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The International Commission on Radiological Protection (ICRP) has indicated that the diagnostic reference level (DRL) has the optimisation of protection as its objective for diagnostic and interventional procedures [International Commission on Radiological Protection. Protection against ionising radiation from external sources: ICRP Report 105 (2007)]. An important aim of this paper was to demonstrate a straightforward and cost-effective mechanism for undertaking patient dose audits that can be employed in the production of local and regional DRLs for use by medical physics experts in the provision of scientific support services to diagnostic radiology. The process developed employs electronic X-ray examination records obtained from multiple hospital sites transferred to a central processing and reporting facility. Results of a large-scale audit of patient doses resulting from CT examinations are presented. Doses are expressed in terms of dose length product (DLP) and were collected by remotely accessing electronic examination records held in hospital radiology information systems. Data were collected from 18 hospital sites involving up to 123 different types of examinations covering an ∼18-month period from July 2011 to December 2012. In total, 177 000 CT examination records were collected. Values have been validated against equivalent records obtained from digital imaging and communications in medicine (DICOM) header data and found to be in excellent statistical agreement. Extremely large variations in DLP values were noted for many examinations when data for all scanners were pooled. Results are discussed in relation to other surveys and differences highlighted in terms of the variations in methodologies employed and the numbers of examination records investigated. A mechanism for establishing DRLs is proposed, which could help to unify mechanisms for establishing DRLs for CT examinations. [ABSTRACT FROM PUBLISHER]

The objective of the paper is to demonstrate that patient dose audits may be undertaken at the local and regional levels by employing electronic examination records contained in Radiology Information Systems (RISs) that have been collected, analysed and managed by modern IT systems. The resulting mean and third quartile values obtained may then be used to establish local and regional dose reference levels (DRLs) as part of an optimisation strategy. The method involved the collection of roughly 1.3 million radiographical examination records stored in hospital RIS over a 3-y period from 10 hospital sites in the north of England. These were analysed according to the process employed in the national patient dose (NPD) audits undertaken every 5 y in the UK. Data processing and analysis methods are described that are suitable for handling very large data sets quickly and efficiently. Because RIS data involve manual data entry it may be susceptible to data entry errors. Therefore, a comparison of results obtained from both RIS and DICOM generated data was first of all undertaken in order to ‘calibrate’ the RIS-based method and demonstrate its accuracy. The results obtained from this comparison indicate that the RIS-based examination records provide patient dose distributions with an equivalent statistical accuracy compared with those employing DICOM data and, therefore, may be employed in patient dose audits in order to establish both local and regional DRLs for use in patient dose management and optimisation strategies. [ABSTRACT FROM AUTHOR]

A system was developed in 2008 to calculate patient doses using Radiology Information System (RIS) data and presents these data as a patient dose audit. One of the issues with this system was the quality of user-entered data. It has been shown that Digital Imaging and Communication in Medicine (DICOM) header data can be used to perform dose audits with a high level of data accuracy. This study aims to show that using RIS data for dose audits is not only a viable alternative to using DICOM header data, but that it has advantages. A new system was developed to pull header data from DICOM images easily and was installed on a workstation within a hospital department. Data were recovered for a common set of examinations using both RIS and DICOM header data. The data were compared on a result-by-result basis to check for consistency of common fields between RIS and DICOM, as well as assessing the value of data fields uncommon to both systems. The study shows that whilst RIS is not as accurate as DICOM, it does provide enough accurate data and that it has other advantages over using a DICOM approach. These results suggest that a ‘best of both worlds’ may be achievable using Modality Performed Procedure Step (MPPS). [ABSTRACT FROM PUBLISHER]

The use of ionising radiation in medicine is the single largest man-made source of population exposure. Individual and collective doses to patients arising from the medical use of ionising radiations continue to rise significantly year on year. This is due to the increasing use of medical imaging procedures in modern healthcare systems as well as the continued development of new high dose techniques. This paper reviews the scientific basis for the principles of radiation protection as defined by the International Commission on Radiological Protection. These principles attempt to include exposures arising from both medical and non-medical applications within a common framework and have evolved over many years and changing socio-economic considerations. In particular, the concepts of justification and ALARA (doses should be as low as reasonably achievable), which underpin the principles for medical exposures are assessed in terms of their applicability to the scientific process and relevance to a rapidly changing technologically-led healthcare system. Radiation protection is an integral component of patient safety in medical practices and needs to be evidence based and amenable to the scientific process. The limitations imposed by the existing philosophy of radiation protection to the development of a quantitative framework for adequately assessing the performance of medical imaging systems are highlighted. In particular, medical practitioners will require quantitative guidance as to the risk–benefits arising from modern X-ray imaging methods if they are to make rational judgements as to the applicability of modern high-dose techniques to particular diagnostic and therapeutic tasks. At present such guidance is variable due to the lack of a rational framework for assessing the clinical impact of medical imaging techniques. The possible integration of radiation protection concepts into fundamental bio-medical imaging research activities is discussed. [ABSTRACT FROM PUBLISHER]

In a multi-centre study more than 600 patient measurements of patients receiving thorax radiography were performed in five European cities. Participating centres were Fulda, Liverpool, Nicosia, Passau and Sofia. The dose quantities measured were the air kerma-area product (AKAP), incident air kerma and entrance surface air kerma (ESAK). In addition, for each patient sex, age, weight, height, focus-to-film distance, focus-to-skin distance, patient thickness, kV, mAs, field size and the nominal film speed were registered. Different X-ray machines were used in the participating centres—Thoravision, flat panel detector and film screen combinations in two centres (analogue system). The tube voltages employed varied between 60 and 150 kV and the nominal film speed between 200 and 400/800. All mean dose values (ESAK and AKAP) for the different centres showed a different value for female and male populations. The differences were up to 100 % and always higher for the mean AKAP. For a thorax posteroanterior examination, the mean ESAK varied between 0.06 and 0.46 mGy and the mean AKAP varied between 60 and 690 mGy cm2. The differences in the results obtained as well as the methodologies for multi-national, multi-centre studies will be discussed. Future perspectives for this type of study within the framework of radiation protection and quality assurance in Europe will also be discussed as well as the role and function of multi-national radiological data sets including patient dose values. [ABSTRACT FROM PUBLISHER]

Practical and philosophical aspects of radiation protection in diagnostic radiology have changed very little over the past 50 y even though patient doses have continued to rise significantly in this period. This rise has been driven by technological developments, such as multi-slice computed tomography, that have been able to improve diagnostic accuracy but not necessarily provide the same level of risk-benefit to all patients or groups of patients given the dose levels involved. Can practical radiation protection strategies hope to keep abreast of these ongoing developments? A project was started in 1992 in Liverpool that aimed to develop IT driven quality assurance (QA)/radiation protection software tools based upon a modular quality assurance dose data system. One of the modules involved the assessment of the patient entrance surface air kerma (ESAK) for an X-ray examination that was based upon the use of calibrated X-ray tube exposure factors to calculate ESAK as well as collecting appropriate patient details (age, sex, weight, thickness etc). The package also contained modules for logging all necessary equipment performance QA data. This paper will outline the experience gained with this system through its transition from a local application on a stand alone PC within the department to the current web-based approach. Advantages of a web-based approach to delivering such an application as well as centrally storing data originating on many hospital sites will be discussed together with the scientific support processes that can be developed with such a system. This will include local, national and international considerations. The advantages of importing radiographic examination details directly from other electronic storage systems such as a hospital's radiology information system will be presented together with practical outcomes already achieved. This will include the application of statistical techniques to the very large data sets generated. The development of new examination QA performance indicators will be discussed. The application of web-based IT tools for QA and radiation protection in diagnostic radiology is already opening up the possibility of developing new and improved scientific support services as well as research possibilities in radiological informatics. These will be outlined together with areas for possible future development by the medical physics community. [ABSTRACT FROM PUBLISHER]

The RADIUS (Radiological Imaging Unification Strategy) project addresses the assessment of image quality in terms of both physical and clinically relevant measures. The aim is to unify our understanding of both types of measure as well as the numerous underlying factors that play a key role in the assessments of imaging performance. In this way it is expected to provide a solid basis for the improvement in radiological safety management, where not only radiation risks are considered but also diagnostic risks of incorrect clinical outcomes (i.e. false positive/false negative). The project has applied a variety of relevant experimental and theoretical methods to this problem, which is generic to medical imaging as a whole. Digital radiography of the chest and the breast has been employed as the clinical imaging domain vehicles for the study. The project addressed the problem from the following directions: role and relevance of pathology, human observer studies including receiver operating characteristics, image quality criteria analysis, structural noise analysis, physical measurements on clinical images, physical measurements on imaging system, modelling of imaging system, modelling of visual processes, modelling of doses delivered and IT-based scientific support strategies. This paper presents an overview of the main outcomes from this project and highlights how the research outcomes actually apply to the real world. In particular, attention will be focused on new and original findings and methods and techniques that have been developed within the framework of the project. The relevance of the project's outcomes to future European research will also be presented. [ABSTRACT FROM AUTHOR]

The implementation of film replacement digital radiographic imaging systems throughout Europe is now gathering momentum. Such systems create the foundations for totally digital departments of radiology, since radiographic examinations constitute the most prevalent modality. Although this type of development will lead to improvements in the delivery and management of radiological service, such widespread implementation of new technology must be carefully monitored. The implementation of effective QA tests on installation, at periodic intervals and as part of a routine programme will aid this process. This paper presents the results of commissioning tests undertaken on a number of computed radiography imaging systems provided by different manufacturers. The aim of these tests was not only to provide baseline performance measurements against which subsequent measurements can be compared but also to explore any differences in performance, which might exist between different units. Results of measurements will be presented for (1) monitor and laser printer set-up; (2) imaging plates, including sensitivity, consistency and uniformity; (3) resolution and contrast detectability; and (4) signal and noise performance. Results from the latter are analysed in relationship with both system and quantum noise components. [ABSTRACT FROM AUTHOR]

The applications of information technology in health care are now widespread and continue to grow. Medical imaging is at the forefront of this revolution and the introduction of digital detection methods to replace film is now addressing the diagnostic X-ray market, the most routinely employed imaging modality. The introduction of picture archiving and communication systems, hospital and radiology information systems is well underway, and the integration of radiation protection initiatives into these developments is desirable. In north-west UK, a project aimed at developing and implementing IT-driven radiation protection strategies has been underway for the past 10 y. Such strategies are geared towards the support of European Commission patient dose directive 97/43 EURATOM, in particular the need to implement clinical audit, patient dose audit and to establish dose reference levels. This paper demonstrates the national and local requirements for establishing a central dose data management system for use in radiation protection strategies. In particular, such a system can help develop and support the role of a medical physics expert in optimisation. The scientific requirements for such an approach are presented in this paper, and a prototype system is described. Preliminary results obtained with the central data management facility are also presented and the implication for analysing multiple site dose data in optimisation strategies for digital radiographic technology is highlighted. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Doses to patients from radiographic and fluoroscopic X-ray imaging procedures in the UK-2005 review" in the previous issue.

The purpose of this study was to assess the suitability of different radiation dosimetry methods and record radiation exposures during paediatric catheterization. Three methods of dosimetry were employed: thermoluminescent dosimetry (TLD), dose-area product and calculation of entrance surface dose from calibrated exposure factors. Examinations included bi-plane fluoroscopy, and cineangiography for diagnosis and treatment of congenital heart disease. The most suitable method of radiation dosimetry for cardiac catheterization is the use of calculated entrance dose or a dose-area product meter. Children were exposed to high levels of radiation during cardiac catheterization but there was a wide variation in radiation dosage. Careful consideration should be given to the suitability of radiation dosimetry for cardiac catheterization.

Quality Criteria for diagnostic radiographic images include the definition of necessary image details, performance of the imaging system and appropriate choice of radiographic parameters. Actions have established a framework for the optimisation of these three groups of Quality Criteria. Their evolution, practice and efficacy will be demonstrated for conventional and digital radiology. The link between the Quality Criteria and exposure of the patient and staff will be discussed. The historical follow up of these aspects will appreciate the efforts done all over Europe since the twenties and will reveal the potential for continuously optimising diagnostic radiology in many respects: in day-to-day practice, new technical design and radiological concepts.

Educational software has been designed and developed for training within the field of diagnostic radiography and is particularly concerned with the science and technology of diagnostic X-rays. The material has been structured into hypertext networks and as such allows interactive exploration of the available information. The courseware development platform was Microsoft Windows and authoring was accomplished using the constructional tool kit ToolBook. The resulting CAL package is highly graphical in nature with a user interface designed to meet the 'friendliness' demands of the end user group. Mechanisms for navigation through, and orientation within, the hypertext have also been established which support two levels of user activities. By changing the level of user freedom, students using the system as a learning tool are restricted to more structured routes than experienced staff using the courseware as an information resource. An aim of this work has been to provide interactive educational activities to support the main courseware, and consequently a novel application has been developed using dynamic data exchange (DDE) and the spreadsheet software Excel. Through a ToolBook front end students can interactively alter an X-ray spectrum by changing the operating conditions of a simulated X-ray tube.

A reject analysis has been undertaken for a 26 week period in the radiology department of an oncological centre. The overall reject and repeat rates are presented here, as well as those arising from individual examinations and X-ray rooms. The variations in reject rates for different examinations as a function of time are highlighted and the role of reject analysis in quality assurance is discussed.

The spectral content and intensity of light emission together with the x-ray attenuation have been measured for a selection of commercially available intensifying screens used in diagnostic radiology. Incident x-ray beam qualities with half value layers between 3.8 to 10 mm AI were employed in order to simulate a wide range of clinical situations. The measurements of spectral content demonstrate the wide variations in spectral emission which now exist between screens employing different phosphor materials. Similarly, a wide variation in the intensity of light emission is observed for screens employing different phosphor materials and also for screens employing the same material. The interrelation of the measured physical properties affects both the system speed and noise properties and needs to be considered when comparing the performance of different systems.

In order to investigate the levels of radiation exposure resulting from fluoroscopic examinations, area-exposure product measurements were performed on 6532 patients whilst undergoing a variety of examinations at a large district general hospital. Results for both the same and different types of examinations, performed in two different X-ray rooms by a number of different radiologists, are compared in order to highlight some of the factors which influence the wide variations in patient exposure which frequently occur in radiological examinations. Variations in exposure of patients of different weights are also presented.

X-ray attenuation and intensity of light emitted were measured for nine intensifying screens used in mammography. Incident beam qualities with half value layers in the range of 0.38 to 2.68 mm Al were used to simulate the range of clinical conditions encountered in mammography. All the screens attenuated the x-ray beam to a similar extent at these beam qualities, but a wide variation in the intensity of light emitted was observed. The interrelation of the measured physical parameters in determining both the system speed and noise properties is discussed.

Lithium fluoride (LiF) thermoluminescent dosimeters (TLD) have been employed to measure the radiation dose distribution within a phantom and the central axis dose in air. Results are presented for seven (four EMI CT1010, one EMI CT5005, one EMI CT7070 and one Siemens DR2) different machines. Organ doses for four different computed tomography (CT) investigations (head, lung, liver and pelvis) have been estimated from previously published tables and the central axis dose in air in 3 CT units. These estimated organ doses were used in turn to deduce the somatic and genetic risks for the four types of CT examination. These calculations indicate that for an 'average' male patient undergoing a CT examination corresponding to the average conditions encountered, the total somatic risks are 3.15 10(-4), 1.98 10(-4), 2.31 10(-4), and 1.38 10(-4) for head, lung, liver and pelvis scans, respectively. The corresponding figures for female patients are 3.39 10(-4), 3.95 10(-4), 2.73 10(-4), and 1.60 10(-4). The risk from head scanning is approximately 250 times that of a dental pantomograph. Somatic and genetic risks will be approximately twice as high for contrast examinations.

Eye dose measurements have been performed when using medium speed conventional and rare-earth screen-film combinations during tomography of the para-nasal sinuses. The measurements show that using conventional intensifying screens with the A.P. view a total eye dose of about 20 rad may be given during an examination. This eye dose can be reduced by 98% using the P.A. position. If rare-earth screen/film combinations are employed the eye dose measured in the A.P. view was reduced by 75% of that obtained with conventional screens without detectable loss of image quality. A total eye dose reduction of about 99.5% was measured in the P.A. view with the rare-earth systems.

Measurements of scattered radiation were made on two fluoroscopic installations, one with an overcouch tube and one with an undercouch tube. The annual doses to staff involved in a fluoroscopic procedure undertaken on both types of unit were estimated using measured dose rates and weighting factors referred to in ICRP 26. Environmental monitoring at the protective barrier was performed for various room layouts to determine the effect of both equipment and room design on the annual dose received by staff at the control panel. In all circumstances the annual dose to staff inside the control cubicle was negligible.

A test phantom containing simulated micro-calcifications was constructed. This was imaged by seven systems suitable for use in mammography, firstly in scatter-free conditions and secondly with the addition of tissue-equivalent scattering material. The ability of the systems to resolve micro-particles of known size was assessed using the techniques of signal detection theory. The resultant receiver operating characteristic curves separated the systems into three major groups. Firstly, high resolution systems requiring high radiation dose techniques; secondly at the other extreme, a mediocre imaging system producing its results at low radiation levels; and thirdly a larger middle group producing intermediate resolution of fine particles at similar, acceptable dose levels. The ability to image small particles does not increase linearly with the radiation dose. Scatter did not affect all of the systems to the same extent.