北京市放射诊断受检者剂量调查与分析

目的 探讨北京地区放射诊断检查对成年受检者的辐射剂量水平。方法 选取北京市城区与远郊共10个区域的30家不同级别医疗机构,以1 182例X射线摄影、542例乳腺摄影和410例CT检查为研究对象,测读不同投照部位下照射野内受检者/模体所受的辐射剂量。结果 普通X射线摄影、CR摄影和DR摄影受检者剂量范围分别为0.4~24.1、0.3~13.9、0.1~15.9 mGy;乳腺受检者乳腺腺体平均剂量为0.3~5.4 mGy;CT受检者CTDI_w值为28.1~96.3 mGy、CTDI_vol值为7.0~23.4 mGy、DLP值为162.2~898.1 mGy ·cm。结论 个别放射诊断检查受检者所受辐射剂量高于国标中医疗照射指导水平值,应引起注意。     

江苏省乳腺X射线摄影频度调查及乳腺癌风险评估

目的 调查估算江苏省乳腺X射线摄影的频度,进而估算乳腺摄影对江苏省女性人口的剂量负担,并评估乳腺摄影对江苏省各年龄组女性人口诱发乳腺癌的风险。方法 采用分层随机抽样调查的方法,通过调查30台乳腺摄影设备年检查人数和受检者年龄分布,估算全省乳腺摄影的频度,并计算乳腺摄影对女性人口的剂量负担。使用美国科学院电离辐射生物效应报告BEIR-Ⅶ中的超额归因风险（EAR）模型估算乳腺摄影检查对3个年龄组诱发乳腺癌的风险。结果 江苏省乳腺摄影检查的频度为3.77次/千人口;乳腺摄影对江苏省女性人口剂量负担为0.02 mGy/人。每次乳腺摄影检查对0~15岁组、16~40岁和>40岁3个年龄组的乳腺癌终生归因风险（LAR）分别为138/10万人、14.7/10万人和1.0/10万人。结论 乳腺摄影对人群乳腺癌诱发风险较小,但低年龄组的风险较大,提示针对低年龄乳腺摄影检查仍应慎重。     

乳腺筛查X射线成像参数与辐射剂量和影像质量的相关性研究

目的 探讨乳腺筛查X射线摄影参数对辐射剂量与影像质量的影响,以获取辐射剂量与影像质量的最佳匹配。 方法 回顾性分析接受数字乳腺X射线筛查摄影的507例受检者的曝光参数与平均腺体剂量的相关性。对不同厚度的亚克力板进行曝光,获取乳腺压迫厚度对辐射剂量的影响。通过对比度细节测试模体(CDMAM3.4)与不同厚度亚克力板的组合测试,分析其与影像质量的相关性。 结果 在507例受检者中,30~49岁为乳腺筛查影像受检者的主体人群,占67.06%。3种曝光模式下,平均腺体剂量(AGD)的均值以对比度优先模式最高,为标准模式的137.5%。 标准模式靶物质/滤过板组合是Mo/Mo、Mo/Rh、Rh/Rh共3种,各占1/3;剂量优先模式选择的是Mo/Rh、Rh/Rh 2种组合,各占50%;对比度优先模式则以选择Mo/Mo组合为主,占52%。乳腺压迫厚度与平均腺体剂量之间均呈正相关。3种曝光模式的逆影像质量指数(IQFinv)分别为98.32、95.41和107.02,其中对比度优先模式的IQFinv值最高;但当亚克力板增加到≥5 cm时,3种曝光模式下的IQFinv值很接近。结论 当受检者乳腺属于致密型乳腺且压迫厚度<4 cm时,应选择剂量优先曝光模式;>4 cm而<6 cm时,选择标准曝光模式;>6 cm选择手动。     

数字乳腺断层摄影及其合成二维影像技术在乳腺癌筛查中的研究进展

目前乳腺X线检查仍是乳腺癌早期诊断的有效检查方法之一,主要包括全视野数字化乳腺摄影（FFDM）、数字乳腺断层摄影（DBT）、合成乳腺X线摄影（SM）以及3种技术的联合应用（FFDM联合DBT、SM联合DBT）。对DBT、SM和SM联合DBT在乳腺筛查中诊断效能、影像质量及辐射剂量等进行比较。SM联合DBT可有效平衡辐射剂量和诊断效能,但仍然在判读时间、信息的存储与传输和检查成本方面存在局限性。就以上3种检查技术在乳腺癌筛查中的研究进展予以综述。     

钼铑双靶乳腺X线摄影剂量优先模式与标准模式对照研究

目的：探讨钼铑双靶剂量优先模式在乳腺低辐射剂量检查中的价值。方法利用钼铑双靶乳腺机,对40例乳腺癌患者双侧乳腺分别进行头尾位(CC)和内外斜位(MLO)位标准模式和剂量优先模式摄影,对比分析160幅乳腺图像质量,分别记录平均腺体剂量(AGD)值和皮肤入射剂量(ESE)值。结果2种乳腺摄影模式均获得良好的图像质量,经检验两者间无显著性差异(χ2=0.427,P >0.05)。与标准模式相比,剂量优先模式摄影 CC 位 AGD 值降低约28.63%,ESE 值降低约28.28%,两者间具有显著性差异(t AGD =12.928,P <0.05,t ESE =8.850,P <0.05);MLO 位 AGD 值降低约26.33%,ESE 值降低约29.43%,两者间具有显著性差异(t AGD =11.006,P <0.05,t ESE =8.400,P <0.05)。结论在获取同等乳腺图像质量的情况下,钼铑双靶乳腺 X 射线摄影检查中剂量优先模式较标准模式能够有效降低受检者的辐射剂量。     

乳腺X射线机泄漏射线测试方法探讨

乳腺X射线机是对妇女进行乳腺疾病诊断和常规检查的常用医疗设备，使用频率极高。由于在进行诊断时，受检者的头部紧靠近X射线管组件，因此泄漏的X射线直接辐射在身体上，严重影响其身体健康。本文介绍的首先对放置在乳腺X射线机管组件周围的胶片进行曝光，定性判断泄漏X射线的位置，然后通过辐射剂量仪进行准确的测试方法。     

两种摄影模式下的乳腺X射线摄影的剂量比较

目的 对比分析数字乳腺X射线断层融合成像和全数字化乳腺X射线摄影两种模式下乳腺X射线摄影剂量比较,以及平均腺体剂量与乳腺密度、压迫厚度的关系。方法 回顾性收集2020年10月至2022年5月在昆明医科大学第一附属医院行数字乳腺X射线断层融合成像（DBT）的乳腺疾病患者以及同时期在本院行全数字化乳腺X射线摄影（FFDM）的体检人群的乳腺X射线摄影资料,记录压迫厚度、压迫力度及平均腺体剂量（AGD）,由两名从事乳腺影像诊断的高年资医师依照2013年ACR BI-RADS MAMMOGRAPHY对乳腺腺体密度进行分型,分为a （腺体组织<25%）、b （腺体组织约25%~50%）、c （腺体组织约50%~75%）、d （腺体组织>75%）4型,分析在FFDM、DBT模式下,不同腺体密度、不同压迫厚度与AGD的关系。结果 无论是FFDM还是DBT模式,随着乳腺腺体密度增加AGD逐渐增加,AGD_a型b_型c_型d_型,差异有统计学意义（F=861.63、617.83、330.33、451.45、290.47,P<0.001）。行FFDM的c、d型乳腺,压迫厚度为31~40 mm时AGD较低。在相同压迫厚度下,a、b、c、d型乳腺AGD_DBT均高于AGD_FFDM,差异有统计学意义（a型：t=-17.88、-42.19、-29.90、-28.14、-24.95,P<0.001;b型：t=-49.18、-35.94、-27.25、-28.37、-24.10,P<0.001;c型：t=-11.78、-32.90、-23.13、-20.51、-18.24,P<0.001;d型：t=-7.94、-26.24、-17.24、-15.44、-13.81,P<0.001）,乳腺厚度为61~70 mm的d型乳腺AGD两者差异最大,为1.07 mGy （95%CI：0.92~1.22）。AGD与乳腺密度、压迫厚度正相关,且FFDM的相关性强于DBT。结论 乳腺X射线摄影AGD与乳腺密度、压迫厚度正相关,与FFDM相比,DBT会增加AGD,但AGD增幅在安全范围内,临床工作中行DBT检查对乳腺疾病患者有益。     

上海市数字化乳腺X射线摄影装置质量控制检测分析

目的 对上海市数字化乳腺X射线摄影装置使用情况与设备性能质量状况进行对比分析,为合理选择数字化乳腺X射线摄影装置提供参考。 方法 依据国家相关标准和规范,采用X射线检测仪和乳腺成像性能检测模体,对上海市53台数字化乳腺X射线摄影装置的9项技术指标进行质量控制检测,并将两类数字化乳腺X射线机——计算机X射线摄影装置（CR）与数字X射线摄影装置（DR）的性能检测结果进行统计学分析。在分析两类乳腺机各项性能指标合格率差异的基础上,对两类乳腺机的乳腺平均剂量与图像质量进行进一步的比较分析。 结果 两类乳腺X射线机的合格率及乳腺平均剂量差异无统计学意义;对于模体影像,两类设备的差异具有统计学意义,DR乳腺机的图像质量优于CR乳腺机。 结论 应加强对数字化乳腺X射线摄影装置的日常检测,从辐射防护最优化角度推荐选择DR乳腺机代替CR乳腺机开展数字化乳腺摄影工作。     

乳腺X线摄影中乳腺肿块、密度与辐射剂量的相关性研究

目的：通过对临床可触及肿块的乳腺肿瘤患者健侧及患侧乳腺的平均腺体剂量（average gland dose,AGD）进行分析,分析乳腺肿块、密度与辐射剂量之间的相关性。方法：收集2019年1—12月于复旦大学附属肿瘤医院就诊的临床可触及乳腺肿块的患者204例,对患者行双侧乳腺头尾（craniocaudal,CC）位及内外斜（mediolateral oblique,MLO）位标准摄影检查,统计乳腺密度、压迫厚度、不同年龄段的辐射剂量,探讨乳腺X线摄影中乳腺肿块、密度与辐射剂量之间是否存在相关性。结果：在204例患者中,右侧乳腺有肿块的患者101例,左侧乳腺有肿块的患者103例。根据腺体类型进行分类,脂肪型（a型）5例,散在纤维腺体型（b型）52例,不均匀致密型（c型）132例,极度致密型（d型）15例;根据年龄进行分类,40岁以下的患者30例,41～50岁的患者65例,51～60岁的患者52例,61～70岁的患者40例,71岁以上的患者17例。比较乳腺肿块患者的健侧及患侧乳腺的AGD时,患侧乳腺的AGD较健侧乳腺的AGD高30.66%,差异有统计学意义（P<0.05）。不同乳腺腺...     

3种无源固体探测器对低能X射线能量响应的研究

目的 研究3种无源固体探测器对低能X射线的能量响应,评估在乳腺X射线摄影检查中测量入射体表剂量和估算平均腺体剂量的可行性。方法 选用LiF(Mg,Ti)和LiF(Mg,Cu,P)热释光(TL)材料和A1₂O₃:C光致发光(OSL)材料的固体探测器,在Mo/Mo低能X射线机上,管电压25～40kV范围的10种线质分别曝光相同的空气比释动能。结果 给出管电压在25kV～40kV范围的10种辐射线质时TL和OSL能量响应,分别小于25％和11％。结论 A1₂O₃:C光释光探测器用于乳腺X射线摄影日常质量控制和入射体表剂量测量具有相当大的潜力。     

Dedicated breast CT: radiation dose and image quality evaluation.

PURPOSE: To evaluate the feasibility of breast computed tomography (CT) in terms of radiation dose and image quality. MATERIALS AND METHODS: Validated Monte Carlo simulation techniques were used to estimate the average glandular dose (AGD). The calculated photon fluence at the detector for high-quality abdominal CT (120 kVp, 300 mAs, 5-mm section thickness) was the benchmark for assessing the milliampere seconds and corresponding radiation dose necessary for breast CT. Image noise was measured by using a 10-cm-diameter cylinder imaged with a clinical CT scanner at 10-300 mAs for 80, 100, and 120 kVp. A cadaveric breast was imaged in the coronal plane to approximate the acquisition geometry of a proposed breast CT scanner. RESULTS: The AGD for 80-kVp breast CT was comparable to that for two-view mammography of 5-cm breasts (compressed breast thickness). For thicker breasts, the breast CT dose was about one-third less than that for two-view mammography. The maximum dose at mammography assessed in 1-mm(3) voxels was far higher (20.0 mGy) than that at breast CT (5.4 mGy) for a typical 5-cm 50% glandular breast. CT images of an 8-cm cadaveric breast (AGD, 6.3 mGy) were subjectively superior to digital mammograms (AGD, 10.1 mGy) of the same specimen. CONCLUSION: The potential of high signal-to-noise ratio images with low anatomic noise, which are obtainable at dose levels comparable to those for mammography, suggests that dedicated breast CT should be studied further for its potential in breast cancer screening and diagnosis.     

Mammography Diagnostic Reference Levels (DRLs) in Ghana

IntroductionDiagnostic Reference Levels (DRLs) are essential for optimisation in mammography. A local DRL for screen-film mammography has been established in Ghana but none exists for the digital mammography systems. Furthermore, technological advancement is phasing out the use of screen-film mammography and replacing it with digital mammography systems. This study aims to establish the local DRLs used in digital mammography across three institutions in Ghana to guide mammography practice.MethodsAverage glandular dose (AGD), compressed breast thickness (CBT), age of patients, entrance surface exposure (ESE), kVp, and mAs were retrospectively extracted from three digital mammography systems. The 75th and 95th percentile values were obtained for the AGD of each mammography projection and at CBT of 60 ± 5 mm. The correlation between the AGD and CBT, kVp, mAs, and ESE were investigated.ResultsThe 75th percentile for the AGD at CBT of 60 ± 5 mm for Centres 1, 2, 3, and all centres were 2.3, 1.8, 2.1, and 2.0 mGy respectively. The DRLs obtained were comparably higher than international studies except those of the United Kingdom. The AGD showed a strong positive correlation with the CBT, kVp, mAs, and ESE. There was variability in the AGD applied across the three centres for the craniocaudal (CC) and mediolateral oblique (MLO) projections. The mean AGD, mAs, and ESE for all the three centres and per centre recorded were higher than previous studies, but the mean kVp and CBT were lower than previous studies.ConclusionThe higher DRLs estimated in this preliminary study indicates that there is a need for dose optimisation in digital mammography practice in Ghana to improve radiation protection.Implications for practiceThe findings will guide the process of optimisation and limit the variations in the radiation dose during mammography practice.     

乳腺X线摄影射线剂量对乳腺X线片质量的影响

目的通过调节乳腺X线摄影的曝光剂量,评价乳腺X线摄影中平均腺体剂量(average glandular dose,AGD)对图像质量的影响。资料与方法应用数字化全景乳腺机系统和PASMAM模体,手动控制条件(kV、mAs),对不同厚度的PASMAM模体在不同AGD条件下进行摄影。采用非参数统计分析不同AGD相同厚度以及相同AGD组不同厚度模体钙化和肿块的显示程度差异是否存在统计学意义,并分析图像信号噪声比(SNR)随剂量和厚度的变化。结果相同曝光剂量条件下,SNR随模体厚度的增加而下降,相同模体厚度SNR随曝光剂量的增加而增加。实验范围内的相同厚度模体组合,在不同AGD条件下,显示钙化和肿块的能力差异无统计学意义(P>0.05)。结论数字化全景乳腺X线摄影盲目提高AGD值会增加患者受辐射量,并不能提高显示钙化和肿块的能力。     

Dose comparison between screen/film and full-field digital mammography

The study purpose was the comparison between doses delivered by a full-field digital mammography system and a screen/film mammography unit, both using the same type of X-ray tube. Exposure parameters and breast thickness were collected for 300 screen/film (GE Senographe DMR) and 296 digital mammograms (GE Senographe 2000D). The entrance surface air kerma (ESAK) was calculated from anode/filter combination, kV_p and mAs values and breast thickness, by simulating spectra through a program based on a catalogue of experimental X-ray spectra. The average glandular dose (AGD) was also computed. Results showed an overall reduction of average glandular dose by 27% of digital over screen/film mammography. The dose saving was about 15% for thin and thick breasts, while it was between 30% and 40% for intermediate thicknesses. Full-field digital mammography dose reduction is allowed by wider dynamic range and higher efficiency of digital detector, which can be exposed at higher energy spectra than screen/film mammography, and by the separation between acquisition and displaying processes.     

Analysis of patient dose in full field digital mammography

Now, full field digital mammography (FFDM) is widely used in diagnosis of breast cancer. With the development of FFDM, the radiation dose delivered to the patients involved in an imaging protocol is of utmost concern. Here, we analyzed the average glandular dose (AGD) and entrance surface exposure (ESE) of 1397 patients (6008 images) who underwent mammographic examinations by FFDM in three modes with automatic optimization of parameters (AOP), namely STD for standard mode, CNT for contrast mode and DOSE for dose mode. In addition, exposure factors including kVp, tube loading (mAs), and target/filter combination were evaluated. As a result, the patient dose was sorted as CNT>STD>DOSE. The dose difference among the three AOP modes was mainly attributed to the selection of mAs. The AGD and breast compressed thickness were well correlated in STD and DOSE modes. However, the correlation between CNT-delivered AGD and breast compressed thickness was dependent on the range of the breast thickness and patient age. The findings on dose and exposure characteristics of the three AOP modes get useful message of patient dose in the acquisition of FFDM.     

Simultaneous measurement of patient dose and distribution of indoor scattered radiation during digital breast tomosynthesis

Introduction

Breast cancer incidence increases from the age of 30 years. As this age range coincides with that in which women usually pursue pregnancy, undergoing medical examinations for conditions such as breast cancer is a concern, especially when pregnancy is uncertain during the first eight weeks. Moreover, in this age range, breast often exhibits a high density, thus compromising diagnosis. For such density, digital breast tomosynthesis (DBT) provides a more accurate diagnosis than 2D mammography given its higher sensitivity and specificity. However, radiation exposure increases during DBT, and it should be determined.

Patient investigation of average glandular dose and incident air kerma for digital mammography

Our aim in this study was to investigate the incident air kerma (IAK) and average glandular dose (AGD) for polymethylmethacrylate (PMMA) phantoms and patient breasts for each thickness by use of digital mammography units, and to determine the correlation between phantom and patient measurements. An additional aim was to calculate the numerical value of the diagnostic reference level (DRL) for digital mammography in Japan based on the AGD from patient measurements. Patient-based IAK and AGD values were calculated for 300 patients who underwent mammographic examinations at three institutions. On examination of a 40-mm PMMA phantom, the IAK and the AGD were 7.89 and 1.84 mGy, respectively. The mean patient breast thickness was 37.6 mm, and the mean IAK and the AGD calculated from actual patient data for breast thicknesses between 40 mm and 50 mm were 8.91 and 2.08 mGy, respectively. Approximately 20 % of the 300 patients had IAK >10 mGy. The distributions of patient-based IAK and AGD values were higher than the IAK and AGD values for the PMMA phantom. The patient dose with use of the PMMA phantom can be underestimated. The DRL was calculated from patient-based AGDs of the regular breast thickness as 2.0 mGy in Japan.     

Manual or auto-mode: Does this affect radiation dose in digital mammography without compromising image quality?

IntroductionIn current practice, auto-filter exposure mode is used for most screening mammography examinations. However, with better understanding of the side effects of radiation, it is important to examine exposure parameters and practises to minimise radiation dose to patients. The purpose of this phantom study is to investigate the impact that different exposure modes (manual, auto-time and auto-filter) have on radiation dose, while maintaining images of diagnostic quality.MethodsThis study was conducted in three stages. In the first stage, 125 images were taken using a Gammex 156 phantom with polymethyl methacrylate blocks to reflect varying thicknesses (4.5, 5.0, 5.5, 6.0 and 6.5 cm). In the second stage, three mammographers independently assessed image quality and assigned scores based on the number of distinct fibers, masses and speck groups visible. Images with acceptable quality were further investigated in the third stage by comparing their average glandular dose (AGD) using the Kruskal–Wallis H test and Dunn's post-hoc pairwise analysis.ResultsSignificant differences in AGD were shown between the auto-filter mode and manual mode techniques for 6.0 cm, and between auto-time mode and manual mode techniques for 6.5 cm (p < 0.05).ConclusionFor 4.5, 5.0 and 5.5 cm phantoms, as AGD was not significantly different among the different modes, the auto-filter may remain the most practical option. However, significant reductions in AGD were obtained for the 6.0 and 6.5 cm phantoms when manual mode techniques were used.Implications for practiceManual mode techniques can potentially provide dose-saving opportunity in 6.0 and 6.5 cm breast thickness though future work on human breast should be done to confirm this. Results from this study will support future research based on patient data.     

基于两种靶-滤过的数字乳腺机对致密型厚乳腺摄影结果的对比研究

目的 探讨对模拟致密型厚乳腺（压迫厚度>65 mm）的模体行全景数字乳腺X射线摄影（FFDM）检查,钼-铑（Mo-Rh）和钨-铑（W-Rh）两种靶-滤过组合对其辐射剂量及图像质量的影响。方法 用聚甲基丙烯酸甲酯有机玻璃（PMMA）模拟标准乳腺,再将铝片置于PMMA板中模拟致密型乳腺,对两组不同致密型（分别放置0.1和0.2 mm铝片）厚度为68 mm的模体进行自动、半自动曝光以及手动曝光,记录靶-滤过（T-F）组合方式、管电压、管电流、平均腺体剂量（AGD）、表面入射剂量（ESE）和图像质量因子反数值（IQFInv）。采用Pearson相关及回归分析评价AGD对IQFInv的影响,两组模体的靶-滤过组合对IQFInv和AGD的差异采用配对样本t检验。结果 AGD和IQFInv具有正相关（r=0.806~0.953,P<0.05）。对于0.1 mm铝片的模体,固定100 mAs或固定28 kVp,两组靶-滤过组合的AGD差异和IQFInv差异均具有统计学意义（t=3.162~8.028,P<0.05）。对于0.2 mm铝片的模体,固定100 mAs时,AGD差异和IQFInv差异均具有统计学意义（t=8.028、4.768,P<0.05）;固定28 kVp时,AGD差异具有统计学意义（t=7.730,P<0.05）,IQFInv差异没有统计学意义（P>0.05）。此外,固定100 mAs时,采用W-Rh,两组模体的IQFInv差异具有统计学意义（t=2.345,P<0.05）。结论 对致密型厚乳腺模体采用W-Rh组合较Mo-Rh组合能在保证影像质量的前提下降低辐射剂量。相同管电流时,W-Rh组合在高管电压下对致密程度较高的乳腺模体的影像显示更佳。