CT扫描所致受检者器官剂量的体模实验研究

目的 了解不同部位X射线CT扫描所致受检者器官或组织的吸收剂量及其分布。方法 实测体模中重要组织器官的CT值,并转换成线性吸收系数与人体正常值进行比较;在体模中 布放光致辐射发光玻璃剂量计,分别模拟测量头部、胸部、腹部和盆腔CT扫描所致受检者主要器官或组织的吸收剂量。结果 实验用仿真人体模具有良好的组织等效性。头部扫描吸收剂量最大的器官是大脑,胸部扫描吸收剂量较大的器官是甲状腺、乳腺、肺和食道,腹部扫描吸收剂量较大的器官是肝、胃、结肠和肺,单次盆腔扫描体所致骨表面和结肠的吸收剂量可达50 mGy以上。结论 X射线CT扫描所致受检者的器官剂量及其分布随扫描部位的不同而异。盆腔扫描时结肠、红骨髓、性腺和膀胱等主要器官的吸收剂量较大,应引起注意。     

儿童CT检查中扫描参数的优化

目的 了解儿童CT检查扫描条件选择及其所致辐射剂量的相关性,以期通过适当调节mAs、扫描长度等参数,降低儿童CT检查患者受照剂量。方法 比较江苏省7家医院不同年龄组（<1岁、1~5岁、6~10岁和11~15岁）儿童头颅、胸部、腹部多排螺旋CT检查主要扫描参数的差异。选用相同的检查参数在TM160剂量模体上测量CTDI₁₀₀,计算DLP,并通过经验加权因子,估算出不同部位检查的有效剂量（E）。对mAs、扫描长度和DLP进行多元线性回归分析,比较两家典型医院由于选择扫描条件不同所导致的剂量差异。结果 儿童头颅、胸部、腹部CT检查所致患者的有效剂量均值分别为2.46、5.69、11.86 mSv,各部位检查DLP与mAs、扫描长度均呈正相关（r=0.81、0.81、0.92,P<0.05）。较高的mAs选择,致使本研究各年龄组儿童胸腹部CT检查有效剂量是德国Galanski等研究的1.2~3.0倍;B医院各年龄组腹部检查选择了较高的扫描长度,以致其所致有效剂量均高于本研究均值。结论 建议通过合理优化儿童不同部位CT检查mAs、扫描长度等扫描参数,降低受检者所受辐射风险。     

热释光剂量计测量125I粒子源植入中职业人员剂量方法研究

目的 研究用热释光剂量计(TLD)测量并计算¹²⁵I粒子源植入中职业人员器官和组织接受的吸收剂量及有效剂量方法。方法 用⁶⁰Co γ射线开展TLD稳定性等相关性能实验。用¹²⁵I粒子源照射一组TLD片,建立空气比释动能标准剂量曲线。将TLD片分别贴在粒子源植入过程中职业人员铅衣内外甲状腺等13个部位,测量平均吸收剂量,计算器官和组织的吸收剂量和有效剂量。结果 3例前列腺癌粒子源植入术中,职业人员铅衣外器官和组织吸收剂量0.02~3.80 μGy,有效剂量0.06~1.81 μSv;铅衣内最高吸收剂量2.35 μGy,有效剂量0.02 μSv,屏蔽65.9%以上γ射线。3例脑癌中,职业人员铅衣外器官和组织吸收剂量0.23~11.31 μGy,有效剂量0.88~4.07 μSv;铅衣内最高吸收剂量2.22 μGy,有效剂量0.09 μSv,屏蔽54.5%以上射线。3例肺癌中,职业人员铅衣外器官和组织吸收剂量0.03~14.78 μGy,有效剂量0.35~7.59 μSv;铅衣内最高吸收剂量4.09 μGy,有效剂量0.22 μSv,屏蔽58.4%以上射线。2例纵隔癌中,职业人员铅衣外器官和组织的吸收剂量为0.06~74.91 μGy,有效剂量0.83~17.96 μSv;铅衣内最高吸收剂量10.29 μGy,有效剂量0.50 μSv,屏蔽85%以上射线。1例卵巢癌中,职业人员铅衣外器官和组织吸收剂量0.09~14.29 μGy,有效剂量2.40~4.50 μSv;铅衣内最高吸收剂量7.77 μGy,有效剂量0.12 μSv,屏蔽33.4%以上射线。植入1例眼睛癌中,职业人员铅衣外器官和组织吸收剂量为2.20~39.84 μGy,有效剂量4.48~10.06 μSv;铅衣内最高吸收剂量5.19 μGy,有效剂量0.16 μSv,屏蔽54.6%以上射线。结论 用TLD监测粒子源植入中职业人员剂量的方法简单易行,是保护近距离植入粒子源治疗中医务人员健康的有效措施。     

CT扫描方式对表浅器官辐射剂量测量值变异性的影响

目的 探讨CT扫描中表浅器官剂量测量值和图像噪声的不确定性。方法 使用GE Revolution CT对离体头颅标本分别行逐层和螺旋两种模式20次重复扫描。取GE Revolution CT和Philips Brilliance iCT准直宽度80 mm,Siemens Somatom Definition Flash CT准直宽度40 mm,螺距均为1,对胸部模体进行45次重复扫描。以上扫描中各序列均保持容积CT剂量指数（volume CT dose index,CTDI_vol）不变。用剂量计测量头颅标本右眼晶状体位置和胸部模体右乳腺中心位置剂量,剂量计传感器位置保持不变。重组传感器中心所在层面的5 mm层厚肺/软组织算法横断面图像,测量空气区CT值的标准偏差（图像噪声）。分别计算扫描3、5、10、20、30、45次剂量测量值及CT值标准偏差的平均值（Av）、标准差（SD）、变异系数（CV）和相对极差（RR）。采用Pearson和Spearman相关分析评估CT值标准偏差与剂量测量值之间的相关性。结果 头颅标本逐层扫描时剂量测量值几乎不变,螺旋扫描时测量值变化较大,20次测量RR达到10.67%。3台CT扫描仪重复扫描45次的剂量测量值RR分别达到43.83%、25.31%、14.32%。肺/软组织算法图像空气区CT值标准偏差变化幅度亦较大,但差异与剂量测量值不完全相关。结论 逐层扫描模式时,表浅器官剂量测量值稳定。螺旋扫描时,表浅器官剂量测量值和图像噪声均有较大变化。     

放射诊断受检者个人放射防护用品使用效果研究

目的 研究受检者个人防护用品使用实际效果,为个人防护用品的正确使用和放射卫生行政执法提供参考和依据。方法 选取青岛市立医院影像科2022年2-6月接受X射线影像检查[口腔全景、牙片摄影、数字X射线摄影（DR）、CT扫描]受检者170例,其中,口腔全景、牙片摄影受检者各25例,CT扫描检查受检者60例、DR影像检查的受检者60例。使用热释光剂量计对170例受检者使用个人防护用品遮挡敏感部位时关注点的周围剂量当量进行检测,分析上述影像检查常规使用个人防护用品时的关注点检测数据。结果 受检者进行口腔全景时大领铅围脖内外相同点位周围剂量当量差异有统计学意义（t=-2.23,P<0.05）;进行牙片摄影时大领铅围脖内外相同点位周围剂量当量差异无统计学意义（P>0.05）;进行DR摄影（胸部正位、侧位和腰椎正位）时为受检者佩戴铅围裙,其中儿童胸部正位与成人胸部侧位铅围裙内外相同点位周围剂量当量差异有统计学意义（U=10.00、19.00,P<0.05）,成人胸部正位与腰椎正位铅围裙内外相同点位周围剂量当量差异无统计学意义（P>0.05）;进行CT扫描（胸部或上腹部）时,包裹式铅围裙内外相同点位周围剂量当量差异有统计学意义（U=878.50、11.00,P<0.05）。结论 受检者个人防护用品的正确使用是复杂的技术问题,全面准确理解辐射防护最优化原则正确落实受检者个人防护用品的使用非常重要,受检者个人防护用品使用方面的放射卫生行政处罚应慎重。     

铋屏蔽联合器官管电流调制技术在颅脑CT检查中应用的体模研究

目的 通过测量敏感器官的辐射剂量,评价铋屏蔽联合器官-管电流调制（X-care）技术在颅脑CT扫描中的应用价值。方法 使用德国德国西门子公司炫速双源CT对头颈体模进行相同容积CT剂量指数（CTDI_vol）下的X-care、铋屏蔽和X-care联合铋屏蔽3种方式扫描颅脑,及无铋屏蔽和铋屏蔽2种方式扫描双能量CT血管造影（DE-CTA）。选取铋屏蔽所在层面测量脑血管、邻近脑组织及脑脊液的CT值以及图像噪声,计算脑血管和脑实质的对比噪声比。通过放置热释光个人剂量计（TLD）的方式计算器官剂量当量（H_T）,并记录每次扫描后生成的CTDI_vol和剂量长度乘积（DLP）。结果 颅脑扫描在相同的CTDI_vol下,采用X-care、铋屏蔽和X-care联合铋屏蔽3种扫描方法的H_T,晶状体均值分别为（37.89±2.00）、（42.20±2.96）、（28.21±1.31） mSv,较颅脑常规序列扫描有明显下降（F=186.52,P<0.05）;采用铋屏蔽和X-care联合铋屏蔽,H_T,甲状腺为（0.77±0.07）和（0.89±0.08） mSv,较颅脑常规扫描和仅采用X-care有明显下降（F=103.26,P<0.05）;DE-CTA采用铋屏蔽扫描后H_T,晶状体和H_T,甲状腺分别为（11.56±1.04）和（0.32±0.03） mSv,较屏蔽前有明显下降（t=5.07,P<0.05）。用与不用X-care、铋屏蔽及X-care联合铋屏蔽,颅脑常规扫描的噪声和对比信噪比（CNR）值无显著性改变;用与不用铋屏蔽,双能量CTA扫描的噪声和CNR无显著性改变。结论 铋屏蔽联合器官管电流调制技术能够在保证一定图像质量的前提下,降低颅脑CT扫描中晶状体及甲状腺的器官剂量当量。     

5岁儿童仿真模体千伏锥束CT模拟剂量测量

目的 利用热释光探测器（TLD）在CIRS 5岁仿真儿童模体内测量瓦里安千伏锥束CT（kV-CBCT）标准扫描参数下各重要器官剂量,并以此计算有效剂量。方法 挑选一致性在2%以内的TLD并退火。首先基于相同骨盆扫描模式分别用CT电离室和TLD测量CIRS骨盆仿真模体相同体积内的剂量和读数,二者比值即为TLD转换系数;将夹在组织等效插件中的TLD放入儿童模体器官内预留的插孔,在头部、胸部和骨盆3种标准扫描条件模式下,测量器官剂量,并计算有效剂量。结果 TLD转换系数是3.91 mGy/每读数;在头部、胸部和骨盆3种标准扫描条件下,得出全身有效剂量分别是0.63、6.85和19.3 mSv。结论 用CT电离室刻度过的TLD测量kV-CBCT给儿童仿真模体带来的辐射剂量的方法具有可行性。本研究中骨盆扫描条件的有效剂量高于胸部和头部,即该条件预期产生的辐射危害较大,诱发继发性癌症风险较高。     

XVI锥形束CT辐射剂量与扫描参数相关性建模

目的 定量研究不同扫描参数组合导致的医科达XVI锥形束CT辐射剂量变化,为评估影像引导放疗中成像剂量的参数依赖性提供数学模型。方法 基于Versa HD加速器XVI,利用PTW 30 009千伏电离室和UNIDOS webline静电计,在PTW标准CT剂量指数（CTDI）体部模体中,测量标准扫描参数及多种扫描电压（kVp）、管电流（mA）组合下的模体内各点比释动能,并计算加权CTDI_w。利用SigmaPlot 10.0软件将测量结果拟合为以管电流和/或扫描电压为变量的模型。结果 标准扫描参数下,瓦里安OBI锥形束CT的CTDI_w值仅为医科达XVI的11.23%（胸部参数）和9.15%（盆腔参数）。在标准及其余4个扫描电压条件下,模体中心和外周各点比释动能与管电流均呈现线性正比关系,但斜率a值差异较大（0.479~6.679）,主要受扫描电压值、模体测量位置、剂量描述方法等因素影响。模体内各点剂量和CTDI_w值均可拟合为以扫描电压为变量的非线性经验公式（R²>0.997）,各系数差异有统计学意义（P<0.05）。同时改变管电流和扫描电压对模体中心点剂量的影响可以表述为mGy=（5.917-0.197×kVp+0.002×kVp²-5.063×10^-6×kVp³）×mA。结论 医科达XVI锥形束CT剂量显著依赖于扫描参数,数学模型可用于快速准确描述其变化特征。     

铋屏蔽对头颈部多层螺旋CT中眼晶状体辐射剂量的降低作用

目的 探讨扫描平面内铋屏蔽在头颈部多层螺旋CT(MSCT)扫描中对影像质量的影响和眼晶状体辐射剂量的降低作用.方法 分别使用颅脑、颞骨和鼻窦临床扫描条件,在无屏蔽、1层、2层和3层铋屏蔽覆盖眼部区域时,对标准水模和离体头颅标本进行扫描,用热释光剂量片测量头颅标本每次扫描时的眼晶状体器官剂量.在屏蔽材料和被扫描体间放置5、10、15和20 mm厚的海绵时,使用鼻窦扫描条件采集影像,并测量眼晶状体的剂量.测量水模影像中与屏蔽物为2、4、6和8 cm距离处的CT值,主观评价头颅标本影像中伪影对解剖结构的影响.结果 颅脑、颞骨和鼻窦CT临床扫描中眼晶状体的器官剂量分别为24.31、27.60和20.01 mGy.使用铋屏蔽时,均使得眼晶状体剂量有显著下降,但下降幅度随着铋屏蔽物的增加而降低.在各种厚度的屏蔽物时,屏蔽物间隙越大,眼晶状体剂量的降低程度越小,测量兴趣区CT值的增加程度也显著降低.颅脑和颞骨CT扫描分别使用2层和3层铋屏蔽,在不影响诊断的前提下,可有效降低眼晶状体剂量分别为47.1%和59.1%;鼻窦CT扫描时,1层屏蔽无间隙、2层屏蔽1.5 cm间隙不影响诊断,可降低眼晶状体剂量分别为31.5%和34.5%.结论 扫描平面内铋屏蔽材料的合理应用,可有效降低头颈部CT扫描中眼晶状体的辐射剂量.     

重复CT模拟定位分析肿瘤体积变化对鼻咽癌调强放疗的影响

目的 利用重复CT模拟定位分析肿瘤体积变化对鼻咽癌调强放疗的影响。 方法 选取2011年7月至2012年11月期间20例鼻咽癌调强放疗的患者,于放疗前进行首次CT模拟定位,放疗中在患者接受30 Gy剂量照射时进行重复CT模拟定位扫描。在治疗计划系统将首次扫描的CT图像与重复扫描的CT图像进行融合,计算GTV体积的退缩率;在重复CT图像上利用原计划重新计算剂量分布,根据剂量体积直方图,分别计算出危及器官脑干和脊髓的受量变化。 结果 重复CT模拟定位比较首次CT模拟定位GTV体积平均退缩率为28.7%。重复CT模拟定位比首次CT模拟定位脑干和脊髓的单次最大剂量、1 cm³体积的剂量和平均剂量的百分比均有所增加(t=0.83~3.17,P<0.05)。 结论 利用重复CT模拟定位发现,鼻咽癌调强放疗患者在接受30 Gy剂量照射时,GTV体积的退缩率较明显,进而导致危及器官剂量的增加。     

Physiologic and pathologic calcifications and ossifications in the face and neck

The aim was to give a systematic presentation of physiologic and pathologic calcifications and ossifications in the face and neck with a special emphasis on clinical relevance. In a sometimes subacute setting one should recognize specific calcifications which often lead to important diagnoses such as fungal sinusitis or sclerosing labyrinthitis. In a more chronic situation intraocular calcifications in small children are pathognomonic for retinoblastoma. Juxtatumoral sclerosis of the laryngeal cartilage in laryngopharyngeal carcinoma is usually caused by tumor infiltration of the cartilage resulting in a higher tumor stage and, this way, has a major impact on the therapeutical strategy. Calcified lymph nodes are mainly unspecific but can be the result of tuberculosis or metastases of thyroid cancer. Cross-sectional imaging methods, most of all computed tomography, are ideally suited to reveal head and neck calcifications and ossifications, especially those which are clinically relevant.     

Head and neck infection and inflammation

This article discusses the imaging manifestations of infectious and inflammatory conditions of the head and neck. Special attention is paid to the sites, routes of spread, and complications of neck infections. Because the clinical signs and symptoms and the complications of these conditions are often determined by the precise anatomic site involved, anatomic considerations are stressed. Familiarity with the fascial layers, spaces of the neck, and the contents of each space is helpful for this discussion. The fascial layers of the neck are important barriers to infection, and once infection is established, the fascial layers play a part in directing its spread.     

Oxygen uptake and ventilation during rowing and running in females and males

This study evaluated if the ventilatory response to exercise is impaired by the cramp position of rowing. Maximal oxygen uptake (VO2max), maximal expiratory volume (VEmax), and maximal heart rate (HRmax) during rowing and running were compared in 55 males (age, mean +/- SD, 21 +/- 3 years; height 176 +/- 5 cm; body mass 72 +/- 6 kg) and 18 females (age 20 +/- 2 years; height 164 +/- 5 cm; body mass 61 +/- 4 kg). VEmax was larger during rowing than during running (males, 157 +/- 16 vs. 147 +/- 13 L min(-1); 114 +/- 9 vs. 105 +/- 11 L min(-1), P<0.01). Also VO2max was larger during rowing than during running (males, 4.5 +/- 0.5 vs. 4.3 +/- 0.4 L min(-1); females, 3.3 +/- 0.4 vs. 3.2 +/- 0.4 L min(-1), P<0.01). However, HRmax was lower during rowing than during running (males, 194 +/- 8 vs. 198 +/- 11 beats min(-1); females, 192 +/- 6 vs. 196 +/- 8 beats min(-1), P<0.05). VEmax was correlated to body mass and fat-free mass, as was VO2max. Thus, the oxygen pulse (VO2max/HRmax) was larger during rowing than during running, while the ventilatory equivalent for oxygen (VEmax/VO2max) was similar. We showed that bending the body during rowing does not seem to impair ventilation either in males or in females. The results indicate that VEmax and VO2max relate to body size and fat-free mass for both females and males. The findings indicate that the involvement of more muscles, the entrainment, and the body position during rowing facilitates ventilation and venous return and lowers maximal heart rate.     

幽门螺杆菌分泌与重组表达的VacA蛋白的分离纯化及其致细胞空泡效应与凋亡的对比研究

目的：分离纯化幽门螺杆菌分泌和重组表达的细胞空泡毒素抗原（ VacA）蛋白,并评价其致细胞空泡效应及致细胞凋亡效应。方法分别从幽门螺杆菌ATCC26695菌株培养上清和重组表达VacA蛋白的pQE30-VacA-E．coliM15基因工程菌中分离纯化VacA蛋白,经酸化后,以不同终浓度（5,10 ng／ml）分别与人胃腺癌AGS细胞共孵24 h,观察致空泡效应,并通过流式细胞术检测细胞凋亡。结果成功分离纯化出幽门螺杆菌分泌和重组表达的VacA蛋白;幽门螺杆菌分泌的VacA蛋白能显著引起AGS细胞的空泡样改变及凋亡（P＜0．01）,而重组表达的VacA蛋白致细胞空泡样改变及凋亡不显著（ P＞0．05）。结论幽门螺杆菌分泌的VacA蛋白有良好的空泡毒性及致凋亡效应,而重组表达的VacA蛋白无致空泡及凋亡效应,幽门螺杆菌分泌的VacA蛋白可用于VacA作用机制的研究。     

化学和生物学融合对国际武器公约履约的影响

化学武器公约（ CWC）和生物武器公约（ BWC）是为禁止生产、发展、储存和使用化学武器和生物武器而制定的国际公约。近年来,科学技术快速发展,知识交叉渗透,学科之间出现整合和融合,促进了科技进步和经济发展。其中化学和生物学融合在有力促进制药、健康卫生、绿色化学和环境保护等产业进步的同时,也对化学和生物武器公约的履约产生了重要的影响。该文综述了与化学武器和生物武器公约相关的化学和生物学融合进展,并分析其对公约履约的影响。     

Old and dangerous: Prison and dementia

Older prisoners are the fastest growing group of prisoners in many countries. The purpose of this study is to explore the phenomenon of detention of persons suffering from dementia. Medline searches were conducted for relevant articles, chapters and books published until August 2016. Search terms included dementia, elderly, prison and criminal. Publications found through this indexed search were reviewed for further relevant references. As results, there is a lack of data about elderly with dementia in prisons. Given the rise in the average age, it is reasonable to hypothesize that the number of older prisoners is growing. Moreover, some elderly are imprisoned with a concomitant cognitive impairment or psychiatric disorder while others will develop such diseases once incarcerated. At the present time, legal and social systems seem unprepared to handle the phenomenon of dementia in prison. As proposal, health assessments for older first time offenders should become a practice inside the correctional facilities and include an evaluation for specific health issues, such as psychiatric comorbidity and cognitive impairment.     

Kidney and iodinated and gadolinium-based contrast agents

In patients with renal failure, iodinated contrast agents may cause acute deterioration of the renal function and gadolinium-based contrast agents (GBCAs) may cause nephrogenic systemic fibrosis (NSF). The administration of a contrast agent must thus be reviewed for each patient and evaluation of renal function is paramount even though its estimation using formulas derived from the creatinine level may fluctuate. For iodinated contrast agents, contrast induced nephropathy is reduced by hydratation, preferably intravenous, when the GFR is less than 60 ml/min. The risk for intravenous injections is less than the risk for arterial injections, and the GFR threshold may be reduced to 45 ml/min. For gadolinium-based contrast agents, patients at risk for NSF are those with end-stage renal disease and patients undergoing dialysis. In such cases, the injection of a gadolinium-based contrast agent is only considered after a risk-benefit analysis has been completed, an alternate linear or macrocyclic agent issued and the dose limited to 0,1 mmol Gd/kg. Recently, recommendations from US and European agencies have converged. Learning objectives: to be familiar with the risk factors of CIN with iodinated contrast agents; to be familiar with hydration procedures for patients at risk of CIN; to be familiar with the diagnostic criteria of NSF; to be familiar with the classification of GBCA with regards to the risk of NSF; to be familiar with the contraindications of the different groups of GBCA.     

Coracoclavicular and coracoacromial ligament calcification and ossification

Thirty-six patients with calcification or ossification at or around the coracoclavicular and coracoacromial regions were analyzed with regard to type, location, and configuration of the deposits and related clinical history. Calcification or ossification in the coracoclavicular region resulted largely from trauma (36%) or renal failure (28%). Trauma patients may develop punctate calcification or ossification but do not develop the tumoral type of calcification. About 5% of the renal failure patients had coracoclavicular ligament calcifications, one-half of which were of the tumoral type. Renal failure patients may have punctate or tumoral calcifications but do not develop ossification.     

Cross-sectional and longitudinal comparisons of self-reported and device-assessed physical activity and sedentary behaviour

ObjectivesTo examine the longitudinal associations and differences between self-reported and device-assessed physical activity (PA) and sedentary behaviour (SB), using a multifaceted statistical approach.DesignLongitudinal measurement burst.MethodsIn total, 52 university students (78% female) aged 18–38 years (mean = 21.94 ± 4.57 years) participated. The study consisted of three blocks of six days of measurement, during which participants wore an accelerometer on their wrist for the entire block, and self-reported their PA over the 6 days at the end of each block.ResultsMeaningful latent differences between methods were observed for moderate PA and SB across all three assessment periods, such that participants underreported the time spent in each activity. Bland–Altman plots revealed a positive mean difference for vigorous PA, with over-reporting increasing as mean levels increased. Negative mean differences were observed for all other intensities. Underreporting of moderate PA increased as the mean level increased, whereas for light PA and SB, underreporting decreased at high levels. Repeated measures correlations revealed a meaningful association for vigorous PA only, suggesting that as self-reported minutes increase so too do device-measured minutes.ConclusionsWe found evidence of cross-sectional and longitudinal differences and weak associations between self-reported and device-assessed PA and SB. Future work is needed to enhance the quality of self-reported methods to assess PA and SB (e.g., face and content validity), and consider improvements to the processing of device-based data.