1.Three laboratory direct test methods for maximal oxygen uptake:Comparison,regression analysis and applications
Ling LIN ; Wenteng WU ; Jiaming LUO ; Kaiwen FAN ; Huaye WANG ; Zhiguang LI ; Xiaoping DUAN
Chinese Journal of Sports Medicine 2024;43(1):29-38
Objective To compare the discrepancies among results of three commonly used laboratory direct test methods for maximal oxygen uptake(VO2max),explore their linear regression relationships,mutual predictability and comparability.Methods Using a quasi-experimental design of cluster sampling and within-group interaction design,20 male cross-country skiers were tested for VO2max using the Bruce protocol(Method 1),90-second incremental load exercise on power bicycle(Method 2),and 1-minute incremental load exercise on treadmill(Method 3),with an interval of one week.The indepen-dent and dependent variable were the three VO2max test methods and the VO2max,respectively.Results Significant differences were found in the average VO2max of the three test results,with the value mea-sured by Method 1 ranking the first,followed by that assessed by Method 3 and Method 2(P<0.05).Moreover,the frequency of individual differences in the results of the three methods showed that the VO2max of Method 1 was about 6 and 3 ml/min·kg higher than that measured by Method 2 and 3.However,at the same treadmill speed,the average blood lactate evaluated using Method 3 was higher than Method 1,and the speed reached aerobic and anaerobic thresholds about one speed unit(1 km/h)lower than Method 1.Meanwhile,linear regression analyses of the test results between Method 1 and 2,as well as Method 1 and 3 showed that both the regression models and coefficients were statis-tically significant(P<0.001),with the R-squared values of 9.25 and 9.05,respectively.Conclusion The Bruce protocol performs best in assessing the maximum value of the athlete's VO2max phase,whose results have linear regression relationships with the other two methods,and can be used for pre-dicting their results.Moreover,athletes of different events and levels can choose different VO2max test methods accordingly.Lastly,the speed and heart rate ranges corresponding to the aerobic and anaero-bic thresholds can serve as an effective and convenient method to control the training intensity.
2.Genome-wide molecular characterization of a rare group A rotavirus equine-like DS-1-like G3P 8 in China
Guangping XIONG ; Yuhang WEI ; Rui PENG ; Jiaxin FAN ; Xiaoping TANG ; Zhimiao HUANG ; Mengjie DONG ; Ruyi CHE ; Dandi LI
Chinese Journal of Experimental and Clinical Virology 2024;38(1):29-36
Objective:A genome-wide molecular characterization of FJ21351116, a strain of G3P[8]-E2 2021 collected in Fujian, China, was performed.Methods:Whole genome sequencing of FJ21351116 was performed using a high-sensitivity group A rotavirus whole genome sequencing method. Genomic characteriza-tion of the virus was assessed by nucleic acid sequence analysis using MEGA 11.0, Geneious 9.0.2 and DNASTAR software. Neutralization epitopes of VP7 and VP4 (VP8*) were analyzed using BioEdit v. 7.0.9.0 and PyMOL v. 2.5.2.Results:In this study, FJ21351116 was shown to be a G3-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2 genotype, and the result of phylogenetic tree showed that the VP7, VP4, VP3, and NSP2-NSP5 genes of the FJ21351116 strain were related to the equine-like DS-1-like G3P[8] genes that have been detected in Japan in recent years. VP6, VP1, VP2, and NSP1 genes are closely related to G2P[4] in most countries, especially in Singapore, suggesting that this strain was formed by genetic reassortment during the evolution of equine-like G3P[8] and G2P[4]. Evolutionary relationships between the VP7/VP4 genes of FJ21351116 and Rotarix and RotaTeq vaccines suggest that the multiple mutations in both VP7 and VP4 (VP8*) neutralizing antigenic epitopes and vaccine amino acid sites. It is hypothesized that the Rotarix and RotaTeq vaccines may be less effective against equine DS-1-like G3P[8] RVA, and the sequence differences with Rotarix are higher than those with RotaTeq.Conclusions:In this study, we found a rare case of DS-1-like G3P [8] RVA strain in China. Currently, horse-like DS-1-like G3P [8] RVA is relatively rare in China and may be poorly protected by vaccine strains, emphasizing the importance of continuous monitoring of RVA strains and the development of efficient and full-coverage RVA vaccines.
3.Study on inhibitory effect of erythrocyte membrane camouflaged gefitinib nanoparticles on lung cancer-bearing nude mice
Yunxiu FAN ; Bo YANG ; Li ZHOU ; Xiaoping HUANG
Chongqing Medicine 2024;53(20):3041-3047,3054
Objective To prepare the erythrocyte membrane camouflaged gefitinib(GEF)nanomedi-cine,and to observe its in vivo half-life and blood drug concentration by using the lung cancer bearing nude mouse model and explore its tumor suppression effect and tumor suppression mechanism.Methods The GEF standard curve was established by HPLC.A549 tumor bearing nude mice were constructed and divided into the GEF group,GEF nanoparticles group(GEF-NPs group),erythrocyte camouflaged GEF nanoparticles group(RBC@GEF-NPs group).The plasma drug concentration at different time points was detected by HPLC,the cell cycle was detected by flow cytometry and the tumor cellular apoptosis was detected by TUNEL.Results The tumor volume in the RBC@GEF-NPs group was significantly smaller than that in the GEF group and GEF-NPs group(P<0.05);the in vivo half-life period in the RBC@GEF-NPs group was sig-nificantly longer than the GEF group and GEF-NPS group(18.90 h vs.2.44 h vs.10.50 h,P<0.05),and the difference was statistically significant(P<0.05);the GEF drug concentration in the tumor tissues of the RBC@GEF-NPs group was 48.5 ng/mg,which was 5 times and 2 times of that in the GEF group(10.8 ng/mg)and GEF-NPs group(24.7 ng/mg)respectively(P<0.05).Compared with the GEF group,the proportion of G0/G1 phase cells in the RBC@GEF-NPs group was increased from 55.5%to 71.35%(P<0.05)and which in the G2/M stage was decreased from 10.05%to 4.22%(P<0.05),which in the S stage was decreased from 34.62%to 24.43%(P<0.05);the cellular apoptosis index in the RBC@GEF-NPs group was significantly higher than that in the GEF group and GEF-NPs group[(23.42±2.47)%vs.(8.34±1.32)%vs.(14.32±2.59)%,P<0.05],and the differences were statistically significant.Conclusion RBC@GEF-NPs could in-crease the half-life and blood concentration of A549 lung cancer bearing nude mice,block and inhibit the lung cancer growth by promoting tumor cell apoptosis and G1 phase arrest.
4.Correlation of HER2 expression and clinicopathological characteristics in patients with urothelial carcinoma in China
Shanshan WANG ; Dingwei YE ; Li YANG ; Fan CHENG ; Tiejun YANG ; Xiaoping ZHANG ; Zhixian YU ; Qingyun ZHANG ; Yong YANG
China Oncology 2024;34(11):1011-1019
Background and purpose:Human epidermal growth factor receptor 2(HER2)is closely associated with drug efficacy and prognosis in urothelial carcinoma(UC).HER2 is a significant biomarker and therapeutic target in various tumors.In recent years,anti-HER2 antibody-drug conjugates have shown significant clinical efficacy in UC patients with HER2 overexpression.Therefore,an in-depth understanding of HER2 expression and its characteristics in Chinese UC patients is crucial to guide treatment decision-making,optimize treatment strategies and achieve personalized therapy.This study aimed to thoroughly investigate correlation of HER2 expression and clinicopathological characteristics in Chinese patients with UC.Methods:This study was a multicenter study that retrospectively included UC patients from urology departments of 8 tertiary hospitals in 5 geographical regions of China(North China,East China,South China,Central China and Northwest)whose tissue samples were collected from January 2023 to March 2024.Inclusion criteria:① age above 18 years;② UC diagnosed by histopathological or cytological examination;③ complete results of HER2 expression detection using immunohistochemistry(IHC)in the primary tumor site were required.Exclusion criteria:① diagnosed patients with tumors in other parts of the body;② physicians evaluated other situations that were not suitable for inclusion in this study.IHC results for HER2 expression and clinicopathological data were collected.HER2 expression was determined according to the criteria outlined in"Clinical pathological expert consensus on HER2 testing in urothelial carcinoma in China",with HER2 2+and 3+defined as HER2 overexpression.The HER2 expression and clinicopathological features were analyzed.This study was approved by the medical ethics committee of Fudan University Shanghai Cancer Center(ethical number:2301268-12)and was registered at China Clinical Trial Registry(registration number:ChiCTR2300069746).Results:A total of 1054 patients with UC were included.Most of the tumors were bladder UC(n=807,76.6%).The mean age of patients was(66.8±10.5)years,and the majority were male(78.5%).The HER2 overexpression rate was 58.4%(n=616),with an additional 23%of patients having HER2 1+expression(n=242),and a small proportion exhibiting negative HER2 expression(n=196,18.6%).HER2 expression was significantly associated with various clinical and pathological characteristics such as Eastern Cooperative Oncology Group(ECOG)performance status,history of cardiovascular disease,history of metabolic disorders,smoking,UC disease location,differentiation grade,pathological type,and tumor stage.Conclusion:Retrospective analysis of multi-center data shows that HER2 expression is frequently observed in Chinese UC patients,with an overexpression rate of up to 58.4%.Furthermore,HER2 expression is closely associated with various clinical and pathological features of UC patients.This study underscores the critical importance of accurately assessing HER2 expression in UC patient to guide personalized therapies.
5.Analysis of sequential chemotherapy efficacy in ovarian epithelial carcinoma, fallopian tube carcinoma and primary peritoneal carcinoma
Xiaoyan SHEN ; Xiaoping LI ; Yue WANG ; Yan WU ; Yi LI ; Yingchao YANG ; Lihui WEI ; Yuan FAN ; Ziqian TANG
Chinese Journal of Obstetrics and Gynecology 2024;59(5):383-390
Objective:To explore the sequential chemotherapy efficacy of different chemotherapeutic regimens in ovarian epithelial carcinoma, fallopian tube carcinoma, and primary peritoneal carcinoma.Methods:A retrospective analysis was conducted on clinical and pathological data of 100 patients with platinum-sensitive ovarian epithelial carcinoma, fallopian tube carcinoma, and primary peritoneal carcinoma treated at Peking University Peopel′s Hospital from January 1992 to January 2019. All patients underwent staging surgery or cytoreductive surgery followed by adjuvant chemotherapy. Based on different postoperative adjuvant chemotherapy regimens, patients were divided into the sequential chemotherapy group (70 cases) and the conventional chemotherapy group (30 cases). Clinical and pathological characteristics, chemotherapy efficacy, adverse reactions, and prognosis were compared between the two groups.Results:(1) Clinical and pathological characteristics: the age, tumor types (including ovarian epithelial carcinoma, fallopian tube carcinoma, and primary peritoneal carcinoma), pathological types, International Federation of Gynecology and Obstetrics (FIGO) stage, postoperative residual disease size, presence of neoadjuvant chemotherapy, and total number of chemotherapy cycles were compared between the sequential chemotherapy group and the conventional chemotherapy group. There were no statistically significant differences observed in these characteristics between the two groups (all P>0.05). (2) Chemotherapy efficacy: the median sum of complete response (CR)+partial response (PR) duration in the sequential chemotherapy group was 80.0 months (range: 39 to 369 months), whereas in the conventional chemotherapy group, it was 28.0 months (range: 13 to 52 months). A statistically significant difference was observed between the two groups ( Z=-7.82, P<0.001). (3) Chemotherapy adverse reactions: in the sequential chemotherapy group, 55 cases (79%, 55/70) experienced bone marrow suppression and 20 cases (29%, 20/70) had neurological symptoms. In the conventional chemotherapy group, these adverse reactions occurred in 11 cases (37%, 11/30) and 2 cases (7%, 2/30), respectively. Statistically significant differences were observed between the two groups for both bone marrow suppression and neurological symptoms (all P<0.05). For the other chemotherapy adverse reactions compared between the two groups, no statistically significant differences were observed (all P>0.05). (4) Prognosis: during the follow-up period, the recurrence rate in the sequential chemotherapy group was 73% (51/70) and in the conventional chemotherapy group was 100% (30/30). The median sum of recurrence-free interval was 70.5 months (range: 19 to 330 months) in the sequential chemotherapy group and 15.0 months (range: 6 to 40 months) in the conventional chemotherapy group. Statistically significant differences were observed between the two groups for both recurrence rate and median recurrence-free interval (all P<0.01).In the sequential chemotherapy group, the median progression-free survival (PFS) time was 84.0 months (range: 34 to 373 months), and the median overall survival (OS) time was 87.0 months (range: 45 to 377 months). In contrast, in the conventional chemotherapy group, the median PFS time was 30.5 months (range: 14 to 60 months), and the median OS time was 37.5 months (range: 18 to 67 months). Statistically significant differences were observed between the two groups for both PFS and OS (all P<0.001). In the sequential chemotherapy group, the 3-year, 5-year, and 10-year OS rates were 100% (70/70), 93% (65/70), and 21% (15/70), respectively. In contrast, in the conventional chemotherapy group, the OS rates were 50% (15/30) at 3 years, 3% (1/30) at 5 years, and 0 at 10 years, respectively. The two groups were compared respectively, and the differences were statistically significant (all P<0.05). Conclusions:Sequential chemotherapy significantly prolongs PFS and OS in patients with ovarian epithelial carcinoma, fallopian tube carcinoma, and primary peritoneal carcinoma. The efficacy is superior to that of the conventional chemotherapy, with manageable adverse reactions. The use of sequential chemotherapy as first-line treatment for patients with ovarian epithelial carcinoma, fallopian tube carcinoma, and primary peritoneal carcinoma is recommended.
6.Study on the Correlation between the Expression of Serum 25(OH)D and GDF1-5 Levels and the Risk of Malignancy in Combined Thyroid Nodules in Patients with Metabolic Syndrome
Xue FAN ; Wenpei QIN ; Yujiao TANG ; Xiaoping YANG
Journal of Modern Laboratory Medicine 2024;39(6):147-151,194
Objective To investigate the correlation between the expression of serum 25hydroxyvitamin D[25(OH)D]and growth differentiation factor 15(GDF-15)levels and the risk of malignancy in patients with metabolic syndrome(MS)and the development of combined thyroid nodules(TN).Methods From August 2019 to August 2023,185 MS patients who visited the First Affiliated Hospital of Xinjiang Medical University were regarded as the study subjects,according to the results of thyroid ultrasound examination,they were separated into MS group(n=73)and MS+TN group(n=112).According to the malignant grading of thyroid nodules,MS+TN patients were separated into benign group(n=89)and malignant group(n=23).Another 68 healthy individuals who underwent physical examinations were regarded as control group.Enzyme-linked immunosorbent assay(ELISA)was applied to determine the levels of serum 25(OH)D and GDF-15 in each group.Pearson was applied to analyze the correlation between serum 25(OH)D and GDF-15 levels and clinical indicators in MS in TN patients.Multivariate Logistic regression was applied to analyze the influencing factors of malignant TN in patients with MS combined with TN.Receiver operating characteristic(ROC)curve was plotted to evaluate the diagnostic value of serum 25(OH)D and GDF-15 levels in MS with malignant TN.Results Comparison of serum 25(OH)D(30.41±6.73 ng/ml,27.23±6.15 ng/ml,24.67±4.38 ng/ml)and GDF-15(167.99±22.56 ng/L,239.75±25.92 ng/L,286.63±26.04 ng/L)levels in control,MS and MS+TN groups,the differences were statistically significant(F=22.219,472.113,all P<0.05).Compared with the benign group,the serum 25(OH)D(26.28±4.53 ng/ml vs 18.44±3.79 ng/ml)level in the malignant group was obviously reduced,while the GDF-15(276.93±24.53 ng/L vs 324.17±31.89 ng/L)level was obviously increased,the differences were statistically significant(t=7.631,7.718,all P<0.05).The BMI,age,FPG,TG,TSH and TGAb levels of patients in the malignant group were obviously higher than those in the benign group,the difference were statistically significant(t=2.868,3.523,3.542,3.603,4.581,5.516,all P<0.05).Pearson correlation analysis,and the serum 25(OH)D level in MS patients with TN was negatively correlated with FPG,TSH,TG and TGAb levels(r=-0.302,-0.482,-0.524,-0.546,all P<0.001),while GDF-15 level was positively correlated with TG,TSH,TGAb and FPG levels(r=0.467,0.541,0.578,0.623,all P<0.05).Multivariate logistic regression analysis,GDF-15(OR=1.673,95%CI:1.146~2.442)was a risk factor for the occurrence of malignant TN in MS patients(P<0.05),and 25(OH)D(OR=0.744,95%CI:0.604~0.916)was a protective factor for the occurrence of malignant TN,the AUC values of serum 25(OH)D and GDF-15 levels in the diagnosis of MS combined with malignant TN were 0.813,0.799 and 0.930,respectively,and the combination was superior to the single diagnosis(Z=2.088,2.021,P=0.037,0.043).Conclusion The levels of serum 25(OH)D and GDF-15 in patients with MS combined with TN are obviously correlated with nodular nature.The decrease in serum 25(OH)D level and the increase in GDF-15 level are risk factors for malignant TN in MS patients.
7.Clinical characteristics and management status of Turner syndrome in 1 089 children
Yan LIANG ; Haiyan WEI ; Ruimin CHEN ; Zhixin ZHANG ; Xinran CHENG ; Na TAO ; Chunlin WANG ; Yu YANG ; Ying XIN ; Xin FAN ; Xingxing ZHANG ; Geli LIU ; Shengquan CHENG ; Min ZHU ; Hongwei DU ; Yan SUN ; Linqi CHEN ; Lanwei CUI ; Xiaoping LUO
Chinese Journal of Pediatrics 2024;62(10):962-968
Objective:To investigate the clinical characteristics and management status of children with Turner syndrome (TS) in China.Methods:As a cross-sectional study, 1 089 TS patients were included in the database of the National Collaborative Alliance for the Diagnosis and Treatment of Turner Syndrome from August 2019 to November 2023. Clinical characteristics (growth development, sexual development, organ anomalies, etc.), karyotypes, auxiliary examinations, and treatments were collected and analyzed.Results:Among the 1 089 TS cases, 809 were recorded karyotypes. The karyotype distribution was as follows: 45, X in 317 cases (39.2%), X chromosome structural variants (including partial deletions of p or q arm, ring chromosome, and marker chromosome) in 89 cases (11.0%), 45, X/46, XX mosaicism in 158 cases (19.5%), mosaicism with X chromosome structural variants in 209 cases (25.8%), and presence of Y chromosome material in 36 cases (4.4%). Among the 824 TS cases, the age of diagnosis was 9.7(6.4, 12.2) years, with a height standard deviation score (HtSDS) of -3.1±1.2. Five hundred and fifty three cases underwent growth hormone (GH) stimulation test, and 352 cases (63.7%) had GH peak values <10 μg/L and 75.9% (577/760) had low IGF1 levels, with IGF1 SDS ≤-2 accounting for 38.2% (290 cases). Among 471 cases aged ≥8 years, 132 cases (28.0%) showed spontaneous sexual development (mean bone age (11.0±1.7) years), 10 cases had spontaneous menarche (mean bone age (12.0±2.2) years), and 2 cases had regular menstrual cycles. Common physical features included cubitus valgus (311 cases (28.5%)), neck webbing (188 cases (17.2%)), low posterior hairline (185 cases (17.0%)), shield chest (153 cases (14.0%)), high arched palate (127 cases (11.6%)), short fourth metacarpal (43 cases (3.9%)), and spinal abnormalities (38 cases (3.5%)). Congenital cardiovascular and urogenital anomalies occurred in 91 cases (19.4%) and 66 cases (12.0%)respectively. Abdominal ultrasound in 33 cases (7.2%) indicated fatty liver, hepatomegaly, intrahepatic bile duct stones, and splenomegaly. Among 23 cases undergoing oral glucose tolerance test (OGTT) test, 2 were diagnosed with diabetes mellitus and 4 with impaired glucose tolerance. Following diagnosis, 669 cases (80.7%) received rhGH treatment at a chronological age of (9±4) years and bone age of (8.3±3.2) years. Additionally, 112 cases (19.4%) received sex hormone replacement therapy starting at the age of (14±4) years and bone age of (12.6±1.2) years.Conclusions:The karyotypes of 45, X and mosaicism were most common in Chinese children with TS. The clinical manifestations were mainly short stature and gonadal dysplasia. However, a few TS children could be in the normal range of height, and some cases among those aged of ≥8 years old had spontaneous sexual development. Some exhibited physical features, congenital cardiovascular and urogenital anomalies, and dysfunction of the hypothalamic-pituitary-IGF1 axis. Moreover, a few of them developed impaired glucose tolerance and diabetes mellitus. Following diagnosis, most of the patients received rhGH treatment, and a few of them received sex hormone replacement therapy.
8.The detection rate of the arc of Buhler by CTA and DSA:a meta-analysis
Luyao JI ; Gaowu YAN ; Hongwei LI ; Yong LI ; Linwei ZHAO ; Xiaoping FAN ; Jiantao DENG ; Jing YAN
Journal of Interventional Radiology 2024;33(6):604-609
Objective To discuss the detection rate of the arc of Bühler(AOB)in CTA and DSA examinations and its clinical significance.Methods A computerized retrieval of academic papers concerning AOB from the databases of PubMed,Web of Science,Scopus,Embase,Google Scholar,CBM,CNKI,WanFang,VIP and Baidu Scholar was conducted.Stata 17.0 software was used to make meta-analysis.Results A total of 11 articles including 3 837 subjects and 65 AOB cases were included in this analysis.The pooled prevalence of AOB was 1.9%(0.8%-3.2%).CTA showed a pooled prevalence of AOB of 2.0%(0.5%-4.3%)and DSA showed a pooled prevalence of AOB of 1.8%(0.5%-3.9%).Conclusion Clinically,AOB is a rarely-seen anatomical variation.The possibility of the presence of an AOB should be considered when performing the relevant abdominal surgery so as to avoid causing operation difficulties and complications such as abdominal visceral organ ischemia or bleeding.(J Intervent Radiol,2024,33:604-609)
9.Clinical efficacy of transcatheter tricuspid valve replacement in cardiac implantable electronic lead-related tricuspid regurgitation: A multi-center retrospective cohort study
Jingyi CAO ; Xiaoping NING ; Ning LI ; Fan QIAO ; Fan YANG ; Bailing LI ; Guangwei ZHOU ; Lin HAN ; Zhiyun XU ; Fanglin LU
Chinese Journal of Clinical Thoracic and Cardiovascular Surgery 2024;31(06):818-825
Objective To analyze the clinical efficacy of transcatheter tricuspid valve replacement (TTVR) in cardiac implantable electronic lead-related tricuspid regurgitation (TR). Methods The patients with severe TR who underwent LuX-Valve TTVR in 9 Chinese medical centers from June 2020 to August 2021 were retrospectively enrolled. They were divided into a cardiac implantable electronic device (CIED) group and a non-CIED group based on whether they had pre-existing CIED implantation. Success of the procedure was defined as safe implantation of the LuX-Valve and complete withdrawal of the delivery system. Prognostic improvement was defined as a decrease of TR grade to≤2+ and an improvement of cardiac function by≥2 grades. Surgical success and postoperative prognosis were compared between the two groups. Results A total of 190 patients were collected, including 50 males and 140 females with a mean age of 66.2±7.8 years. There were 29 patients in the CIED group, and 161 patients in the non-CIED group. In the CIED group, 28 patients were implanted with a permanent pacemaker and 1 patient with a cardioverter-defibrillator. Preoperative New York Heart Association (NYHA) cardiac function class, TR degree, left ventricular ejection fraction, tricuspid annular plane systolic excusion, and cardiac risk scores were comparable between the two groups (P>0.05). Postoperative TR was reduced to≤2+ in all patients, and there was no statistical difference in the incidence of perivalvular leakage between the two groups (P=0.270). Postoperative CT of CIED patients showed the valve was in place, and the lead was not extruded, twisted, or deflected. The in-hospital mortality of the two groups were 10.3% and 1.9%, respectively, and the difference was statistically significant (P=0.047). In addition, there was no statistical difference between the two groups in terms of postoperative improvement of cardiac function and mortality in the 1- and 2-year follow-up. Conclusion TTVR is feasible, safe, and effective in patients with CIED implantation, and the pre-existing lead has no significant effect on the clinical efficacy.
10.PET/MR attenuation correction method based on transmission scan
Shengnan FAN ; Xingzhao GUO ; Weidong MA ; Jun DENG ; Lei DENG ; Xiaoping LIU
Chinese Journal of Radiological Health 2024;33(5):499-504
Objective To propose a method for correcting the attenuation of positron emission tomography (PET) data in PET/magnetic resonance (MR) based on transmission scan, and to improve image quality, diagnostic accuracy, and lesion location accuracy. Methods In this study, the head phantom in the national standard GB/T 18988.1—2013 was used as the experimental model. The head phantom contained three 50 mm diameter cylindrical inserts filled with air, water, and solid teflon. The attenuation correction coefficients were calculated and analyzed based on transmission scan. Results With slice = 33 and theta = 0, the attenuation correction coefficient was the largest (about 7.5) when the coincidence line passed through the axis of the phantom. The spatial distribution of the attenuation correction coefficients clearly showed the positions of air insert and teflon insert, indicating that the attenuation correction coefficients calculated from transmission scan data were accurate. In the clinical verification experiment, the attenuation correction method based on transmission scan significantly improved the image quality and showed efficient attenuation correction. Conclusion This paper studied the attenuation correction method for PET data in PET/MR based on transmission scan. This method can improve the image quality. In the future work, the attenuation correction method of PET/MR will be further studied and optimized to facilitate clinical applications.

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