乳腺癌诊断中应用高频彩色多普勒超声联合X射线钼靶的效果分析

目的：探讨高频彩色多普勒超声联合X射线钼靶检查在乳腺癌疾病中的诊断效果。方法：抽取2019年2月～2022年2月本院拟诊乳腺癌患者30例（均属于女性）。病理检查证实阳性乳腺癌患者25例，阴性5例，所有患者均进行彩色多普勒超声检查、X射线钼靶、两者联合检查。记录三种不同方式对乳腺癌病理分型的诊断准确率、特异性、敏感性、漏诊率及误诊率。结果：彩色多普勒超声诊断准确率与X射线钼靶准确率比较无差异，P<0.05；联合式检查诊断结果准确率显著优于彩色多普勒超声结果以及X射线钼靶结果，P<0.05；病理诊断结果对比显示，联合式检查在敏感性、特异性方面均优于其他2组，P<0.05，且联合式检查在漏诊、误诊率明显低于其他两组，P<0.05。结论：相比较于单独一种检查方法，联合性检测方式可同时弥补两种检测方式的不足，提高诊断准确率，且联合式检查方法简单并更具有经济性。     

医用直线加速器不同靶材料对X射线能谱的影响研究

目的:研究无均整过滤器(FFF)模式下不同靶材料对加速器能谱结构的影响,以及该模式下是否有必要切换靶材料以满足不同的临床治疗需求。方法:以基于蒙特卡罗算法(统计试验法)的EGSnrc程序用于电离辐射传输模拟,使用BEAMnrc建立VarianTrueBeam系列加速器机头结构,并设置不同材料和不同厚度的靶,使用BEAMdp调用其计算生成的相空间文件进行能谱与能量注量的结果分析比较。结果:在靶材料中厚度为0.2 cm的金靶在能谱结构表现较钽靶、钨靶更为优异,高原子序数材料光子能量注量差异不大,低原子序数材料铜靶在能谱与能量注量都不能满足使用要求。金靶在<2 cm厚度时具有很高的电子污染,低能光子份额高达20%,非平坦度高于80%,但较薄材料具有更高的能量份额与更低的热量损失,在常规模式较为适用。结论:FFF模式较常规模式提高了射野范围内光子的产生效率,高原子序数材料更适合作为靶材料,在常规模式切换到FFF模式时可以考虑同时切换靶材料以提高轫致辐射产生效率。     

调强放疗逆向计划优化中基于剂量的目标函数改进

目的：研究调强放疗射野参数优化中基于剂量的目标函数的建立方法。方法：对传统的基于剂量的目标函数进行改进，在靶区周围勾画辅助器官，建立靶区剂量均匀性约束、辅助器官与靶区最高剂量约束和组织重要因子约束；用遗传算法对笔射柬权重进行优化，比较优化结果。结果：在目标函数约束下，能够显著提高靶区剂量均匀性和高剂量照射区与靶区在三维方向上的适型度。结论：上述目标函数在调强放疗逆向计划优化中具有重要临床应用价值。     

控制点数量对右侧乳腺癌术后容积旋转调强放疗的剂量学影响

目的：比较控制点数量对右侧乳腺癌术后容积旋转调强放疗（volumetric modulated arc therapy,VMAT）计划的剂量学影响。方法：选取15例右侧乳腺癌术后患者，利用Monaco 5.1计划系统进行计划靶区（planning target volume,PTV）勾画和计划设计。将控制点数量分别设置为20、30、40、50、60，在同等优化条件下，比较不同控制点计划目标靶区和危及器官的剂量学差异。采用SPSS 22.0软件进行统计学分析。结果：随着控制点数量的增加，靶区的适形性指数逐渐增大（分别为0.59±0.07、0.67±0.06、0.70±0.06、0.71±0.08、0.70±0.08）且差异有统计学意义（P=0.00），均匀性指数也逐渐增大（分别为1.23±0.10、1.11±0.03、1.09±0.02、1.07±0.02、1.08±0.02）且差异具有统计学意义（P=0.00）。当控制点数量低于30时，右肺V5更小但是靶区剂量覆盖较差（P<0.05）；当控制点数量设置为50时，目标靶区均匀性指数和适形性指数最优；当控制点数量大于50时，目标靶区适...     

人工智能乳腺超声在基层乳腺癌筛查中的应用价值初探

目的 比较传统手持超声(HHUS)、钼靶和人工智能乳腺超声(AIBUS)在基层妇女乳腺癌初筛中的一致性。方法纳入2021年8月21日—9月30日在成都市双流区妇幼保健院接受农村“两癌”筛查的2 356名女性，研究对象知情同意后平行接受两种超声检查，按并联设计原则分流至钼靶检查或多学科会诊。采用Kappa系数分别对AIBUS vs.HHUS、AIBUS vs.钼靶、HHUS vs.钼靶进行一致性评价。结果 共2 356人接受两种超声检查，959人接受钼靶检查。两种超声检查分流结果一致性的Kappa=0.433(95%CI:0.394～0.472), P<0.001。AIBUS与钼靶分流结果一致性(Kappa=0.078, 95%CI:0.075～0.081, P<0.001)略高于HHUS与钼靶分流结果一致性(Kappa=0.051, 95%CI:0.018～0.084,P=0.004)。结论 两种超声在分流结果上具有中等强度的一致性，AIBUS与钼靶对比的一致性略高于HHUS,AIBUS在基层乳腺癌初筛中具有一定的应用价值。     

MRI与钼靶对乳腺癌的诊断价值比较

目的探讨MRI、钼靶对乳腺癌诊断的价值。方法选择经病理证实的乳腺癌患者的同期MRI、钼靶资料进行分析，比较诊断的准确率。结果钼靶在显示钙化方面占有绝对优势，MRI在显示肿瘤肿瘤部位、内部结构、形态、边缘、与周围组织关系及肿瘤定性方面优于钼靶。结论MRI无电离辐射，有良好的软组织分辨率，敏感性高于钼靶摄影，特别是对小病灶或位于乳腺深部的病灶敏感性高，有利于乳腺癌的早期诊断。     

靶区中心平均位置在肺部三维适形放疗中的应用

目的：探讨靶区中心的平均位置应用于肺部三维适形放射治疗的可行性。方法：选取可接受三维适形放射治疗的周围型肺癌患者8例，在治疗体位和自由呼吸的情况下，应用多序列时相特异性快速CT扫描技术进行扫描。扫描图像传输到三维治疗计划系统后，按序列进行三维重建，计算各序列肿瘤中心坐标，求出靶区中心的平均位置。制定治疗计划时将照射野中心置于靶区中心的平均位置，计算靶体积，并于放射治疗前和过程中应用电子射野影像系统进行验证，并与靶区中心平均位置法的靶体积进行比较。结果：按靶区中心平均位置方法计算出的靶体积与GTV外放10mm和20mm的靶体积相比，平均靶区中心法的靶体积显著减少（P值分别为0．014和0．000）。放射治疗前和过程中的电子射野影像系统验证片未发现肿瘤运动到照射野外。结论：靶区中心的平均位置法应用于肺部肿瘤的三维适形放射治疗是可行的。     

磁共振对乳腺肿瘤的鉴别与诊断价值

目的 分析磁共振（MRI）检查对乳腺肿瘤的鉴别与诊断价值。方法 选取2021年12月至2022年12月就诊于医院并经手术病理确诊的60例乳腺肿瘤患者为研究对象，均先后接受钼靶X线检查和MRI检查。以手术病理结果为金标准，比较钼靶X线与MRI诊断的准确率、特异度、灵敏度。比较钼靶X线和MRI检查的有效放射剂量、图像质量优良率。结果 MRI检查的诊断准确率、特异度、灵敏度均高于钼靶X线，差异有统计学意义（P <0.05）；钼靶X线检查的有效放射剂量高于MRI检查，差异有统计学意义（P<0.05）;MRI检查的图像质量优良率高于钼靶X线检查，差异有统计学意义（P<0.05）。结论 MRI检查对乳腺良恶性肿瘤均有较高的诊断准确率、特异度和灵敏度，图像质量优良，且无辐射，安全性高。     

数字化CR乳腺摄影临床应用及探讨

目的：探讨数字化CR乳腺钼靶X线摄影及普通屏，胶摄影。方法：各抽取200例乳腺钼靶X线摄影进行质量比较。结果：数字化CR乳腺钼靶摄影图像诊断质量高于普通屏，胶图像诊断质量。结论：数字化CR钼靶对乳腺肿瘤周围的改变．如细小钙化、毛刺症或小的结节能清晰显示。     

钼/铑双靶X线检查筛查早期乳腺癌的优点

目的：探讨乳腺钼／铑双靶X线机(传统的为钼单靶机)筛查早期乳腺癌的优点。方法：育龄妇女512例，年龄23～54岁。做常规体检与X线钼靶检查的对比，其中部分病例再分别进行钼／铑靶检查对照，比较早期乳腺癌的检出率：摄影条件：27～31KV，30～60MAS，钼、铑靶作轴位(头足位，The Craniocaudal Proiection，CC)和内斜位(The mediolateral oblique Pro-jection，MLO)投照。结果：体检512例，扪及肿块76例、占15．0％；钼靶检查512例，发现良性肿物49例，占受检人数9．6％，乳腺癌8例，占1．6％。钼铑靶对比组：①体检乳房肿块16例，钼靶未见异常，铑靶发现良性肿瘤4例，乳癌1例。②取有家族史等41例，钼靶见良性肿瘤4例，乳癌1例；铑靶发现良性肿瘤6例，乳癌2例。③声像图异常4例，钼靶见乳癌1例；铑靶见良性肿瘤1例，乳癌3例。结论：体检应为筛查早期乳腺癌的第一关。钼靶检查，对于普通乳腺带来很好的图像，但对于致密性乳腺或较大的乳腺略显穿透不足，病灶的检出能力受到局限，阳性检出率不高，能较好诊断肿瘤的良恶性及很好的定位。铑靶检查，能弥补钼靶的不足，更好的穿透性，恰好满足了所有乳腺类型的应用。对无症状、未扪及肿块的早期乳腺癌，钼／铑双靶机中的铑靶优于钼靶。     

Statistical methods for determining the accuracy of quantitative polymerase chain reaction-based tests

Quantitative polymerase chain reaction (PCR)-based tests are used in several different scientific fields to determine levels of a target DNA sequence of interest (the target molecule). The accuracy of quantitative PCR-based tests can be assessed by using the assay to determine the number of copies of the target molecule in a sample with a known concentration of the target molecule. For example, a sample with a known concentration of a target DNA sequence is serially diluted into replicate aliquots and these are tested to determine if the observed quantity of the target is close to the expected quantity (given the concentration in the original sample and the dilution). Statistical methods that are conventionally used to assess the accuracy of these assays do not take into account the variability in the number of target molecules in each aliquot from the original sample. We develop methods that take into account this extra variation and which determine the accuracy of quantitative PCR-based tests in estimating the number of target molecules based on a set of assays of serial dilutions from an original sample with a known concentration of target molecules. These methods are applied to data from an experiment to test the accuracy of a real-time PCR assay at low HIV-1 DNA copy levels.     

The waiting game

Progress on the 18-week target is difficult to measure due to a lack of available information. A lack of alignment between the target and available IT support is a key reason for the lack of progress. Electronic access to information on patient pathways is crucial to achieving the target.     

医用回旋加速器束流引出位置对液体靶工作效率的影响

目的探讨医用回旋加速器引出束流轰靶的位置对液体靶生产正电子同位素能力的影响。方法选择最佳磁场电流范围;固定轰靶的束流强度（30μA）、靶室压力（350±10Psi）、核反应时间（T=30min）及靶水体积（1.5mL H2O18）,利用18O（p,n）18F核反应生产18F同位素;以圆形靶膜正中为坐标原点,建立直角坐标平面,调整回旋加速器加速粒子的引出位置,分别使2/3束流截面面积位于不同的两个相邻象限内,测量不同条件下反应结束后获得的18F的放射性活度。结果束流中心定位于靶膜正中位置时获得的18F的放射性活度为（710±30）mCi（n=15）;束流中心定位于靶膜正中位置垂直偏下,且2/3束流截面积位于圆形靶膜的第三、四象限内时,获得的18F的放射性活度为（860±50）mCi（n=15）;束流中心定位于靶膜正中位置偏左或偏右,且2/3束流截面积位于第二、三象限或第一、四象限时,获得的18F的放射性活度都为（640±35）mCi（n=15）;束流中心定位于靶膜正中位置偏上,且2/3束流截面积位于第一、二象限时,获得的18F的放射性活度为（550±40）mCi（n=15）。结论轰靶束流的引出位置的改变会直接影响液体靶的工作效率;当束流中心定位于靶膜正中位置偏下通过时,液体靶的工作效率最好。     

磁锚定肺结节定位装置的研制

磁锚定肺结节定位装置由靶磁体、锚定磁体、同轴穿刺针和穿刺导航模板组成,衍生出新型肺小结节准确定位技术.该装置通过在CT引导下将靶磁体置入肺结节旁的肺组织中,借由两靶磁体的相互吸引,靶磁体在肺内得以固定于肺组织内,避免肺内移动,术前精准定位目标肺结节.在胸腔镜手术中,通过锚定磁体与靶磁体的相互吸引,达到定位目标结节的目的...     

Modeling and validating Bayesian accrual models on clinical data and simulations using adaptive priors

Slow recruitment in clinical trials leads to increased costs and resource utilization, which includes both the clinic staff and patient volunteers. Careful planning and monitoring of the accrual process can prevent the unnecessary loss of these resources. We propose two hierarchical extensions to the existing Bayesian constant accrual model: the accelerated prior and the hedging prior. The new proposed priors are able to adaptively utilize the researcher's previous experience and current accrual data to produce the estimation of trial completion time. The performance of these models, including prediction precision, coverage probability, and correct decision‐making ability, is evaluated using actual studies from our cancer center and simulation. The results showed that a constant accrual model with strongly informative priors is very accurate when accrual is on target or slightly off, producing smaller mean squared error, high percentage of coverage, and a high number of correct decisions as to whether or not continue the trial, but it is strongly biased when off target. Flat or weakly informative priors provide protection against an off target prior but are less efficient when the accrual is on target. The accelerated prior performs similar to a strong prior. The hedging prior performs much like the weak priors when the accrual is extremely off target but closer to the strong priors when the accrual is on target or only slightly off target. We suggest improvements in these models and propose new models for future research. Copyright © 2014 John Wiley & Sons, Ltd.     

Identifying reservoirs of infection: a conceptual and practical challenge

Many infectious agents, especially those that cause emerging diseases, infect more than one host species. Managing reservoirs of multihost pathogens often plays a crucial role in effective disease control. However, reservoirs remain variously and loosely defined. We propose that reservoirs can only be understood with reference to defined target populations. Therefore, we define a reservoir as one or more epidemiologically connected populations or environments in which the pathogen can be permanently maintained and from which infection is transmitted to the defined target population. Existence of a reservoir is confirmed when infection within the target population cannot be sustained after all transmission between target and nontarget populations has been eliminated. When disease can be controlled solely by interventions within target populations, little knowledge of potentially complex reservoir infection dynamics is necessary for effective control. We discuss the practical value of different approaches that may be used to identify reservoirs in the field.     

Doubly robust estimation of the weighted average treatment effect for a target population

The weighted average treatment effect is a causal measure for the comparison of interventions in a specific target population, which may be different from the population where data are sampled from. For instance, when the goal is to introduce a new treatment to a target population, the question is what efficacy (or effectiveness) can be gained by switching patients from a standard of care (control) to this new treatment, for which the average treatment effect for the control estimand can be applied. In this paper, we propose two estimators based on augmented inverse probability weighting to estimate the weighted average treatment effect for a well-defined target population (ie, there exists a predefined target function of covariates that characterizes the population of interest, for example, a function of age to focus on elderly diabetic patients using samples from the US population). The first proposed estimator is doubly robust if the target function is known or can be correctly specified. The second proposed estimator is doubly robust if the target function has a linear dependence on the propensity score, which can be used to estimate the average treatment effect for the treated and the average treatment effect for the control. We demonstrate the properties of the proposed estimators through theoretical proof and simulation studies. We also apply our proposed methods in a comparison of glucagon-like peptide-1 receptor agonists therapy and insulin therapy among patients with type 2 diabetes, using the UK Clinical Practice Research Datalink data.     

食管癌调强放疗靶区与肺体积比和处方剂量的关系

目的 研究食管癌调强放射治疗中能够做出既定目标的放疗计划时,靶区体积与肺体积比值和处方剂量的关系,从而帮助临床医生根据靶区情况,选择适合的处方剂量。方法 随机选取临床上已进行放射治疗的食管癌患者80例;其中病变范围包括全部食管癌类型,靶区根据ICRU（International Commission Radiological Units）50、62号文件进行勾画;设定统计参数及计划目标。根据参数的统计结果进行统计学分析;通过拟合计算求出满足既定目标的体积比临界值。结果 体积比与肺V₅、V₂₀、V₃₀以及肺平均受量具有线性正相关关系。给予60 Gy的处方剂量时,体积比的临界值为10%;给予50 Gy的处方剂量时,体积比的临界值为13%。结论 根据研究结果可以预见：食管癌调强放疗中当靶区体积与肺体积比值超过10%时,考虑给予的处方剂量不高于60 Gy;当靶区体积与肺体积比值超过13%时,给予处方剂量时应谨慎选择,但对于各段食管癌靶区超出肺段的患者可适当放宽。这为临床医生勾画靶区期间在处方剂量和靶区范围的选择上提供了参照。     

Prognostic Value of Early Therapeutic Alliance in Weight Recovery: A Prospective Cohort of 108 Adolescents With Anorexia Nervosa

PurposeTo determine whether patients' perception of early therapeutic alliance (TA) could predict time to achieve a target weight among adolescents undergoing treatment for anorexia nervosa.MethodTA was assessed in a prospective cohort recruited from both inpatient and outpatient settings by self-administered and validated questionnaires. Kaplan–Meier survival curves were compared by log rank test, and Cox regression was used to test whether patients' perception of early TA predicted time to achieve a target weight.ResultsIn total, 108 patients were included, and 79.6% achieved a target weight. Better patient perception of early TA increased the hazard ratio (HR) of achieving a target weight (HR = 2.7, 95% confidence interval: 1.7–4.4, p < .001) such as being in the inpatient setting by 6.7. Being very severely underweight at admission decreased the HR of achieving the target weight.ConclusionPatients' perception of early TA is a good predictor of achieving a target weight. Because TA is a modifiable construct, it could be a target for intervention.     

Meditations on birth weight: is it better to reduce the variance or increase the mean?

A conceptual model is presented here in which the birth weight distribution is decomposed into a distribution of target weights and a distribution of perturbations from the target. The target weight is the adaptive goal of fetal development. In the simplest model, perinatal mortality is independent of variation in target weight and determined solely by the magnitude of the perturbation of birth weight from the target. In this model, mortality risk is concentrated in the tails of the birth weight distribution. A difference between populations in their distributions of target weights will be associated with a corresponding shift in their curves of weight-specific risk, without any difference between the populations in overall risk. In this model, risk would be reduced by decreasing the variance of the distribution of perturbations. The model is discussed in the context of the so-called "paradoxes of low birth weight."