Ethical issues in medico-legal exposures

The Medical Exposure Directive (MED) 97/43/Euratom defines medico-legal procedures as 'procedures performed for insurance or legal purposes without a medical indication'. The term 'medico-legal exposures' covers a wide range of possible types of exposures, very different in nature, for which the only feature in common is the fact that the main reason for performing them does not relate directly to the health of the individual being exposed to ionising radiation. The key issue in medico-legal exposures is justification. Balancing the advantages and disadvantages of such exposures is complex because not only can these be difficult to quantify and hence compare, but often the advantage may be to society whereas the disadvantage is usually to an individual. This adds an additional layer of ethical complexity to the problem and one, which requires input from a number of sources beyond the established radiation protection community. Because medico-legal exposures are considered to be medical exposures, they are not subject to dose limits. In medico-legal exposures where the benefit is not necessarily to the individual undergoing the exposure, the question must be asked as to whether or not this is an appropriate framework within which to conduct such exposures. This paper looks at the current situation in Europe, highlighting some of the particular problems that have arisen, and tries to identify the areas, which require further clarification and guidance.     

Fifty years of individual monitoring of ionising radiation in Switzerland: history, trends and perspectives

In the last 50 y, individual monitoring of ionising radiation in Switzerland underwent substantial development, strongly influenced by type of applications of ionising radiation, monitoring technologies, knowledge of health risks, protection philosophies and regulatory frameworks. The role of individual monitoring in the system of radiation protection moved from a passive, a posteriori control of limits towards an important and more interactive tool for optimisation. Dose trends for occupational exposures document these developments. In the future, new and emerging dose intensive applications in medicine and an increasing demand for international harmonisation, particularly in Europe, will pose new challenges in individual monitoring.     

Dose quantities in radiation protection and their limitations

For more than 50 years the quantity absorbed dose has been the basic physical quantity in the medical applications of ionising radiation as well as radiological protection against harm from ionising radiation. In radiotherapy relatively high doses are applied (to a part of the human body) within a short period and the absorbed dose is mainly correlated with deterministic effects such as cell killing and tissue damage. In contrast, in radiological protection one is dealing with low doses and low dose rates and long-term stochastic effects in tissue such as cancer induction. The dose quantity (absorbed dose) is considered to be correlated with the probability of cancer incidence and thus risk induced by exposure. ICRP has developed specific dosimetric quantities for radiological protection that allow the extent of exposure to ionising radiation from whole and partial body external radiation as well as from intakes of radionuclides to be taken into account by one quantity. Moreover, radiological protection quantities are designed to provide a correlation with risk of radiation induced cancer. In addition, operational dose quantities have been defined for use in measurements of external radiation exposure and practical applications. The paper describes the concept and considerations underlying the actual system of dose quantities, and discusses the advantage as well as the limitations of applicability of such a system. For example, absorbed dose is a non-stochastic quantity defined at any point in matter. All dose quantities in use are based on an averaging procedure. Stochastic effects and microscopic biological and energy deposition structures are not considered in the definition. Absorbed dose is correlated to the initial very short phase of the radiation interaction with tissue while the radiation induced biological reactions of the tissue may last for minutes or hours or even longer. There are many parameters other than absorbed dose that influence the process of cancer induction, which may influence the consideration of cells and/or tissues at risk which are most important for radiological protection.     

Does exposure to residential radon increase the risk of lung cancer?

In assessing the risks of exposure to ionising radiation, it is important to neither overstate nor understate the effects of the hazard. These requirements are often difficult to satisfy, especially since much of our knowledge about the effects of low levels of radiation is subject to rather large uncertainties. Our participants have given their opinions about the risk of lung cancer induction resulting from exposure to radon in residences. Each agrees that exposures to high concentrations of radon are hazardous. However, as with low level exposures to other types of ionising radiation, quantifying relatively small risks is quite difficult. The national and international standards setting bodies have recommended a fairly conservative approach that may overestimate the 'true' magnitude of deleterious effects and their dependence upon exposure, but this is to be expected given the uncertainties in the data and the need to avoid underestimates. A conservative approach can have both positive and negative consequences, and it is also important to neither overstate nor understate these consequences.     

Justification in clinical radiological practice: a survey among staff of five London hospitals

This study represents a survey performed among staff who, according to the Ionising Radiation (Medical Exposures) Regulations of 2000 (IRMER), are responsible for justifying radiological examinations in the UK. The aim of the survey is to map the current situation regarding knowledge of risks from X-ray exposures and the criteria used for their justification. An anonymous electronic questionnaire was emailed to 219 radiologists and radiographers of five National Health Service hospitals. The questions were designed to investigate the way the sample group defines/assesses risk and benefit when justifying medical exposures, and to test their knowledge on radiation doses, risk communication, and on relevant national legislation. The majority of the respondents are aware of the relevant legislation/guidelines. Patient's medical condition, age and sex, and alternative techniques using less or no ionising radiation are the main criteria used for justification. However, when estimating the effective dose of various examinations in chest radiograph equivalents, the majority of the responses were incorrect. Although there is good knowledge of legislation around justification of medical exposures, there seems to be a lack of knowledge on radiation doses and risks among IRMER practitioners.     

Radiation protection dosimetry for diagnostic radiology patients

The radiation protection of patients undergoing medical X-ray examinations is governed by the principles of justification and optimisation. Radiation dosimetry is required to inform medical practitioners of the levels of exposure and hence the risks from the diagnostic procedures that they have to justify and to assist the operators of X-ray imaging equipment to determine whether their procedures are optimised. This paper describes the main dosimetric methods that have been developed to meet these requirements. Suitable radiation risk projection models are used to predict the risks to patients in the UK from computed tomography examinations, as a function of age at exposure and sex, and show that the lifetime risk of fatal cancer can reach 1 in 1000 for children. The concept of 'diagnostic reference levels' as an aid to the optimisation of medical exposures is described, and progress in implementing them in the UK is reported.     

Mammographic screening: is the benefit worth the risk?

Justification of medical exposures is a fundamental principle of radiation protection. This principle applies to mammographic screening, both for the screened population and at an individual level. The benefit of mammographic screening may be considered to be the number of cancers detected or lives saved by breast screening. The risk is the hypothetical number of fatal cancers induced by the use of ionising radiation in screening mammography. Benefit can be deduced from the cancer detection rate in the NHS Breast Screening Programme. The number of additional lives saved by the intervention of a screening programme may be deduced from knowledge of the change in tumour size, stage and nodal status (and hence prognosis) in women with screening detected breast cancers compared with symptomatic women before screening. Calculations of benefit risk ratios to the UK population have been performed. It is concluded that breast screening is justified in radiation protection terms.     

Regulation of radiation protection of the patient: how and how much, the current Belgian situation

Regulation of radiation protection has always been a cornerstone to protect the patient when exposed to ionising radiation. However, large differences exist between the implementation of international approved recommendations. Even when a well-established supra-national legislative format exists, further translation is always adapted to a suitable level of the medical sector in a country. Actual trends are given for the Belgian situation, where the legislation on radiation protection in medicine is currently under revision.     

Cost-benefit analysis of road safety measures: applicability and controversies

This paper discusses the applicability of cost-benefit analysis as an aid to policy making for road safety measures. A framework for assessing the applicability of cost-benefit analysis is developed. Five main types of criticism of cost-benefit analysis are identified: 1. rejecting the basic principles of cost-benefit analysis as not applicable to road safety, 2. excluding some types of issues from the scope of calculation of costs and benefits, 3. setting policy objectives that are not amenable to cost-benefit analysis, 4. rejecting the need for maintaining a separation between policy objectives and policy programmes as required for cost-benefit analysis, and 5. rejecting, or denying the possibility of ever obtaining, acceptably valid and reliable economic valuations of the consequences of alternative policy programmes. It is concluded that rejecting the basic principles of cost-benefit analysis is a difficult position to defend, since these principles are simply a re-statement in economic terms of very general principles of rational choice. These principles are part of the normative basis of all formal techniques designed to aid policy making as well as the democratic system of government. Everybody, including those who advocate the use of cost-benefit analysis, agree that some issues are unsuitable for cost-benefit analysis, in particular those that involve basic human rights and fairness in distribution. There may, however, be disagreement with respect to the perception of a specific policy issue in terms of whether it is mainly about rights and fairness or mainly about the effective use of policy instruments to solve a social problem. Politicians may be tempted to set policy objectives that are ill suited for cost-benefit analysis, but this does not imply that cost-benefit analysis makes unreasonable assumptions. Perhaps the most important issue for the applicability of cost-benefit analysis is whether people in general have sufficiently well ordered preferences for economic valuations based on these preferences to make sense.     

Personal dose monitoring in hospitals: global assessment, critical applications and future needs

It is known that medical applications using ionising radiation are wide spread and still increasing. Physicians, technicians, nurses and others constitute the largest group of workers occupationally exposed to man-made sources of radiation. Many hospital workers are consequently subjected to routine monitoring of professional radiation exposures. in the university hospital, UZ Brussel, 600 out of 4000 staff members are daily monitored for external radiation exposures. The most obvious applications of ionising radiation are diagnostic radiology, diagnostic or therapeutic use of radionuclides in nuclear medicine and external radiation therapy or brachytherapy in radiotherapy departments. Other important applications also include various procedures in interventional radiology (IR), in vitro biomedical research and radiopharmaceutical production around cyclotrons. Besides the fact that many of the staff members, involved in these applications, are not measurably exposed, detailed studies were carried out at workplaces where routine dose monitoring encounters difficulties and for some applications where relatively high occupational exposures can be found. most of the studies are concentrated around nuclear medicine applications and IR. They contain assessments of both effective dose and doses at different parts of the body. The results contribute to better characterisation of the different workplaces in a way that critical applications can be identified. Moreover, conclusions point out future needs for practical routine dose monitoring and optimisation of radiation protection.     

Medical radiation protection in next decade

Interest in medical radiation protection today is the same as what it would have been almost a century ago. After many decades of relatively safe application of radiation in medicine, the recent spurt in over exposures, over-use of imaging and accidental exposures has created the need for stakeholders to join hands and contribute towards increasing radiation safety levels. Whether it be the need for technological developments to achieve sub-mSv CT scans, tracking of patient exposure history, accounting for repeated exposures of the same patient, specific consideration of requests for radiological examinations that deliver few mSv of dose, or utilization of regulatory approaches, radiological equipment will need to alert users whenever the radiation dose to the patient is above a defined value. The current decade will focus increasingly on carcinogenic effects in patients.     

Interventional magnetic resonance imaging: an alternative to image guidance with ionising radiation

At present, interventional procedures, such as stent placement, are performed under X-ray image guidance. Unfortunately with X-ray imaging, both patient and interventionalist are exposed to ionising radiation. Furthermore, X-ray imaging is lacking soft tissue contrast and is not capable of true 3-D displays of either interventional device or tissue morphology. Magnetic resonance imaging (MRI) offers excellent soft tissue contrast, 3-D acquisition techniques, as well as rapid image acquisition and reconstruction. Despite these advantages, MR-guided interventions are challenging owing to the limited access to the patient, strong magnetic and radio-frequency fields that require special interventional devices, inferior image frame rates and spatial resolution, and high MRI scanner noise. For MR-guided intravascular interventions, where access to the target organ is achieved through catheters, dedicated hardware and automated image slice positioning techniques have been developed. We illustrate that MR-guided renal embolisations can be performed in closed-bore high-field MR scanners.     

Industrial radiation processing--working behind the scenes

Industrial radiation processing is generally a rather low-keyactivity perhaps because of the possible perception of a largerisk being associated with what is actually a rather routinecommercial operation. As an example, disposable bandages forconsumer use have been sterilised using ionising radiation fordecades, but this fact has not been widely publicised. The factthat large quantities of ionising radiation are utilised forindustrial radiation processing tends to result in a generalapprehension about a type of work that is quite beneficial innature. Accidental exposures at radiation processing installationsare extremely rare and have not affected more than one or twopersons, but they     

State-of-the-art radiation detectors for medical imaging: Demands and trends

Over the last half-century a variety of significant technical advances in several scientific fields has been pointing to an exploding growth in the field of medical imaging leading to a better interpretation of more specific anatomical, biochemical and molecular pathways. In particular, the development of novel imaging detectors and readout electronics has been critical to the advancement of medical imaging allowing the invention of breakthrough platforms for simultaneous acquisition of multi-modality images at molecular level. The present paper presents a review of the challenges, demands and constraints on radiation imaging detectors imposed by the nature of the modality and the physics of the imaging source. This is followed by a concise review and perspective on various types of state-of-the-art detector technologies that have been developed to meet these requirements. Trends, prospects and new concepts for future imaging detectors are also highlighted.     

The great advances in radiation measurements

The title of this banquet talk was selected to entertain conferees with recollections of major advances in dosimetry that have stimulated appetites for scientific progress. Recalling over fifty years of use of dosimetric instruments and concepts in the 1950-2000 era leads to an appreciation of many advances in solid state dosimetry, which others here know well and pursue vigorously. This author has been mainly a user, admirer, and interpreter of the fundamental methods of dose measurement. These advances have allowed ease of application in radiation protection and medical physics, for determining current routine and accidental exposures to workers, and for precise radiotherapeutic dose delivery. In more recent years, advances in identifying means of locating selective depositions of energy in various materials are providing ways of retrospectively assessing doses to tissue that were deposited many years ago. These methods also will allow development of quantitative theories of radiation damage once the lesions of interest are identified through further advances in molecular genetics. Yet, reflections on the past fifty years lead to increasing appreciation of the enormous achievements of our predecessors in the 1900-1950 period. Therefore, this presentation emphasises methods used by the author and some of his data interpretations during his 52 year career, with somc examination of the earlier origin of some of these methods.     

Review of existing issues, ethics and practices in general medical research and in radiation protection research

A literature review was carried out in relation to general medical research and radiation protection research. A large number of documents were found concerning the subject of ethics in general medical research. For radiation protection research, the number of documents and the information available is very limited. A review of practices in 13 European countries concerning general medical research and radiation protection research was carried out by sending a questionnaire to each country. It was found that all countries reviewed were well regulated for general medical research. For research that involves ionising radiation, the UK and Ireland are by far the most regulated countries. For other countries, there does not seem to be much information available. From the literature review and the review of practices, a number of existing ethical issues were identified and exposed, and a number of conclusions were drawn.     

Accreditation in radiation protection for cardiologists and interventionalists

Training in radiation protection is widely recognised as one of the basic components of optimisation programmes for medical exposures. Occupational and patient radiation risks in interventional radiology can be quite high and international bodies have shown concern on this item. Following recommendations of the International Commission on Radiological Protection and in accordance with the European Directive on medical exposures, some initiatives for training in radiation protection took place in Spain and Luxembourg. These provided practitioners of interventional radiology adequate theoretical and practical training in radiation protection. The main outcome of the pilot courses organised to this end is discussed, concluding its suitability to implement the European Directive in practice.     

面向产业化的光学相干断层成像仪用户体验设计

目的 以光学相干断层成像扫描系统为研究对象,以产业化为导向,结合人本设计、用户体验设计理论,探讨如何更好地使其适应中国市场需求,提高产品使用效率和精准度,缓解患者紧张心理,促进医疗设施智慧化发展。方法 根据人本设计和包容性设计的原则,采用桌面研究和用户调研的方法,确定了传统光学相干断层成像扫描系统在用户使用过程中的影响因素与需求。结合以上信息和品牌设计理念,设计了适用于中国市场的光学相干断层成像扫描系统,并将其模块化,为医疗机构提供智能化改进方案,延长设备寿命并提供升级改造的空间。结果 提高了产品的使用便捷性和精准度,降低了因地区、群体不同产生的仪器测绘偏差,同时成功缓解了患者使用设备时可能产生的心理障碍。此外,本方案也符合Carl Zeiss公司的设计规范,提供了智能医疗的设计新思路。结论 通过将人本设计、用户体验设计等理念应用于光学相干断层成像扫描系统的产业化流程中,打造符合中国市场需求的新兴产品,对公共医疗设施的设计具有指导性意义,同时为其他医疗设施的设计与规范提供实践参考。     

基于环保理念下的外卖包装设计优化

随着互联网时代的飞速发展,新兴行业迅速崛起,外卖行业即是互联网标志性的产物,为在外奔忙的人们解决了就餐难题。但便捷背后所产生的塑料垃圾严重威胁着生态环境,包装的材料和功能结构与回收处理均存在问题。将绿色环保理念植入外卖包装的设计中,从源头减少外卖包装中过剩的供给,对外卖包装中冗余复杂的设计进行减量优化。