug resistant bacteria in provincial hospitals is higher than those in municipal hospitals.
5.Clinical characteristics and risk factors for hypotension in children with multisystem inflammatory syndrome related to SARS-CoV-2
Guorui DAI ; Jie WU ; Jun LIU ; Quan WANG
Chinese Pediatric Emergency Medicine 2024;31(3):189-194
Objective:To summarize the clinical characteristics of multisystem inflammatory syndrome in children(MIS-C)related to SARS-CoV-2 and analyze the risk factors for hypotension.Methods:The clinical data of children with MIS-C who visited Beijing Children's Hospital from January 2023 to March 2023 were retrospectively collected,and the clinical characteristics and risk factors for hypotension were analyzed.Results:Thirty-six patients were included,the median age was 3.1 (2.3,5.8) years; 61.1% were boys.All cases had a history of SARS-CoV-2 infection between 1 and 9 weeks before onset.Clinical symptoms included fever (100.0%); rash (94.4%); bilateral conjunctival congestion (88.8%); lips/oral cavity changes (100.0%); swollen hands and foot (61.1%); cervical lymphadenopathy (88.8%); acute gastrointestinal symptoms (61.1%) of diarrhea,abdominal pain and vomiting; neurologic manifestations (33.3%) of lethargy,headache,and convulsions; respiratory symptoms(41.6%) of cough,sore throat and shortness of breath.Nineteen (52.8%) cases developed hypotension and needed vasoactive drugs support to maintain blood pressure.Mechanical ventilation was required in four(11.1%) cases,and one patient was intubated and treated with continuous renal replacement therapy.The level of ferritin in hypotension group was significantly higher than those in normal blood pressure group( P<0.05),while the levels of platelet count,serum sodium and potassium in hypotension group were significantly lower than those in normal blood pressure group( P<0.05).Logistic regression multivariable analysis found the elevated serum ferritin ( OR=20.000,95% CI:2.750-145.481, P=0.003) was an independent risk factor for hypotension. Conclusions:MIS-C may be observed following SARS-CoV-2 infection.Various symptoms and signs,including fever,multiple organ dysfunction,and hypotension,may occur in children with MIS-C.Elevated ferritin is a risk factor for hypotension.
6.Correlation between 23 metals and metalloids elements in the urine and thyroid function of traffic police
Yaru WANG ; Chao QUAN ; Tian XYU ; Shuxia LIU ; Lizhao YANG ; Ling ZHANG ; Xiayun DAI
Journal of Public Health and Preventive Medicine 2024;35(2):25-29
Objective To investigate the correlation between 23 metals and metalloids elements in the urine and thyroid function indicators in the blood of traffic police. Methods A cross-sectional study was performed to assess the effects of 23 metals and metalloids elements in the urine on blood thyroid function indicators in 166 traffic policemen (122 field staff and 44 internal staff) in Wuhan, Hubei Province. Each subject received an occupational health examination. Results After multiple corrections for false detection rates, in the polymetallic model, the levels of urinary manganese and urinary uranium were positively correlated with the levels of thyroid peroxidase antibody (TPOAb) in the blood (β = 66.57, 95% CI 2.92-130.22, P = 0.040 and β = 62.43, 95% CI 14.37-110.49, P = 0.011), and the level of urinary uranium was positively correlated with thyroid stimulating hormone (TSH) levels in the blood (β = 6.20, 95% CI 2.68-9.72 , P = 0.001). Urinary uranium level was negatively correlated with free thyroxine level in the blood (FT4) (β = -2.03, 95 % CI (-3.67 )- (-0.39), P = 0.015), and urinary lead level was negatively correlated with blood TSH level (β = -4.59, 95% CI (-8.67) - (-0.51), P = 0.027). Conclusion Manganese exposure is related to the increase of TPOAb level in blood, uranium exposure is related to the increase of TPOAb and TSH levels and the decrease of FT4 level in blood, and lead exposure is related to the decrease of TSH level in blood, suggesting that more attention should be paid to the effects of heavy metals on the thyroid of traffic police.
7.Exploring Intervention Mechanism of Changzhou Tongbian Formula on Functional Constipation Combined with Depressive-like Behaviors in Rats Based on TRPV4-mediated BDNF/TrkB/CREB Signaling Pathway
Ling YAO ; Longfang QUAN ; Zhennian XIE ; Jie DAI ; Qiuning LIU ; Yonghai LI ; Xiaoqiang JIA
Traditional Chinese Drug Research & Clinical Pharmacology 2024;35(9):1289-1298
Objective To explore the intervention mechanism of Changzhou Tongbian Formula on functional constipation(FC)combined with depression in rats.Methods A rat model of FC combined with depressive-like behaviors was established by using gastric gavage of berberine hydrochloride and chronic unpredictable mild stress.The model rats were randomly divided into blank group,model group,lactulose group,and Changzhou Tongbian Formula high-,medium-,and low-dose groups,and the intervention was carried out for five weeks.The fecal water content was calculated before and after intervention.The small intestinal propulsion rate was calculated after intervention.The depressive-like behavior levels of rats were evaluated by forced swimming test and sucrose preference test before and after intervention.The colonic mucosal morphology was observed by HE staining.The morphology and number of pyramidal cells in the hippocampal CA1 and DG regions were observed by Nissl staining.The relative protein expression levels of the transient receptor potential vanilloid 4(TRPV4)in colonic tissue,as well as brain-derived neurotrophic factor(BDNF),tyrosine kinase receptor B(TrkB),mitogen-activated protein kinase(MAPK),and cAMP-response element binding protein(CREB)in the hippocampus of rats in each group were detected by Western Blot method.Results Compared with the blank group,the fecal water content of rats in the model group was significantly reduced(P<0.001),the small intestinal propulsion rate was significantly lower(P<0.01),the sucrose preference index was significantly decreased(P<0.001),the number of pyramidal cells in the CA1 and DG regions of the hippocampus was significantly reduced(P<0.001),and the TRPV4 in the colon and the BDNF,TrkB,MAPK,and CREB protein contents in the hippocampus were all significantly decreased(all P<0.001).Compared with the model group,the fecal water content of the Changzhou Tongbian Formula high-,midium-,low-dose groups and the lactulose group were significantly increased(P<0.001,P<0.01).The small intestinal propulsion rate of the Changzhou Tongbian Formula high-,low-dose groups and lactulose group were significantly increased(P<0.01,P<0.05).The sucrose preference indices of the Changzhou Tongbian Formula high-,midium-,low-dose groups and lactulose group were significantly increased(P<0.01,P<0.05).There was no abnormality in the colonic histology.The numbers of pyramidal cells in the CA1 and DG regions of the hippocampus of the Changzhou Tongbian Formula high-,midium-,low-dose groups and lactulose group were significantly increased(P<0.01,P<0.001).The TRPV4 content in the colon of the Changzhou Tongbian Formula high-,midium-,low-dose groups and lactulose group were significantly increased(P<0.001),and the BDNF,TrkB,MAPK,and CREB protein contents in the hippocampus were all significantly increased(P<0.05,P<0.01,P<0.001).Conclusion After intervention,Changzhou Tongbian Formula can significantly improve the TRPV4 content in the colon of model rats with the comorbidity of FC with depression,increase the moisture content of feces,promote intestinal peristalsis and improve constipation.Meanwhile,TRPV4 can activate the BDNF/TrkB/MAPK pathway,trigger an increase in downstream CREB,improve neuroplasticity and thus alleviate some depressive-like behavior.
8.Observation on the efficacy of continuous veno-venous hemodia-filtration combined with hemoperfusion HA380 in the treatment of 15 cases of heat stroke with multiple organ dysfunction syndrome
Yuqin HUANG ; Lei LONG ; Qiang HUANG ; Qunbo WANG ; Ke JIN ; Tao JU ; Luting DAI ; Huaqiang XU ; Wenguo WANG ; Quan ZHOU
Chinese Critical Care Medicine 2024;36(5):532-537
Objective:To investigate the clinical efficacy of continuous veno-venous hemodia-filtration (CVVHDF) combined with hemoperfusion (HP) HA380 in the treatment of heat stroke patients with multiple organ dysfunction syndrome (MODS).Methods:A retrospective and observational study was conducted. A total of 15 patients with heat stroke combined with MODS who were admitted to the department of intensive care unit (ICU)of Suizhou Central Hospital/Hubei University of Medicine from July to September 2022 were selected as the study objects. All 15 patients were treated with CVVHDF combined with HA380 based on the comprehensive management strategy for severe illness. Organ function indicators [including total bilirubin (TBil), aspartate aminotransferase (AST), creatine kinase (CK), lactate dehydrogenase (LDH), creatinine (Cr), cardiac troponin T (cTnT), myoglobin (Myo), MB isoenzyme of creatine kinase (CK-MB), sequential organ failure assessment (SOFA)] and inflammatory indicators [including white blood cell count (WBC), neutrophil count (NEU), C-reactive protein (CRP), procalcitonin (PCT), and interleukin-6 (IL-6)] were collected. The improvements of the above indexes at admission, after the first HP, after the second HP, after the third HP, and on the 5th day of treatment were compared. Combined with the clinical outcome of patients, the comprehensive efficacy of CVVHDF combined with HA380 in the treatment of severe heat radiation disease was evaluated.Results:There were 10 males and 5 females among the 15 patients. The average age was (64.5±11.5) years old. There were 6 cases of classical heat stroke and 9 cases of exertional heat stroke. Glasgow coma scale (GCS) was 3-8 at admission; SOFA score was 9-17 within 12 hours after admission; acute physiology and chronic health evaluation Ⅱ(APACHEⅡ) was 25-45 within 24 hours after admission. After treatment, the IL-6 level and SOFA score gradually decreased, and there were significant differences in the decrease after the second HP compared to admission [IL-6 (ng/L): 48.37 (15.36, 113.03) vs. 221.90 (85.87, 425.90), SOFA: 8.3±3.3 vs. 11.1±2.4, both P < 0.05]. The PCT level reached its peak after the first HP [12.51 (6.07, 41.65) μg/L], and then gradually decreased, and the difference was statistically significant after the third HP [1.26 (0.82, 5.40) μg/L, P < 0.05]. Compared those at admission, Cr level significantly improved after the first HP (μmol/L: 66.94±25.57 vs. 110.80±31.13, P < 0.01), Myo significantly decreased after the second HP [μg/L: 490.90 (164.98, 768.05) vs. 3?000.00 (293.00, 3?000.00), P < 0.05], After the third HP, the CK level also showed significant improvement [U/L: 476.0 (413.0, 922.0) vs. 2?107.0 (729.0, 2?449.0), P < 0.05]. After CVVHDF combined with 3 times HP treatment, the patient's inflammatory response was gradually controlled and organ function gradually recovered. On the 5th day of the disease course, WBC, PCT and IL-6 levels were significantly improved compared to admission, and AST, CK, LDH, Cr, Myo, CK-MB, and SOFA score were significantly corrected compared with those on admission. The 24-hour survival rate of 15 patients was 86.67%, and the 24-hour, 7-day and 28-day survival rates were both as high as 73.33%. The average mechanical ventilation time of 11 surviving patients was (101.8±22.0) hours, the average continuous renal replacement therapy (CRRT) time was (58.8±11.0) hours, the average length of ICU stay was (6.3±1.0) days, and the average total hospitalization was (14.6±5.2) days. Conclusion:CVVHDF combined with HP HA380 in the treatment of heat stroke patients with MODS can effectively improve organ function and alleviate the inflammatory storm, which is an effective means to improve the rescue rate and reduce the mortality of severe heat stroke patients.
9.Mechanism of Shenkang injection in treatment of renal fibrosis based on bioinformatics and in vitro experimental verification
Gao-Quan MENG ; Ming-Liang ZHANG ; Xiao-Fei CHEN ; Xiao-Yan WANG ; Wei-Xia LI ; Dai ZHANG ; Lu JIANG ; Ming-Ge LI ; Xiao-Shuai ZHANG ; Wei-Ting MENG ; Bing HAN ; Jin-Fa TANG
Chinese Pharmacological Bulletin 2024;40(10):1953-1962
Aim To explore the mechanism and mate-rial basis of Shenkang injection(SKI)in the treatment of renal fibrosis(RF)by bioinformatics and in vitro experiments.Methods The differentially expressed genes of RF were screened by GEO database.With the help of CMAP database,based on the similarity princi-ple of gene expression profile,the drugs that regulated RF were repositioned,and then the components of SKI potential treatment RF were screened by molecular fin-gerprint similarity analysis.At the same time,the core targets and pathways of SKI regulating RF were predic-ted based on network pharmacology.Finally,it was verified by molecular docking and cell experiments.Results Based on the GEO database,two RF-related data sets were screened,and CMAP was relocated to three common RF therapeutic drugs(saracatinib,da-satinib,pp-2).Molecular fingerprint similarity analysis showed that RF therapeutic drugs had high structural similarity with five SKI components such as salvianolic acid B and hydroxysafflor yellow A.Molecular docking results showed that salvianolic acid B,hydroxysafflor yellow A and other components had good binding abili-ty with MMP1 and MMP13,which were the core targets of SKI-regulated potential treatment of RF.Network pharmacology analysis suggested that the core targets of SKI were mainly enriched in signaling pathways such as Relaxin and AGE-RAGE.Cell experiments showed that SKI could significantly reduce the mRNA expres-sion levels of AGER,NFKB1,COL1A1,SERPINE1,VEGFC in AGE-RAGE signaling pathway and MMP1 and MMP13 in Relaxin signaling pathway in RF model cells,and significantly increase the mRNA expression level of RXFP1.Conclusions SKI can play a role in the treatment of RF by regulating Relaxin and AGE-RAGE signaling pathways,and its material basis may be salvianolic acid B,hydroxysafflor yellow A and other components.
10.Acceptance testing for MR simulator:guideline-based practice and result analysis
Cuiyun YUAN ; Xinyuan CHEN ; Chenbin LIU ; Yang LI ; Enzhuo QUAN ; Jianrong DAI
Chinese Journal of Medical Physics 2024;41(10):1199-1205
Objective Magnetic resonance simulator(MR Sim)is a novel type of simulation equipment utilized in radiotherapy.Acceptance testing is an essential quality assurance procedure prior to the clinical use of the MR Sim.The report provides the detailed procedures and result analysis of acceptance testing for an MR Sim.Methods The acceptance testing scheme was developed following the recently published AAPM TG284 report and the NCC/T-RT 002-2023 guidelines.Quality control equipments such as ACR(American College of Radiology)large phantom and geometric distortion measurement phantom were used for evaluating various aspects of the MR Sim,including the effectiveness of shielding,the functionality of imaging system,the image quality,the performance of radio frequency coils,the geometric accuracy of large field imaging,the precision of external laser markings,the couch movement accuracy,and the image transmission accuracy.Results The shielding effectiveness at a frequency of 150 MHz exhibited an average value of 105 dB.All of 8 image quality indices,namely geometric accuracy,slice position accuracy,slice thickness accuracy,image uniformity,artifact ratio,signal-to-noise ratio,high-contrast spatial resolution,and low-contrast resolution,fell within recommended tolerances.The maximum geometric distortion observed across a 25 cm field of view was less than 2 mm.The errors in external laser markings and couch movement accuracy were both less than 1 mm.The couch levelness was less than 1°.Both radio frequency coils and image transmission passed the required tests.Conclusion MR Sim is high-precision and complex.To ensure its precise application in radiotherapy,the acceptance testing for an MR Sim should be meticulously designed and executed following the established guidelines and accounting for its unique performance characteristics.


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