螺旋断层治疗系统的质量保证

螺旋断层治疗系统(HT)是一种集调强放射治疗和影像引导放射治疗于一体的放射治疗系统,是目前最先进的放疗设备之一。考虑其与常规直线加速器质量保证的差异,由国家癌症中心/国家肿瘤质控中心提出,多家医疗单位共同参与制定了本指南。指南包括国内医疗机构HT用于临床工作的验收项目、操作制度、应急预案等内容,明确了质量控制的测试方法、评价标准、检测频率。指南结合国内医疗单位实际情况给出了推荐性检测项目,主要包括机械精度、剂量输出与分布、激光定位系统、治疗床运动精度、MVCT影像系统质控检测、临床治疗计划验证等具体实施方法步骤,使得指南具有很强的可操作性。本指南能给临床工作人员提供质量保证技术指导,使HT质量保证工作有章可循,可提高放射治疗的准确性和精度。对国内各医疗机构建立规范HT质量保证体系具有指导意义。     

Antibodies to the neuronal cytoskeleton are elicited by Alzheimer paired helical filament fractions

Antibodies were raised to paired helical filament (PHF) enriched fractions obtained from brains of individuals with Alzheimer disease by extraction with ionic detergent followed by sucrose gradient centrifugation. Electron microscopic examination showed that the fractions were enriched in Alzheimer PHF but contained also lipofuscin, amyloid, granular material and membranous elements. Analysis of these fractions with SDS-PAGE stained with Coomassie blue showed only a faint band at approximately 60 kDa while most of the material was excluded from the stacking gel. BALB/c mice were injected weekly with 100 or 200 μg of these fractions or corresponding fractions from age-matched control brains. The 3 mice injected with Alzheimer brain, but not the 5 mice injected with control brain fractions, produced antibodies that reacted with central and peripheral nervous system axons, Alzheimer neurofibrillary tangles in intact tissue as well as with isolated, SDS-treated paired helical filaments. In gel strips antibodies from all 3 mice injected with Alzheimer brain fractions reacted with the 200-kDa and 168-kDa but not the 68-kDa neurofilament subunits. The 3 antisera reacted also with some forms of the microtubule-associated protein τ. Adsorptions with the insoluble fraction from Alzheimer but not from control brains blocked staining of axons and NFT by all 3 antisera. Adsorption with highly purified neurofilament proteins or with a preparation containing the 200-kDa 168-kDa neurofilament subunits blocked axon and NFT immunostaining only in one antiserum. Adsorptions with microtubule protein, heat-stable microtubule-associated protein, or a preparation of τ did not completely block immunostaining by any of the 3 antisera. These results demonstrate that fractions enriched with Alzheimer paired helical filaments contain insoluble neurofilament, τ and other yet unidentified antigens.     

超声造影与增强螺旋CT评估原发性肝癌非手术治疗的对比研究

目的:探讨超声造影在原发性肝癌非手术治疗评估中的价值.方法:对56例(64个病灶)经超声引导穿刺活检病理确诊的原发性肝癌患者进行非手术治疗.治疗后分别行超声造影和增强螺旋CT检查,以判断肿瘤的灭活程度,并对其判别能力进行比较.结果:超声造影发现46个病灶没有增强(46/64),18个病灶有部分增强(18/64).增强螺旋CT发现48个病灶没有增强(48/64),16个病灶有部分增强(16/64).与临床追踪结果比较,超声造影和增强螺旋CT对非手术治疗疗效判定的敏感性、特异性及准确率分别为94.4%,97.8%,96.9%和83.3%,97.8%,93.8%,差异有统计学意义(P＞0.05).结论:超声造影是判定非手术治疗原发性肝癌效果的一种敏感而有效的方法.对肝动脉插管栓塞化疗(TACE)疗效评估及少数血供不是特别丰富的病灶,超声造影具有较增强螺旋CT更重要的临床价值.     

Helical Structure of the Cardiac Ventricular Anatomy Assessed by Diffusion Tensor Magnetic Resonance Imaging With Multiresolution Tractography

Introduction and objectives

Deeper understanding of the myocardial structure linking the morphology and function of the heart would unravel crucial knowledge for medical and surgical clinical procedures and studies. Several conceptual models of myocardial fiber organization have been proposed but the lack of an automatic and objective methodology prevented an agreement. We sought to deepen this knowledge through advanced computer graphical representations of the myocardial fiber architecture by diffusion tensor magnetic resonance imaging.

Methods

We performed automatic tractography reconstruction of unsegmented diffusion tensor magnetic resonance imaging datasets of canine heart from the public database of the Johns Hopkins University. Full-scale tractographies have been built with 200 seeds and are composed by streamlines computed on the vector field of primary eigenvectors at the diffusion tensor volumes. We also introduced a novel multiscale visualization technique in order to obtain a simplified tractography. This methodology retains the main geometric features of the fiber tracts, making it easier to decipher the main properties of the architectural organization of the heart.

Results

Output analysis of our tractographic representations showed exact correlation with low-level details of myocardial architecture, but also with the more abstract conceptualization of a continuous helical ventricular myocardial fiber array.

Conclusions

Objective analysis of myocardial architecture by an automated method, including the entire myocardium and using several 3-dimensional levels of complexity, reveals a continuous helical myocardial fiber arrangement of both right and left ventricles, supporting the anatomical model of the helical ventricular myocardial band described by F. Torrent-Guasp.     

盆腔脂肪过多症的影像学诊断

目的：探讨盆腔脂肪过多症的影像诊断。材料与方法：回顾性分析６例盆腔脂肪过多症的影像学表现。６例均经ＣＴ和超声检查,其中３例还作了钡灌肠检查,２例行静脉肾盂造影检查。结果：（１）钡灌肠和静脉肾盂造影显示膀胱输尿管下段以及直肠、乙状结肠远端推移受压;（２）超声检查显示盆腔内良性、实性占位性病变;（３）ＣＴ扫描可显示出脂肪组织密度。结论：ＣＴ扫描诊断盆腔脂肪过多症可作为首选影像学检查方法。     

多层螺旋CT容积漫游技术诊断呼吸系统发育异常的价值

目的:探讨多层螺旋CT容积漫游技术(Volume rendering technique,VRT)诊断呼吸系统发育异常的价值。材料和方法:搜集经影像学检查及临床诊断证实的呼吸系统发育异常22例,均行多层螺旋CT薄层扫描及支气管树VRT重建,评价其诊断呼吸系统发育异常的优势与不足。结果:VRT立体显示气管性支气管3例中,伴副心支气管、气管及支气管多发节段性狭窄1例,右上叶尖段支气管直接开口于气管2例。VRT清晰显示气管支气管狭窄14例,表现为管腔气柱变窄,解剖标志明确。VRT显示支气管肺发育不良3例,相应肺体积缩小或无充气肺组织,气管支气管不规则狭窄或不发育。直观显示支气管树呈囊、柱状扩张1例,左上隔离肺1例(手术病理证实),阻塞性肺气肿8例,纵隔疝4例。结论:MSCT-VRT可直观、立体也显示呼吸系统发育异常,但显示肺叶以下支气管狭窄,节段性肺不张、肺气肿及肺感染有一定限度。     

成人型多囊肾及并发症的MSCT诊断及优势

目的 探讨MSCT诊断ADPKD并发症的优势及临床应用价值.方法 回顾性分析18例多囊肾患者的CT表现,观察多囊肾肾实质、周围脏器及肾周筋膜的变化,确定有无并发症及病变范围.结果 18例患者中,无任何症状1例,高血压症状并肝脏多发囊肿,表现双肾及肝脏多发大小不等囊肿,或并出血、结石、钙化者共8例,其中1例脾脏见一小囊肿;腹部包块、疼痛及尿路感染症状者9例,双肾体积明显增大,轮廓呈球形突出,但仍有肾形,显示肾实质明显受压,肾盂肾盏变形,并见弧形和不规则型高密度影,肾筋膜增厚,肾周脂肪间隙模糊,呈不均匀密度增高影.结论 多螺旋CT能清楚显示肾周脂肪和筋膜,是病灶检出和定位的有效方法.对临床早期发现病变、制定治疗方案、预防并发症及预后的判断具有重要的价值.     

质子点扫描技术与光子Tomotherapy在前列腺癌应用中的剂量学比较

目的:比较前列腺癌质子点扫描技术（SSS-PT）与光子螺旋断层放射治疗（HT）两者之间的剂量学特点,其数据将为临床提供一定的参考。方法:选取12例既往前列腺癌患者作为研究对象,定位后,将CT图像分别传至Raystation和HT计划系统进行放疗计划设计。处方剂量为69 Gy/25 F。比较分析两种放疗计划的靶区适形度指数（CI）、均匀性指数（HI）、靶区和危及器官剂量学参数。结果:靶区的均匀性方面,SSS-PT优于HT（P=0.001）;直肠平均剂量SSS-PT［（21.92±4.00） Gy］低于HT［（31.97±2.60） Gy］（P=0.000）;膀胱平均剂量SSS-PT［（17.62±3.15） Gy］低于HT［（30.52±3.94） Gy］（P=0.000）;对于直肠和膀胱的保护,SSS-PT在低、中剂量区总是优于HT。结论:SSS-PT和HT两种治疗方式在靶区剂量分布均可满足临床需求,在同样靶区覆盖条件下,SSS-PT相较于HT能够更好地保护直肠和膀胱,尤其是在低、中剂量区。     

TQA数据趋势与TomoTherapy输出稳定性的联系

目的:探讨TomoTherapy QualityAssurance（TQA）数据趋势与螺旋断层放疗（Helical Tomotherapy,HT）系统输出的联系。方法:回顾性分析了本院HT系统近3年内TQA各个模块的参数和数据趋势,探讨其与HT系统的静态输出剂量和输出能量（D20/D10）变化的相关性。结果:楔形阶梯静态模块的z轴偏移参数与HT的静态输出剂量的相关性最强（r=0.883,P<0.01）。基本剂量测定模块的出口检测器平整度值对能量变化最敏感（r=0.902）,其次是楔形阶梯静态模块的能量差异（r=0.897）和楔形阶梯螺旋模块的能量差异（r=0.852）,灵敏度分别为2.3×10-4、3.1×10-4和5.7×10-4。结论:TQA有助于用户追踪HT输出剂量和能量变化,及早进行必要的机器维护或剂量校准。