大型海绵窦海绵状血管瘤的体积分割伽玛刀治疗

目的 研究按体积分割分次伽玛刀治疗大型海绵窦海绵状血管瘤的治疗效果和副反应发生情况。方法 分析18例直径大于3 cm的海绵窦海绵状血管瘤患者,均采用体积分割的方式予以2~4次伽玛刀治疗,首次治疗一般选择肿瘤的基底部,边缘剂量为13 Gy,其后每次治疗间隔3~12个月,边缘剂量根据肿瘤的缩小情况以及解剖位置取12~13 Gy,并保证9 Gy的剂量曲线不与视神经和视交叉重合。结果 随访6~51个月,平均随访18个月,所有患者在第1次伽玛刀治疗后3~6个月就可见病灶明显缩小,5例患者在首次治疗3个月后病灶体积缩小25.3%~46.6%,平均缩小36.7%,13例患者首次治疗6个月后病灶体积缩小25.8%~65.5%,平均缩小47.1%。随着剩余分次伽玛刀治疗的完成,病灶继续缩小。所有患者在伽玛刀治疗后未出现临床症状加重以及新的神经功能受损,其中15例患者在第1次治疗后3~6个月后症状就得到改善,3例患者复查中症状无明显变化,症状改善率为83.3%。结论 采用从基底部开始的体积分割分次伽玛刀治疗大型海绵窦海绵状血管瘤是一种安全有效的治疗方式,在有效控制肿瘤生长的同时能改善患者的临床症状,可作为此类病变的主要治疗方式。

大型脑动静脉畸形的伽玛刀体积分割治疗

目的探讨伽玛刀体积分割治疗大型(体积>10 cm^(3))脑动静脉畸形(AVM)的临床疗效。方法回顾性分析2007~2017年收治的13例大小脑AVM的临床资料,均采用伽玛刀体积分割治疗,时间间隔3~18个月,治疗的AVM总体积平均为18.2 cm^(3)(13.5~52 cm^(3)),首次治疗的体积平均为14.1 cm^(3)(8~23 cm^(3));边缘剂量平均为16.6 Gy(14~20 Gy)。13例随访24~92个月,平均为43.2个月。结果末次随访影像显示,6例血管巢闭塞,4例病灶体积减小>75%,3例病灶缩小<50%。8例癫痫中,6例缓解或改善。1例治疗后7个月出现脑出血,1例治疗后6个月因脑放射性副反应出现肢体感觉运动障碍。结论伽玛刀体积分割治疗大型脑AVM是一种安全、有效的方法,大多数临床症状可明显改善。

分析3D slicer体积分割准确性及在法医实践应用的展望

目的 探索基于虚拟解剖的尸体计算机断层扫描肝脏三维切片(three dimensional slicer,3D slicer)人工智能(Artificial Intelligence,AI)体积重建辅助法医实践的应用效果。方法 选取本中心20例同时进行虚拟解剖及传统尸检的死者,对其进行3D slicer法、多田公式法、文献法进行肝脏体积分割,并与传统尸检所得数据进行对比分析,得出准确率。结果 与多田公式法及文献中提及的方法相比,3D slicer法得到了更高的一致性(95%置信区间)、更低的体积变异性(标准差)以及较小的不确定区域(方差齐)。结论 基于虚拟解剖的3D slicer AI重建可以对虚拟解剖进行可视化,有助于增加传统尸检诊断准确率,辅助进行病理诊断,并对虚拟解剖的影像组学发展提供新方向、新手段。

浅谈类比推理在立体几何中的应用

数学家、教育家乔治·波利亚曾说,＂一般化,特殊化和类比是获得发现的源泉。类比是一种最富于创造性的逻辑推理方法和探索的工具。它凭借少量的知识和个别熟悉对象,可以探测和推移到未知的陌生的对象。＂近年来,利用类比推理的方法编拟的高考创新试题屡见不鲜,如2000年上海卷春季第12题,2003年全国卷文科第16题,2006年湖北文科第15题,2008年高考全国卷Ⅱ理16题,其中三分之二的是立体几何问题。由于中学生对两个或两类对象之间的类比关系不很明确,导致考试时思维混乱,类比盲目,针对这一现象,本文谈谈平面几何与立体几何中的类比关系。

The Partition of Unity Method for High-Order Finite Volume Schemes Using Radial Basis Functions Reconstruction

This paper introduces the use of partition of unity method for the development of a high order finite volume discretization scheme on unstructured grids for solving diffusion models based on partial differential equations.The unknown function and its gradient can be accurately reconstructed using high order optimal recovery based on radial basis functions.The methodology proposed is applied to the noise removal problem in functional surfaces and images.Numerical results demonstrate the effectiveness of the new numerical approach and provide experimental order of convergence.

Automatic Liver Segmentation Scheme for MRI Images Based on Cellular Neural Networks

Currently, the processing speed of exist-ing autormtic liver segmentation for Magnetic Res-onance Imaging （MRI） images is rehtively slow. An automatic liver segmentation scheme for MRI irmges based on Cellular Neural Networks （CNN） is presented in this paper. It ensures the validity of this scheme and at the same time completes the im-age segmentation faster to accurately calculate the liver volume by using parallel computing in real time. In order to facilitate the CNN irmge process-hag, firstly, three-dimensional liver MRI images should be transformed into binary images; second- ly, an appropriate template parameter of the Global Connectivity Detection CNN （GCD CNN） shall be selected to probe the connectivity of the liver to extract the entire liver; and then the Hole-Filler CNN （HF CNN） are used to repair the entire extracting liver and improve the accuracy of fiver segmentation; final-ly, the liver volume is obtained. Results show that the scheme can ensure the accuracy of the automatic seg-mentation of the liver, and it can also improve the processing speed at the same time. The liver volume calculated is in line with the clinical diagnosis.

Mass transfer characteristics in a rotating packed bed with split packing

The rotating packed bed （RPB） with split packing is a novel gas-liquid contactor, which intensifies the mass transfer processes controlled by gas-side resistance. To assess its efficacy, the mass transfer characteristics with adjacent rings in counter-rotation and co-rotation modes in a split packing RPB were studied experimentally. The physical absorption system NH3-H2O was used for characterizing the gas volumetric mass transfer coeffi- cient （kyae） and the effective inteffacial area （ae） was determined by chemical absorption in the CO2-NaOH sys- tem. The variation in kyae and ae with the operating conditions is also investigated. The experimental results indicated that kyae and ae for counter-rotation of the adjacent packing rings in the split packing RPB were higher than those for co-rotation, and both counter-rotation and co-rotation of the split packing RPB were superior over conventional RPBs under the similar ooerating conditions.

截锥体矿段分割前后储量估算误差分析

在矿产资源储量估算中,将矿体分割为块段估算资源储量,在年报、核实报告的储量估算中,将原块段进一步分割,探求矿山保有和消耗资源储量。截锥体是矿体块段的基本形态之一。截锥体块段分割后,其总体积与分割前原矿段体积不相等,有计算误差,从而导致了储量估算误差。块段分割前后体积计算误差随断面分割系数及其差值变化而变化。