Dosimetric evaluation of prostate rotations and their correction by couch rotations

PURPOSE: To investigate the dosimetric effect of prostate rotations and limited on-line corrections by couch rotations (相似文献   

HPGe探测效率和符合相加修正系数的蒙特卡罗计算

目的 介绍用蒙特卡罗(MC)方法编写的计算HPGe探测器探测效率和符合相加修正系数的程序(Cool 2000-HpGe),及实验值与计算值的比较研究。方法 用MC计算得到的探测效率和符合相加修正系数与实验得到的值进行比较。结果 对空气、水和土壤三种模拟基质体标准源由实验(ORTEC ADCOM100+GEM50195 HPGe γ谱仪系统)得到的符合相加修正系数值与模拟计算值之间的相对偏差绝对值分别为5.14%、12.1%和10.4%,在点源距探测器端窗5、10和25 cm处的由实验得到的探测效率值与模拟计算值之间的相对偏差绝对值分别为10.6%、5.6%和3.0%。结论 笔者报道的MC计算软件Cool 2000可以在环境放射性监测中用于计算HPGe探测器探测效率和符合相加修正系数。     

体重指数校正心电图QRS电压对左心室肥大诊断的影响

目的探讨体重指数校正心电图QRS电压诊断左心室肥大的临床意义.方法检测58例原发性高血压患者和健康体检者心脏超声左心室质量指数(LVMI)、QRS电压校正值[实测值(SV11+Rv5/v6)×(BMI/22)2],观察QRS电压实测值、校正值与LVMI的相关性.结果QRS电压校正值与LVMI呈明显相关,回归方程为y(Sv1+Rv5/v6)c=0.298X(LVMI)-2.481,当LVMI=134g/m2时,取(Sv1+Rv5/v6)c近似值≥40mm,诊断左心室肥大敏感性69.6%,特异性91.4%、准确性82.8%,阳性预测值84.2%,阴性预测值82.1%.结论体重指数校正心电图QRS电压能显著提高左心室肥大的诊断价值.     

A predictive factor for acquiring an ideal lower limb realignment after opening-wedge high tibial osteotomy

Obtaining a correct postoperative limb alignment is an important factor in achieving a successful clinical outcome after an opening-wedge high tibial osteotomy (OWHTO). To better predict some of the aspects that impact upon the clinical outcomes following this procedure, including postoperative correction loss and over correction, we examined the changes in the frontal plane of the lower limb in a cohort of patients who had undergone OWHTO using radiography. Forty-two knees from 33 patients (23 cases of osteoarthritis and 10 of osteonecrosis) underwent a valgus realignment OWHTO procedure and were radiographically assessed for changes that occurred pre- and post-surgery. The mean femorotibial angle (FTA) was found to be 182.1 ± 2.0° (12 ± 2.0 anatomical varus angulation) preoperatively and 169.6 ± 2.4° (10.4 ± 2.4 anatomical valgus angulation) postoperatively. These measurements thus revealed significant changes in the weight bearing line ratio (WBL), femoral axis angle (FA), tibial axis angle (TA), tibia plateau angle (TP), tibia vara angle (TV) and talar tilt angle (TT) following OWHTO. In contrast, no significant change was found in the weight bearing line angle (WBLA) after these treatments. To assess the relationship between the correction angle and these indexes, 42 knees were divided into the following three groups according to the postoperative FTA; a normal correction group (168° ≤ FTA ≤ 172°), an over-correction group (FTA < 168°), and an under-correction group (FTA > 172°). There were significant differences in the delta angle [DA; calculated as (pre FTA − post FTA) − (pre TV − post TV)] among each group of patients. Our results thus indicate a negative correlation between the DA and preoperative TA (R ² = 0.148, p < 0.05). Hence, given that the correction errors in our patients appear to negatively correlate with the preoperative TA, postoperative malalignments are likely to be predictable prior to surgery.     

尿中氚含量的两种测定方法及比较

目的 为了保证从事涉氚工作人员的健康,为常规监测探索一种快速、方便而又可靠的制样和测量方法。方法 采用常规蒸馏脱色(使用氧化回流蒸馏)和不脱色猝灭校正两种方法预处理尿样后进行液闪测量、统计分析两者测量结果。结果 上述两种不同尿样预处理后,测得的结果差异无统计学意义。结论 这两种测定方法均可用于核设施工作人员及涉氚工作人员的常规检测。但不脱色猝灭校正法在操作上要比常规蒸馏脱色法更为简捷且省时省力,适合对大量样本进行短时间的制样、测量、分析。     

Harris-Benedict equation for critically ill patients: Are there differences with indirect calorimetry?

Purpose

The aim of this study was to compare the measured energy expenditure (EE) and the estimated basal EE (BEE) in critically ill patients.

Materials and Methods

Seventeen patients from an intensive care unit were randomly evaluated. Indirect calorimetry was performed to calculate patient's EE, and BEE was estimated by the Harris-Benedict formula. The metabolic state (EE/BEE × 100) was determined according to the following criteria: hypermetabolism, more than 130%; normal metabolism, between 90% and 130%; and hypometabolism, less than 90%. To determine the limits of agreement between EE and BEE, we performed a Bland-Altman analysis.

Results

The average EE of patients was 6339 ± 1119 kJ/d. Two patients were hypermetabolic (11.8%), 4 were hypometabolic (23.5%), and 11 normometabolic (64.7%). Bland-Altman analysis showed a mean of −126 ± 2135 kJ/d for EE and BEE. Only one patient was outside the limits of agreement between the 2 methods (indirect calorimetry and Harris-Benedict).

Conclusions

The calculation of energy needs can be done with the equation of Harris-Benedict associated with lower values of correction factors (approximately 10%) to avoid overfeeding, with constant monitoring of anthropometric and biochemical parameters to assess the nutritional changing and adjust the infusion of energy.     

病理性近视黄斑病变相关因素分析及其OCT形态学研究

目的 探讨病理性近视黄斑病变OCT图像特征及其与年龄、屈光度、矫正视力的关系.方法 取140只眼按OCT图像特点分为7组,每组20只眼:(1)单纯性黄斑出血;(2)视网膜劈裂;(3)黄斑脉络膜新生血管膜;(4)视网膜脱离;(5)黄斑裂孔;(6)黄斑萎缩;(7)视网膜前膜.分析年龄、屈光度、矫正视力与各组黄斑病变的关系.结果 单纯性黄斑出血组平均年龄最小(31.05±14.96)岁,与各组间均有统计学意义(P<0.05).视网膜劈裂组、黄斑脉络膜新生血管膜组平均年龄分别为(48.00±16.59)岁、(52.30±10.98)岁,两组间无统计学意义,视网膜劈裂组与其余各组均有统计学意义(P<0.05).黄斑脉络膜新生血管膜组与黄斑萎缩、视网膜前膜组之间有统计学意义(P<0.05).视网膜脱离、黄斑裂孔、黄斑萎缩、视网膜前膜组四组间平均年龄无统计学意义.黄斑萎缩组屈光度最高,平均(-17.30±3.53)D,与各组均有统计学意义(P<0.05),其余各组之间无统计学意义(P>0.05).视网膜脱离组平均矫正视力最差,为0.04±0.03,与各组间有统计学意义(P<0.05).黄斑萎缩与黄斑裂孔组矫正视力较视网膜脱离组好,视网膜劈裂和视网膜前膜组矫正视力最好,平均矫正视力大于0.3.结论 病理性近视黄斑病变随年龄增加,病变类型不同;屈光度越高,病变越严重;病变类型不同,矫正视力不同.根据其OCT图像分类有助于明确病变性质、判断预后及指导治疗.     

尿中氚化水及有机氚浓度的测定方法及结果比较

目的 为涉氚工作人员摄入体内的氚寻找一种快速、方便而又可靠的常规监测方法。方法 采用常规蒸馏脱色、高锰酸钾祛色蒸馏法、双氧水氧化脱色和过硫酸钾氧化法四种方法预处理尿样后进行液闪测量,统计分析四者测量结果。结果 经上述四种不同尿样预处理后测得的尿氚结果有显著性差异,不是所有方法均可用于核设施工作人员及涉氚工作人员体内氚化水及有机氚的检测。结论 从测量结果来看,高锰酸钾祛色蒸馏法适合对氚化水的测量;过硫酸钾氧化法更加适合用于总氚的测定。在需要快速处理大批量样品的时候,可使用双氧水氧化法。     

用标准样品刻度γ能谱仪效率值的变化比较

目的 比较γ能谱仪刻度用标准样品探测效率的差别,为样品测量分析中的效率校正提供参考。方法 利用水、鱼肉灰、蔬菜灰和大米灰四个标准样品,在同一台HPGe γ能谱仪进行测量分析,比较效率值的相对偏差。结果 水样品与生物灰样品由于样品的几何形状和样品介质不同,导致各个能量点的效率值都有较大差别。三个生物灰样品仅装样密度不同,各个能量点的效率值略有差别。结论 γ能谱仪刻度时应首先保障被测样品与效率刻度用样品在几何形状和介质上一致,其次是样品装样密度应尽量一致,当密度不一致时效率的偏差在低能部分表现较大,应注意样品中低能区的自吸收校正问题。     

学术期刊更正文献的特征分析

【目的】学术期刊更正是学术界自我纠错的重要方式,其产生的更正文献包含大量的纠错信息,具有重要的研究价值。对更正文献的分布特点与规律予以分析和揭示,以期加强科研工作者对更正文献的了解和利用,完善学术期刊对论文更正的规范与管理,从而加强学术界与期刊界对更正行为本身以及更正文献的关注,并为后续的相关研究提供借鉴与参考。【方法】选取Web of Science核心合集数据库中近十年的更正文献记录,从年度分布、国家分布、学科分布、期刊分布四个角度对更正文献进行文献计量学分析。【结果】分析发现,近十年来,更正文献的总量逐年攀升,进入高速增长阶段。在国家分布上,更正文献广泛分布在全球184个国家和地区,且高度集中在科研实力较为发达的国家;就其学科分布而言,更正文献具有显著的分散性特点,几乎涵盖了全部的学科;在期刊分布上,更正文献广泛分布在9000余种期刊,且集中分布于高质量优秀期刊。【结论】更正文献是科学研究中不容忽视的文献类型之一,学术期刊应从更正文献的发布、传播与引用三个角度予以规范;此外,各领域专家学者应积极参与,发挥其群体智慧;同时,应采用开放评审,提升论文质量,完善期刊建设,促进学术信息交流的健康有序发展。