电离辐射剂量监测用热释光探测器

用固体能带（晶格能级）理论阐述了热释光探测用于剂理测量的机制；介绍了热释光探测器常用的５种磷光体，即ＬｉＦ，ＣａＳＯ４，ＣａＦ２，Ｌｉ２Ｂ４Ｏ７和ＢｅＯ的剂量学特性及其优缺点和使用中应注意的问题；给出了热压挤片法、热压切片法、冷压烧结法、毛细管封装法和树脂粘合法等热释光探测器的制备工艺，以及它们的适应范围。     

Pharmacokinetics and Early Tumor Response to Conventional Transarterial Chemoembolization with Sorafenib and Doxorubicin in a VX2 Rabbit Tumor Model

PurposeTo investigate the pharmacokinetics (PK) and early effects of conventional transarterial chemoembolization (TACE) using sorafenib and doxorubicin on tumor necrosis, hypoxia markers, and angiogenesis in a rabbit VX2 liver tumor model.Materials and MethodsVX2 tumor-laden New Zealand White rabbits (N = 16) were divided into 2 groups: 1 group was treated with hepatic arterial administration of ethiodized oil and doxorubicin emulsion (DOX-TACE), and the other group was treated with ethiodized oil, sorafenib, and doxorubicin emulsion (SORA-DOX-TACE). Animals were killed within 3 days of the procedure. Levels of sorafenib and doxorubicin were measured in blood, tumor, and adjacent liver using mass spectrometry. Tumor necrosis was determined by histopathological examination. Intratumoral hypoxia-inducible factor (HIF) 1α, vascular endothelial growth factor (VEGF), and microvessel density (MVD) were determined by immunohistochemistry.ResultsThe median intratumoral concentration of sorafenib in the SORA-DOX-TACE group was 17.7 μg/mL (interquartile range [IQR], 7.42–33.5 μg/mL), and its maximal plasma concentration (C_max) was 0.164 μg/mL (IQR, 0.0798–0.528 μg/mL). The intratumoral concentration and C_max of doxorubicin were similar between the groups: 4.08 μg/mL (IQR, 3.18–4.79 μg/mL) and 0.677 μg/mL (IQR, 0.315–1.23 μg/mL), respectively, in the DOX-TACE group and 1.68 μg/mL (IQR, 0.795–4.08 μg/mL) and 0.298 μg/mL (IQR, 0.241–0.64 μg/mL), respectively, in the SORA-DOX-TACE group. HIF-1α expression was increased in the SORA-DOX-TACE group than in the DOX-TACE group. Tumor volume, tumor necrosis, VEGF expression, and MVD were similar between the 2 groups.ConclusionsThe addition of sorafenib to DOX-TACE delivered to VX2 liver tumors resulted in high intratumoral and low systemic concentrations of sorafenib without altering the PK of doxorubicin.     

Comparing Radiomics features of tumour and healthy liver tissue in a limited CT dataset: A machine learning study

IntroductionLiver cancer lesions on Computed Tomography (CT) withholds a great amount of data, which is not visible to the radiologists and radiographer. Radiomics features can be extracted from the lesions and used to train Machine Learning (ML) algorithms to predict between tumour and liver tissue. The purpose of this study was to investigate and classify Radiomics features extracted from liver tumours and normal liver tissue in a limited CT dataset.MethodsThe Liver Tumour Segmentation Benchmark (LiTS) dataset consisting of 131 CT scans of the liver with segmentations of tumour tissue and healthy liver was used to extract Radiomic features. Extracted Radiomic features included size, shape, and location extracted with morphological and statistical techniques according to the International Symposium on Biomedical Imaging manual. Relevant features was selected with chi2 correlation and principal component analysis (PCA) with tumour and healthy liver tissue as outcome according to a consensus between three experienced radiologists. Logistic regression, random forest and support vector machine was used to train and validate the dataset with a 10-fold cross-validation method and the Grid Search as hyper-parameter tuning. Performance was evaluated with sensitivity, specificity and accuracy.ResultsThe performance of the ML algorithms achieved sensitivities, specificities and accuracy ranging from 96.30% (95% CI: 81.03%–99.91%) to 100.00% (95% CI: 86.77%–100.00%), 91.30% (95% CI: 71.96%–98.93%) to 100.00% (95% CI: 83.89%–100.00%)and 94.00% (95% CI: 83.45%–98.75%) to 100.00% (95% CI: 92.45%–100.00%), respectively.ConclusionML algorithms classifies Radiomics features extracted from healthy liver and tumour tissue with perfect accuracy. The Radiomics signature allows for a prognostic biomarker for hepatic tumour screening on liver CT.Implications for practiceDifferentiation between tumour and liver tissue with Radiomics ML algorithms have the potential to increase the diagnostic accuracy, assist in the decision-making of supplementary multiphasic enhanced medical imaging, as well as for developing novel prognostic biomarkers for liver cancer patients.     

Are risk factors necessary for pretest probability assessment of coronary artery disease? A patient similarity network analysis of the PROMISE trial

BackgroundPretest probability (PTP) calculators utilize epidemiological-level findings to provide patient-level risk assessment of obstructive coronary artery disease (CAD). However, their limited accuracies question whether dissimilarities in risk factors necessarily result in differences in CAD. Using patient similarity network (PSN) analyses, we wished to assess the accuracy of risk factors and imaging markers to identify ≥50% luminal narrowing on coronary CT angiography (CCTA) in stable chest-pain patients.MethodsWe created four PSNs representing: patient characteristics, risk factors, non-coronary imaging markers and calcium score. We used spectral clustering to group individuals with similar risk profiles. We compared PSNs to a contemporary PTP score incorporating calcium score and risk factors to identify ≥50% luminal narrowing on CCTA in the CT-arm of the PROMISE trial. We also conducted subanalyses in different age and sex groups.ResultsIn 3556 individuals, the calcium score PSN significantly outperformed patient characteristic, risk factor, and non-coronary imaging marker PSNs (AUC: 0.81 vs. 0.57, 0.55, 0.54; respectively, p ?< ?0.001 for all). The calcium score PSN significantly outperformed the contemporary PTP score (AUC: 0.81 vs. 0.78, p ?< ?0.001), and using 0, 1–100 and ?> ?100 cut-offs provided comparable results (AUC: 0.81 vs. 0.81, p ?= ?0.06). Similar results were found in all subanalyses.ConclusionCalcium score on its own provides better individualized obstructive CAD prediction than contemporary PTP scores incorporating calcium score and risk factors. Risk factors may not be able to improve the diagnostic accuracy of calcium score to predict ≥50% luminal narrowing on CCTA.     

Perivascular fat attenuation for predicting adverse cardiac events in stable patients undergoing invasive coronary angiography

BackgroundInflammation surrounding the coronary arteries can be non-invasively assessed using pericoronary adipose tissue attenuation (PCAT). While PCAT holds promise for further risk stratification of patients with low coronary artery disease (CAD) prevalence, its value in higher risk populations remains unknown.MethodsCORE320 enrolled patients referred for invasive coronary angiography with known or suspected CAD. Coronary computed tomography angiography (CCTA) images were collected for 381 patients for whom clinical outcomes were assessed 5 years after enrollment. Using semi-automated image analysis software, PCAT was obtained and normalized for the right coronary (RCA), left anterior descending (LAD), and left circumflex arteries (LCx). The association between PCAT and major adverse cardiovascular events (MACE) during follow up was assessed using Cox regression models.ResultsThirty-seven patients were excluded due to technical failure. For the remaining 344 patients, median age was 62 (interquartile range, 55–68) with 59% having ≥1 coronary artery stenosis of ≥50% by quantitative coronary angiography. Mean attenuation values for PCAT in RCA, LAD, and LCx were ?74.9, ?74.2, and ?71.2, respectively. Hazard ratios and 95% confidence intervals (CI) for normalized PCAT in the RCA, LAD, and LCx for MACE were 0.96 (CI: 0.75–1.22, p ?= ?0.71), 1.31 (95% CI: 0.96–1.78, p ?= ?0.09), and 0.98 (95% CI: 0.78–1.22, p ?= ?0.84), respectively. For death, stroke, or myocardial infarction only, hazard ratios were 0.68 (0.44–1.07), 0.85 (0.56–1.29), and 0.57 (0.41–0.80), respectively.ConclusionsIn patients referred for invasive coronary angiography with suspected CAD, PCAT did not predict MACE during long term follow up. Further studies are needed to understand the relationship of PCAT with CAD risk.     

D-二聚体在深静脉血栓形成诊断中临界值的确定

目的 评估D-二聚体的临床应用价值并建立D-二聚体在深静脉血栓形成（DVT）诊断中的临界值.方法 应用免疫比浊法分别检测DVT患者108例,非DVT可疑患者94例及健康对照96例的血浆D-二聚体含量,通过绘制接受者工作特征曲线（ROC）确立本实验室D-二聚体在DVT诊断中的临界值.结果 与非DVT可疑患者相比较,DVT患者D-二聚体水平显著增加（P 〈 0.01）;与健康对照组比较,非DVT可疑患者D-二聚体水平显著增加（P 〈 0.01）,DVT患者中D-二聚体的ROC曲线下面积为0.914（SD：0.030;95%CI：0.86 ~ 0.97）,临界值为250 μg/L（敏感度0.85,特异性0.89,Youden指数0.74,阴性似然比0.17）.结论 D-二聚体有较高的临床应用价值.建立本实验室的D-二聚体临界值有助于临床对DVT的安全排除.     

全胸腔镜房间隔室间隔缺损修补手术学习曲线

目的 总结全胸腔镜下心脏手术的学习曲线.方法 回顾性收集2004年10月至2010年1月由同一术者连续完成的125例全胸腔镜下房间隔缺损、室间隔缺损修补手术病例资料,按手术先后顺序分为A、B、C、D、E5组,每组25例,从各组手术时间、体外循环时间、主动脉阻断时间、中转开胸率及手术并发症等指标比较手术效果.结果 各组病例年龄、性别、体重、病种及手术方式差异无统计学意义(P＞0.05).手术时间、体外循环时间、主动脉阻断时间3项指标A、B组明显长于C、D、E组(P＜0.05),A、B两组间差异无统计学意义(P＞0.05),C、D、E3组之间差异亦无统计学意义(P＞0.05).各组中转开胸率及手术并发症发生率比较差异均无统计学意义(P＞0.05).结论 全胸腔镜房间隔、室间隔缺损修补术的学习曲线约为50例.     

A comparison of mammography and ultrasound in women with breast disease: a receiver operating characteristic analysis

The purpose of this study was to compare mammography and sonography, as well as their combination, for detecting breast tumors in symptomatic patients. The effects of age and hormonal status were also examined. From 1999 to 2007, 549 patients underwent 665 examination sessions (mammography and ultrasound). Abnormalities were deemed positive if biopsy findings revealed malignancy and negative if findings from biopsy or all screening examinations were negative. On pathology, 246 lesions were malignant and 419 were benign in the 549 patients. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the receiver operating characteristic curve (AUC) of mammography and sonography were 81.71% and 95.53%, 85.44% and 80.43%, 76.72% and 74.13%, 88.83% and 96.84%, and 0.886 and 0.948, respectively. The sensitivity and diagnostic accuracy among patients <50 years of age were significantly higher for sonography than for mammography (p < 0.05). The sensitivity and diagnostic accuracy among premenopausal or perimenopausal patients were significantly higher for sonography than for mammography (p < 0.05). The sensitivity among postmenopausal patients was significantly higher for sonography than for mammography (p < 0.05). The results of combined mammography and sonography were classified using American College of Radiology Breast Imaging Reporting and Data System (BI-RADS). There were 244 positive and two negative examinations of malignant lesions, and 106 positive and 313 negative examinations of benign lesions. The diagnostic accuracy of the combination was significantly higher than that of mammography (p < 0.05) and similar to that of sonography (p > 0.05). Sonography had better sensitivity and diagnostic accuracy than mammography for diagnosing breast diseases, while their specificities were similar. The diagnostic accuracy of diagnostic sonography was significantly better than that of mammography among patients <50 years of age and premenopausal or perimenopausal patients. The combination of mammography and sonography increased the sensitivity and diagnostic accuracy.