Assessment of the uterine dose in digital mammography and digital breast tomosynthesis

IntroductionDigital Mammography (DM-2D) and more recently Digital Breast Tomosynthesis (DBT), are two of the most effective imaging modalities for breast cancer detection, often used in screening programmes. It may happen that exams using these two imaging modalities are inadvertently performed to pregnant women. The objective of this study is to assess the dose in the uterus due to DM-2D and DBT exams, according to two main irradiation scenarios: in the 1st scenario the exposure parameters were pre-selected directly by the imaging system, while in the 2nd scenario, the maximum exposure parameters were chosen.MethodsThe mammography equipment used was a Siemens Mammomat Inspiration. A physical anthropomorphic phantom, PMMA plates (simulating a breast thickness of 6 cm) and thermoluminescent dosimeters (TLDs) were used to measure entrance air kerma values on the phantom's breast and abdomen in order to successively estimate the mean glandular dose (MGD) and the dose in the uterus. For the two irradiation scenarios chosen, two-breast imaging modalities were selected: 1) DBT in Cranio-Caudal (CC) view (with 28 kV and 160 mAs as exposure parameters), 2) DBT and DM in Medio Lateral-Oblique (MLO) and CC views (with 34 kV and 250 mAs as exposure parameters).ResultsIn the 1st scenario, the TLD measurements did not detect significant dose values in the abdomen whereas the MGD estimated using the D.R. Dance model was in close agreement with data available in the literature. In the 2nd scenario, there was no significant difference in MGD estimation between the different views, whereas the air kerma values in the abdomen (in DBT mode, CC and MLO) were 0.049 mGy and 0.004 mGy respectively. In CC DM-2D mode the abdomen air kerma value was 0.026 mGy, with no significant detected value in MLO view.ConclusionsFor the dose in the uterus, the obtained values seem to indicate that DM-2D and DBT examinations inadvertently performed during pregnancy do not pose a significant radiological risk, even considering the case of overexposure in both breasts.Implications for practiceThe accurate knowledge of the doses in DM-2D and DBT will contribute to raise the awareness among medical practitioners involved in breast imaging empowering them to provide accurate information about dose levels in the uterus, improving their radiation risk communication skills and consequently helping to reduce the anxiety of pregnant women undergoing this type of examinations.     

钼靶X线假阴性的女性乳腺癌的临床、病理及预后分析

目的:回顾分析钼靶X线诊断假阴性病例与真阳性病例之间的差异,了解X线假阴性病人的特点。方法:通过分析1988～1989年天津医科大学肿瘤医院外科治疗、均经病理证实431例女性原发乳腺癌,比较96例钼靶X线假阴性病例与335例真阳性病例之间临床、病理及预后的差异。结果:与真阳性组相比(1)假阴性组发病年龄低(43.2±1.66)岁对(49.1±1.10)岁。(2)肿块小(3.1±0.36)cm对(3.7±0.20)cm。(3)浸润性导管癌比例多(29.6%对16.8%)。(4)单纯癌比例少(58.0%对68.6%)。(5)雌激素受体阳性率低(63.3%对84.9%)。(6)假阴性组腋窝淋巴结转移数目3个以下者多(60.4%对40.6%)。(7)假阴性组雌激素受体阳性者10年生存率比真阳性组低(53.5%对69.7%)。结论:钼靶假阴性的乳腺癌病人年轻、乳腺致密、肿瘤较小且缺乏细胞成分,虽然其临床表现较早,但预后差。临床有可疑之处时,应当积极诊治,以免病程延误。     

计算机辅助检测对检出乳腺X线片中成簇微钙化灶的价值

目的:探讨计算机辅助检测系统(CAD)对检出乳腺X线钼靶摄影片中成簇微钙化灶的临床应用价值。方法:将22例乳腺X线钼靶片上疑有簇状钙化灶患者和13例正常对照者的140张乳腺钼靶X线片,经专业扫描仪数字化处理后,应用CAD软件标记其中的微钙化灶,由6位放射科医师分别单独阅片,再结合CAD阅片,结果采用受试者操作特性(ROC)曲线法进行分析。结果:6位放射科医师结合CAD阅片后,评价效果均优于未结合CAD时,其中3位低年资医师(有1年临床经验)和1位中年资医师(有5年以上临床经验)的两次评价结果有显著性差异(P<0.05)。结论:CAD有助于提高乳腺X线片中成簇微钙化灶的检出率,尤其对缺少诊断经验医师的作用更大。     

周围剂量当量仪的研制

周围剂量当量仪研制是根据国际辐射单位和测量委员会（ＩＣＲＵ）３９号报告推荐的周围剂量当量而设计的一种数字化智能型辐射防护仪。方法采用能量补偿对探测器进行能响校正。结果补偿结果使得探测器在４７～２３０ｋｅＶ与ＩＳＯ推荐的Ｈ＊（１０）／Ｋａ值误差在５％以内。本文重点描述了周围剂量当量仪探测器部分的工艺结构和剂量学性能以及电子学测量部分的主要功能。结论通过实际应用我们初步获得的结论是由于该仪器可直接测量周围剂量当量，稳定性好且具有自动取平均值特点，它可做为实验室校准用测量仪器，又由于该仪器体积小，电池供电，读数面板又有背光功能，它也可以做为现场仪器用于辐射防护实践的现场测量     

应用统计学体模评价CR乳腺摄影影像的探讨

目的应用ALVIM统计学体模TRM,探讨乳腺计算机X线摄影(CR)获得尺寸最小的Al2O3斑点(钙化灶)和尼龙纤维(肿块灶)信号的能力。方法将具有各5种大小不同Al2O3斑点和尼龙纤维组成的ALVIM统计学体模TRM置于成像板(IP)上,用钼靶X线机26kV,调节毫安量,选择适当图像处理参数,获得一张密度值D=0·70±0·05的实验照片,用5值判断法取得每一行由5个信号和噪声所组成的10行信号的记分总值,用ALVIM统计学体模的计算公式计算出一组真阳性概率P(S/s)和假阳性概率P(S/n)值,绘制ROC曲线,并计算出每种信号的判断概率值Pdet,再用SPSS10·0统计学单因素方差分析软件处理数据,获得尺寸最小的钙化灶和软组织肿块灶。结果用概率统计方法获得制作ROC曲线的数据和判断概率平均值Pdet,5种大小不同的Al2O3斑点(钙化灶)中,0·20mm的Pdet=0·6250最小,0·55mm的Pdet=0·9000最大,而0·20mm与0·25mm的Pdet差异无统计学意义,与其他的差异有统计学意义;5种大小不同的尼龙纤维(肿块灶)中,0·45mm的Pdet=0·5313最小,1·00mm的Pdet=0·8813最大,而0·45mm的与0·60mm的差异无统计学意义,0·45mm与其他的差异有统计学意义。结论应用ALVIM统计学体模TRM制作ROC曲线和获得判断概率值Pdet的计算简单、快捷,宜于日常临床工作开展的评价影像质量控制,值得推广。     

BMP-2在乳腺癌组织中的表达及其与OPN、ON表达和微钙化的关系

目的探讨乳腺癌组织中骨形态发生蛋白-2（BMP-2）在微钙化形成中的作用。资料与方法搜集钼靶X线检查及临床资料齐全的61例浸润性乳腺癌组织标本,依据钼靶片中癌瘤微钙化征象进行描述并分组。应用SP免疫组织化学技术检测BMP-2的表达,并分析其与骨桥蛋白（OPN）、骨连接蛋白（ON）表达以及微钙化的关系。结果BMP-2阳性表达率为65.57%（40/61）。钙化组与无钙化组比较,BMP-2表达差异有统计学意义（χ^2=5.528,P〈0.05）。BMP-2阳性表达与OPN的高表达存在着显著的正相关关系（r=0.627,P〈0.05）,与ON间无明显相关性（r=-0.067,P〉0.05）。结论乳腺癌组织中BMP-2的表达与OPN的表达及微钙化的出现具有密切关系,BMP-2在乳腺癌微钙化形成中可能发挥了重要调控作用。     

早期乳腺导管原位癌X线表现与预后生物学标记关系的研究

目的评价乳腺导管原位癌（DCIS）及DCIS伴微浸润的X线片表现，分析X线表现与预后生物学标记的相关性。方法对50例乳腺DCIS及45例DCIS伴微浸润的患者行X线检查，共62例行预后生物学标记，分析影像表现与孕激素受体（PR）、癌基因（C—erbB-2）、抑癌基因（p53）的相关性。用卡方检验进行统计学处理，并对有意义者行优势比（OR值）分析。结果（1）单独1个X线征象表现者62例；合并2个征象26例；阴性7例。（2）各种X线征象单独分析显示，62例有钙化的病灶中恶性钙化占73％（45例），其余为中间性钙化；钙化以簇状分布最为常见（36例），其次为段样分布（18例）。22例有肿块的病灶中，以卵圆形肿块最为常见（13例）；肿块的边缘表现为浸润、小分叶、清晰和模糊各为15、1、4和2例；等密度肿块占的比例较高（55％，12例）。结构扭曲7例，除1例外多与其他征象伴行；局灶性不对称占16％（15／95），可单独发生或与其他征象伴发。（3）将病灶的X线表现分成恶性钙化、中间性钙化和非钙化3组，PR与C-erbB-2在3组中的分布有统计性意义，PR阳性表达者X线上非钙化征象发生率是中间性钙化的11．00倍[χ^2=8．571，P=0．003；95％可信区间（CI）为1．998～60．572]、恶性钙化的8．80倍（χ^2=9．748，P=0．002；95％CI为2．024～38．253）；而C—erbB-2高表达者，恶性钙化是非钙化发生的12．35倍（χ^2=7．353，P=0．007；95％CI为1．447—105．443），中间性钙化的5．74倍（χ^2=4．977，P=0．026；95％CI为1．110～29．645）。结论乳腺DCIS及DCIS伴微浸润X线征象有特征。X线征象可以作为早期乳腺DCIS的一个预后因子。     

群集钙化对鉴别乳腺良恶性病变的意义

目的评价乳腺钼靶片群集钙化对鉴别乳腺良恶性病变的意义。方法分析76例乳腺X线钼靶片群集钙化病例,全部经手术病理证实,其中,乳腺恶性病变52例,良性病变24例。采用下列4项指标分析上述76例群集钙化的特征并进行良恶性对照研究:a)病灶钙化总数;b)每平方厘米钙化数目(N/S);c)钙化灶的大小、形态;d)钙化灶合并肿块。结果76例群集钙化病例中钙化总数大于30个、N/S大于等于10个、钙化灶大小形态不一致、钙化合并肿块,这4项指标诊断恶性钙化的特异性和敏感性分别为83.3%和69.2%,79.2%和76.9%,62.5%和92.3%,62.5%和53.8%。结论N/S大于等于10个、钙化总数大于30个及钙化灶大小、形态不一致这3个特征对恶性钙化最具有诊断价值。     

Detection of primary breast cancer in women with known adenocarcinoma metastatic to the axilla: Use of MRI after negative clinical and mammographic examination

The purpose of this study was to evaluate the ability of MRI to identify a primary site of malignancy in the breast of patients who present clinically with ipsilateral lymph nodes containing metastatic carcinoma but whose physical and mammographic examination are negative. MRI of the breast was performed on four patients using a variety of imaging parameters, all with and without gadolinium contrast. All patients had biopsy-proven adenocarcinoma of the ipsilateral axilla, with negative physical and mammographic examinations. Foci of enhancement assessed visually on precontrast and postcontrast scans (n = 1) and on substraction studies (n = 3) were considered suspicious under the clinical circumstances defined for this study. Lesions identified on MRI were re-identified on ultrasound examination and either preoperative localization for excisional biopsy or tissue sampling was performed. Surgery was performed and histopathologic correlation was obtained in all cases. Primary sites of breast carcinoma were identified in all four patients, with multiple sites of malignancy identified in three of four patients. Breast conservation therapy was made possible for three of four patients based on the results of the MRI study showing sites of malignancy and no features of cancer elsewhere in the breast. Follow-up data of 1, 2, and 5 years of these patients show no evidence of recurrent disease. MRI of the breast is a useful technique for identifying primary sites of malignancy in patients presenting with ipsilateral lymph nodes positive for metastatic adenocarcinoma when the physical and mammographic examinations are negative.