Performance measurement of the microPET focus 120 scanner.

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.     

氯胺酮对荷包牡丹碱诱导PC12细胞内Ca2+浓度波动方式的影响

目的研究氯胺酮对荷包牡丹碱诱导PCI2细胞内Ca^2＋浓度波动方式的影响。方法使用含25ng／LNGF的DMED培养基在多聚赖氨酸包被的培养皿中培养PCl2细胞；与终浓度10gmol／L的Ca^2＋指示剂Fluo-3 AM ester共孵育30min洗涤后，加入终浓度50gmol／L荷包牡丹碱；在激光共聚焦显微镜选定多个细胞分别测定荧光强度的变化；随后加入氯胺酮，记录细胞荧光强度的改变。在试验结束前依次加入Triton X-100和EGTA分别记录单个细胞最大荧光强度（Fmax）和最小荧光强度（Fmin），以计算细胞内Ca^2＋的相对强度。结果氯胺酮不改变荷包牡丹碱诱导PCl2细胞内Ca^2＋浓度波动的基线，但抑制细胞内Ca^2＋浓度升高的幅度（P〈0．05），缩短相邻波峰间的时间间隙（P〈0．05）。结论氯胺酮不仅改变荷包牡丹碱诱导PCl2细胞内Ca^2＋浓度升高的幅度，而且改变Ca^2＋浓度波动的周期。     

医源性桡神经损伤46例分析

目的阐述医源性桡神经损伤的伤因、治疗和预防措施。方法分析1991年～2003年间收治的46例医源性桡神经损伤的病例。结果伤因分为上肢手术误伤，肱骨干和桡骨上端闭合性骨折复位手法不当，头静脉穿刺致桡神经浅支损伤。本组21例保守治疗，22例手术治疗，3例行肌腱转位功能重建。结论手术误伤是医源性桡神经损伤的首要原因；临床医生丰富的解剖知识和细致、轻柔的操作是预防医源性桡神经损伤的关键。     

磁共振扩散加权成像对超急性期、急性期脑缺血的应用价值

磁共振扩散加权成像(DWI)可以快速、无创地反映脑缺血区分子水平发生的微观变化,为临床提供信息,本文对其在超急性期、急性期脑缺血的应用价值和限度进行综述。     

改良神经刺激仪定位在全麻下乳腺癌术中对神经的保护作用

目的探讨改良神经刺激仪对神经定位的效果，以防止乳腺癌手术对运动神经的损伤，提高手术成功率及术后生活质量。方法选择ASAⅠ～Ⅱ级，乳腺癌预计手术中难以辨认神经血管走行的女性患者20例。应用Stimuplex HNS 12／BRAUN周围神经刺激仪，改良为双极刺激电极在术前、术后均对胸背神经支配的背阔肌、胸长神经支配的前锯肌以及胸前神经支配的胸肌进行肌电检测，以确定手术中神经损伤情况。结果18例患者手术前胸大肌动作电位为（1．59±0．4）mv，手术后为（1．58±0．3）mv，前后比较差异无统计学意义（P〉0．05）。手术前神经传导速度为（40．57±2．33）m／s，手术后为（40．43±2．18）m／s，前后比较差异无统计学意义（P〉0．05）。仅2例出现轻度神经损伤。结论改良神经刺激仪能准确定位神经，避免了神经的直接损伤，基本上达到了肌电图仪的神经探测功能。     

^125I放射微粒微创植入治疗前列腺癌

目的观察^125I放射微粒植入对前列腺癌的治疗效果。方法对26例临床确诊为前列腺癌患者经皮穿刺在癌组织植入^125I放射微粒，每例平均36粒，术后复查肛诊、B超、影像学及血生化指标。结果患者植入治疗经过顺利，2例少量出血，留置导尿后愈合，3个月后经肛诊、直肠B超示结节缩小，前列腺特异性抗原（PSA）降低，多普勒超声显示结节内动脉收缩期最大血流速度（VS）、阻力指数（RI）及动脉搏动指数（PI）均明显下降。结论^125I放射微粒植入对前列腺癌的治疗安全性好、效果可靠。     

微创小切口全髋关节置换术的手术配合

目的 探讨医疗服务中心工作中常见的安全问题及其对策。方法 对我院医疗服务中心2004年4月至2007年3月存在的护理安全隐患问题进行回顾性分析。结果 发生安全隐患共80次，造成不良后果25次。结论 医疗服务中心工作存在较大的安全隐患，应采取措施优化服务流程，严格遵守操作规程；强化法律意识．做好各项记录；建立不良事件报告系统，加强职业防护意识培训；完善医疗职业保险制度，保障员工利益等措施以保障医疗安全，提高服务质量。     

麻醉剂量羟甲芬太尼对大鼠脑内单胺递质及其代谢物含量的影响

麻醉剂量羟甲芬太尼对大鼠脑内单胺递质及其代谢物含量的影响金昔陆１唐琴梅金文桥周德和李桂芬池志强（中国科学院上海药物研究所，上海２０００３１）羟甲芬太尼（ｏｈｍｅｆｅｎｔａｎｙｌ，ＯＭＦ）是一种新的高选择性高亲和力μ阿片受体激动剂，在动物中能产生麻醉作...     

老年人免疫功能异常变化的临床观察及其评价(Ⅰ)

老年人生理适应与防卫能力进行性下降,对有害因子易伤性增加,导致多种老年病的发生。因此,免疫系统功能与衰老的关系问题,已是现代老年病学和免疫学进行多方深入研究的重要内容。我们近两年多来对老年人免疫功能变化做了临床观察检测与统计分析。现报告如下。 1.临床资料     

小肠广泛切除术后高胃泌素血症与结肠代偿性变化的关系

观察大鼠小肠广泛切除术后血清胃泌素和结肠粘膜代偿性改变的动态变化规律,发现术后14天内血清胃泌素稍低于正常组,从第14天开始血清胃泌素升高加快,至21天时差异有显著性意义(P<0.05),第28天时差异有非常显著性意义(P<0.01).血清胃泌素变化与术后结肠粘膜DNA、RNA变化呈正相关关系(P<0.001),提示高胃泌素血症可能是引起小肠广泛切除术后结肠粘膜代偿性变化的主要因素之一.