质子束治疗中Bragg峰分布特性的SRIM模拟研究

目的 在质子治疗中,对SRIM程序在模拟质子Bragg峰分布特性方面进行探讨.方法 基于SRIM程序,对50～250MeV的不同能量的质子束入射到水、聚苯乙烯,有机玻璃以及铝、铁等不同介质中的输运过程进行了模拟分析,对不同的质子入射能量、介质材料及厚度与其Bragg峰深度的关系进行了研究,并与专业的蒙特卡罗程序Fluk...     

我国首台碳离子治疗系统的开发及应用

重离子是目前治疗癌症较理想的射线,其中碳离子因更高的生物学效应而用于多种癌症的治疗。2019年,武威重离子中心建成了中国首台医用重离子加速器——碳离子治疗系统,并获得了国家药品监督管理局注册许可证,并于2020年3月开始正式接诊肿瘤患者。该文针对我国首台碳离子治疗系统的开发及应用进行综述。     

北京市室内外PM_(2.5)中有机碳和元素碳分布特征研究

目的研究室内外PM_(2.5)中有机碳(organic carbon,OC)和元素碳(elemental carbon,EC)的分布特征。方法选择7个典型地区,每个地区设置室内外两个监测点,2013年5月—2014年4月连续监测PM_(2.5)中OC和EC。结果室内OC和EC年均浓度(中位值和四分位值)分别为13.4μg/m~3(8.82~26.6μg/m~3)和3.79μg/m~3(2.09~6.98μg/m~3),室外分别为15.4μg/m~3(10.6~35.2μg/m~3)和4.96μg/m~3(2.92~9.39μg/m~3),室内外OC分别占总碳的78%和73%。统计发现,碳类物质室外高于室内,OC浓度高于EC;燃煤季室外OC浓度最高,其他季节无差异;周六日室外OC浓度最高,周一至周三最低;7个典型地区室外OC浓度为:扬尘区、航油区、工业区、轻工业区汽车尾气区、发电厂区清洁对照区。室外OC与室外EC呈直线关系(r=0.886),室内外OC呈直线关系(r=0.915),室内外EC呈直线关系(r=0.894),碳类物质与PM_(2.5)呈直线关系(rOC-PM 2.5=0.785,rEC-PM 2.5=0.775)。夏季OC类物质室内与室外比值(I/O值)最高且与另外三季的结果有差异。燃煤季室外OC与EC比值最高,夏季最低。结论北京空气中碳类物质污染值得关注,雾霾期间应特别加强对OC防护,应采取有的放矢的措施控制OC污染。     

对碱性磷酸酶试剂盒特征吸收峰的分析

从检测一厂家生产的碱性磷酸酶(ALP)试剂盒的试剂空白吸光度所得的值,分析企业标准中所涉及的检测波长是否合理。     

耐碳青霉烯类革兰阴性菌分布特征及耐药性分析

目的了解临床分离的耐碳青霉烯类革兰阴性菌的分布特征及耐药特点,为临床合理使用抗菌药物提供理论依据。方法收集2016年1月-12月耐碳青霉烯类革兰阴性菌临床分离株,采用自动化仪器法和K-B纸片扩散法对上述菌株进行药物敏感性试验,药敏结果依据美国临床实验室标准化协会(CLSI)2016年版的要求进行判断。结果共收集耐碳青霉烯类革兰阴性菌722株,其中耐碳青霉烯类肠杆菌(CRE)52株,耐碳青霉烯类鲍氏不动杆菌(CRAB)492株,耐碳青霉烯类铜绿假单胞菌(CRPA)178株;痰标本检出耐碳青霉烯类病原菌最多,为560株占77.6%,主要来自重症监护病房,以60岁老年患者居多;CRE和CRAB对阿米卡星和替加环素敏感率较高(67.7%~86.5%),对头孢菌素类、喹诺酮类和加酶抑制剂类抗菌药物敏感率均≤23.1%;CRPA除对碳青霉烯类敏感率低外,对头孢菌素类、喹诺酮类和氨基糖苷类抗菌药物敏感率较高,均≥55.1%;CRE对阿米卡星、替加环素和亚胺培南的MIC值主要分布在≤2μg/ml(58%)、≤0.5μg/ml(52%)、≥16μg/ml(48%);CRAB对阿米卡星的MIC值主要分布在4μg/ml(24.4%)、8μg/ml(27.4%)和≥64μg/ml(28.9%),亚胺培南和替加环素的MIC值主要分布在≥16μg/ml(96.7%)、4μg/ml(47.4%);CRAB对阿米卡星、亚胺培南的MIC值集中在≤2μg/ml(53.4%)、≥16μg/ml(69.7%)。结论耐碳青霉烯类革兰阴性菌对常见抗菌药物敏感性较低,临床医生应根据实验室结果及MIC值合理使用抗菌药物,以减少或延缓耐碳青霉烯类细菌的产生。     

基于离子液体复合膜的葡萄糖生物传感器

目的建立一种电化学葡萄糖生物传感器,进而评价其在血糖检测的应用前景。方法将葡萄糖氧化酶（GOD）分散在N,N-二甲基甲酰胺（DMF）-离子液体（[BMIM]PF6）复合膜中滴于二茂铁（Fc）修饰的丝网印刷碳电极（SPCE）上,制备一种新型三电极葡萄糖电化学生物传感器。用扫描电子显微镜（SEM）、循环伏安法（CV）和计时电流法表征生物传感器的制备以及其电化学特性。结果该生物传感器有良好的稳定性和灵敏性,响应电流与葡萄糖浓度在0.5～16mM之间有良好的线性相关,检出限为0.1mM。结论制备的电化学葡萄糖生物传感器具有良好性能,可用于血糖检测。     

北京市大气PM_(2.5)中9种水溶性阴阳离子的分布特征及影响因素分析

目的了解北京市大气PM_(2.5)中9种水溶性阴阳离子的分布特征及其影响因素。方法于2014年3月至2015年2月每月连续7 d在北京市采用大气颗粒物采样器采集大气PM_(2.5),同时记录大气的温度、压力、相对湿度和风速等。样品经超声提取和离心后,使用离子色谱测定颗粒物中的F~-、Cl~-、SO_4~(2-)、NO_3~-、Na~+、NH_4~+、K~+、Ca~(2+)和Mg~(2+)的浓度。采用Spearman相关分析离子浓度和气象因素的相关性。结果本研究所检测9种离子中NO_3~-、SO_4~(2-)和NH_4~+3种离子的质量浓度占所检测离子浓度的85.9%。大气中9种离子浓度之间的相关系数范围为0.409~0.941(P0.01)。F~-、Cl~-、SO_4~(2-)、NO_3~-、Na~+、NH_4~+和K~+与温度和风速有明显的负相关关系,与相对湿度呈正相关。霾日9种离子的质量浓度高于非霾日差异有统计学意义(P0.01)。春、夏、秋、冬大气PM_(2.5)中NO_3~-和SO_4~(2-)的平均比值分别为1.54、0.89、1.39和1.22。结论大气PM_(2.5)中水溶性离子的浓度与温度、相对湿度和风速等气象因素有关,大气水溶性离子及其来源有明显的季节变化,霾日大气水溶性离子的浓度较高。     

离子色谱法测定饮用矿泉水中硝酸盐的不确定性分析

目的了解用离子色谱法测定饮用矿泉水中硝酸盐离子的不确定度评定。方法利用离子色谱仪对饮用矿泉水中硝酸盐离子进行测定实践,建立测量数学模式,分析影响因素主要有:①来自重复测量引入的A类不确定度;②来自工作曲线的不确定度;③来自标准溶液的不确定度。结果利用离子色谱法测定饮用矿泉水中硝酸盐离子浓度为0.800 mg/L时,其扩展不确定度为U=0.086 mg/L,k=2。扩展相对不确定度为Urel=10.8%。结论测定过程中,不确定度的主要来源是来自工作曲线的标准不确定度。     

非呼吸道标本中耐碳青霉烯类肠杆菌科细菌的分布、耐药性和碳青霉烯酶型分析

目的 了解非呼吸道标本中耐碳青霉烯类肠杆菌科细菌（CRE）的临床分布特点、耐药性和碳青霉烯酶分型情况,为指导临床合理使用抗菌药物提供依据。方法 收集2017年7月—2021年6月医院从非呼吸道标本中分离出的CRE,使用WHONET 5.6软件和Excel进行数据分析。结果 共收集CRE 420株,其中耐碳青霉烯类肺炎克雷伯菌（CRKP）276株（65.7%）。CRE主要分布在ICU（占比22.9%）;尿液标本占比43.8%;CRE对常用β内酰胺类抗菌药物产生了高度耐药。CRE的碳青霉烯酶分型主要是KPC,其次是NDM,其中肺炎克雷伯菌以KPC酶为主（占比94.2%）,大肠埃希菌以NDM型碳青霉烯酶为主（占比91.7%）。结论 CRE在非呼吸道标本中也广泛存在,特别是ICU患者,耐药情况非常严重,不同菌种碳青霉烯酶型差异较大,临床医生应做到精准用药,同时加强感染控制,减少CRE的院内感染和传播。     

基于主导频峰方法的心外膜标测信号节律分析

正常情况下心肌以一定的节律顺序激动,而房颤时这种节律性就会发生改变。该文以心外膜标测信号为基础,在与时域特征点法对比后,采用频域主导频峰的方法,分析了窦性心律和房颤情况下心房各部位激动节律情况。研究发现房颤时心房各部位的激动节律差异很大,个别部位自律性发生了明显改变。结果表明主导频峰法非常适用于房颤时心房标测信号的节律分析。另外该文还粗略探讨了该方法在寻找房颤激动源方面的作用。     

Clinical trial of carbon ion radiotherapy for gynecological melanoma

Carbon ion radiotherapy (C-ion RT) is an advanced modality for treating malignant melanoma. After we treated our first case of gynecological melanoma using C-ion RT in November 2004, we decided to conduct a clinical trial to evaluate its usefulness for the treatment of gynecological melanoma. The eligibility criteria for enrollment in this study were histologically proven malignant melanoma of the gynecological regions with lymph node metastasis remaining in the inguinal and pelvic regions. The small pelvic space, including the GTV and the metastatic lymph node, was irradiated with up to a total dose of 36 GyE followed by a GTV boost of up to a total dose of 57.6 GyE or 64 GyE in 16 fractions. A series of 23 patients were treated between November 2004 and October 2012. Patient age ranged from 51–80 with a median of 71. Of the tumor sites, 14 were located in the vagina, 6 in the vulva, and 3 in the cervix uteri. Of the 23 patients, 22 were irradiated with up to a total dose of 57.6 GyE, and 1 patient was irradiated with up to a total dose of 64 GyE. Chemotherapy and interferon-β were also used to treat 11 of the patients. Acute and late toxicities of Grade 3 or higher were observed in 1 patient treated with concurrent interferon-β. The median follow-up time was 17 months (range, 6–53 months). There was recurrence in 14 patients, and the 3-year local control and overall survival rates were 49.9% and 53.0%, respectively. C-ion RT may become a non-invasive treatment option for gynecological melanoma.     

RBE and OER within the spread-out Bragg peak for proton beam therapy: in vitro study at the Proton Medical Research Center at the University of Tsukuba

There are few reports on the biological homogeneity within the spread-out Bragg peak (SOBP) of proton beams. Therefore, to evaluate the relative biological effectiveness (RBE) and the oxygen enhancement ratio (OER), human salivary gland tumor (HSG) cells were irradiated at the plateau position (position A) and three different positions within a 6-cm-wide SOBP (position B, 26 mm proximal to the middle; position C, middle; position D, 26 mm distal to the middle) using 155-MeV/n proton beams under both normoxic and hypoxic conditions at the Proton Medical Research Center, University of Tsukuba, Japan. The RBE to the plateau region (RBE_plateau) and the OER value were calculated from the doses corresponding to 10% survival data. Under the normoxic condition, the RBE_plateau was 1.00, 0.99 and 1.09 for positions B, C and D, respectively. Under the hypoxic condition, the RBE_plateau was 1.10, 1.06 and 1.12 for positions B, C and D, respectively. The OER was 2.84, 2.60, 2.63 and 2.76 for positions A, B, C and D, respectively. There were no significant differences in either the RBE_plateau or the OER between these three positions within the SOBP. In conclusion, biological homogeneity need not necessarily be taken into account for treatment planning for proton beam therapy at the University of Tsukuba.     

12^C^6＋对小鼠肝组织中脂类过氧化和血清抗氧化活力的影响

目的研究12^C^6＋重离子全身照射对小鼠肝组织中脂类过氧化和血清抗氧化活力的影响。方法采用硫代巴比妥酸法测定重离子6Gy辐照后各组肝组织中脂质过氧化值;采用电子自旋共振自旋捕集技术检测辐照后各组血清对羟基的清除率。结果12^C^6＋重离子全身辐照后46、70、82h组肝组织中脂质过氧化值明显增加,与对照组相比差异有显著性（P〈0.01）,但未出现峰值;辐照后各组血清对羟基的清除率明显下降,其中82h组的清除率最低,辐照后各组与对照组相比差异有显著性（P〈0.01）。结论12^C^6＋重离子全身辐照能引起小鼠肝组织中脂类过氧化并能使血清抗氧化活力下降。     

12C6+对小鼠肝组织中脂类过氧化和血清抗氧化活力的影响

目的研究12C6 重离子全身照射对小鼠肝组织中脂类过氧化和血清抗氧化活力的影响。方法采用硫代巴比妥酸法测定重离子6Gy辐照后各组肝组织中脂质过氧化值;采用电子自旋共振自旋捕集技术检测辐照后各组血清对羟基的清除率。结果12C6 重离子全身辐照后46、70、82h组肝组织中脂质过氧化值明显增加,与对照组相比差异有显著性(P<0.01),但未出现峰值;辐照后各组血清对羟基的清除率明显下降,其中82h组的清除率最低,辐照后各组与对照组相比差异有显著性(P<0.01)。结论12C6 重离子全身辐照能引起小鼠肝组织中脂类过氧化并能使血清抗氧化活力下降。     

Relative clinical effectiveness of carbon ion radiotherapy: theoretical modelling for H&N tumours

Comparison of the efficiency of photon and carbon ion radiotherapy (RT) administered with the same number of fractions might be of limited clinical interest, since a wide range of fractionation patterns are used clinically today. Due to advanced photon treatment techniques, hypofractionation is becoming increasingly accepted for prostate and lung tumours, whereas patients with head and neck tumours still benefit from hyperfractionated treatments. In general, the number of fractions is considerably lower in carbon ion RT. A clinically relevant comparison would be between fractionation schedules that are optimal within each treatment modality category. In this in silico study, the relative clinical effectiveness (RCE) of carbon ions was investigated for human salivary gland tumours, assuming various radiation sensitivities related to their oxygenation. The results indicate that, for hypoxic tumours in the absence of reoxygenation, the RCE (defined as the ratio of D₅₀ for photons to carbon ions) ranges from 3.5 to 5.7, corresponding to carbon ion treatments given in 36 and 3 fractions, respectively, and 30 fractions for photons. Assuming that interfraction local oxygenation changes take place, results for RCE are lower than that for an oxic tumour if only a few fractions of carbon ions are used. If the carbon ion treatment is given in more than 12 fractions, the RCE is larger for the hypoxic than for the well-oxygenated tumour. In conclusion, this study showed that in silico modelling enables the study of a wide range of factors in the clinical considerations and could be an important step towards individualisation of RT treatments.     

重离子技术治疗肿瘤的进展

重离子治疗作为一种新型的放疗技术,正在受到越来越多的关注。重离子治疗肿瘤在疗效和安全性方面与传统的放疗手段相比都展现出了一定的优越性。美国、德国、日本是世界上重离子治疗肿瘤技术最先进的国家。中国是世界上第四个掌握重离子治疗肿瘤技术的国家。重离子治疗在未来的肿瘤治疗领域会逐渐发挥越发重要的作用。     

Clinical oxygen enhancement ratio of tumors in carbon ion radiotherapy: the influence of local oxygenation changes

The effect of carbon ion radiotherapy on hypoxic tumors has recently been questioned because of low linear energy transfer (LET) values in the spread-out Bragg peak (SOBP). The aim of this study was to investigate the role of hypoxia and local oxygenation changes (LOCs) in fractionated carbon ion radiotherapy. Three-dimensional tumors with hypoxic subvolumes were simulated assuming interfraction LOCs. Different fractionations were applied using a clinically relevant treatment plan with a known LET distribution. The surviving fraction was calculated, taking oxygen tension, dose and LET into account, using the repairable–conditionally repairable (RCR) damage model with parameters for human salivary gland tumor cells. The clinical oxygen enhancement ratio (OER) was defined as the ratio of doses required for a tumor control probability of 50% for hypoxic and well-oxygenated tumors. The resulting OER was well above unity for all fractionations. For the hypoxic tumor, the tumor control probability was considerably higher if LOCs were assumed, rather than static oxygenation. The beneficial effect of LOCs increased with the number of fractions. However, for very low fraction doses, the improvement related to LOCs did not compensate for the increase in total dose required for tumor control. In conclusion, our results suggest that hypoxia can influence the outcome of carbon ion radiotherapy because of the non-negligible oxygen effect at the low LETs in the SOBP. However, if LOCs occur, a relatively high level of tumor control probability is achievable with a large range of fractionation schedules for tumors with hypoxic subvolumes, but both hyperfractionation and hypofractionation should be pursued with caution.     

阈值触发法与小剂量测试法在CTA冠状动脉峰值采集中的对比分析

目的:对比采用阈值触发法与小剂量测试法在CT血管造影(CT angiorgraphy,CTA)冠状动脉峰值采集中的效果差异.方法:回顾性分析212例冠状动脉CTA成像患者的影像资料,采用阈值触发法扫描的患者109例(作为阈值触发法组),采用小剂量测试法扫描的患者103例(作为小剂量测试法组),以升主动脉根部(左冠开口层...     

Electrocardiographic features of Korean carbon disulfide poisoned subjects after discontinuation of exposure

Objective Mass poisoning by carbon disulfide (CS₂) was reported at a viscose rayon factory in Korea in the late 1980s; the factory was subsequently closed in 1993. In this study, we evaluated the late electrocardiographic features in the CS₂ poisoned subjects. Methods The cases were composed of 198 retired workers with a history of CS₂ poisoning. An age- and sex-matched reference group was randomly selected from people visiting a hospital for regular health checkups. Intervals, amplitudes and abnormal findings from the electrocardiograms (ECGs) of the two groups were compared. Results Except for the PQ interval, there were no significant ECG differences between the two groups. The cases exhibited ECG abnormalities more frequently than the reference group. Multiple logistic regression analysis revealed that CS₂ poisoning was positively associated with the presence of abnormal ECG findings (OR = 1.603; 95% CI, 1.008–2.549). Conclusion This study suggests that CS₂ poisoned subjects may have an increased risk of ECG abnormalities even after the exposure to CS₂ is no longer present.