| 1. |
- Almén, Anja, 1964, et al.
(författare)
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A CONCEPTUAL FRAMEWORK FOR MANAGING RADIATION DOSE TO PATIENTS IN DIAGNOSTIC RADIOLOGY USING REFERENCE DOSE LEVELS
- 2016
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Ingår i: Radiation protection dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 169:1-4, s. 17-23
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Tidskriftsartikel (refereegranskat)abstract
- The overall aim of the present work was to develop a conceptual framework for managing radiation dose in diagnostic radiology with the intention to support optimisation. An optimisation process was first derived. The framework for managing radiation dose, based on the derived optimisation process, was then outlined. The outset of the optimisation process is four stages: providing equipment, establishing methodology, performing examinations and ensuring quality. The optimisation process comprises a series of activities and actions at these stages. The current system of diagnostic reference levels is an activity in the last stage, ensuring quality. The system becomes a reactive activity only to a certain extent engaging the core activity in the radiology department, performing examinations. Three reference dose levels-possible, expected and established-were assigned to the three stages in the optimisation process, excluding ensuring quality. A reasonably achievable dose range is also derived, indicating an acceptable deviation from the established dose level. A reasonable radiation dose for a single patient is within this range. The suggested framework for managing radiation dose should be regarded as one part of the optimisation process. The optimisation process constitutes a variety of complementary activities, where managing radiation dose is only one part. This emphasises the need to take a holistic approach integrating the optimisation process in different clinical activities.
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| 2. |
- Almén, Anja, 1964, et al.
(författare)
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OPTIMISATION OF OCCUPATIONAL RADIATION PROTECTION IN IMAGE-GUIDED INTERVENTIONS: EXPLORING VIDEO RECORDINGS AS A TOOL IN THE PROCESS
- 2016
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Ingår i: Radiation protection dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 169:1-4, s. 425-429
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Tidskriftsartikel (refereegranskat)abstract
- The overall purpose of this work was to explore how video recordings can contribute to the process of optimising occupational radiation protection in image-guided interventions. Video-recorded material from two image-guided interventions was produced and used to investigate to what extent it is conceivable to observe and assess dose-affecting actions in video recordings. Using the recorded material, it was to some extent possible to connect the choice of imaging techniques to the medical events during the procedure and, to a less extent, to connect these technical and medical issues to the occupational exposure. It was possible to identify a relationship between occupational exposure level to staff and positioning and use of shielding. However, detailed values of the dose rates were not possible to observe on the recordings, and the change in occupational exposure level from adjustments of exposure settings was not possible to identify. In conclusion, the use of video recordings is a promising tool to identify dose-affecting instances, allowing for a deeper knowledge of the interdependency between the management of the medical procedure, the applied imaging technology and the occupational exposure level. However, for a full information about the dose-affecting actions, the equipment used and the recording settings have to be thoroughly planned.
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| 3. |
- Almén, Anja, 1964, et al.
(författare)
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Optimisation of occupational radiological protection in image-guided interventions: potential impact of dose rate measurements.
- 2015
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Ingår i: Journal of radiological protection : official journal of the Society for Radiological Protection. - : IOP Publishing. - 1361-6498. ; 35:1, s. 47-62
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Tidskriftsartikel (refereegranskat)abstract
- The optimisation of occupational radiological protection is challenging and a variety of factors have to be considered. Physicians performing image-guided interventions are working in an environment with one of the highest radiation risk levels in healthcare. Appropriate knowledge about the radiation environment is a prerequisite for conducting the optimisation process. Information about the dose rate variation during the interventions could provide valuable input to this process. The overall purpose of this study was to explore the prerequisite and feasibility to measure dose rate in scattered radiation and to assess the usefulness of such data in the optimisation process.Using an active dosimeter system, the dose rate in the unshielded scattered radiation field was measured in a fixed point close to the patient undergoing an image-guided intervention. The measurements were performed with a time resolution of one second and the dose rate data was continuously timed in a data log. In two treatment rooms, data was collected during a 6month time period, resulting in data from 380 image-guided interventions and vascular treatments in the abdomen, arms and legs. These procedures were categorised into eight types according to the purpose of the treatment and the anatomical region involved.The dose rate varied substantially between treatment types, both regarding the levels and the distribution during the procedure. The maximum dose rate for different types of interventions varied typically between 5 and 100mSvh(-1), but substantially higher and lower dose rates were also registered. The average dose rate during a complete procedure was however substantially lower and varied typically between 0.05 and 1mSvh(-1). An analysis of the distribution disclosed that for a large part of the treatment types, the major amount of the total accumulated dose for a procedure was delivered in less than 10% of the exposure time and in less than 1% of the total procedure time.The present study shows that systematic dose rate measurements are feasible. Such measurements can be used to give a general indication of the exposure level to the staff and could serve as a first risk assessment tool when introducing new treatment types or x-ray equipment in the clinic. For example, it could provide an indication for when detailed eye dose measurements are needed. It also gives input to risk management considerations and the development of efficient routines for other radiological protection measures.
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| 4. |
- Almén, Anja, 1964, et al.
(författare)
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The process of optimisation of radiological protection – the significance of diagnostic reference levels
- 2015
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Ingår i: Optimisation in X-ray and Molecular Imaging 2015 - the Fourth Malmö Conference on Medical Imaging, Gothenburg, Sweden, 28-30 May 2015.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The system of diagnostic reference levels in medicine has been presented as a tool to advice on when a local review of the procedures and equipment is warranted in order to determine whether the protection has been adequately optimised. The system is somewhat country specific, presumably due to different national regulations or guidelines, but as a whole relies on the same principles and standards. Diagnostic reference levels are typically set for standardised patients and procedures with minor considerations of the need to manage individual patient characteristics or specific medical tasks in the optimisation process. Optimisation of radiological protection should involve key aspects influencing the radiation dose to the patients and also include the needs of optimising the protection for each patient individually. The actual given radiation dose to the patient is affected by a number of factors, amongst other things equipment specific features and training of staff performing the examinations. This emphases the need to take a holistic approach and integrate different clinical processes - e.g. purchasing of equipment or the implementation of new examination protocols in the clinic – in the process of optimisation. Taking this approach gives the opportunity to evaluate the significance of the current system of diagnostic reference levels in the process of optimisation and to identify other reference levels supporting the process of optimisation. This paper will investigate the optimisation process and identify key instances where reference levels could provide support to the optimisation process. The issue of optimising the individual examination with regard to patient characteristics and medical indication will be specifically addressed.
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| 7. |
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| 8. |
- Lundh, Charlotta, 1977, et al.
(författare)
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Optimisation of radiological protection in a complex hybrid environment using detailed dose rate information
- 2015
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Ingår i: Optimisation in X-ray and Molecular Imaging 2015 - the Fourth Malmö Conference on Medical Imaging, Gothenburg, Sweden, 28-30 May 2015.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Purpose: Physicians performing image-guided interventions are exposed to one of the highest radiation risk levels in healthcare. Hybrid environments combine the imaging technology of the image-guided interventions with operation environments, engaging more medical specialties to the use of advanced imaging devices. This complicates the risk management of radiological protection. The aim of this study was to explore the possibilities of using dose rate data for risk assessment in a multi-purpose hybrid room. Method: Dose rate data was collected for three types of image guided interventions in a hybrid room at Sahlgrenska University Hospital. The three procedure types studied were EndoVascular Aortic Repair (EVAR), Transcatheter Aortic Heart Valve (TAVI) and an orthopedic procedure of the back (Ort Back). Dose rate data for scattered radiation was collected using an active dosimeter system, giving dose rate data with a time resolution of 1 second in a fixed unshielded point on the C-arm. Data was analysed and visualized as histograms. Results: The dose rates varied substantially between the three types of procedures studied. The median dose rates were 2.3 mSv/h (EVAR), 1.4 mSv/h (TAVI) and 0.1 mSv/h (Ort back). During EVAR-procedures the absolute majority of the dose rates were between 1 and 10 mSv/h while it during Ort Back-procedures was dominated by dose rates below 0.1 mSv/h. Conclusions: A multi-purpose hybrid room have dose rates that vary substantially between the different areas of use, both regarding dose rate levels and dose rate distribution. The use of dose rate information adds important information that can improve the management of risk in these environments.
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| 9. |
- Magee, Jill S, et al.
(författare)
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Derivation and application of dose reduction factors for protective eyewear worn in interventional radiology and cardiology.
- 2014
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Ingår i: Journal of radiological protection : official journal of the Society for Radiological Protection. - : IOP Publishing. - 1361-6498. ; 34:4, s. 811-823
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Tidskriftsartikel (refereegranskat)abstract
- Doses to the eyes of interventional radiologists and cardiologists could exceed the annual limit of 20mSv proposed by the International Commission on Radiological Protection. Lead glasses of various designs are available to provide protection, but standard eye dosemeters will not take account of the protection they provide. The aim of this study has been to derive dose reduction factors (DRFs) equal to the ratio of the dose with no eyewear, divided by that when lead glasses are worn. Thirty sets of protective eyewear have been tested in x-ray fields using anthropomorphic phantoms to simulate the patient and clinician in two centres. The experiments performed have determined DRFs from simulations of interventional procedures by measuring doses to the eyes of the phantom representing the clinician, using TLDs in Glasgow, Scotland and with an electronic dosemeter in Gothenburg, Sweden. During interventional procedures scattered x-rays arising from the patient will be incident on the head of the clinician from below and to the side. DRFs for x-rays incident on the front of lead glasses vary from 5.2 to 7.6, while values for orientations similar to those used in the majority of clinical practice are between 1.4 and 5.2. Specialised designs with lead glass side shields or of a wraparound style with angled lenses performed better than lead glasses based on the design of standard spectacles. Results suggest that application of a DRF of 2 would provide a conservative factor that could be applied to personal dosemeter measurements to account for the dose reduction provided by any type of lead glasses provided certain criteria relating to design and consistency of use are applied.
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| 10. |
- Martin, Colin, et al.
(författare)
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Eye dosimetry and protective eyewear for interventional clinicians
- 2015
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Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 0144-8420 .- 1742-3406. ; 165:1-4, s. 284-288
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Tidskriftsartikel (refereegranskat)abstract
- Doses to the eyes of interventional clinicians can exceed 20 mSv. Various protective devices can afford protection to the eyes with the final barrier being protective eyewear. The protection provided by lead glasses is difficult to quantify, and the majority of dosimeters are not designed to be worn under lead glasses. This study has measured dose reduction factors (DRFs) equal to the ratio of the dose with no protection, divided by that when lead glasses are worn. Glasses have been tested in X-ray fields using anthropomorphic phantoms to simulate the patient and clinician. DRFs for X-rays incident from the front vary from 5.2 to 7.6, while values for orientations reminiscent of clinical practice are between 1.4 and 5.2. Results suggest that a DRF of two is a conservative factor that could be applied to personal dosimeter measurements to account for the dose reduction provided by most types of lead glasses.
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