目的 通过建立大鼠泛耐药铜绿假单胞菌肺炎模型,对其进行联合用药,观察疗效,以便为治疗泛耐株引起的感染提供理论基础。方法 选择体外药敏实验中各药物组合同时有效的一株铜绿假单胞菌建立小鼠肺炎模型,于感染后6小时给药,对照组腹腔注射0.5 mL生理盐水,治疗组分别用头孢他啶+阿米卡星+环丙沙星以及头孢他啶+阿米卡星+环丙沙星+氨氯地平两组用药方案连续治疗三天后,根据肺组织匀浆细菌计数及病理结果评价疗效。结果 体内药敏试验显示用药组不管有无氨氯地平干预,对细菌的清除作用与对照组比较差异有统计学意义(P﹤0.05),而两用药组之间比较,差异无统计学意义。结论 对泛耐药铜绿假单胞菌感染后肺炎模型,联合应用体外单药药敏试验耐药的抗菌药后对细菌仍有一定的清除作用,但加入氨氯地平干预未显示有明显的治疗效应。

目的 比较肺炎支原体肺炎(MPP)、非MPP患儿和健康儿童的免疫球蛋白、补体水平,以探讨儿童MPP体液免疫指标的变化规律。方法 分别检测52例MPP、55例非MPP患儿和33例健康儿童的血清免疫球蛋白(IgG、IgA、IgM)、补体(C3、C4),并比较儿童MPP急性期和恢复早期体液免疫指标。结果 MPP组急性期血清IgM、C3、C4水平高于非MPP组急性期和健康儿童(P<0.05)。儿童MPP恢复早期IgM水平高于急性期,C4水平低于急性期(P<0.05)。结论 与非MPP和健康儿童比较,MPP患儿存在明显体液免疫功能紊乱,从急性期到恢复早期,血清IgM逐渐升高,补体C4先升高后降低,自身免疫反应可能参与了儿童MPP的发病过程。

Objective To investigate the changes of serum immunoglobulins and complement in children with mycoplasma pneumoniae pneumonia (MPP). Methods 52 children with MPP, 55 children with non-MPP and 33 healthy children were enrolled. The levels of serum immunoglobulins (IgG, IgA and IgM) and complements (C3, C4) were detected. Results Compared with the non-MPP group and healthy control, the levels of IgM, C3 and C4 in MPP group during their acute phase were significantly higher (P<0.05). And among the MPP group the levels of IgM were hisher and C4 were lower than that in the acute phase. Conclusion Immune function disturbance exists in children with MPP. From acute to recovery stage, the level of IgM increased while C4 increased firstly and then decreased. Immune injury may be involved in the pathophysiology of childhood MPP.

目的 分析基层医院ICU VAP的危险因素及病原学情况。方法 回顾性分析2013年1月—2014年12月本院ICU收治的机械通气>48 h 的118例患者,分VAP组和非VAP组,分析VAP的危险因素及病原学情况。结果 VAP组与非VAP组在紧急气管插管,机械通气时间,抗生素种类,糖皮质激素,PPI及镇静药物使用>7天,返流,MODS,ICU停留时间的项目,两组比较差异有统计学意义。紧急插管:52.2％ vs 31.9％,P＝0.029;机械通气时间:(9.8±3.5)vs(7.3±2.8)天,P＝0.038;抗生素种类>2种:52.2％ vs 26.4％,P＝0.005;使用糖皮质激素:56.5％ vs 27.0％,P＝0.001;PPI使用>7天:65.2％ vs 40.3％,P＝0.008;镇静药物使用>7天:58.7％ vs 38.9％,P＝0.035;返流:50％ vs 29.2％,P＝0.022;合并MODS:47.8％ vs 22.2％,P＝0.004;ICU停留时间:(13.6±6.6)vs(10.2±5.3)天,P＝0.023。使用糖皮质激素、机械通气时间、ICU停留时间是VAP的独立危险因素(多因素Logistic分析的OR值:2.481、1.234、1.075)。基层医院ICU VAP主要以革兰氏阴性菌(82.3%)为主。结论 使用激素、机械通气时间、ICU停留时间是基层医院ICU VAP的独立危险因素;而VAP病原菌感染以G-菌为主,可经验使用G-菌敏感的抗生素。

Objective To analyze pathogens and risk factors of VAP in a general ICU of a primary hospital. Methods Totally 112 patients(from 2013-01 to 2014-12) under mechanical ventilation over 48 h were retrospectively studied. The patients were assigned into VAP group and non-VAP group. The independent risk factors and pathogens of VAP were analyzed. Results There was significant difference between VAP group and non-VAP group in terms of emergent tracheal intubation, MV time, types of antibiotics used, the use of hormones,the use of PPI and sedative drugs for more than 7 days, regurgitation, MODS, ICU stay time. Emergent tracheal intubation:52.2％ vs 31.9％,P＝0.029;MV time:9.8±3.5day vs 7.3±2.8day,P＝0.038;types of antibiotics used > 2 kinds:52.2％ vs 26.4％,P＝0.005;the use of hormones:56.5％ vs 27.0％,P＝0.001;the use of PPI >7day:65.2％ vs 40.3％,P＝0.008;the use of sedative drugs >7day:58.7％ vs 38.9％,P＝0.035;regurgitation:50％ vs 29.2％,P＝0.022;MODS:47.8％ vs 22.2％,P＝0.004;ICU stay time:13.6±6.6day vs 10.2±5.3day,P＝0.023. The use of hormones,MV time, ICU stay time were the independent risk factors of VAP[odds ratio(OR) of multivariate logistic regression:2.481、1.234、1.075]. The main pathogens of VAP were gram-negative bacteria (82.3%). Conclusion The study shows that the use of hormones,MV time, ICU stay time are the independent risk factors of VAP; gram-negative bacteria are the main pathogens of VAP. Once VAP occurs, they can be treated with anti-gram-negative bacteria antibiotics.

目的 建立胎儿左、右肺面积及肺头比的正常参考值范围。方法 对501例正常单胎妊娠12～40周胎儿在标准四腔心切面应用手工描绘法分别描迹左肺、右肺面积,分别除以头围获得左、右肺头比。结果 获得正常妊娠胎儿左、右肺面积及肺头比各孕周参考值范围。胎儿左、右肺面积及肺头比均随孕周的增长而增大。结论 正常妊娠胎儿左、右肺面积及肺头比与孕周呈正相关。不同孕周LHR参考值的建立有利于临床评价膈疝及其他胸腔占位性疾病的预后。

Objective To establish reference intervals for fetal left and right lung areas and lung area to head circumference ratio (LHR). Methods In 501 cases of normal singleton pregnancy between 12 to 40 weeks, the left and right lung areas were measured respectively by ultrasound in the standard four chamber view, using manual tracing of the limits of the lungs. The left and right LHR were calculated when head circumferences were divided by the left and right lung area. Results Normal fetal reference intervals of left and right lung areas and LHR with gestational age were obtained. Fetal left and right lung areas and LHR increased with gestational age. Conclusion Fetal left and right lung areas and LHR values positively correlated with gestational age in normal pregnancy. Normal reference intervals of fetal LHR for every gestational age are valuable for evaluation of prognosis of fetal diaphragmatic hernia and other pulmonary peripheral space-occupying lesions.

目的 构建抑癌基因SEMA3B真核表达载体pcDNA3.1-SEMA3B,并检测其对肺癌A549细胞恶性生物学行为的影响。方法 应用PCR扩增SEMA3B全长cDNA片段,构建真核表达载体pcDNA3.1-SEMA3B。克隆PCR、双酶切法、基因测序验证过表达载体构建成功。将pcDNA3.1-SEMA3B真核表达载体和空载体pcDNA3.1分别转染入A549细胞中,应用qRT-PCR、Western blot检测SEMA3B mRNA、蛋白表达水平的变化;MTS法检测细胞增殖;流式细胞仪检测细胞凋亡、细胞周期;克隆形成实验检测细胞集落形成能力。结果 SEMA3B基因扩增片段与预测片段一致,克隆成功,且测序鉴定证实真核表达载体构建成功。转染pcDNA3.1-SEMA3B真核表达载体可上调SEMA3B mRNA、蛋白表达水平,且可抑制A549细胞的增殖,诱导凋细胞亡,细胞被阻滞在G1期,抑制细胞集落形成能力。结论 成功构建了SEMA3B基因真核表达载体,抑癌基因SEMA3B在肺癌恶性生物学进程中可能发挥重要作用。

Objective To construct the eukaryotic expression vector of the cancer suppressor gene, SEMA3B, and research the effects on malignant biological behavior of lung cancer A549 cells. Methods By reverse transcriptase-polymerase chain reaction (RT-PCR), the full length SEMA3B gene was amplified and then was inserted into pcDNA3.1. The recombinant plasmid pcDNA3.1-SEMA3B was confirmed correctly through double enzyme digestion and PCR identification, which was transfected into lung cancer A549 cells by lipid media transfection. The untransfected A549 and A549 transfected with pcDNA3.1 were used as controls. SMEA3B gene was detected by qRT-PCR and western blot. MTS assay, flow cytometry, and colony formation test were performed to evaluate the effect of overexpression of SEMA3B gene on A549 cell proliferation, apoptosis, cell cycle, and colony forming ability. Results The amplied fragment of SEMA3B gene by PCR was consistent with the anticipated result, the SEMA3B gene was cloned successfully. And the recombinant plasmid pcDNA3.1-SMEA3B was constructed successfully through gene sequence identification. After transfection of pcDNA3.1-SEMA3B, SEMA3B mRNA and protein expression levels were raised, and overexpression of SEMA3B gene in A549 cells significantly inhibited the proliferation of A549 cells, induced apoptotic cell death, blocked cell cycle in the G1 phase, and suppressed cell colony-forming ability. Conclusion The recombinant pcDNA3.1-SEMA3B is constructed successfully. SEMA3B gene can significantly inhibit the malignant biological behavior of lung cancer A549 cells.

       随着糖尿病患者的增加,因肺炎住院的糖尿病患者数也呈现出明显上升趋势。由于糖代谢紊乱及机体免疫功能下降等因素,细菌在高血糖的机体环境中快速繁殖并分泌大量毒素,增加了抗菌药物使用的时间跨度和细菌清除难度,对患者预后造成了极大的威胁。文章主要对糖尿病合并细菌性肺炎患者的病原学特征、耐药情况及药物治疗等进行阐述,旨在进一步为临床预防和治疗提供参考依据。

        With the increasing incidence in diabetes, the number of hospitalized diabetes patients with pneumonia is also increasing. Due to factors such as glucose metabolism disorders and decreased immune function in the body, bacteria rapidly multiply and secrete a large amount of toxins in the hyperglycemic environment,increasing the duration of antibiotic use and the difficulty of bacterial clearance, posing a great threat to patient prognosis. This article mainly elaborates on the pathogenic characteristics, drug resistance, and drug treatment of diabetes patients with bacterial pneumonia, aiming to provide reference for the clinical prevention and treatment.

       目的   探讨支气管镜灌洗用于儿童重症肺部感染合并肺实变的治疗效果及对CT特征、肺功能的影响。方法   选取2022年5月—2024年5月铜仁市人民医院收治的100例重症肺部感染合并肺实变患儿开展前瞻性研究，应用随机数表法分为对照组和观察组，每组各50例。对照组患儿采取常规治疗，观察组则采取常规治疗加支气管镜灌洗治疗。对比其临床疗效，治疗前后炎症因子、CT特征及肺功能变化。结果   观察组治疗总有效率高于对照组（P＜0.05）；治疗后观察组患儿白细胞计数（10.36±2.52）×10⁹ /L、白细胞介素-6（20.57±5.05）ng/L、C反应蛋白（13.12±2.64）mg/L、降钙素原（101.62±12.16）pg/L均低于对照组白细胞计数（13.25±3.32）×10⁹ /L、白细胞介素-6（31.69±4.11）ng/L、C反应蛋白（16.16±4.44）mg/L、降钙素原（113.46±18.11）pg/L（P＜0.05）；治疗后两组患儿胸腔积液、支气管壁增厚、空气支气管征、肺部实变、磨玻璃影等相关CT影像特征占比下降，且观察组低于对照组（P＜0.05）；治疗后两组患儿呼气流量峰值水平均升高，观察组（90.67±18.45）L/s高于对照组（81.27±17.69）L/s，用力肺活量水平均更高，观察组（3.33±0.68）L高于对照组（2.68±0.25）L（P＜0.05）。结论   针对儿童重症肺部感染合并肺实变，在常规治疗基础上增加支气管镜灌洗可提升临床疗效，减轻机体炎症反应，改善胸部CT各种表现及肺功能。

        Objective  To explore the therapeutic effects of bronchoalveolar lavage in children with  severe pulmonary infection complicated by lung consolidation and its impact on CT features and pulmonary function．Methods A prospective study was conducted on 100 children with severe pulmonary infection complicated with pulmonary consolidation in a hospital from May 2022 to May 2024．They were randomly divided into observation group and control group using a random number table method，50 cases in each group．The control group of children received routine treatment，and the observation group received conventional treatment plus bronchoalvelar lavage．Clinical efficacy，inflammatory factors，CT features，and alterations in pulmonary function before and after therapy were compared．Results  The total effective rate of the observation group was higher than that of the control group（P＜0.05）．After treatment，the white blood cell count（10.36±2.52）×10⁹ /L，interleukin-6（20.57±5.05）ng/L，C-reactive protein（13.12±2.64）mg/L，and procalcitonin（101.62±12.16）pg/L in the observation group were all lower than those in the control group（13.25±3.32）×10⁹ /L，interleukin-6（31.69±4.11）ng/L，C-reactive protein（16.16±4.44）mg/L，and procalcitonin（113.46±18.11）pg/L（P＜0.05）．After treatment，the proportion of CT imaging features such as pleural effusion，bronchial wall thickening，air bronchogram sign，lung consolidation，ground glass opacities，decreased in both groups of children，and the observation group was lower than the control group（P＜0.05）．After treatment，the peak levels of expiratory flow in both groups of children increased，with the observation group（90.67±18.45）L/s higher than the control group（81.27±17.69）L/s．The forced vital capacity levels were also higher，with the observation group（3.33±0.68）L higher than the control group（2.68±0.25）L（P＜0.05）．Conclusions  Adding bronchoalvelar lavage to routine treatment for children with severe pulmonary infection complicated with pulmonary consolidation can improve their clinical efficacy，alleviate inflammatory reactions，and improve various chest CT manifestations and lung function．

       目的     探讨CT增强延迟扫描技术在非小细胞肺癌术前诊断中的应用价值。方法    对2021年5月—2024年5月商丘市第一人民医院收治的82例非小细胞肺癌手术治疗患者进行回顾性分析，将其分为观察组，另选取82例肺部良性肿瘤患者作为对照组，收集其术前CT增强延迟扫描结果，以术后病理诊断结果为金标准，分析CT增强延迟扫描技术在非小细胞肺癌术前诊断中的应用价值。并对比不同临床病理特征非小细胞肺癌患者CT增强延迟扫描的CT增强值，采用Spearman相关性分析法分析CT增强值与非小细胞肺癌病理特征的关系。结果  CT增强延迟扫描显示观察组患者分叶征（12.50% vs 53.57%）、内部空泡征数量（6.25% vs 39.29%）低于对照组（χ ² =26.560、24.680，P＜0.05），观察组患者边缘毛刺（56.25% vs 17.86%）、胸部凹陷征（59.38% vs 14.29%）、高于对照组（χ ² =43.330、64.600，P＜0.05）；82例非小细胞肺癌通过CT增强延迟扫描共确诊79例，CT增强延迟扫描诊断对非小细胞肺癌的准确率为96.34%（79/82），与病理诊断结果100.00%对比差异无统计学意义（χ ² =3.060，P=0.080）；82例非小细胞肺癌平均CT增强值为（39.14±7.31），不同性别、年龄、肿瘤最大直径、淋巴结浸润情况患者CT增强值对比差异无统计学意义（P＞0.05），不同病理类型［腺癌（43.75±7.15）vs 鳞癌（34.74±6.12）］、细胞分化程度［中、低分化（45.71±7.21）vs 高分化（32.81±5.11）］、临床分期［Ⅰ期（31.03±2.12）vs Ⅱ期（36.61±3.13）vs Ⅲa期（46.32±6.83）］患者、淋巴结转移［是（42.75±4.21）vs 否（35.77±8.13）］CT增强值对比差异有统计学意义（t/F=5.243、8.804、84.828、4.378，P＜0.05）；Spearman相关分析结果显示：病理类型、细胞分化程度、临床分期、淋巴结转移与非小细胞肺癌患者CT增强值呈正相关（r=0.431，P=0.021；r=0.511，P=0.009；r=0.586，P=0.005；r=0.579，P=0.008，P＜0.05）。结论  CT增强延迟扫描技术对非小细胞肺癌术前确诊具有重要价值，其诊断准确率与病理诊断并无显著差异，且可通过CT增强延迟扫描技术确定患者CT增强值，从而为非小细胞肺癌患者术后病理特征判断提供参考。

      Objective  To explore the application value of CT enhanced  delayed  scanning in  preoperative  diagnosis of non-small cell lung cancer（NSCLC）．Methods  A retrospective analysis was conducted on 82 patients with NSCLCwho underwent surgical treatment in a hospital from May 2021 to May 2024．They were included into  an  observation  group and another 82 patients with benign lung tumors were included in the control group．The  preoperative CT enhanced  delayed scanning results were collected，and the postoperative pathological diagnosis was used as the “gold standard” to analyze the application value of CT enhanced delayed scanning in the preoperative diagnosis of NSCLC．And the CT enhancement values of delayed CT scans in NSCLC patients with different clinical and pathological features were compared，and Spearman correlation analysis was used to analyze the relationship between CT enhancement values and pathological features of NSCLC．Results  CT enhanced delayed scanning showed that the number of lobular（12.50% vs 53.57%）and internal vacuolar signs（6.25% vs39.29%）in the observation group was significantly lower than that in the control group（χ ² =26.560，24.680，P＜0.05），while the edge spicules（56.25% vs 17.86%）and chest depression signs（59.38% vs 14.29%）in the observation group were significantly higher than that in the control group（χ ² =43.330，64.600，P＜0.05）．A total of 79 cases of 82 NSCLC were diagnosed by CT-enhanced delayed scan，and the accuracy of CT-enhanced delayed scan diagnosis for NSCLC was 96.34%（79/82），with no significant difference from the pathological diagnosis result of 100.00%（χ ² =3.060，P=0.080）．The average CT enhancement value of 82 NSCLC cases was（39.14±7.31）．There was no significant difference in CT enhancement values among patients of different genders，ages，maximum tumor diameter，and lymph node infiltration（P＞0.05）．Patients with different pathological types ［adenocarcinoma（43.75±7.15）vs squamous cell carcinoma（34.74±6.12）］，degree of cell differentiation ［moderate，and low differentiation（45.7±7.21）vs high differentiation（32.81±5.11）］，clinical stage ［I（31.03±2.12）vs II（36.61±3.13）vs IIIa（46.32±6.83）］ and lymph node metastasis ［yes（42.75±4.21），vs no（35.77±8.13）］ CT enhancement had significant difference（t/F=5.243，8.804，84.828，4.378，P＜0.05）．The Spearman correlation analysis results showed that pathological type，degree of cell differentiation，clinical stage，lymph node metastasis were positively correlated with CT enhancement values in NSCLC patients（r=0.431，P=0.021；r=0.511，P=0.009；r=0.586，P=0.005；r=0.579，P=0.008）．Conclusions  CT enhanced delayed scanning has important value in preoperative diagnosis of NSCLC．Its diagnostic accuracy is not significantly different from pathological diagnosis，and the CT enhanced value of patients can be determined through CT enhanced delayed scanning，providing reference for postoperative pathological feature judgment of NSCLC patients．

        目的   探究支气管镜联合雾化吸入药物对肺炎支原体肺炎患儿症状持续时间及肺部影像学好转情况。方法   选取94例肺炎支原体肺炎患儿为研究对象，以随机数字表法分为A组、B组，各47例，分别实施布地奈德雾化吸入治疗、支气管镜肺泡灌洗联合布地奈德雾化吸入治疗，比较两组症状持续时间、治疗后肺部影像改善情况、炎症指标水平及不良反应发生率。结果  B组体温恢复时间（2.73±0.51）d、咳嗽消失时间（5.98±1.24）d、住院时间（10.96±3.36）d，A组分别为（3.14±0.83）（7.06±2.33）（13.27±3.18）d，B组较A组短（t=2.885、2.809、3.423，均P＜0.05）；治疗后B组40.43%阴影完全消失、34.04%阴影显著缩小、23.40%阴影有所缩小、2.13%阴影改善不明显，A组分别为21.28%、36.17%、25.53%、17.02%，B组肺部阴影改善情况优于A组（Z=8.311，P＜0.05）；治疗前B组白细胞计数（WBC）、超敏C-反应蛋白（hs-CRP）、降钙素原（PCT）水平与A组相近（P＞0.05）；治疗后B组WBC（7.71±1.94）×109 /L、hs-CRP（4.96±1.44）mg/L、PCT（84.32±21.40）pg/mL，A组分别为（9.05±2.48）×109 /L、（6.17±1.85）mg/L、（105.46±34.02）pg/mL，B组水平较A组低（t=2.918、3.538、3.606，均P＜0.05）；B组不良反应发生率为8.52%，A组为4.26%，B与A组相近（χ ² =0.178，P＞0.05）。结论   对肺炎支原体肺炎患儿实施支气管镜联合雾化吸入药物治疗，可缩短康复时间，促进肺部阴影消退，降低其炎症指标水平，且未增加不良反应发生率。

     Objective  To investigate the effect of bronchoscopy combined with nebulized inhalation of medication on the duration of symptoms and pulmonary imaging conversion in children with Mycoplasma pneumoniae pneumonia（MPP）．Methods  A total of 94 children with MPP were selected as the research subjects and randomly divided into Group A and Group B using a random number table，with 47 cases in each group．They were treated with budesonide nebulization inhalation therapy and bronchoalveolar lavage combined with budesonide nebulization inhalation therapy，respectively．The duration of symptoms，improvement of lung imaging before and after treatment，levels of inflammatory indicators，and incidence of adverse  reactions were compared between the two groups．The results showed that the temperature recovery time was（2.73±0.51）days，cough disappearance time was（5.98±1.24）days，and hospitalization time was（10.96±3.36）days in Group B，（3.14±0.83）days，（7.06±2.33）days，and（13.27±3.18）days in Group A，respectively．Durpation in Group B was shorter than Group A（t=2.885，2.809，3.423，all P＜0.05）． After treatment，40.43% of the shadows in Group B completely disappeared，34.04% of the shadows significantly reduced，23.40% of the shadows reduced，and 2.13% of the shadows showed no significant improvement，better than 21.28%，36.17%，25.53%，and 17.02% in Group A（Z=8.311，P＜0.05）． Before treatment，the white blood cell count（WBC），high-sensitivity C-reactive protein（hs CRP），and procalcitonin（PCT）levels in group B were similar to those in Group A（P＞0.05）．After treatment，the WBC（7.71±1.94）×109 /L，hs CRP（4.96±1.44）mg/L，and PCT（84.32±21.40）pg/mL in Group B were lower than those in Group A（9.05±2.48）×109 /L，（6.17±1.85）mg/L，and（105.46±34.02）pg/mL，respectively（t=2.918，3.538，3.606，all P＜0.05）．The incidence of adverse reactions in Group B was 8.52%，while in Group A it was 4.26%．The incidence of adverse reactions in group B was similar to that in group A（χ ² =0.178，P＞0.05）．Conclusions  Bronchoscopy combined with nebulized inhalation therapy for children with MPP can shorten the recovery time，promote the disappearance of lung shadows，reduce their inflammatory index levels，and without increasing the incidence of adverse reactions．

       目的   研究核磁共振（MR）引导的海马保护技术应用于小细胞肺癌全脑放射治疗（放疗）的效果。方法  对确定行全脑放疗的30例小细胞肺癌脑转移患者，行常规放疗CT定位后以定位体位行全头颅MR平扫，将计算机断层扫描（CT）和MR的T1加权像在Monaco 5.1计划系统上进行精准融合，勾画全脑放疗及海马区域，在海马区域三维方向上分别外扩5、15 mm作为海马与计划靶区之间的剂量跌落，每一例患者在Monaco 5.1计划系统上按照不保护海马组织以及外扩5、15 mm进行保护设计3个容积旋转调强技术（VMAT）放疗计划，观察海马组织的平均及最大放疗剂量。结果  增加保护海马组织之后，3个放疗计划的D100均≥95%，每例的3个放疗计划间D100比较差异无统计学意义（P＞0.05）；设置外扩5、15 mm的剂量跌落区后，左、右海马的平均剂量、最大剂量均明显降低，而且3个放疗计划的海马平均剂量、最大剂量之间对比差异有统计学意义。结论   小细胞肺癌脑转移患者进行全脑放疗时，利用MR引导的海马保护技术并设置外扩15 mm的剂量跌落区，能够显著降低海马的剂量，达到保护目的。

       Objective  To explore the application of MR guided hippocampal avoidant whole brain radiotherapy（WBRT）for small cell lung cancer（SCLC）．Methods  Thirty SCLC patients with brain metastases who underwent WBRT were enrdled．After routine CT localization was performed，and a head MR was performed in a the same position．T1 weighted images of MR and CT images were accurately fused on the Monaco 5.1 planning system．The entire brain tissue and hippocampus region were delineated．The dose drop areas between the hippocampusand the planned target area were expanded 5mm and 15mm in the three-dimensional direction of the hippocampus，respectively．Three volumetric modulated arc therapy（VMAT）radiotherapy plans were designed for each patient on the Monaco 5.1 planning system based on whether the hippocampal tissue was avoid．The average and maximum doses of hippocampal tissue were observed．Results  After the avoidance of hippocampal tissue，the D100 of the three radiotherapy plans reached ≥95%，and there was no significant difference in D100 between the three radiotherapy plans in each case．After setting dose drop areas of 5mm and 15mm for external expansion，the average and maximum doses of the left and right hippocampus were significantly reduced，and there was a significant difference in the comparison between the average and maximum doses in the hippocampus of the three radiotherapy plans．Conclusions  MR guided hippocampal avoidant technology and the setting of a 15 mm dose drop area can significantly reduce the dose to the hippocampus in patients with SCLC undergo whole brain radiotherapy．