1.The Diversity of Filamentous Morphologies and Magnetic Sensitivity Modulated by Diverse MagR Expression in Bacteria
Ya-Fei CHANG ; Jing ZHANG ; Peng ZHANG ; Xiu-Juan ZHOU ; Meng-Ke WEI ; Tian-Tian CAI ; Pei-Qi HE ; Jun-Feng WANG ; Can XIE
Progress in Biochemistry and Biophysics 2026;53(5):1439-1456
Objective Magnetoreception, the remarkable ability of diverse animals to sense and utilize the geomagnetic field for orientation and navigation, remains a molecularly unresolved mystery in sensory biology. The putative magnetoreceptor (MagR, previously known as IscA1) is a highly conserved iron-sulfur protein implicated in both magnetoreception and iron metabolism; however, the functional diversity among its cross-species homologs remains poorly understood. Cellular morphology is a key genetically determined trait that can be altered through genetic or environmental modifications—a process known as cell morphology engineering. Constructing engineered cells with specific morphological features and magnetic sensitivity to achieve remote, non-invasive magnetic modulation represents a crucial goal in this field with significant application potential. Therefore, this study aims to systematically investigate the effects of MagR heterologous expression on bacterial morphology and magnetic sensing capabilities, screen for MagR-based magnetically sensitive morphology engineering pathways, and reveal the underlying molecular mechanisms. Methods We systematically screened 28 MagR homologous genes from diverse prokaryotic and animal taxa to evaluate their expression and corresponding phenotypic effects in Escherichia coli (E. coli). To compare the differential magnetic responses among bacteria expressing various recombinant MagR proteins, we utilized high-throughput automated bright-field microscopic imaging and scanning electron microscopy (SEM). Furthermore, comprehensive biochemical and biophysical characterizations of iron and iron-sulfur cluster binding were performed using Ferrozine colorimetric assays, electron paramagnetic resonance (EPR) spectroscopy, ultraviolet-visible (UV-Vis) absorption, and circular dichroism (CD) spectroscopy. Additionally, 100 mT static magnetic field (SMF) exposure experiments were conducted to assess magnetically tunable phenotypes, while the intrinsic magnetic properties of purified MagR proteins were directly measured using a superconducting quantum interference device (SQUID) magnetometer. Results Our results demonstrated that the heterologous expression of MagR homologs induced varying degrees of bacterial filamentation. From this comprehensive screen, two distinct morphological patterns were identified: hydra (Hydra vulgaris) MagR (hyMagR) promoted uniform cell elongation and filamentation, exhibiting robust magnetic sensitivity manifested as significantly enhanced filamentation under the 100 mT SMF. In contrast, pigeon (Columba livia) MagR (clMagR) induced only low-frequency, extreme filamentation (sporadically exceeding 80 μm) with a relatively weaker magnetic morphological response. Mechanistically, our data unambiguously proved that these phenotypic differences are primarily driven by distinct iron redox preferences rather than total cellular iron accumulation. Specifically, hyMagR preferentially binds ferrous iron (Fe2+), whereas clMagR favors ferric iron (Fe3+) and forms more stable iron-sulfur clusters. Intriguingly, although SQUID magnetometry showed that purified clMagR exhibited approximately five-fold higher mass magnetic susceptibility than hyMagR, its cellular magnetic response was weaker. We hypothesize that the Fe2+-preferred intracellular environment associated with hyMagR overexpression primes the cell for enhanced generation of reactive oxygen species (ROS) via the Fenton reaction. Exposure to an SMF synergizes with this primed redox state, triggering the bacterial SOS response and upregulating cell division inhibitors to efficiently induce uniform filamentation. Conclusion Our findings identify the Fe2+/Fe3+ redox state as a critical determinant of MagR-mediated morphological remodeling and magnetic responsiveness. This discovery suggests a potential strategy for engineering magnetically responsive cellular systems for synthetic biology applications, and provides a plausible framework, which potentially combines intrinsic protein magnetism with redox-state modulation, for further investigating the evolutionary mechanisms of MagR-mediated magnetoreception.
2.The Diversity of Filamentous Morphologies and Magnetic Sensitivity Modulated by Diverse MagR Expression in Bacteria
Ya-Fei CHANG ; Jing ZHANG ; Peng ZHANG ; Xiu-Juan ZHOU ; Meng-Ke WEI ; Tian-Tian CAI ; Pei-Qi HE ; Jun-Feng WANG ; Can XIE
Progress in Biochemistry and Biophysics 2026;53(5):1439-1456
Objective Magnetoreception, the remarkable ability of diverse animals to sense and utilize the geomagnetic field for orientation and navigation, remains a molecularly unresolved mystery in sensory biology. The putative magnetoreceptor (MagR, previously known as IscA1) is a highly conserved iron-sulfur protein implicated in both magnetoreception and iron metabolism; however, the functional diversity among its cross-species homologs remains poorly understood. Cellular morphology is a key genetically determined trait that can be altered through genetic or environmental modifications—a process known as cell morphology engineering. Constructing engineered cells with specific morphological features and magnetic sensitivity to achieve remote, non-invasive magnetic modulation represents a crucial goal in this field with significant application potential. Therefore, this study aims to systematically investigate the effects of MagR heterologous expression on bacterial morphology and magnetic sensing capabilities, screen for MagR-based magnetically sensitive morphology engineering pathways, and reveal the underlying molecular mechanisms. Methods We systematically screened 28 MagR homologous genes from diverse prokaryotic and animal taxa to evaluate their expression and corresponding phenotypic effects in Escherichia coli (E. coli). To compare the differential magnetic responses among bacteria expressing various recombinant MagR proteins, we utilized high-throughput automated bright-field microscopic imaging and scanning electron microscopy (SEM). Furthermore, comprehensive biochemical and biophysical characterizations of iron and iron-sulfur cluster binding were performed using Ferrozine colorimetric assays, electron paramagnetic resonance (EPR) spectroscopy, ultraviolet-visible (UV-Vis) absorption, and circular dichroism (CD) spectroscopy. Additionally, 100 mT static magnetic field (SMF) exposure experiments were conducted to assess magnetically tunable phenotypes, while the intrinsic magnetic properties of purified MagR proteins were directly measured using a superconducting quantum interference device (SQUID) magnetometer. Results Our results demonstrated that the heterologous expression of MagR homologs induced varying degrees of bacterial filamentation. From this comprehensive screen, two distinct morphological patterns were identified: hydra (Hydra vulgaris) MagR (hyMagR) promoted uniform cell elongation and filamentation, exhibiting robust magnetic sensitivity manifested as significantly enhanced filamentation under the 100 mT SMF. In contrast, pigeon (Columba livia) MagR (clMagR) induced only low-frequency, extreme filamentation (sporadically exceeding 80 μm) with a relatively weaker magnetic morphological response. Mechanistically, our data unambiguously proved that these phenotypic differences are primarily driven by distinct iron redox preferences rather than total cellular iron accumulation. Specifically, hyMagR preferentially binds ferrous iron (Fe2+), whereas clMagR favors ferric iron (Fe3+) and forms more stable iron-sulfur clusters. Intriguingly, although SQUID magnetometry showed that purified clMagR exhibited approximately five-fold higher mass magnetic susceptibility than hyMagR, its cellular magnetic response was weaker. We hypothesize that the Fe2+-preferred intracellular environment associated with hyMagR overexpression primes the cell for enhanced generation of reactive oxygen species (ROS) via the Fenton reaction. Exposure to an SMF synergizes with this primed redox state, triggering the bacterial SOS response and upregulating cell division inhibitors to efficiently induce uniform filamentation. Conclusion Our findings identify the Fe2+/Fe3+ redox state as a critical determinant of MagR-mediated morphological remodeling and magnetic responsiveness. This discovery suggests a potential strategy for engineering magnetically responsive cellular systems for synthetic biology applications, and provides a plausible framework, which potentially combines intrinsic protein magnetism with redox-state modulation, for further investigating the evolutionary mechanisms of MagR-mediated magnetoreception.
3.Association of different surrogate indicators of insulin resistance with diabetic retinopathy
Xue HUANG ; Peng ZHAO ; Juan ZHANG ; Yaxin ZHAO
International Eye Science 2026;26(3):499-505
AIM:To investigate the associations of triglyceride glucose(TyG)index, triglyceride glucose-body mass index(TyG-BMI), and homeostatic model assessment of insulin resistance(HOMA-IR)with diabetic retinopathy(DR), and to evaluate their diagnostic value.METHODS: This study was a single-center retrospective study. Patients with type 2 diabetes mellitus(T2DM)who were hospitalized in the endocrinology department of 3201 Hospital from January 1, 2023 to March 1, 2025 were included. According to the diagnostic criteria for DR, participants were classified into DR group and non-DR(NDR)group. Then the association of TyG index, TyG-BMI, and HOMA-IR index with DR of the two groups of patients were alalyzed.RESULTS:A total of 969 patients with T2DM were enrolled in this study, including 816 patients in the DR group. Among DR group, 271 were males(33.2%)and 545 were females(66.8%), with a mean age of 56.78±11.88 years. The NDR group consisted of 153 patients, including 41 males(26.8%)and 112 females(73.2%), with a mean age of 59.40±10.52 years. Statistically significant differences were observed between the DR group and the NDR group in terms of age, BMI, TyG index, TyG-BMI, HOMA-IR index, fasting blood glucose(FBG), 2-h postprandial blood glucose(2 hPBG), fasting insulin(FINS), 2-h postprandial insulin(2 hPINS), fasting C-peptide(FCP), 2-h postprandial C-peptide(2 hPCP), total cholesterol(CHO), triglyceride(TG), low-density lipoprotein(LDL-C), blood urea nitrogen(BUN), uric acid(UA), direct bilirubin(DBIL), glycated hemoglobin(HbA1c), milligrams per total protein(M-TP), microalbuminuria(MALB), urinary albumin to creatinine ratio(UACR), 24-hour urine protein, white blood cell(WBC), neutrophil(N), and platelets(PLT; all P<0.05), while no significant differences were found in the remaining indicators(all P>0.05). In multivariable Logistic regression, both TyG index(aOR=198.65, 95% CI: 66.73-591.41, P<0.001)and TyG-BMI(aOR=1.03, 95% CI: 1.02-1.04, P<0.001)remained independently positive associated with DR. Quartile analysis indicated a progressive increase in DR risk with ascending quartiles of TyG index and TyG-BMI(all Ptrend<0.001). In contrast, HOMA-IR was not significantly associated with DR. Restricted cubic spline analysis, fully adjusted for confounders, showed a nonlinear upward trend in DR risk with increasing TyG index(Pnonlinearity<0.001), whereas TyG-BMI exhibited a U-shaped association(Pnonlinearity<0.05). No significant association was found between HOMA-IR and DR after propensity score matching. Receiver operating characteristic(ROC)curve demonstrated area under curve(AUC)values of 0.870(95% CI: 0.839-0.901)for TyG index, 0.710(95% CI: 0.665-0.755)for TyG-BMI, and 0.657(95% CI: 0.608-0.706)for HOMA-IR.CONCLUSION:The TyG index and TyG-BMI are risk factors for DR. A dose-dependent increase in DR risk was associated with elevated TyG index values. TyG-BMI exhibited an inverted U-shaped relationship with DR risk. The TyG index had better diagnostic efficiency for DR compared to both TyG-BMI and HOMA-IR index.
4.Clinical characteristics and prognosis of immunotherapy for recurrent/metastatic nasopharyngeal carcinoma: a single-center retrospective analysis
WANG Haoqiang ; LIU Baiyang ; YANG Ning ; LIU Peng ; CHENG Donghai ; PENG Lijun ; WANG Xianci ; HUANG Xueqin ; DONG Enlai ; JIANG Yiming ; ZHOU Juan ; XIE Bo
Chinese Journal of Cancer Biotherapy 2026;33(1):84-90
[摘 要] 目的:探讨复发/转移性鼻咽癌(NPC)接受含PD-1单抗免疫治疗的临床特征和预后影响因素。方法:回顾性分析2019年3月至2024年7月期间南部战区总医院确诊的95例NPC患者的临床资料和外周血生化及免疫学指标。预后分析采用Kaplan-Meier曲线,组间比较使用Log-rank检验,采用Cox比例风险模型进行单因素和多因素分析。结果:95例患者中男性81例,女性14例,中位年龄49.72岁(16~74岁),Ⅳ期91例(95.79%),所有患者均采用免疫治疗,联合或不联合化疗方案治疗,中位无进展生存期(mPFS)为10.5个月,客观缓解率(ORR)70.53%,疾病控制率(DCR)89.47%,接受含铂治疗方案患者PFS相对更长,且差异有统计学意义。紫杉醇 + 顺铂 + 氟尿嘧啶(TPF)对比吉西他滨 + 顺铂(GP)和紫杉醇 + 顺铂(TP)显示出更长的PFS,但差异无统计学意义。不同PD-1单抗治疗组间的PFS未显示出有统计学意义的差异。单因素及多因素Cox回归分析结果显示,肿瘤复发状态、初始血浆EBV感染状态、治疗周期数、基线外周血SII是复发/转移性NPC患者接受PD-1抑制剂治疗疗效预测的独立相关因素(均P < 0.05),并且非复发患者、初始血浆EBV DNA阳性、接受 ≥ 4治疗周期、基线外周血SII < 772.81的患者接受PD-1抑制剂治疗预后相对更好。结论:在接受PD-1抑制剂治疗的复发/转移性NPC患者中,非复发患者、初始血浆EBV DNA阳性、≥ 4治疗周期且外周血SII < 772.81者PFS相对更长,可早期识别免疫治疗效果不佳患者并精准干预。
5.Gene Mutation Analysis of an Individual with a RHD Variant RHD*DV.5 and RHD Negative Gene Heterozygote
Shi-Shi WU ; Juan PENG ; Li-Bo WU ; Hong-Xiao CHEN ; Dong-Mei ZHAN ; Yue-Mei DONG ; Wan-Qin WANG ; Liang WU
Journal of Experimental Hematology 2025;33(6):1758-1764
Objective:To perform RHD gene detection on a blood sample with serological weak D phenotype.Methods:A specimen received by the People's Hospital of Zhijin County was serologically identified by the microcolumn gel method and saline method.RHD gene detection was conducted by the PCR-SSP method,and the full sequence determination of the 10 exons amplified was performed.The sequencing results were compared with the ISBT database to determine the genotype.Bioinformatics tool was used to predict the functional damage of mutant proteins,and Alphafold-3 was used for tertiary structural modeling of wild-type and mutant RhD proteins,and the structures of the two proteins were compared and analyzed to explore the reasons why mutations lead to weak serological manifestations.Results:The patient's genotype was identified as RHD*DV.5/RHD*01N.01 heterozygote,with the complete deletion of RHD genes on one chromosome,unable to express the D antigen.On the other chromosome,a G>A mutation occurred at the 697th base of the 5th exon,resulting in a partial D phenotype.This mutation causes internal hydrogen bond changes at the 233 position of RhD protein,resulting in a change in the conformation of the protein,affecting binding to the corresponding antibody.Conclusion:The patient is a heterozygous mutant individual with RHD*DV.5/RHD*01N.01,exhibiting a partial D phenotype serologically.This variation is extremely rare and has been scarcely reported globally.
6.The effect of prevention and control measures on drinking water-borne endemic fluorosis in Taiyuan City from 2019 to 2024
Yanyan LI ; Jing LIU ; Ping ZHANG ; Xiaoyong WEI ; Juan DU ; Xiaojia ZHANG ; Tingting PENG ; Ruijun ZHANG
Chinese Journal of Endemiology 2025;44(11):895-900
Objective:To investigate the water improvement status and current disease situation in drinking water-borne endemic fluorosis areas of Taiyuan City, evaluate the effect of prevention and control measures, and provide a basis for optimizing control measures.Methods:Monitoring data from 2019 to 2024 for drinking water-borne endemic fluorosis in the diseased areas in Taiyuan City were collected from the Taiyuan Center for Disease Control and Prevention. A retrospective analysis was conducted on water improvement status, water fluoride content, dental fluorosis in children aged 8 - 12, skeletal fluorosis, and urinary fluoride monitoring results in all endemic villages.Results:From 2019 to 2024, all endemic villages in the six endemic counties (districts) of Taiyuan City completed water improvement. The number of water improvement projects each year was 75, 75, 72, 68, 64, and 57, respectively, with all projects operating normally. The qualified rates of water fluoride content each year were 81.33% (61/75), 100% (75/75), 98.61% (71/72), 75.00% (51/68), 87.50% (56/64), and 75.44% (43/57), respectively, with statistical significant differences ( χ2 = 36.99, P < 0.001). The detection rates of dental fluorosis each year were 18.19% (600/3 298), 14.42% (530/3 676), 11.14% (435/3 904), 11.13% (421/3 781), 11.59% (435/3 754), and 5.37% (299/5 567), respectively, with statistical significant differences ( χ2 = 386.42, P < 0.001). In 2024, 824 people were screened for skeletal fluorosis, with 250 cases showing positive symptoms and signs. Among the 250 positive cases, 210 underwent X-ray examination, detecting 170 skeletal fluorosis patients, with an X-ray positive rate of 80.95% (170/210) and a skeletal fluorosis detection rate of 20.63% (170/824). Urinary fluoride monitoring results showed that the geometric mean of urinary fluoride in villages with excessive water fluoride content was 2.95 mg/L, which was higher than the normal upper limit (1.60 mg/L). However, there was no statistically significant difference in urinary fluoride levels between skeletal fluorosis patients and non-skeletal fluorosis individuals ( Z = 0.78, P = 0.434). Conclusions:From 2019 to 2024, the drinking water-borne endemic fluorosis areas in Taiyuan City have undergone comprehensive water improvement and the water improvement projects are operating well. The qualified rate of water fluoride content has fluctuated, while the detection rate of dental fluorosis has decreased. Continuous monitoring is needed in the future to implement long-term water improvement measures and strengthen screening and treatment efforts for patients with fluorosis.
7.The correlation between serum osteopontin, annexin A2 and recurrence after partial laryngectomy in patients with early-stage glottic laryngeal cancer
Zhenxing PENG ; Juan BAI ; Wei JI ; Jinshu YIN ; Hong PENG ; Xiaohong CHEN
Chinese Journal of Postgraduates of Medicine 2025;48(7):584-590
Objective:To explore the relationship between serum osteopontin (OPN), annexin A2 (ANXA2) and recurrence after partial laryngectomy in patients with early-stage glottic laryngeal cancer (EGC).Methods:A retrospective study was conducted by collecting clinical data from EGC patients who underwent partial laryngectomy at Beijing Shijitan Hospital from June 2020 to May 2022. Serum levels of OPN and ANXA2 were measured at the time of admission. Clinical data during the perioperative period were also collected. The recurrence within 2 years after surgery was used as the endpoint event. Patients were divided into a recurrence group and a non-recurrence group based on the occurrence of recurrence. The data were compared between the groups, and Cox regression was used to analyze the correlation between recurrence after partial laryngectomy and key factors. Receiver operating characteristic (ROC) curve and decision curve were used to evaluate the predictive value of serum OPN and ANXA2 for recurrence within 2 years after surgery.Results:Among 167 EGC patients, 42 patients experienced recurrence within 2 years after surgery (recurrence group), with a median recurrence time of 16.00 (13.75, 19.25) months, and a recurrence rate of 25.15%; 125 patients did experience recurrence within 2 years after surgery (non-recurrence group). Compared to the non-recurrence group, the proportions of poorly differentiated tumors and anterior commissure invasion in the recurrence group were higher, the serum levels of OPN, ANXA2 and testosterone were higher: 52.38% (22/42) vs. 20.80% (26/125), 52.38% (22/42) vs. 20.00% (25/125), (24.26 ± 4.64) μg/L vs. (18.83 ± 4.17) μg/L, (37.62 ± 6.15) μg/L vs. (31.24 ± 5.56) μg/L, (27.26 ± 5.31) nmol/L vs. (22.85 ± 4.62) nmol/L, with significant differences ( P<0.05). Cox regression analysis result showed that recurrence after partial laryngectomy in EGC patients was potentially related to tumor differentiation, anterior commissure invasion, and abnormal serum expression of OPN, ANXA2 and testosterone ( P<0.05). ROC curve analysis revealed that serum OPN and ANXA2 had an area under the curve of 0.80 and 0.79, respectively, showing predictive value, with optimal cutoff values of 21.40 and 34.72 μg/L. Decision curve analysis indicated that serum OPN and ANXA2 had predictive significance for recurrence after partial laryngectomy in EGC patients, and the combined use of pathological grade, anterior commissure invasion, and testosterone improved the net benefit. Conclusions:Recurrence after partial laryngectomy in EGC patients may be associated with elevated serum OPN and ANXA2 levels, which could increase the risk of postoperative recurrence. Early detection of serum OPN and ANXA2 could be valuable for predicting recurrence after surgery in EGC patients.
8.Development and validation of a risk prediction model for non-cuffed catheter dysfunction in hemodialysis patients
Haiqiang JIANG ; Juan GONG ; Shuang WU ; Jia PENG ; Chuanfang WU
Chinese Journal of Nursing 2025;60(19):2313-2320
Objective To develop and validate a risk prediction model for non-cuffed catheter(NCC)dysfunction in hemodialysis patients,aiming to provide a reference for early clinical identification and warning.Methods A prospective study design was adopted.A total of 569 patients with indwelling NCC from the hemodialysis center of a tertiary hospital in Nanchang between December 1,2023 to May 20,2024,were included as a modeling cohort.An additional 172 patients from the hemodialysis center of a tertiary hospital in Changsha,enrolled between May 30 to October 20,2024,formed a validation cohort.Data were collected on general patient characteristics,dialysis information,catheterization details,and clinical parameters.The risk prediction model was constructed using a combination of variables identified through univariate analysis,Lasso regression,logistic regression,and the Boruta algorithm.Model performance was evaluated accordingly.Results The incidence of NCC dysfunction in hemodialysis patients was 44.94%.A total of 5 common predictors were identified by both algorithms,including age,ultrafiltration volume,catheter insertion site,catheter indwelling time,and C-reactive protein.The area under the receiver operating characteristic curve(AUC)was 0.720 for internal validation and 0.766 for external validation.The Brier scores for curve calibration were 0.213 and 0.203,respectively.The decision curve analysis showed clinical benefit within risk threshold ranges of 22%~82%and 22%~96%,respectively.Conclusion The risk prediction model developed in this study demonstrates good predictive performance and can serve as a screening and assessment tool for identifying the risk of NCC dysfunction in hemodialysis patients.
9.Enriching Vitamin C in Tomato Fruits by CRISPR/Cas9-Mediated SlCSN5B Gene Editing
Xuan-Sen AN ; Yan-Wei WANG ; Wen-Chao TIAN ; Ya-Juan REN ; Peng-Fei AI
Chinese Journal of Biochemistry and Molecular Biology 2025;41(3):460-469
Subunit 5B of constitutively photomorphogenic 9 signalosome(CSN5B)is an inhibitory factor for the biosynthesis of vitamin C in the L-galactose synthesis pathway in plants.To create mutants with richer vitamin C in tomato fruits,a dual-target vector of pKSE402-SlCSN5Bwas constructed and trans-formed into the breeding parent of 1912.Based on the molecular biological assay and DNA sequencing,17 transgenic positive lines were determined,and 6 lines of them were genetically mutated at the target site of SlCSN5B,with an editing efficiency of 35.3%.Among the mutants,2 lines were homozygous mu-tants,csn5b-6 with 180 bp deletion and csn5b-8 with 3 bp deletion.The biological traits of two types of deficiency homozygotes without exogenous T-DNA insertion derived from the T1 generation were observed,and there were no significant differences in phenotypes of the plant and fruit.Through physiological tes-ting of red-ripe fruits from T,generation lines of csn5b-6,the GMPase activity and the vitamin C content significantly increased by 43%and 37.8%,respectively,the content of hydrogen peroxide significantly decreased by 25.9%,and the content of soluble solids did not obviously change,compared with the wild type.There were no significant differences in plant traits and physiological characteristics between T1 gen-eration lines of csn5b-8 and the wild type.Based on gene expression analysis and protein structure predic-tion,the results showed that the gene of SlCSN5B normally transcribed,and the loss of large peptide seg-ments of CSN5B encoded by SlCSN5B caused changes in its structure to affect functioning,which led to an increase of vitamin C content in the line of csn5b-6-1 1.The findings suggest that the vitamin C content of tomato fruit can be improved by CRISPR/Cas9-mediated SlCSN5B gene editing,which provides the valuable resources for high-quality breeding in tomato.
10.The effect of the out-of-plane shield on the tube current and radiation dose of CT examination
Juan ZHOU ; Yuxin HAN ; Peng QU ; Rong LÜ
Journal of Practical Radiology 2025;41(4):669-672
Objective To explore the effect of different ways of out-of-plane shield on the tube current and cumulative radiation dose of CT scan.Methods The CT water membrane was scanned using Philips 128 row iCT scanner in different scanning methods:the 1-3 times,without the out-of-plane shield,the total length of localizer was 150 mm,270 mm,and 390 mm,respectively;the fourth time,the out-of-plane shield was used but was not present in the localizer;from the 5th to 7th pass,with out-of-plane shield and develop it in the localizer,with out-of-plane shield development lengths of 60 mm,180 mm,and 300 mm,respectively,and the out-of-plane shield was not within the formal scanning range.The tube current and cumulative radiation dose of various scanning methods were compared and a line graph of the tube current for scanning each layer was figured.Results(1)There was no statistically significant difference in tube current when there was no out-of-plane shield but the length of the localizer was different(P>0.05).(2)When the pitch was 0.8,1.0,and 1.15 respectively,with out-of-plane shield but no shield object in the localizer,the scanning tube current was lower than that without shield scanning(P<0.05).(3)When scanning with three different lengths of out-of-plane shield(60 mm,180 mm,300 mm)in the localizer,regardless of the pitch,the tube current was greater than that of unshield scanning(P<0.05).(4)When there was a shield in the localizer,the closer to the shield,the higher the tube current in the formal scan.(5)The cumulative dose of scans with out-of-plane shield but without the presence of shield in the localizer was smaller than that of unshield scanning.However,with shield and the presence of shield scanning in the localizer,the cumulative radiation dose was greater than that of unshield scanning.Conclusion The presence of out-of-plane shield in the localizer may increase the tube current and radiation dose for formal scanning,and the closer to the shield,the more significant the increase in tube current.

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