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81.
Performance measurement of the microPET focus 120 scanner. 总被引:6,自引:0,他引:6
Jin Su Kim Jae Sung Lee Ki Chun Im Su Jin Kim Seog-Young Kim Dong Soo Lee Dae Hyuk Moon 《Journal of nuclear medicine》2007,48(9):1527-1535
The microPET Focus 120 scanner is a third-generation animal PET scanner dedicated to rodent imaging. Here, we report the results of scanner performance testing. METHODS: A (68)Ge point source was used to measure energy resolution, which was determined for each crystal and averaged. Spatial resolution was measured using a (22)Na point source with a nominal size of 0.25 mm at the system center and various off-center positions. Absolute sensitivity without attenuation was determined by extrapolating the data measured using an (18)F line source and multiple layers of absorbers. Scatter fraction and counting rate performance were measured using 2 different cylindric phantoms simulating rat and mouse bodies. Sensitivity, scatter fraction, and noise equivalent counting rate (NECR) experiments were repeated under 4 different conditions (energy window, 250 approximately 750 keV or 350 approximately 650 keV; coincidence window, 6 or 10 ns). A performance phantom with hot-rod inserts of various sizes was scanned, and several animal studies were also performed. RESULTS: Energy resolution at a 511-keV photopeak was 18.3% on average. Radial, tangential, and axial resolution of images reconstructed with the Fourier rebinning (FORE) and filtered backprojection (FBP) algorithms were 1.18 (radial), 1.13 (tangential), and 1.45 mm full width at half maximum (FWHM) (axial) at center and 2.35 (radial), 1.66 (tangential), and 2.00 mm FWHM (axial) at a radial offset of 2 cm. Absolute sensitivities at transaxial and axial centers were 7.0% (250 approximately 750 keV, 10 ns), 6.7% (250 approximately 750 keV, 6 ns), 4.0% (350 approximately 650 keV, 10 ns), and 3.8% (350 approximately 650 keV, 6 ns). Scatter fractions were 15.9% (mouse phantom) and 35.0% (rat phantom) for 250 approximately 750 keV and 6 ns. Peak NECR was 869 kcps at 3,242 kBq/mL (mouse phantom) and 228 kcps at 290 kBq/mL (rat phantom) at 250 approximately 750 keV and 6 ns. Hot-rod inserts of 1.6-mm diameter were clearly identified, and animal studies illustrated the feasibility of this system for studies of whole rodents and mid-sized animal brains. CONCLUSION: The results of this independent field test showed the improved physical characteristics of the F120 scanner over the previous microPET series systems. This system will be useful for imaging studies on small rodents and brains of larger animals. 相似文献
82.
目的 研究原核表达及纯化、复性的重组人白介素24蛋白(recombined human interlukin 24,rhIL-24)对荷人A375细胞黑素瘤裸鼠的抑制肿瘤生长的作用.方法 将人A375黑素瘤细胞注射至裸鼠体内,待肿瘤生长到一定体积后,向裸鼠的肿瘤内注射rhIL-24,2周后切取肿瘤称重、量体积,进行病理检查及免疫组化检测.结果 经rhIL-24注射的肿瘤体积及重量与对照组相比明显减小、减轻;Bax基因表达上调、Bcl-2、CD34及VEGF基因表达下调,显示肿瘤细胞生长受到抑制,凋亡率增加.结论 rhIL-24对荷人A375细胞黑素瘤裸鼠的肿瘤有显著抑制生长的功能,可促进A375细胞凋亡,而对裸鼠则无明显的不良反应. 相似文献
83.
云南省宁蒗县不明原因猝死病例调查研究 总被引:1,自引:0,他引:1
目的探讨云南省宁蒗县不明原因猝死病例的死因。方法对云南省宁蒗县不明原因猝死病例进行现场流行病学调查,采集样本进行病理学、病毒学等相关检验及分析研究。结果猝死病例的临床表现类似阿-斯综合征发作,心电图示窦性心动过速、Q-T间期延长、ST段改变、室颤,病理检验主要以心肌间质水肿、弥漫性炎细胞浸润、心肌纤维断裂、心肌灶性坏死以及其他脏器炎细胞浸润等改变为主;同发病例的临床表现亦类似阿-斯综合征发作,心电图示Q-T间期延长、室扑,粪便标本病毒分离阴性,但是从中检测到了埃可病毒11型(ECHO11)的基因片段。结论猝死病例及同发病例与既往报道的云南地方性爆发性心肌炎类似,心肌炎性改变可能诱发快速心律失常,引起阿-斯综合征发作,最后导致发病甚至猝死。 相似文献
84.
目的 克隆表达结核分枝杆菌促Rv1009基因,序列测定正确后进行融合、表达.方法 采用热启动聚合酶链反应(Polymerase Chain Reaction,PCR)从结核分枝杆菌H37Rv基因组中扩增出Rv1009编码基因,用限制性内切酶消化后插入pGEX 4T-2载体中,将重组质粒转化大肠杆菌BL21(DE3),目的基因经IPTG诱导,表达Rv1009基因蛋白.结果 经PCR扩增在1300bp处发现一条目的片段,获得了结核分枝杆菌H37Rv株Rv1009基因蛋白,经诱导后高效表达分子量为64KD的外源蛋白,与预期分子量大小一致,凝胶自动扫描分析,在A600值为0.6,IPTG终浓度为0.3 mmol/L,诱导表达3 h时融合蛋白表达量即达峰值,占菌体总蛋白的22.8%.结论 构建了结核分枝杆菌Rv1009基因重组表达载体,获得了RPF样融合蛋白的高效表达,为今后深入研究奠定了基础. 相似文献
85.
中风后癫痫的临床研究 总被引:5,自引:0,他引:5
本文报告36例中风后癫痫发作的临床和CT资料。通过回顾性病历复习和随访发现,中风后癫痫的发生率占同期住院中风患者的5.26%,以蛛网膜下腔出血和脑栓塞发生癫痫比率最高,分别为15%和12.5%。癫痫发作与CT所见病灶分布密切相关,皮质病灶较皮质下病灶更易发生病病。癫痫发作可发生于中风后任何时期,但早期癫痫以出血性中风多见,而迟发性癫痫则更多见于脑梗塞患者。 相似文献
86.
33例肝占位性病变MRI误诊的分析 总被引:1,自引:0,他引:1
我院1988年以来4000余例腹部MRI中,发现肝占位性病变误诊33例。所用机型为美国Disonics公司0.5T超导MRI,自旋回波序列(SE序列)、常规T1加权(T1WI)、质子加权(PDWI)、T2加权(T2WI),覆盖全肝。其中,PHC误诊为MHC5例、MHC误诊为PHC6例、PHC误为HHE5例、MHC误诊为HHE2例、HHE误诊为PHC6例、肝硬化结节误诊为PHC2例、炎性假瘤误诊为PHC3例、肝结核误诊为PHC1例、HCY误诊为HHE3例。本文从病变的影像学特征和扫描技术方面详细探讨了误诊的原因和鉴别诊断要点。 相似文献
87.
88.
采用高效液相色谱法测定了异丙酚在不同温度下及其甲醇 水(V∶V=70∶30)混合溶液在不同pH值下的反应速率常数,并求出了异丙酚氧化反应的活化能,结果表明pH值与温度对异丙酚的氧化动力学均有影响 相似文献
89.
Expression and distribution of vascular endothelial growth factor protein in human brain tumors 总被引:9,自引:0,他引:9
T. Pietsch Markus M. Valter Helmut K. Wolf A. von Deimling H.-J. Su Huang Webster K. Cavenee Otmar D. Wiestler 《Acta neuropathologica》1997,93(2):109-117
Marked neovascularization is a hallmark of many neoplasms in the nervous system. Recent reports indicate that the endothelial
mitogen vascular endothelial growth factor (VEGF) may play a critical role in the regulation of vascular endothelial proliferation
in malignant gliomas. Using novel monoclonal antibodies to the VEGF polypeptide we have determined the expression and cellular
distribution of VEGF protein in a representative series of 171 human central nervous system (CNS) tumors by immunohistochemistry
and immunoblotting. In agreement with previous in situ hybridization data, 19 out of 20 glioblastomas (95%) showed immunoreactivity
for VEGF, whereas both the percentage of immunoreactive tumors and the extent of immunoreactivity for VEGF were significantly
lower in astrocytomas. Of the pilocytic astrocytomas (WHO grade I) 44% were immunoreactive for VEGF, but we observed several
cases with pronounced vascular proliferates in the absence of VEGF. In ependymomas, meningiomas, hemangioblastomas, and primitive
neuroectodermal tumors, there was no correlation between VEGF expression, vascular endothelial proliferation and the grade
of malignancy. Oligodendrogliomas and the oligodendroglial component of mixed gliomas lacked immunoreactive VEGF, indicating
that endothelial growth factors other than VEGF may regulate tumor angiogenesis in these neoplasms. Western blot analysis
showed a predominant VEGF protein species of 23 kDa and confirmed the immunohistochemical data in all cases. Our findings
demonstrate that VEGF is expressed in a wide spectrum of brain tumors in which it may induce neovascularization. However,
other angiogenic factors also appear to contribute to the vascularization of CNS neoplasms.
Received: 18 April 1996 / Revised, accepted: 20 August 1996 相似文献
90.
应用ATL-ultramark超6型彩色多普勒超声诊断仪诊断扩张型心肌病100例,并与性别、年龄相应的正常人对比分析。结果:除扩张型心肌病各组室间隔及左室后壁舒张期厚度与相应正常对照组相比无显著性差异(P>0.05)外,其左室舒张内径及收缩内径、左房内径明显大于正常对照组(P<0.01),左室射血分数及左室内径缩短分数较正常对照组明显降低(P<0.01),并见心腔内血流速度缓慢,颜色变淡。另在77例病人中探及40例瓣膜返流。提示该诊断方法对扩张型心肌病具有直观、简便、准确、迅速的优点,为本病的诊断及鉴别诊断提供了良好的手段。 相似文献