平衡帽材料直器散射因子测量值的影响探讨

目的：探讨平衡帽材料对准直器散射因子（Sc)测量值的影响。材料和方法：采用由A－150塑料和铜制做成的两种平衡帽。用Farmer2570剂量仪分别测量6MV X线不同射野条件下电离室的电离值,并归一到参考射野,得到两组Sc值进行比较。结果：使用铜材平衡帽时,电离室的电离值明显高于使用A－150塑料平衡帽时电离室的电离值,最大离出14％,但两组Sc值的差异并不显著,均在1％以内。结论：虽然高密度材料和空气严重不等效,但对Sc测量值的影响较小,因此选用高密材料的平衡帽测量Sc(尤其在小野条件下）也不失为一种较好的方法。     

PMMA与铜平衡帽对6MV光子线反散射因子和准直器散射因子测量结果影响的比较研究

目的:通过比较聚甲基丙烯酸甲酯(PMMA)与铜平衡帽对6 MV光子线反散射因子(BSF)和准直器散射因子(Sc)测量结果的影响,提出一种简单易行的测量高能光子线BSF和Sc的方法。材料与方法:分别使用PMMA与铜制平衡帽在SAD和SSD两种方式下测量6MV光子线的BSF和Sc,并比较分析测量数据。结果:相同条件下铜制平衡帽的吸收剂量值测量结果明显偏大,而Sc的数值与变化趋势在不同的平衡帽材料和测量方式下基本不发生变化;BSF、Sc在同一平衡帽、两种测量方式下得到的结果变化不大,但使用PMMA平衡帽的结果略优于铜制平衡帽。结论:为了满足精确测量和简化方法的要求,建议采用SAD测量方式并使用PMMA平衡帽测量Sc与BSF。     

GE saturne42型直线加速器准直器散射因子的测量

对ＧＥ公司ｓａｔｕｒｎｅ４２型直线加速器对准直器散射校正因子的性质进行研究,用英国ＮＥ公司生产的２６２０测量仪,臂架旋转９０°测量了６ＭＶ、１８ＭＶ的源——电离室中心距离１米及３．７米两个条件下的校正因子的数值,结果证实了校正因子只是与准直器有关与源皮距无关的结论。     

多叶准直器中散射空气比(SAR)的计算

在放疗中，常把除方野、矩形和圆形野以外的其他任何形状射野称为不规则野。而多叶准直器所形成的射野就是不规则野，对不规则射野，剂量计算要将原射线、散射线分开，而组织中散射剂量的计算需要用散射空气比。作者在此对多叶准直器中散射空气比的计算方法作了一些探讨。     

多叶准直器中散射空气比（SAP）的计算

在放疗中，常把除方野、矩形和圆形野以外的其他任何状态射野称为不规则野。而多叶准直器所形成的射野就是不规则野，对不规则射野，剂量计算要将原射线、散射线分开，而组织中散射剂量的计算需要用散射空气比。作者在此对多叶准直器中散射空气比的计算方法法作了一些探讨。     

基于旋转准直器的锥形束CT散射矫正方法

针对锥形束CT（CBCT）图像质量受散射影响比较严重的情况,提出一种基于旋转准直器的CBCT散射矫正方法。该方法在射线源和模体之间放置一个圆形的旋转准直器,并通过准直器的旋转使透过准直器的射线不断沿轴向来回扫描,以获取整个容积图像的投影图像信息,然后利用投影图像的遮挡区域估计整幅图像的散射信息并将其从投影图像中去除,最后利用改进FDK算法重建图像。结果表明,与CBCT图像相比,散射矫正后的重建图像CBCT值的均方根误差从16.00%下降为1.18%,杯状伪影从14.005%下降为0.660%,峰值信噪比从16.959 4提高到31.450 0。CBCT图像质量得到明显提高。     

基于Monte Carlo的西门子6MV加速器散射因子的模拟研究

目的：研究探讨西门子（Siemens）6MV加速器总散射因子受射野变化的影响,为临床剂量计算提供参考。方法：利用蒙特卡罗程序BEAMnrc以及DOSXYZnrc对西门子加速器6MV光子束进行了模拟研究,详细分析了总散射因子受射野变化的影响．并结合模拟结果分析不同计算方法计算矩形野总散射因子的精度。结果：方形野总散射因子随着射野射野边长减小而减小。当方野边长小于2cm时,总散射因子减小趋势明显。当矩形野边长都大于2cm时,使用面积周长比方法以及K因子法计算总散射因子有较好的精度,但如果有一边边长小于2cm时,使用B因子法明显降低了误差。结论：在计算一般矩形野总散射因子时面积周长比方法比以及K因子法都能够达到良好的精度,但是蒙卡模拟是否存在准直器互换效应仍需进一步研究。对于矩形小野总散射因子,由于在模体中剂量分布梯度大,侧向电子难以平衡,因此使用面积周长比公式计算结果误差较大,建议采用B因子算法,模拟计算的结果与该算法计算的结果近似。     

铱192后装放射源在空气中刻度的散射因子

目的:研究铱192后装放射源在空气中刻度的散射因子。方法:PTW井形电离室放置在离地1 m高的支架上,测量在电离室外缘离墙距离5 cm到200 cm处进行,读数以200 cm处读数归一。按多步法、DGMP法和遮挡法要求在空气中用Farmer指形电离室在不同源室距(SCD)上对铱192后装放射源进行测量,遮挡法测量中在放射源和电离室之间放置6 cm厚度的圆锥台型铅挡,测得数据用Origin8.0软件进行拟合处理分析。测量中读数均摈弃端效应、暗电流并做梯度修正。结果:井形电离室对铱192放射源刻度,读数在电离室和墙壁距离较近时受到墙面散射影响,电离室外缘离墙壁距离在1 m以上时散射影响可以忽略,Farmer指形电离室在空气中测量结果表明用Goetsch法和DGMP法计算,散射因子恒定与测量距离(SCD)无关且可以忽略,SF法的散射因子略小。结论:井形电离室刻度后装放射源需在最小散射情况下进行,在空气中用指形电离室进行刻度应对散射进行实际测量,遮挡法是较为符合实际的测量方法。     

剂量率和准直器角度对二维电离室矩阵调强验证Gamma通过率的影响

目的：研究剂量率和准直器角度对二维电离室矩阵调强验证Gamma通过率的影响。方法：使用PTw二维电离室矩阵对2组36例测试病例进行验证。两组病例分别对应不同剂量率组和不同准直器角度组,比较不同的剂量率（100cGy／min-600Gy／min的整百剂量率）和准直器角度对3％、3mm标准Gamma分析的影响。结果：本研究中6档剂量率两两配对共计15对,配对t检验结果中,除了200和500这一对t=-3．68,P〈0．05,有统计学差异,其余14对配对t检验结果均为P〉0．05,无统计学差异;不同的准直器角度Gamma通过率配对t检验结果t=-15．582,P〈0．05,有统计学差异。结论：不同的剂量率对二维电离室矩阵调强验证Gamma通过率无明显影响,不同的准直器角度对二维电离室矩阵调强验证Gamma通过率有明显的影响．制订治疗计划时适当的调整准直器角度,使不同射野的准直器角度互不相同能够明显提高调强验证的通过率。     

独立准直器位置精度对半野联合处剂量的影响

目的:介绍在乳腺癌和鼻咽癌放射治疗中的单一等中心半野联合放疗技术,并对独立准直器位置精度对半野联合处剂量的影响进行研究,提出对策.方法:用带独立准直器的直线加速器,以一个等中心,上下半野技术照射体模,用胶片剂量仪分析半野衔接处剂量分布情况,并将研究结果应用于乳腺癌和鼻咽癌病人的放射治疗.结果:受加速器独立准直器位置精度的影响,半野衔接处可能存在最大不超过2mm的过剂量区或欠剂量区.如果消除该系统误差的影响,则半野衔接处可得到均匀的剂量分布.结论:单一等中心半野联合照射,半野衔接处处于照射靶区,必须重视独立准直器位置精度对衔接处剂量的影响,并加以修正.     

The role of rheumatoid factor in an electron microscope study of hepatitis B antigens

An immune electron microscopic (IEM) study of the hepatitis B e antigen (HBeAg) system has shown that rheumatoid factor (RE) can be an important complicating factor when examining preparations containing multiple antigenic specificities. For example, in the presence of RF, mixed immune complexes were produced that suggested HBeAg might be antigenically related to either Dane particles or cores. When RF was removed, however, the putative HBeAg--anti-Hbe complexes showed no relationship with any other hepatitis B component. It has been shown that RF can have a positive practical application in IEM by using it to link preformed marker complexes to immune complexes which do not contain morphologically recognizable antigen.     

Ultrastructural effects of granulocyte colony stimulating factor (G-CSF) and macrophage colony stimulating factor (M-CSF) on rat neutrophils and monocytes

Human granulocyte colony stimulating factor (G-CSF) and macrophage colony stimulating factor (M-CSF) were administered intravenously to rats, and their effects on neutrophils and monocytes were examined by electron microscopy. G-CSF increased the number of cytoplasmic granules in neutrophils. It also enhanced maturation of the nuclear shape in the neutrophils, while chromatin condensation and peroxidase distribution remained immature. M-CSF induced proliferation of monocytes in peripheral blood and bone marrow, but did not affect morphology or distribution of peroxidase reactivity. This study was presented at the 25th Annual Meeting of the Clinical Electron Microscopy Society of Japan, Matsumoto, September 28–30, 1993.     

Varian 2300 C／D直线加速器高能电子束铅挡野输出因子的测定与分析

目的：探讨Varian 2300 C/D直线加速器高能电子束射野输出因子变化规律。方法：用电离室法实测在各种能量下对四种限光筒的不同铅挡野的射野输出因子。结果：铅挡野输出因子随射野边长及限光筒大小变化没有明显的规律;铅挡野输出因子与能量有关。结论：射线能量、限光铜和铅挡野大小时输出因子的影响较大,临床应用时需要针对性地精确测量。     

食管癌组织中血管内皮生长因子的表达对树突状细胞的影响

目的：研究食管癌组织中血管内皮生长因子（VEGF）的表达对树突状细胞（DC）的影响。方法：对94例食管癌组织采用辣根过氧化物酶（HRP）标记的链霉亲和素-生物素法（LSAB）,分别检测VEGF、S100蛋白的表达水平,并分析VEGF与S100^＋ DC的相关性。结果：食管癌组织中VEGF的表达率为74.46%（70/94）,VEGF的表达与患者的临床分期及癌组织的分化呈正相关（r=0.864,0.803,P〈0.05）。临床分期越晚,病癌组织的分化越低,癌组织内S100^＋ DC的密度越小（r=-0.763,-0.908,P〈0.05）。随着癌组织内VEGF表达量的上升,S-100^＋ DC的密度降低,二者呈负相关（r=-0.817,P〈0.05）。结论：食管癌组织中VEGF的表达可降低S100^＋DC的密度,从而影响机体的免疫功能。     

Pathological research output in China and other top-ranking countries: 10-year survey of the literature

The present study was designed to study the research output in pathology journals from the United States (USA), Japan, Germany, the United Kingdom (UK), France, and China between 2000 and 2009. Articles published in 67 pathology-related journals were retrieved from the PubMed database. US-American publications, which rank first, accounted for 30.9% of the total world's output and for 35.4% in the top 10% journals with impact factor (IF) scores. Chinese publications accounted for 2.8% of a total of 67 journals, and for 2.0% in the top 10% journals with IF scores.     

新生儿缺氧缺血性脑病与血管内皮生长因子水平的临床观察

目的观察新生儿缺血缺氧性脑病(HIE)血浆和脑脊液中血管内皮生长因子(Vascular endothelial growthfactor,VEGF)与神经元特异性烯醇化酶(Neuron-specific enolase NSE)含量的动态变化,探索VEGF与HIE早期诊断、预后判断及有关机理的临床相关性。方法选择确诊HIE足月新生儿38例(轻度15例,中度12例,重度11例)作为观察组,12例无神经系统疾病的足月新生儿为对照组;分别于生后24h、7、10天测血浆VEGF和NSE,于生后24h测脑脊液VEGF和NSE,分析VEGF与NSE、疾病程度相关性及意义。结果观察组VEGF与NSE在生后24h即升高,与对照组比较有显著差异(P<0.01);以后逐渐下降,与生后7天比较有显著差异(P<0.05);VEGF与NSE、疾病程度有相关性。结论血管内皮生长因子(VEGF)可能作为新生儿缺血缺氧性脑病(HIE)诊断、疾病严重程度和预后判断的一种重要指标。     

Immunohistochemical detection of epidermal growth factor and epidermal growth factor receptor in the lingual mucosa of rats during the morphogenesis of filiform papillae

We examined the immunofluorescence labelling epidermal growth factor (EGF) and epidermal growth factor receptor (EGFR), as well as differential interference contrast (DIC) images, during the morphogenesis of filiform papillae and the keratinization of the lingual epithelium of rats on semi-ultrathin sections of epoxy resin-embedded samples using laser-scanning microscopy. We also examined semi-ultrathin sections of epoxy resin-embedded, toluidine blue-stained samples by light microscopy to obtain details of cell histology and morphology. No immunoreactivity specific for EGF and EGFR was detected on the lingual epithelium of fetuses on days 12 and 16 after conception (E12 and E16), during which time the number of layers of cuboidal cells in the lingual epithelium increased from one to several. Immunoreactivity specific for EGF and EGFR was first detected on the lingual epithelium of fetuses at birth or on postnatal day 0 (P0). Immunoreactivity specific both for EGF and EGFR appeared in the connective tissue and the basal cells of the papillary and interpapillary cell columns. The lingual epithelium was composed of stratified squamous cells. The rudiments of filiform papillae were compactly arranged and interpapillary cell columns were very narrow. Immunoreactivity specific for EGF and EGFR was distinct on the cell membrane of basal cells of the papillary cell column and weakly positive on the cell membrane of basal cells of the interpapillary cell column on postnatal day 21 (P21). Thus, the patterns of immunoreactivity of EGF and EGFR differed as the filiform papillae developed. Filiform papillae developed gradually from P0 to P21. The width of interpapillary spaces also increased during this period. These observations indicate a possibility that EGF might affect the expression of keratins in the lingual epithelium via epithelium-mesenchymal interactions.     

改构体aFGF对颈动脉窦损伤的保护作用

目的　探讨损伤大白鼠颈动脉窦压力感受器神经末梢后 ,改构体aFGF的保护作用。方法　将Wistar大鼠随机分成对照组、改构体aFGF1组、改构体aFGF2 组、改构体aFGF3 每组各 10只。改构体组分别经静脉注射 0 14 μg/ml、0 4 3μg/ml、1 30 μg/ml的改构体aFGF(1ml/ 10 0g) ,而对照组注射同剂量的生理盐水。 2 0min后 ,用蘸有 80 %乙醇的棉球轻轻擦拭右颈动脉窦区 ,损伤颈动脉窦压力感受器神经末梢 ,并放置 5min。观察记录各组损伤前后夹闭颈总动脉血压即 :收缩压 (SP)、舒张压(DP)、平均动脉压 (MP)和心率 (HR)的变化。结果　 (1)损伤右颈动脉窦前 ,夹闭右颈总动脉 ,实验组和对照组血压均升高 ,夹闭前后相比差异均有统计学意义 (P <0 0 1) ;(2 )损伤右颈动脉窦后 ,夹闭右颈总动脉 ,改构体aFGF1组、对照组血压不变 ,夹闭前后相比差异无统计学意义 (P >0 0 5 ) ;改构体aFGF2 组、改构体aFGF3 组血压升高 ,夹闭前后相比差异有统计学意义 (P <0 0 5 ) ,夹闭前后两组的血压差分别与对照组的差值相比有统计学意义 (P <0 0 5 )。在本实验中 ,HR均无明显变化。结论　改构体aFGF对颈动脉窦损伤有保护作用 ,并显示一定的量效关系     

Bilateral visual inputs to the dorsal cap of inferior olive: Differential localization and inhibitory interactions

Summary There are two pathways known to mediate optic signals to the rabbit flocculus through the dorsal cap of the inferior olive; one (I) projects from the contralateral and the other (II) from the ipsilateral eye, both to the contralateral flocculus. The present study on anesthetized rabbits revealed that the two pathways are relayed at different loci of the dorsal cap, I at its caudal and II its rostral half. The ventrolateral outgrowth of the inferior olive also projects to the flocculus, but a prominent field potential could not be produced by optic signals. The present study further demonstrated that transmission in pathway I accompanies an inhibitory action upon that in II. Since direct stimulation of these pathways at preolivary levels revealed similar inhibition, and since this was reflected in the depression of antidromic invasion of dorsal cap neurons, it is concluded that inhibition occurs postsynaptically in dorsal cap neurons. Inhibition is unidirectional, as activities in pathway II did not influence those in I.This work was supported by grants from the Ministry of Education of Japan to T.T. (No. 377060) and K.M. (No. 311401)