高电压胸部摄影诊断和防护效果研究

作者以体模实验为基础。测定了不同管电压拍摄胸片时的病人剂量，考察了提高管电压对胶片影像质量的影响，结果表明，使用高电压拍摄胸片比使用低电压有利于降低病人剂量，在增加影像信息量，提高肋骨阴影区和纵膈区灶检出率方面更有较大优越性，此外，使用高电压技术不家利于延长Ｘ射线管的使用寿命。     

Radiation protection of patients in diagnostic and interventional radiology in Asian countries: Impact of an IAEA project

Recognizing the lack of information on image quality and patient doses in most countries in Asia, the International Atomic Energy Agency (IAEA) initiated a project to assess the status of imaging technology, practice in conventional radiography, mammography, computed tomography (CT) and interventional procedures, and to implement optimisation actions. A total of 20 countries participated. Obsolete practices of use of fluoroscopy for positioning, photofluorography, chest fluoroscopy and conventional tomography were reported by 4 out of 7 countries that provided this information. Low-kV technique for chest radiography is in use in participating countries for 20-85% of cases, and manual processing is in 5-85% of facilities in 5 countries. Instances of the use of adult CT protocol for children in three participating countries were observed in 10-40% of hospitals surveyed. After implementation of a Quality Control programme, the image quality in conventional radiography improved by zero to 13 percentage points in certain countries and dose reduction was from 10% to 85%. In mammography, poor quality, ranging from 10 to 29% of images in different countries was observed. The project increased attention to dose quantities and dose levels in computed tomography, although doses in most cases were not higher than reference levels. In this study 16-19% of patients in interventional cardiology received doses that have potential for either stochastic risk or tissue reaction. This multi-national study is the first of its kind in the Asia, and it provided insight into the situation and opportunities for improvement.     

Radiation protection of patients in diagnostic radiology: status of practice in five Eastern-European countries, based on IAEA project

The purpose of this work was to investigate status of imaging technology and practice in five countries in Eastern-European region and evaluate the impact of IAEA projects on radiation protection of patients. Information collected using standardized IAEA protocol included status of technology, practices and patient dose levels in interventional procedure, radiography, mammography and computed tomography (CT). In spite of increased number of digital units, single phase generators or units older than 30 year are still in use. Examples of obsolete practice such as using fluoroscopy for positioning, photofluorography, chest fluoroscopy and soft-beam technique for chest radiography are also in use. Modern multi-slice CT or digital mammography units are available; however, there is lack of adequate radiation protection and medical physics support in hospitals. Information on patient doses in interventional procedures, conventional radiography, mammography and CT was collected to have baseline data and corrective measures were proposed with appropriate follow up actions taken.     

数字摄影受检者辐射剂量调查

目的 了解数字摄影（DR）检查中受检者的辐射剂量水平,为数字放射摄影受检者指导水平的制定提供基础数据。方法 使用热释光剂量计TLD测量受检者不同部位、不同投照方向的入射体表剂量（ESD）;使用剂量面积乘积仪测量受检者不同部位、不同投照方向的剂量面积乘积（DAP）,并利用测量的DAP值,估算出有效剂量（E）。结果 同类检查中,kV和mAs的变化范围较大,不同部位DR检查中ESD、DAP和E的差别均具有统计学意义（F=33.47、24.68、43.19,P<0.05）。其中,ESD和DAP均以腰椎（LAT）最高,均数为4.62mGy/次和2.26Gy·cm²/次;E以腹部（AP）最高,均数为0.59mSv,高于腰椎（LAT）的0.31mSv。结论 DR在加强受检者放射防护最优化方面很有潜力,应尽快建立适合我国国民体质特征的数字放射摄影受检者辐射剂量的指导水平。     

成年人CT扫描中辐射剂量和诊断参考水平的探讨

目的 通过全国范围内CT辐射剂量的调查,了解成年人辐射剂量的现状,进而探讨成年人CT的诊断参考水平不符,需要根据我国的实际建立自己的DRL。方法 2015年9月至2016年3月在全国30个省、自治区、直辖市调查168家医院,其中三级和二级医院各约占一半。随机调查年度状态检测合格的168台CT,包括了临床应用中普遍使用的品牌和型号。每台CT收集头颅、鼻窦、颈部、胸部、腹部、盆腔、腰椎、尿路造影、冠状动脉CT血管造影（CTA）、颅脑CTA、颈部CTA和胸腹CTA共12个检查项目、每个项目10个随机病例。以容积CT剂量指数（CTDI_vol）和剂量长度乘积（DLP）作为剂量参量,每个检查项目的所有数据按照大小排序,取25%、50%和75%位数,其中75%位数为参考水平。所得剂量数值与国际相关放射防护组织发布的DRL进行比较。结果 共收集16 244个标准体型成年病例的剂量数据,经逐一检查剔除274个无效数据,剩余15 970个病例数据。全国范围内不同的CT使用单位,同一检查项目的CTDI_vol、DLP和扫描期项都有很大差异。与国际放射防护组织发布的数据相比,不同检查项目的诊断参考水平的差异程度各不相同,颅脑诊断水平与参考值相当、胸部腹部较低。剂量指数值最大的几种检查项目为头颅、冠状动脉CTA、颅脑CTA和鼻窦。尿路造影的CTDI_vol虽然仅为20 mGy,但DLP却高达2 620 mGy·cm。结论 我国现有的CT剂量水平与国际相关组织发布的诊断标准水平（DRL）不符,需要根据我国的实际建立自己的DRL。     

CT radiation dose in children: a survey to establish age-based diagnostic reference levels in Switzerland

This work aimed at assessing the doses delivered in Switzerland to paediatric patients during computed tomography (CT) examinations of the brain, chest and abdomen, and at establishing diagnostic reference levels (DRLs) for various age groups. Forms were sent to the ten centres performing CT on children, addressing the demographics, the indication and the scanning parameters: number of series, kilovoltage, tube current, rotation time, reconstruction slice thickness and pitch, volume CT dose index (CTDI(vol)) and dose length product (DLP). Per age group, the proposed DRLs for brain, chest and abdomen are, respectively, in terms of CTDI(vol): 20, 30, 40, 60 mGy; 5, 8, 10, 12 mGy; 7, 9, 13, 16 mGy; and in terms of DLP: 270, 420, 560, 1,000 mGy cm; 110, 200, 220, 460 mGy cm; 130, 300, 380, 500 mGy cm. An optimisation process should be initiated to reduce the spread in dose recorded in this study. A major element of this process should be the use of DRLs.     

Optimisation of radiation dose and image quality in mobile neonatal chest radiography

PurposeTo optimise the radiation dose and image quality for chest radiography in the neonatal intensive care unit (NICU) by increasing the mean beam energy.MethodsTwo techniques for the acquisition of NICU AP chest X-ray images were compared for image quality and radiation dose. 73 images were acquired using a standard technique (56 kV, 3.2 mAs and no additional filtration) and 90 images with a new technique (62 kV, 2 mAs and 2 mm Al filtration). The entrance surface air kerma (ESAK) was measured using a phantom and compared between the techniques and against established diagnostic reference levels (DRL). Images were evaluated using seven image quality criteria independently by three radiologists. Images quality and radiation dose were compared statistically between the standard and new techniques.ResultsThe maximum ESAK for the new technique was 40.20 μGy, 43.7% of the ESAK of the standard technique. Statistical evaluation demonstrated no significant differences in image quality between the two acquisition techniques.ConclusionsBased on the techniques and acquisition factors investigated within this study, it is possible to lower the radiation dose without any significant effects on image quality by adding filtration (2 mm Al) and increasing the tube potential. Such steps are relatively simple to undertake and as such, other departments should consider testing and implementing this dose reduction strategy within clinical practice where appropriate.     

放射防护最优化对数字X射线摄影中受检者辐射剂量降低的价值

目的 通过评价辐射防护最优化前后患者剂量和废弃影像的差异,探讨在应用数字X射线摄影(DR)系统进行日常摄影中实施最优化的必要性.方法 200名近标准体格患者纳入研究,制定DR摄影防护最优化程序,100例执行最优化前方案摄影,100例执行最优化方案摄影.测量最优化前后患者剂量-面积乘积(DAP)和体表入射剂量(ESD).同时统计最优化前后各2个月内的废弃影像,并按废弃原因分类.比较最优化前后患者辐射剂量和影像废弃率的差异.结果 最优化后的ESD和DAP显著低于最优化前(z=9.31、16.22,P＜0.05),影像废弃率明显低于最优化前(x2=36.5,P＜0.05).结论 使用最优化程序的DR摄影可以有效降低患者辐射剂量并减小影像废弃率.     

Diagnostic reference levels in plain radiography for paediatric imaging: A Portuguese study

ObjectiveTo determine diagnostic reference levels (DRLs) for the most frequent paediatric plain radiography examinations in Portugal (chest, pelvis and abdomen) and to characterise a standard paediatric patient for each age group used in literature.MethodsAnthropometric data was collected from 9935 patients. Each age group (<1, 1–<5, 5–<10, 10–<16, ≥16) was categorised by the median values of weight, height and BMI, to define a standard patient. Exposure parameters, kerma-area product (KAP-mGy cm²) and entrance surface air kerma (ESAK-μGy) were collected. DRLs for KAP and ESAK were defined as the 75th percentile (P75) of dose values and presented by age and weight.ResultsIn each age group the P75 of KAP varied from 11 to 77 mGy cm² for chest; 23–816 mGy cm² for pelvis; 25–979 mGy cm² for abdomen. The P75 of ESAK varied from 49 to 67 μGy for chest; 98–1129 μGy for pelvis and 70–1060 μGy for abdomen.ConclusionThe P75 of dose values determined in this study were lower than those published in literature. When available, weight is the preferred parameter to categorise paediatric patients. The large ranges of dose values found in this study, demonstrates a clear need for the optimisation and harmonisation of practice.     

床旁防护装置对冠状动脉造影术者辐射防护效果的体模研究

目的 测量冠状动脉造影8个投照体位在有与无床旁防护装置防护下术者所受辐射剂量,为冠心病介入治疗中减少术者辐射暴露提供参考。方法 在第一及第二术者站位,距地面20至180 cm处,每隔20 cm放置一个实时剂量测量仪。采用冠状动脉造影8个体位投照,测量在有与无床旁防护装置防护下,术者在不同投照体位的不同高度接受辐射剂量情况。结果 在第一术者位,除1.2 m高度仍可测到较高剂量(剂量率0.35~4.78 mSv/h,屏蔽率27.67%~89.33%),其余各点屏蔽率均在91%以上。左前斜尾位、左前斜位、左前斜头位辐射剂量较高。第二术者位屏蔽率较第一术者位低,剂量峰值可出现在0.8、1.0及1.4 m高度(剂量率0.27~1.86 mSv/h,屏蔽率30.34%~92.13%)。右前斜尾位、左前斜尾位、正头位、左前斜位辐射剂量较高。结论 床旁防护装置防护下,术者在左前斜尾位、左前斜位、左前斜头位、右前斜尾位的辐射暴露较高,应尽量少采用上述投照体位长时间曝光。同时应加强0.8~1.4 m高度的辐射防护。     

加强放射诊断辐射剂量管理的必要性及应对策略

近年来, 我国放射诊断检查特别是CT检查的频次迅猛增加, 已经成为国民人均辐射剂量的最大人工辐射来源, 并有可能超过天然辐射源的贡献。临床诊疗活动中, 患者和受检者短时间内可能进行多项目、多频次的放射诊断成像, 所接受的累积辐射剂量较高, 甚至一天检查的剂量贡献超过50或100 mSv, 从而对其健康产生潜在风险。因此, 有必要对放射诊断辐射剂量信息进行统计分析与控制管理, 以尽可能降低过高剂量及其辐射危险的发生概率。本文对放射诊断辐射风险的国际认识、我国放射诊断设备和检查频次、放射诊断辐射剂量及其管理现状进行阐述, 并就辐射剂量的管理提出应对策略, 为进一步推进临床实践中的辐射防护提供参考。     

Interprofessional working in diagnostic radiography

This paper considers interprofessional working within one diagnostic imaging department.The literature is still divided about the long-term impact of interprofessional learning in pre-registration health and social care education, and its impact on the quality of care provided. When reading the literature about interprofessional working the main topics considered by other authors are team working, communication between professionals, stereotyping and tribalism.The results presented are from an ethnographic study in one department with participant observation and semi-structured interviews.The three main aspects discussed in this paper are; tribalism and culture within the diagnostic radiography profession, communication between different professional groups, and a lack of understanding of the roles of other professional groups.It was evident from the results of this study that tribalism and culture, and a lack of understanding were significant barriers to interprofessional working.It was felt by the authors that pre-registration and post-registration interprofessional education could be significant in changing the culture of the NHS in the future as more professionals learn from and about one another.     

Towards image quality, beam energy and effective dose optimisation in digital thoracic radiography

This paper outlines how objective measurements of both image quality, in terms of signal-to-noise ratio, and effective dose may be used as tools to find the optimum kVp range for a digital chest radiography system. Measurements were made with Thoravision, an amorphous selenium-based digital chest X-ray system. The entrance surface dose and the effective dose to an anthropomorphic chest phantom were determined demonstrating how effective dose is related to beam quality. The image quality was measured using detective quantum efficiency, threshold contrast and a radiologist preference trial involving 100 patients. The results show that, despite the fact that the entrance surface dose decreases as the kVp increases, the effective dose, a better measure of the risk, reaches a minimum value between 90 and 110 kVp; however, the image quality decreases as the kVp increases. In this study the optimum kVp for chest radiography, using a selenium-based radiography system, is in the range 90–110 kVp. This is contrary to the 120- to 150-kVp range that is commonly used. Also, this study shows how objective measurements can be used to optimise radiographic technique without prolonged patient trials. Received: 4 November 1999 Revised: 10 May 2000 Accepted: 11 May 2000     

A snapshot of patients' awareness of radiation dose and risks associated with medical imaging examinations at an Australian radiology clinic

BackgroundCumulative radiation exposure is linked to increasing the lifetime attributable risk of cancer. To avoid unnecessary radiation exposure and facilitate shared decision making, patients should be aware of these issues. This paper examines patients' awareness of radiation dose and risks associated with medical imaging examinations.MethodsConsecutive patients attending a private radiology clinic over a nine week period in 2014 in Metropolitan Melbourne were surveyed while waiting to undergo an imaging examination. Patients who were under 18 years of age, did not speak English and/or were referred for interventional imaging procedures were excluded from participation. Survey questions addressed patients' awareness of radiation dose associated with various imaging modalities' and patients' experience and preferences regarding communication of information about radiation. Data was analysed using SPSS (Ver 20.1).ResultsA total of 242 surveys were completed. Most participants were male (143/239, 59.8%) and aged between 33 and 52 years (109/242, 45%). Over half of participants were not concerned about radiation from medical imaging (130/238, 54.6%). Only a third of participants (80/234, 34.2%) correctly reported that CT has a higher radiation dose than X-ray. Very few participants correctly identified mammography, DEXA, PET and PET/CT as radiation emitting examinations. The majority of participants (202/236, 85.6%) indicated that they were not informed about radiation dose and risks by their referring doctor in advance.ConclusionThis paper provides information relevant to a single private radiology clinic in Australia. Nevertheless, our results have shown that patients presenting for medical imaging have little awareness of radiation dose and risks associated with these examinations and received little information by their referring physicians or staff at the radiology clinic.     

床旁DR与CR胸部摄影质量的对比研究

目的通过床旁数字化X线摄影(digitalradiography,DR)系统与计算机X线摄影(computedradiography,CR)系统胸部摄影图像质量的对比分析,探讨床旁DR摄影的优势。方法随机抽取2010年拍摄的DR床旁X线胸片1000份和既往CR床旁X线胸片1000份进行对比分析。结果床旁DR摄影的应用提供了更加优良的图像质量,明显减少了放射技师的工作量,同时还降低了患者接受的辐射剂量。结论床旁DR胸部摄影比CR胸部摄影有着明显的优势,对手术患者和危重患者的诊治起到了积极作用。     

A comparison of effective dose and risk for different collimation options used in AP shoulder radiography

IntroductionRadiography forms the cornerstone of the evaluation of shoulder disorders. While the benefits of radiography exceed the risks, there continues to be a compelling case for reduction of radiation exposure from diagnostic radiography. The aim of this project was to evaluate the radiation dose and risk for a variety of collimation settings used during anteroposterior (AP) shoulder radiography.MethodsThis was a phantom based study where an ATOM adult dosimetry phantom was loaded with 272 thermoluminescent dosimeters (TLDs). Following loading, the phantom was setup for an AP shoulder X-ray projection with standard 25 × 30 cm rectangular collimation. The phantom was exposed three times and then the TLDs were removed and read. The experiment was repeated using a diamond shaped collimation and rectangular collimation with a minimum field of view to portray only relevant anatomy. Using the TLD dose measurements the effective doses and radiation risks were determined and compared.ResultsAs expected, organs neighbouring the shoulder experienced the highest absorbed doses (greater than 0.01 mGy); these organs included breast, lung and thyroid gland. The effective doses for standard rectangular, small rectangular and diamond collimation were 0.011, 0.008 and 0.016 mSv, respectively. When compared to standard collimation, a small field of view reduced effective dose by 27.3% and when moving to a diamond shape there was a 45.5% increase. The differences are likely driven by differences in the coverage of the radiosensitive lung and breast tissue.ConclusionBy utilising a variety of different collimation settings, effective dose can be reduced. Reducing the radiation dose is both financially beneficial and results in a lower stochastic risk for patients. Image quality must also be considered when choosing different collimation settings. It stands to reason that by reducing the field size, dose will be reduced, and our study has served to quantify the effects in a practical situation.Implications for practiceThe utilisation of smaller/tight collimation is recommended as it offers the lowest dose when compared with other types of collimations. Although well-known this study serves to remind practitioners of the practical importance of collimation and is associated effect on effective dose and risk.     

核医学诊断工作场所辐射水平及防护现状调查

目的 对我国核医学诊断工作场所辐射防护现状进行调查.方法 2013年2—12月期间,在东北、华中和华北地区分别选择1家三甲医院,用γ剂量率仪巡测核医学诊断制药、淋洗、分装、注射、扫描过程中工作场所周围剂量当量率,光致发光剂量计测量放射工作人员个人有效剂量和当量剂量.结果 在放射性药物分装、注射和受检者摆位等操作环节中周围剂量当量率较高, 分装时最高达1.92 mSv/h,注射时距针管5 cm处剂量率最高达1.2 mSv/h,受检者体表30 cm处剂量率范围为5.36~240 μSv/h,某医院护士手部当量剂量为0.01~0.02 mGy,部分工作场所存在人员路线交叉及注射后受检者停留在公众区域的现象.结论 核医学实践中放射工作人员应加强个人防护,提高操作熟练程度以缩短作业时间,应优化放射工作人员出入路线,加强注射后受检者的管理,以免公众人员受到不必要的照射.     

Importance of establishing radiation protection culture in Radiology Department

The increased use of ionization radiation for diagnostic and therapeutic purposes, the rapid advances in computed tomography as well as the high radiation doses delivered by interventional procedures have raised serious safety and health concerns for both patients and medical staff and have necessitated the establishment of a radiation protection culture (RPC) in every Radiology Department. RPC is a newly introduced concept. The term culture describes the combination of attitudes, beliefs, practices and rules among the professionals, staff and patients regarding to radiation protection. Most of the time, the challenge is to improve rather than to build a RPC. The establishment of a RPC requires continuing education of the staff and professional, effective communication among stakeholders of all levels and implementation of quality assurance programs. The RPC creation is being driven from the highest level. Leadership, professionals and associate societies are recognized to play a vital role in the embedding and promotion of RPC in a Medical Unit. The establishment of a RPC enables the reduction of the radiation dose, enhances radiation risk awareness, minimizes unsafe practices, and improves the quality of a radiation protection program. The purpose of this review paper is to describe the role and highlight the importance of establishing a strong RPC in Radiology Departments with an emphasis on promoting RPC in the Interventional Radiology environment.