| 1. |
- Almén, Anja, et al.
(författare)
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Challenges assessing radiation risk in image-guided treatments-implications on optimisation of radiological protection
- 2018
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Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 38:3, s. 1064-1076
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Tidskriftsartikel (refereegranskat)abstract
- The present work explores challenges when assessing organ dose and effective dose concerning image-guided treatments. During these treatments considerable x-ray imaging is employed using technically advanced angiographic x-ray equipment. Thus, the radiation dose to organs and the related radiation risk are relatively difficult to assess. This has implications on the optimisation process, in which assessing radiation dose is one important part. In this study, endovascular aortic repair treatments were investigated. Organ dose and effective dose were assessed using Monte Carlo calculations together with a detailed specification of the exposure situation and patient size. The resulting normalised organ dose and effective dose with respect to kerma-area product for patient sizes and radiation qualities representative for the patient group were evaluated. The variability and uncertainty were investigated and their possible impact on optimisation of radiation protection was discussed. Exposure parameters, source to detector distances etc varied between treatments and also varied between image acquisitions during one treatment. Thus the derived normalised organ dose and effective dose exhibited a large range of values depending greatly on used exposure parameters and patient configuration. The derived normalised values for effective dose varied approximately between 0.05 and 0.30 mSv per Gy.cm(2) when taking patient sizes and exposure parameters into consideration, the values for organ doses exhibited even larger variation. The study shows a possible systematic error for derived organ doses and effective dose up to a factor of 7 if detailed exposure or patient characteristics are not known and/or not taken into consideration. The intra-treatment variability was also substantial and the normalised dose values varied up to a factor of 2 between image acquisitions during one treatment. The study shows that the use of conversion factors that are not adapted to the clinic can cause the radiation dose to be exaggerated or underestimated considerably. A conclusion from the present study is that the systematic error could be large and should be estimated together with random errors. A large uncertainty makes it difficult to detect true differences in radiation dose between methods and technology-a prerequisite for optimising radiation protection for image-guided treatments.
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| 2. |
- Hinrichsen, Y, et al.
(författare)
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Introducing the concept of the isodose for optimisation of decontamination activities in a radioactive fallout scenario
- 2018
-
Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 1361-6498 .- 0952-4746. ; 38:4, s. 1293-1310
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Tidskriftsartikel (refereegranskat)abstract
- In the recovery phase after a radioactive release incident, it is important to be able to focus decontamination operations on the areas that contribute most to the radiation dose. Monte Carlo simulations were applied to determine the shielding effect of a building against radiation from various directions, also giving information on the dose contributions at various locations inside the building from specific areas outside. The concept of the isodose was developed to optimise decontamination activities, and was applied as isodose lines to define the smallest areas that lead to a certain dose reduction through decontamination of areas surrounding the building. The shape and position of the isodose lines depend on the building's geometry, wall thickness, and material, and on the observation point inside the building. Calculations have been made with a surface resolution of 1 m2 for four observation points in a modular building, assuming depositions of 137Cs and 60Co on the ground surface and on the roof, as well as 1 cm below the ground surface to represent ground penetration. For example, a ten times as large area would have to be decontaminated to increase the dose reduction from 10% to 30%, if it is assumed that all the contamination is located at a depth of 1 cm.
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| 3. |
- Isaksson, Mats, 1961, et al.
(författare)
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Absorbed dose rate coefficients for 134Cs and 137Cs with steady-state distribution in the human body : S-coefficients revisited
- 2021
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Ingår i: Journal of Radiological Protection. - : Institute of Physics Publishing (IOPP). - 0952-4746 .- 1361-6498. ; 41:4, s. 1213-1227
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Tidskriftsartikel (refereegranskat)abstract
- In the event of an accidental release of radioactive elements from a nuclear power plant, it has been shown that the radionuclides contributing the most to long-term exposure are Cs-134 and Cs-137. In the case of nuclear power plant fallout, with subsequent intake of radionuclides through the food chain, the internal absorbed dose to target tissues from protracted intake of radionuclides needs to be estimated. Internal contamination from food consumption is not caused by a single intake event; hence, the committed equivalent dose, calculated by a dose coefficient or dose per content function, cannot be easily used to calculate the cumulative absorbed dose to relevant target tissues in the body. In this study, we calculated updated absorbed dose rate coefficients for Cs-134 and Cs-137 based on data from the International Commission on Radiological Protection (ICRP) on specific absorbed fractions. The absorbed dose rate coefficients are provided for male and female adult reference phantoms, respectively, assuming a steady-state distribution of Cs that we calculated from the ICRP biokinetic model for Cs. With these coefficients, the absorbed dose to the listed target tissues, separately and to the total body, are related to the number of nuclear transitions (time-integrated activity) in each listed source region. Our new absorbed dose rate coefficients are given for the complete set of target tissues and have not been presented before. They are also provided for aggregated categories of organs to facilitate epidemiological studies.
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| 4. |
- Lagergren Lindberg, Marita, et al.
(författare)
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Mental health and psychosocial consequences linked to radiation emergencies - Increasingly recognised concerns
- 2022
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Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 42:3
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Forskningsöversikt (refereegranskat)abstract
- A major radiological or nuclear emergency may, apart from causing a substantial loss of life and physical damage, also put a substantial strain on affected societies with social, economic and political consequences. Although such emergencies are relatively uncommon, it is now being increasingly recognised that their subsequent psychosocial impact can be widespread and long lasting. Mental health effects, such as depression, anxiety and post-traumatic stress disorder, are highly represented in a population affected by a radiation disaster. In order to reach the majority of the people affected by radiation accidents, we need to be aware of how to distribute relevant and accurate information related to both short- and long-term medical effects. Effective risk communication is associated with improved compliance with any given recommendations. It is important to protect the public from physical radiation damage, but it is also essential to take into account the social and mental health effects that radiation disasters may induce. This article provides a brief review of recent reporting on the psychological consequences after a major radiation emergency.
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| 5. |
- O'Connor, U, et al.
(författare)
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Feasibility study of computational occupational dosimetry : evaluating a proof-of-concept in an endovascular and interventional cardiology setting
- 2022
-
Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 1361-6498 .- 0952-4746. ; 42:4
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Tidskriftsartikel (refereegranskat)abstract
- Individual monitoring of radiation workers is essential to ensure compliance with legal dose limits and to ensure that doses are As Low As Reasonably Achievable. However, large uncertainties still exist in personal dosimetry and there are issues with compliance and incorrect wearing of dosimeters. The objective of the PODIUM (Personal Online Dosimetry Using Computational Methods) project was to improve personal dosimetry by an innovative approach: the development of an online dosimetry application based on computer simulations without the use of physical dosimeters. Occupational doses were calculated based on the use of camera tracking devices, flexible individualised phantoms and data from the radiation source. When combined with fast Monte Carlo simulation codes, the aim was to perform personal dosimetry in real-time. A key component of the PODIUM project was to assess and validate the methodology in interventional radiology workplaces where improvements in dosimetry are needed. This paper describes the feasibility of implementing the PODIUM approach in a clinical setting. Validation was carried out using dosimeters worn by Vascular Surgeons and Interventional Cardiologists during patient procedures at a hospital in Ireland. Our preliminary results from this feasibility study show acceptable differences of the order of 40% between calculated and measured staff doses, in terms of the personal dose equivalent quantity Hp(10), however there is a greater deviation for more complex cases and improvements are needed. The challenges of using the system in busy interventional rooms have informed the future needs and applicability of PODIUM. The availability of an online personal dosimetry application has the potential to overcome problems that arise from the use of current dosimeters. In addition, it should increase awareness of radiation protection among staff. Some limitations remain and a second phase of development would be required to bring the PODIUM method into operation in a hospital setting. However, an early prototype system has been tested in a clinical setting and the results from this two-year proof-of-concept PODIUM project are very promising for future development.
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| 6. |
- Raaf, Christopher L., et al.
(författare)
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In vivo measurement of pre-operational spallation source workers : Baseline body burden levels and detection limits of relevant gamma emitters using high-resolution gamma spectrometry
- 2019
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Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 40:1, s. 119-133
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Tidskriftsartikel (refereegranskat)abstract
- As a measure to prepare for long-term internal dose monitoring of workers at the European Spallation Source (ESS) in Lund, Sweden, operated by the European Research Infrastructure Consortium (ERIC), as well as to enhance emergency preparedness against accidental releases, a series of in vivo measurements were conducted using a high-resolution HPGe detector with a 123% relative efficiency (1.332 MeV). This study describes the whole-body counting set-up, calibration procedure, and subsequent validation measurements using conventional NaI(Tl)-scanning-bed geometry on a selection of workers from the ESS. Detection limits for the relevant gamma emitters 7Be, 172Hf, and 182Ta were determined to be 65 Bq, 130 Bq, and 22 Bq, respectively, using a 2400 s acquisition time. The baseline measurements suggest that care must be taken to ensure that the fluctuations in the presence of radon daughters 214Bi and 214Pb are minimised by, for example, ensuring a minimum air exchange between the measuring room and the ambient air, and by demanding that the measured subjects change clothes and shower before measurement. Furthermore, in a monitoring program for internal doses to spallation source workers, the presence of radionuclides originating from non-work-related sources (such as 226Ra from private water wells or 137Cs from intakes of Chernobyl contaminated foodstuffs), or radionuclides from previous work history (such as 60Co within the nuclear power industry), must be considered.
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| 7. |
- Rääf, C., et al.
(författare)
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Averting cumulative lifetime attributable risk (LAR) of cancer by decontamination of residential areas affected by a large-scale nuclear power plant fallout: Time aspects of radiological benefits for newborns and adults
- 2020
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Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 40:3, s. 790-814
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Tidskriftsartikel (refereegranskat)abstract
- The averted cumulative lifetime attributable risk (LAR), the residual dose and highest ground deposition of 137Cs complying with a reference dose level of 20 mSv y-1 to an individual returning after one year to an area contaminated by nuclear power plant (NPP) fallout were evaluated by applying an existing exposure model designed to compute age- and gender-dependent time integrated LAR. The model was applied to four types of nuclear fallout scenarios, partly based on data from the Chernobyl and Fukushima releases and from theoretical source terms from Swedish NPPs. For rapid decontamination measures that achieve a 50% relative reduction in external dose rate within 1 y, compliance with the reference level 20 mSv y-1 can be attained for an initial 137Cs ground deposition of up to 2 MBq m-2 with relaxed food restrictions. This compliance can be attained at even higher ground deposition (up to 3.5 MBq m-2) if using the strict food restrictions employed in Japan after 2011. Considering longer than 1 year return times it was also found that the benefit of implementing decontamination decreases rapidly with time (2-3 y half-time), especially if the fallout has a high initial 134Cs to 137Cs activity ratio and if the ecological half-time of the external dose rate is short (<5 y). Depending on fallout scenario the averted cumulative LAR for newborn girls by decontamination that is achieved after 5 y is only between 6% and 11% of that obtained by evacuation alone during the same time, indicating a rather limited radiological benefit of decontamination if delayed more than a few years. We conclude that decision makers and emergency response planners need to consider that protracted decontamination measures may have limited radiological benefit compared with evacuation in terms of averted future cancer cases, albeit it may have other societal benefits.
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| 8. |
- Waldner, Lovisa, et al.
(författare)
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Experimentally determined and Monte Carlo-calculated energy dependence of NaCl pellets read by optically stimulated luminescence for photon beams in the energy range 30 keV to 1.25 MeV
- 2020
-
Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 40:4, s. 1321-1335
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Tidskriftsartikel (refereegranskat)abstract
- Ordinary salt, NaCl, has many properties suitable for dosimetry and has been suggested for both retrospective and prospective optically stimulated luminescence (OSL) dosimetry. Lately, the focus has been on NaCl that is compressed into solid pellets, as this improves both its handling and dosimetric properties. In this project, the energy dependence of NaCl pellets produced in-house was investigated for photon energies between 30 and 1.25 MeV. The NaCl pellets were first exposed to free-in-air conditions, and the estimated absorbed dose to the NaCl pellets was compared to the air kerma, K air, at the point of exposure. Second, a backscatter medium of polymethyl methacrylate (PMMA) was added, and NaCl pellets were exposed when positioned on a ISO slab phantom to relate the response in the NaCl to the personal dose equivalent, H p(10). The results show a significant energy dependence for exposure to low-energy photons with a peak over-response compared to K air and H p(10) of up to 18. Comparisons with Monte Carlo simulations show good agreement, even though the simulations cannot account for properties related to the intrinsic luminescence effects of the NaCl pellets or the readout and calibration process. The finite thickness of the NaCl pellet makes it an imperfect Bragg-Grey cavity, which complicates the behaviour of the energy dependence. The results presented here may serve as an important basis for further experimental and theoretical modelling of a build-up layer and filters in efforts to develop a passive personal dosemeter based on NaCl.
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| 9. |
- Raaf, C. L., et al.
(författare)
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A model for estimating the total absorbed dose to the thyroid in Swedish inhabitants following the Chernobyl Nuclear Power Plant accident : implications for existing international estimates and future model applications
- 2019
-
Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 39:2, s. 522-547
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Tidskriftsartikel (refereegranskat)abstract
- The time-integrated absorbed dose to the thyroid gland in the years after a fallout event can indicate the potential excess number of thyroid cancers among young individuals after a radionuclide release. Typical mean values of the absorbed dose to the thyroid have been calculated previously using reported data on radioiodine obtained from air sampling and dairy milk surveys in Sweden after the Chernobyl fallout, not including the contribution from Cs-134 and Cs-137. We have developed a model for Swedish conditions taking these additional dose contributions into account. Our estimate of the average time-integrated absorbed dose to the thyroid, D-th,D-tot, during the first 5 years after fallout ranged from 0.5-4.1 mGy for infants and from 0.3-3.3 mGy for adults. The contribution to D-th,D-tot, from I-131 through inhalation and milk consumption varied considerably among different regions of Sweden, ranging from 9%-79% in infants, and from 4%-58% in adults. The external irradiation and exposure from the ingestion of (CS)-C-134,137 in foodstuffs accounted for the remaining contributions to D-th,D-tot, (i.e. up to 96% for adults). These large variations can be explained by the highly diverse conditions in the regions studied, such as different degrees of fractionation between wet and dry deposition, different grazing restrictions on dairy cattle, and differences in (CS)-C-134,137 transfers through food resulting from differences in the local fallout. It is our conclusion that the main contribution to D-th,D-tot, from nuclear power plant fallout in areas subjected to predominantly wet deposition will be from external exposure from ground deposition, followed by internal exposure from contaminated food containing the long-lived fission product Cs-137 and the neutron-activated fission product (CS)-C-134. The contribution from (CS)-C-134,137 to the thyroid absorbed dose should thus be taken into account in future epidemiological studies.
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| 10. |
- Akleyev, A, et al.
(författare)
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In memory of Leonid Ilyin (1928-2023)
- 2024
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Ingår i: Journal of radiological protection : official journal of the Society for Radiological Protection. - 1361-6498. ; 44:1
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 11. |
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| 12. |
- Bazzi, May, 1979, et al.
(författare)
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Factors affecting radiographers' use of dose-reduction measures
- 2024
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Ingår i: JOURNAL OF RADIOLOGICAL PROTECTION. - : Institute of Physics (IOP). - 0952-4746 .- 1361-6498. ; 44:1
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates radiographers' views on implementing dose-reduction measures, with a focus on verifying patient identity and pregnancy status, practising gonad shielding in men and using compression. An electronic questionnaire was distributed to radiographers working in general radiography and/or computed tomography. The questionnaire was based on factors from a framework for analysing risk and safety in clinical medicine. Ordered logistic regressions were used to analyse associations among factors and use of dose-reduction measures. In total, 466 questionnaires were distributed and 170 radiographers (36%) completed them. Clear instructions and routines, support from colleagues, knowledge and experience, a strong safety culture, managerial support and access to proper equipment influence the likelihood of using dose-reduction measures. The strongest associations were found between support from colleagues and verifying pregnancy status (OR = 5.65, P = 0.026), safety culture and use of gonad shielding (OR = 2.36, P = 0.042), and having enough time and use of compression (OR = 2.11, P = 0.003). A strong safety culture and a supportive work environment appears to be essential for the use of dose-reduction measures, and education, training and stress management can improve utilisation of dose-reduction measures.
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| 13. |
- Bradshaw, Clare, et al.
(författare)
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Education and training in radioecology during the EU-COMET project-successes and suggestions for the future
- 2018
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Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 38:1, s. 140-151
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Tidskriftsartikel (refereegranskat)abstract
- The 2014 Strategic Research Agenda (SRA) for Radioecology identified the key challenge in education and training (E&T) as being 'to maintain and develop a skilled workforce in Europe and world-wide, through university candidates and professionals trained within radioecology' since 'scientific research in radioecology and application of that knowledge K requires scientists and workers with adequate competence and appropriate skills.' Radioecology is a multidisciplinary science and E&T is needed by both students and professionals within research, industry and radiation protection. In order to address these needs, the EU COMET project has developed an E&T web platform and arranged a number of field courses, training courses, PhD and MSc courses, refresher courses and workshops, drawing on the COMET consortium to assemble relevant experts. In addition, COMET has been engaged in discussions with stakeholders for more long-term solutions to maintain the sustainability of radioecology E&T after the end of the project. Despite much progress in some areas, many of the challenges outlined in the 2014 SRA remain, mainly due to the lack of sustainable dedicated funding. Future plans within the ALLIANCE radioecology platform and the CONCERT-European Joint Programme for the Integration of Radiation Protection Research must urgently address this lack of sustainability if radioecological competence is to be maintained in Europe.
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| 14. |
- Engström, Andreas, 1983, et al.
(författare)
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Lead aprons and thyroid collars: to be, or not to be?
- 2023
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Ingår i: Journal of radiological protection : official journal of the Society for Radiological Protection. - 1361-6498. ; 43:3
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Tidskriftsartikel (refereegranskat)abstract
- Wearing lead aprons and thyroid collars for long periods of time has a subjective component: to balance the effective dose reduction with the effort of carrying a heavy load. Occupational radiation exposure has decreased dramatically in the last century within the health care system. During the same period the use of lead aprons and thyroid collars has also gone up. Therefore, a question that may be raised is: how safe is safe enough? In order to promote stakeholder involvement, the aim of the present study was to investigate staff's experience of discomforts associated with wearing lead aprons and thyroid collars for long periods of time, and also to investigate staff's willingness to tolerate personal dose equivalent (expressed as radiation dose) and the corresponding increase in future cancer risk to avoid wearing these protective tools. A questionnaire was developed and given to staff working in operating or angiography rooms at Skaraborg Hospital in Sweden. The results from the 245 respondents showed that 51% experienced bothersome warmth, 36% experienced fatigue and 26% experienced ache or pain that they believed was associated with wearing lead aprons. One third of the respondents would tolerate a personal dose equivalent of 1 mSv per year to avoid wearing lead aprons, but only a fifth would tolerate the corresponding increase in future cancer risk (from 43% to 43.2%). In conclusion, discomforts associated with wearing lead aprons and thyroid collars for long periods of time are common for the staff using them. At the same time, only a minority of the staff would tolerate a small increase in future cancer risk to avoid wearing them. The present study gives an example of stakeholder involvement and points at the difficulties in making reasonable decisions about the use of these protective tools.
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| 15. |
- Hamnerius, Yngve, 1950, et al.
(författare)
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Evaluating exposure from electric fields in a high voltage switchyard according to the EU directive
- 2019
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Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 1361-6498 .- 0952-4746. ; 39:1, s. 150-160
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Tidskriftsartikel (refereegranskat)abstract
- An assessment according to Directive 2013/35/EU of exposure in a 400 kV switchyard has been performed. Part of the body was exposed to electric field strength above the high action level. We therefore performed simulations of the electric fields induced in the body to assess these accoding to the exposure limit values (ELVs). The simulations show that as long as the body is not grounded nor touching any grounded metallic objects, worker exposure is compliant with the directive. When grounded metallic objects are touched with hand or foot the ELV are exceeded. The ELV is exceeded already at very low contact currents (2-3 mu A) in the finger. If not appropriate measures are taken, this would lead to a severe limitation of the work tasks that can be performed in switchyards.
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| 16. |
- Hjellström, Martin, 1993, et al.
(författare)
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Medical gamma cameras in radiological emergency preparedness: determination of calibration factors and MDA for the GE Discovery NM/CT 670 Pro.
- 2023
-
Ingår i: Journal of radiological protection : official journal of the Society for Radiological Protection. - : IOP Publishing. - 1361-6498. ; 43:1
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Tidskriftsartikel (refereegranskat)abstract
- A survey was performed of the available gamma camera models and whole-body counters (WBCs) in Sweden, revealing that there are about 75 gamma cameras and 15 WBCs currently in operation in Sweden. One of the most common gamma camera models (GE Discovery NM/CT 670 Pro), with the collimators removed, was calibrated for Eu-152, Cs-137, Co-60 and K-40 in three different measurement geometries (supine, close-up sitting and distant sitting) for six different phantom sizes (12-110 kg). Minimum detectable activities (MDAs) were calculated for the gamma camera and a typical WBC, both at the Sahlgrenska University Hospital in Gothenburg, Sweden. An energy window of 30-510 keV was used to calibrate the gamma camera. The calibration factors for this gamma camera for supine and close-up sitting geometry, including all phantom sizes, were 138-208 cps/kBq for Eu-152, 63-83 cps/kBq for Cs-137 and 99-126 cps/kBq for Co-60; the MDAs were 50-73 Bq for Eu-152, 125-198 Bq for Cs-137 and 83-105 Bq for Co-60. The International Commission on Radiological Protection dose coefficients for members of the public were used to calculate the committed effective doses (CEDs) corresponding to the MDAs, showing that CEDs down to a fewμSv can be estimated with this gamma camera for the inhalation of aerosols of absorption type M. The distant sitting geometry was used to enable the estimation of higher contamination levels, and a hypothetical maximum CED was calculated. This was shown to be 256-2000 mSv, depending on the radionuclide and phantom size. However, further investigations are needed into the dead time losses for higher activity levels for the radionuclides studied. The results show that the use of gamma cameras for radiological triage and, in some cases, to estimate the internal activity of relevant radionuclides in radiological and nuclear events, is feasible.
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| 17. |
- Lundvall, Liselotte, et al.
(författare)
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Occupational doses in interventional angiography after radiological protection training and use of a real-time direct display dosimeter
- 2022
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Ingår i: Journal of Radiological Protection. - : IOP Publishing Ltd. - 0952-4746 .- 1361-6498. ; 42:3
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Tidskriftsartikel (refereegranskat)abstract
- Vascular x-ray guided interventions are complex and may result in high occupational doses to ionising radiation if staff do not take appropriate actions to minimise their exposure. In this prospective intervention study, ten staff members wore an extra personal dosimeter on the upper body above their regular protective clothing during four consecutive periods. Between each period either additional practical radiological protection training was given or a real-time direct display dosimeter were provided to the staff. Each staffs personal dose equivalent, Hp(10) normalised to the total air kerma-area product for the procedures where each staff were involved, KAPt, was used as the dependent variable. A focus-group interview with the staff were performed about the usefulness of the training and real-time dose rate display system. Our aim was to investigate if the interventions (practical training or real-time dose rate display) did affect the staff doses in the short and long term (five months later). Significant (p < 0.05) reductions of staff doses Hp(10)/KAPt were found after practical radiological protection training, but not after using real-time dose rate displays. Significant reductions were maintained after five months without additional interventions. The results from the focus-group interview indicated that making radiation visible, during practical training and usage of real-time direct display dosimeter, made it easier to understand how to act to lower occupational doses.
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| 18. |
- Nocum, D. J., et al.
(författare)
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Predictors of radiation dose for uterine artery embolisation are angiography system-dependent
- 2022
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Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 42:1
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Tidskriftsartikel (refereegranskat)abstract
- This study sought to achieve radiation dose reductions for patients receiving uterine artery embolisation (UAE) by evaluating radiation dose measurements for the preceding generation (Allura) and upgraded (Azurion) angiography system. Previous UAE regression models in the literature could not be applied to this centre's practice due to being based on different angiography systems and radiation dose predictor variables. The aims of this study were to establish whether radiation dose is reduced with the upgraded angiography system and to develop a regression model to determine predictors of radiation dose specific to the upgraded angiography system. A comparison between Group I (Allura, n = 95) and Group II (Azurion, n = 95) demonstrated a significant reduction in kerma-area product (KAP) and Ka, r (reference air kerma) by 63% (143.2 Gy cm(2) vs 52.9 Gy cm(2); P < 0.001, d = 0.8) and 67% (0.6 Gy vs 0.2 Gy; P < 0.001, d = 0.8), respectively. The multivariable linear regression (MLR) model identified the UAE radiation dose predictors for KAP on the upgraded angiography system as total fluoroscopy dose, Ka, r, and total uterus volume. The predictive accuracy of the MLR model was assessed using a Bland-Altman plot. The mean difference was 0.39 Gy cm(2) and the limits of agreement were +28.49 and -27.71 Gy cm(2), and thus illustrated no proportional bias. The resultant MLR model was considered system-dependent and validated the upgraded angiography system and its advance capabilities to significantly reduce radiation dose. Interventional radiologist and interventional radiographer familiarisation of the system's features and the implementation of the newly established MLR model would further facilitate dose optimisation for all centres performing UAE procedures using the upgraded angiography system.
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| 19. |
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| 20. |
- Rühm, W., et al.
(författare)
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Summary of the 2021 ICRP workshop on the future of radiological protection
- 2022
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Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 42:2
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The International Commission on Radiological Protection (ICRP) has embarked on a process to review and revise the current System of Radiological Protection ('the System'). To stimulate discussion, the ICRP published two open-access articles: one on aspects of the System that might require review, and another on research that might improve the scientific foundation of the System. Building on these articles, the ICRP organized a Workshop on the Future of Radiological Protection as an opportunity to engage in the review and revision of the System. This digital workshop took place from 14 October–3 November 2021 and included 20 live-streamed and 43 on-demand presentations. Approximately 1500 individuals from 100 countries participated. Based on the subjects covered by the presentations, this summary is organized into four broad areas: the scientific basis, concepts and application of the System; and the role of the ICRP. Some of the key topics that emerged included the following: classification of radiation-induced effects; adverse outcome pathway methodologies; better understanding of the dose–response relationship; holistic and reasonable approaches to optimization of protection; radiological protection of the environment; ethical basis of the System; clarity, consistency and communication of the System; application of the System in medicine and application of the principles of justification and optimization of protection.
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| 21. |
- Valentin, J, et al.
(författare)
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Those who cannot remember the past are condemned to repeat it
- 2020
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Ingår i: Journal of radiological protection : official journal of the Society for Radiological Protection. - : IOP Publishing. - 1361-6498. ; 40:4, s. E25-E30
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 22. |
- Valentin, J, et al.
(författare)
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To be (prepared) or not to be-that is hardly the question
- 2022
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Ingår i: Journal of radiological protection : official journal of the Society for Radiological Protection. - : IOP Publishing. - 1361-6498. ; 42:3
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 23. |
- Wojcik, Andrzej, et al.
(författare)
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Considerations on the use of the terms radiosensitivity and radiosusceptibility
- 2018
-
Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 38:3, s. N25-N29
-
Tidskriftsartikel (refereegranskat)abstract
- The separate use of the terms 'radiosensitivity' and 'radiosusceptibility' has been suggested to describe variability in the risk of, respectively, adverse tissue reactions (deterministic effect) following radiotherapy and radiationinduced cancer (stochastic effect). The aim of this note is to present arguments against such distinction. We feel that it is premature to make a concrete final judgement on these definitions because of the limited understanding of the mechanisms underlying individual sensitivity to both radiation-related cancers and radiation-related tissue injury. Moreover, the exclusive application of 'radiosensitivity' in relation to deterministic effects and the term 'radiosusceptibility' in relation to cancer carries the risk of being wrongly interpreted as evidence for a high, genetically driven sensitivity to radiation in all patients who develop adverse tissue reactions and a high genetic susceptibility to cancer in those who develop radiation-induced malignancies. There is a need for further research to better define these phenomena and their interrelationships.
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| 24. |
- Wojcik, Andrzej
(författare)
-
Reflections on effects of low doses and risk inference based on the UNSCEAR 2021 report on 'biological mechanisms relevant for the inference of cancer risks from low-dose and low-dose-rate radiation'
- 2022
-
Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 42:2
-
Tidskriftsartikel (refereegranskat)abstract
- The 2021 United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) report summarises the knowledge on biological mechanisms of radiation action at low doses where, due to low statistical power of epidemiological investigations, the level of cancer risk must be inferred. It is the fourth UNSCEAR report since 1994 that looks into biological effects following low dose exposure with the aim of examining whether they support the assumption of the linear non-threshold (LNT) dose response for radiation-induced cancers. The conclusions of all four reports are affirmative. The new aspect of the 2021 report is that it focuses on the process of cancer risk inference. The aim of this article is to discuss the consequences of the conclusions regarding LNT and the possibilities of inferring risks from biological studies.
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| 25. |
- Gonzalez, AJ, et al.
(författare)
-
Bo Lindell (1922-2016)
- 2017
-
Ingår i: Journal of radiological protection : official journal of the Society for Radiological Protection. - : IOP Publishing. - 1361-6498. ; 37:2, s. 555-557
-
Tidskriftsartikel (refereegranskat)
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| 26. |
- Rollenhagen, Carl, et al.
(författare)
-
Challenges, dilemmas, and quality criteria for safety reviews
- 2017
-
Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 37:1, s. 279-295
-
Tidskriftsartikel (refereegranskat)abstract
- Five generic dilemmas shared by most safety reviews are identified, namely the complexity dilemma, the specialisation dilemma, the criteria dilemma, the independence dilemma and the ethical dilemma. These dilemmas are not always made sufficiently transparent, which may lead to a too optimistic view of what can be achieved by safety reviews. A two-dimensional characterisation of safety reviews is suggested; the dimensions are the degree of independence and the scope of the review. In conclusion ten quality criteria are proposed that can be used to cope with the dilemmas of conducting safety reviews.
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| 27. |
- Lindberg, K, et al.
(författare)
-
Medical consequences of radiation exposure of the bronchi-what can we learn from high-dose precision radiation therapy?
- 2021
-
Ingår i: Journal of radiological protection : official journal of the Society for Radiological Protection. - : IOP Publishing. - 1361-6498. ; 41:4, s. S355-S370
-
Tidskriftsartikel (refereegranskat)abstract
- The bronchial tolerance to high doses of radiation is not fully understood. However, in the event of a radiological accident with unintended exposure of the central airways to high doses of radiation it would be important to be able to anticipate the clinical consequences given the magnitude of the absorbed dose to different parts of the bronchial tree. Stereotactic body radiation therapy (SBRT) is a radiation treatment technique involving a few large fractions of photon external-beam radiation delivered to a well-defined target in the body. Despite generally favourable results, with high local tumour control and low-toxicity profile, its utility for tumours located close to central thoracic structures has been questioned, considering reports of severe toxic symptoms such as haemoptysis (bleedings from the airways), bronchial necrosis, bronchial stenosis, fistulas and pneumonitis. In conjunction with patient- and tumour-related risk factors, recent studies have analysed the absorbed radiation dose to different thoracic structures of normal tissue to better understand their tolerance to these high doses per fraction. Although the specific mechanisms behind the toxicity are still partly unknown, dose to the proximal bronchial tree has been shown to correlate with high-grade radiation side effects. Still, there is no clear consensus on the tolerance dose of the different bronchial structures. Recent data indicate that a too high dose to a main bronchus may result in more severe clinical side effects as compared to a smaller sized bronchus. This review analyses the current knowledge on the clinical consequences of bronchial exposure to high dose hypofractionated radiation delivered with the SBRT technique, and the tolerance doses of the bronchi. It presents the current literature regarding types of high-grade clinical side effects, data on dose response and comments on other risk factors for high-grade toxic effects.
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| 28. |
- Stenke, L, et al.
(författare)
-
The acute radiation syndrome-need for updated medical guidelines
- 2022
-
Ingår i: Journal of radiological protection : official journal of the Society for Radiological Protection. - : IOP Publishing. - 1361-6498. ; 42:1
-
Tidskriftsartikel (refereegranskat)abstract
- The major immediate and severe medical consequences in man following exposure to high doses of ionising radiation can be summarised within the concept of the acute radiation syndrome (ARS). In a dose-dependent fashion, a multitude of organ systems can be affected by such irradiation, presenting considerable medical challenges to treating physicians. Accidents or malevolent events leading to ARS can provoke devastating effects, but they occur at a low frequency and in a highly varying manner and magnitude. Thus, it is difficult to make precise medical predictions and planning, or to draw conclusive evidence from occurred events. Therefore, knowledge from on-going continuous developments within related medical areas needs to be acknowledged and incorporated into the ARS setting, enabling the creation of evidence-based guidelines. In 2011 the World Health Organization published a first global consensus on the medical management of ARS among patients subjected to nontherapeutic radiation. During the recent decade the understanding of and capability to counteract organ damage related to radiation and other agents have improved considerably. Furthermore, legal and logistic hurdles in the process of formally approving appropriate medical countermeasures have been reduced. We believe the time is now ripe for developing an update of internationally consented medical guidelines on ARS.
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| 29. |
- Almén, Anja, 1964, et al.
(författare)
-
Optimisation of occupational radiological protection in image-guided interventions: potential impact of dose rate measurements.
- 2015
-
Ingår i: Journal of radiological protection : official journal of the Society for Radiological Protection. - : IOP Publishing. - 1361-6498. ; 35:1, s. 47-62
-
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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| 30. |
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| 31. |
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| 32. |
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| 33. |
- Garnier-Laplace, Jacqueline, et al.
(författare)
-
Assessing ecological effects of radionuclides : data gaps and extrapolation issues
- 2004
-
Ingår i: Journal of Radiological Protection. - 0952-4746 .- 1361-6498. ; 24:4A, s. A139-A155
-
Tidskriftsartikel (refereegranskat)abstract
- By inspection of the FASSET database on radiation effects on non-human biota, one of the major difficulties in the implementation of ecological risk assessments for radioactive pollutants is found to be the lack of data for chronic low-level exposure. A critical review is provided of a number of extrapolation issues that arise in undertaking an ecological risk assessment: acute versus chronic exposure regime; radiation quality including relative biological effectiveness and radiation weighting factors; biological effects from an individual to a population level, including radiosensitivity and lifestyle variations throughout the life cycle; single radionuclide versus multi-contaminants. The specificities of the environmental situations of interest (mainly chronic low-level exposure regimes) emphasise the importance of reproductive parameters governing the demography of the population within a given ecosystem and, as a consequence, the structure and functioning of that ecosystem. As an operational conclusion to keep in mind for any site-specific risk assessment, the present state-of-the-art on extrapolation issues allows us to grade the magnitude of the uncertainties as follows: one species to another > acute to chronic = external to internal = mixture of stressors > individual to population > ecosystem structure to function.
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| 34. |
- Hansson, Sven Ove
(författare)
-
Ethics and radiation protection
- 2007
-
Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 27:2, s. 147-156
-
Tidskriftsartikel (refereegranskat)abstract
- Some of the major problems in radiation protection are closely connected to issues that have a long, independent tradition in moral philosophy. This contribution focuses on two of these issues. One is the relationship between the protection of individuals and optimisation on the collective level, and the other is the relative valuation of future versus immediate damage. Some of the intellectual tools that have been developed by philosophers can be useful in radiation protection. On the other hand, philosophers have much to learn from radiation protectors, not least when it comes to finding pragmatic solutions to problems that may be intractable in principle.
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| 35. |
- Hansson, Sven Ove
(författare)
-
Should we protect the most sensitive people?
- 2009
-
Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 29:2, s. 211-218
-
Tidskriftsartikel (refereegranskat)abstract
- The recommendations of the International Commission on Radiological Protection (ICRP) are based on a population average, rather than on the available data for subpopulations. From an ethical point of view, this approach is far from unproblematic. Strong reasons can be given in support of a right for each radiation-exposed person to have the best possible information about the risk to himself or herself, which is often group-specific information. Risk exposures have to be defensible from the perspective of each identifiable group for which a specific risk assessment can be made. Exposing a person to a high risk cannot be justified by pointing out that the risk to an average person would have been much lower. There are two major ways to protect a sensitive group: special standards for the group (differentiated protection) and general standards that are strict enough to protect its members (unified protection). Some major factors that are relevant for the choice between these two protective strategies are identified.
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| 36. |
- Hendry, Jolyon H, et al.
(författare)
-
Human exposure to high natural background radiation : what can it teach us about radiation risks?
- 2009
-
Ingår i: Journal of Radiological Protection. - 0952-4746 .- 1361-6498. ; 29:2A, s. A29-42
-
Tidskriftsartikel (refereegranskat)abstract
- Natural radiation is the major source of human exposure to ionising radiation, and its largest contributing component to effective dose arises from inhalation of (222)Rn and its radioactive progeny. However, despite extensive knowledge of radiation risks gained through epidemiologic investigations and mechanistic considerations, the health effects of chronic low-level radiation exposure are still poorly understood. The present paper reviews the possible contribution of studies of populations living in high natural background radiation (HNBR) areas (Guarapari, Brazil; Kerala, India; Ramsar, Iran; Yangjiang, China), including radon-prone areas, to low dose risk estimation. Much of the direct information about risk related to HNBR comes from case-control studies of radon and lung cancer, which provide convincing evidence of an association between long-term protracted radiation exposures in the general population and disease incidence. The success of these studies is mainly due to the careful organ dose reconstruction (with relatively high doses to the lung), and to the fact that large-scale collaborative studies have been conducted to maximise the statistical power and to ensure the systematic collection of information on potential confounding factors. In contrast, studies in other (non-radon) HNBR areas have provided little information, relying mainly on ecological designs and very rough effective dose categorisations. Recent steps taken in China and India to establish cohorts for follow-up and to conduct nested case-control studies may provide useful information about risks in the future, provided that careful organ dose reconstruction is possible and information is collected on potential confounding factors.
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| 37. |
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| 38. |
- Högberg, Jonas, 1976, et al.
(författare)
-
Radiation exposure during liver surgery after treatment with (90)Y microspheres, evaluated with computer simulations and dosimeter measurements.
- 2012
-
Ingår i: Journal of radiological protection : official journal of the Society for Radiological Protection. - : IOP Publishing. - 1361-6498. ; 32:4, s. 439-46
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose. Two patients with liver tumours were planned for a combined treatment, including surgery with preceding injections of β(-) radiation emitting (90)Y microspheres (SIRTEX(®)). The aim of this paper is to present a method of pre-surgical computer simulations of the absorbed dose rate on the surface of tumour tissue, combined with measurements of the actual absorbed dose rate on resected tissue, in order to estimate the absorbed dose to a surgeon's fingers during such surgery procedures. Methods and Materials. The dose rates from β(-) radiation on the surface of tumour tissue were simulated with the software VARSKIN(®)Mod2. The activity concentrations in tumours were estimated, based on SPECT/CT distribution studies of (99m)Tc-MAA and confirmed by SPECT/CT bremsstrahlung studies of (90)Y microspheres. The activity distributions were considered as homogeneous within the tumour regions. The absorbed dose rates at different tumour tissue spots were calculated based on measurements with thermo-luminescent dosimeters (TLD) fastened on resected tissue. Results. The simulations showed a good agreement with the averaged absorbed dose rates based on TLD measurements performed on resected tissue, differing by 13% and 4% respectively. The absorbed dose rates at the measured maximum hotspots were twice as high as the average dose rates for both patients. Conclusion. The data is not sufficient in order to draw any general conclusions about dose rates on tumour tissue during similar surgeries, neither about the influence of dose rate heterogeneities nor about average dose rates. However, the agreement between simulations and measurements on these limited data indicate that this approach is a promising method for estimations of the radiation exposure to the surgeons' fingers during this kind of surgery procedure. More data from similar surgeries are necessary in order to validate the method.
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| 39. |
- Jones, Celia, et al.
(författare)
-
Overview of programmes for the assessment of risks to the environment from ionising radiation and hazardous chemicals
- 2004
-
Ingår i: Journal of Radiological Protection. - 0952-4746 .- 1361-6498. ; 24:4A, s. A157-A177
-
Tidskriftsartikel (refereegranskat)abstract
- Within the FASSET project, a review of existing programmes for the assessment of environmental risks from radioactive or hazardous substances was carried out in order to identify appropriate aspects that could be incorporated into the FASSET framework. The review revealed a number of different approaches, arising from the need to balance the information value of the assessment against the availability of data and the need to keep the assessment manageable. Most of the existing assessment programmes fit into a three-phase approach to environmental risk assessment: problem formulation, assessment and risk characterisation. However, the emphasis on particular assessment phases varies between programmes. The main differences between the different programmes are: the degree of specificity to a particular site, the level of detail of the assessment, the point at which a comparison is made between a criterion intended to represent 'what is acceptable' and a measured or predicted quantity, the choice of end-point for the assessment and the relationship between measurement end-points and assessment end-points. The existing assessment programmes are based on a similar general structure, which is suitable for use as a basis for the FASSET framework. However, certain aspects of the assessment of exposure and effects of ionising contaminants, e.g. dosimetry, require further development before incorporation into such a framework.
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| 40. |
- Magee, Jill S, et al.
(författare)
-
Derivation and application of dose reduction factors for protective eyewear worn in interventional radiology and cardiology.
- 2014
-
Ingår i: Journal of radiological protection : official journal of the Society for Radiological Protection. - : IOP Publishing. - 1361-6498. ; 34:4, s. 811-823
-
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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| 41. |
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| 42. |
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| 43. |
- Salomaa, Sisko, et al.
(författare)
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State of the art in research into the risk of low dose radiation exposure-findings of the fourth MELODI workshop
- 2013
-
Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 33:3, s. 589-603
-
Tidskriftsartikel (refereegranskat)abstract
- The fourth workshop of the Multidisciplinary European Low Dose Initiative (MELODI) was organised by STUK-Radiation and Nuclear Safety Authority of Finland. It took place from 12 to 14 September 2012 in Helsinki, Finland. The meeting was attended by 179 scientists and professionals engaged in radiation research and radiation protection. We summarise the major scientific findings of the workshop and the recommendations for updating the MELODI Strategic Research Agenda and Road Map for future low dose research activities.
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| 44. |
- Sandblom, Viktor, 1987, et al.
(författare)
-
Evaluation of the impact of a system for real-time visualisation of occupational radiation dose rate during fluoroscopically guided procedures
- 2013
-
Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 33:3, s. 693-702
-
Tidskriftsartikel (refereegranskat)abstract
- Optimisation of radiological protection for operators working with fluoroscopically guided procedures has to be performed during the procedure, under varying and difficult conditions. The aim of the present study was to evaluate the impact of a system for real-time visualisation of radiation dose rate on optimisation of occupational radiological protection in fluoroscopically guided procedures. Individual radiation dose measurements, using a system for real-time visualisation, were performed in a cardiology laboratory for three cardiologists and ten assisting nurses. Radiation doses collected when the radiation dose rates were not displayed to the staff were compared to radiation doses collected when the radiation dose rates were displayed. When the radiation dose rates were displayed to the staff, one cardiologist and the assisting nurses (as a group) significantly reduced their personal radiation doses. The median radiation dose (Hp(10)) per procedure decreased from 68 to 28 μSv (p = 0.003) for this cardiologist and from 4.3 to 2.5 μSv (p = 0.001) for the assisting nurses. The results of the present study indicate that a system for real-time visualisation of radiation dose rate may have a positive impact on optimisation of occupational radiological protection. In particular, this may affect the behaviour of staff members practising inadequate personal radiological protection.
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| 45. |
- Sollazzo, Alice, et al.
(författare)
-
Interaction of low and high LET radiation in TK6 cells-mechanistic aspects and significance for radiation protection
- 2016
-
Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 36:4, s. 721-735
-
Tidskriftsartikel (refereegranskat)abstract
- Most environmental, occupational and medical exposures to ionising radiation are associated with a simultaneous action of different radiation types. An open question remains whether radiations of different qualities interact with each other to yield effects stronger than expected based on the assumption of additivity. It is possible that DNA damage induced by high linear energy transfer (LET) radiation will lead to an opening of the chromatin structure making the DNA more susceptible to attack by reactive oxygen species (ROS) generated by the low LET radiation. In such case, the effect of mixed beams should be strongly expressed in cells that are sensitive to ROS. The present investigation was carried out to test if cells with an impaired capacity to handle oxidative stress are particularly sensitive to the effect of mixed beams of alpha particles and x-rays. Clonogenic cell survival curves and mutant frequencies were analysed in TK6 wild type (wt) cells and in TK6 cells with a knocked down hMYH glycosylase. The results showed a synergistic effect of mixed beams on clonogenic cell survival of TK6(wt) but not TK6(MYH)-cells. The frequencies of mutants showed a high degree of interexperimental variability without any indications for synergistic effects of mixed beams. TK6(MYH)-cells were generally more tolerant to radiation exposure with respect to clonogenic cell survival but showed a strong increase in mutant frequency. The results demonstrate that exposure of wt cells to a mixed beam of alpha particles and x-rays leads to a detrimental effect which is stronger than expected based on the assumption of additivity. The role of oxidative stress in the reaction of cells to mixed beams remains unclear.
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| 46. |
- Wikman, Per
(författare)
-
On effects of low doses : Reply
- 2004
-
Ingår i: Journal of Radiological Protection. - 0952-4746 .- 1361-6498. ; 24:4, s. 428-429
-
Tidskriftsartikel (refereegranskat)
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| 47. |
- Wikman, Per
(författare)
-
Trivial risks and the new radiation protection system
- 2004
-
Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 24:1, s. 3-11
-
Tidskriftsartikel (refereegranskat)abstract
- The International Commission on Radiological Protection proposes that doses below a certain level should be excluded from the system of protection, without regard to the number of people exposed. As the Commission assumes that there is a risk of harm even from very low doses, the proposal also disregards these very low risks. The arguments for this proposal are examined here. It is argued that the fact that risks are small compared to natural sources cannot be used as justification for accepting them. The principle 'if the risk of harm to the health of the most exposed individual is trivial, then the total risk is trivial-irrespective of how many people are exposed' is analysed. It is found to equivocate on the meaning of the word trivial and to ignore the total risk. It is also argued that the new proposal is not justified by a change from a utilitarian ethic to an ethic based on individual rights. Finally, it is suggested that small doses should only be disregarded if the expected value of harm is small, and the exclusion level should thus depend on the number of people exposed.
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| 48. |
- Wikman-Svahn, Per, et al.
(författare)
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Principles of protection : a formal approach for evaluating dose distribution
- 2006
-
Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 26:1, s. 69-84
-
Tidskriftsartikel (refereegranskat)abstract
- One of the central issues in radiation protection consists in determining what weight should be given to individual doses in relation to collective or aggregated doses. A mathematical framework is introduced in which such assessments can be made precisely in terms of comparisons between alternative distributions of individual doses. In addition to evaluation principles that are well known from radiation protection, a series of principles that are derived from parallel discussions in moral philosophy and welfare economics is investigated. A battery of formal properties is then used to investigate the evaluative principles. The results indicate that one of the new principles, bilinear prioritarianism, may be preferable to current practices, since it satisfies efficiency-related properties better without sacrificing other desirable properties.
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| 49. |
- Wojcik, Andrzej, et al.
(författare)
-
Chromosomal aberrations in peripheral blood lymphocytes exposed to a mixed beam of low energy neutrons and gamma radiation
- 2012
-
Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 32:3, s. 261-274
-
Tidskriftsartikel (refereegranskat)abstract
- Cells exposed to thermal neutrons are simultaneously damaged by radiations with high and low linear energy transfer (LET). A question relevant for the assessment of risk of exposure to a mixed beam is whether the biological effect of both radiation types is additive or synergistic. The aim of the present investigation was to calculate whether the high and low LET components of a thermal neutron field interact when damaging cells. Human peripheral blood lymphocytes were exposed to neutrons from the HB11 beam at the Institute for Energy and Transport, Petten, Netherlands, in a 37 degrees C water phantom at varying depths, where the mix of high and low LET beam components differs. Chromosomal aberrations were analysed and the relative biological effectiveness (RBE) values as well as the expected contributions of protons and photons to the aberration yield were calculated based on a dose response of aberrations in lymphocytes exposed to Co-60 gamma radiation. The RBE for 10 dicentrics per 100 cells was 3 for mixed beam and 7.2 for protons. For 20 dicentrics per 100 cells the respective values were 2.4 and 5.8. Within the limitations of the experimental setup the results indicate that for this endpoint there is no synergism between the high and low LET radiations.
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| 50. |
- Ören, Ünal, et al.
(författare)
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Detection of radioactive fragments in patients after radiological or nuclear emergencies using computed tomography and digital radiography.
- 2014
-
Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 1361-6498 .- 0952-4746. ; 34:1, s. 231-247
-
Tidskriftsartikel (refereegranskat)abstract
- A comparison has been carried out between standard-dose computed tomography, non-diagnostic computed tomography and digital radiography with respect to their suitability for detecting radioactive fragments associated with nuclear or radiological events such as debris from radiological dispersal devices. The purpose was to investigate if radiographic imaging is justified for the detection and localisation of radioactive fragments in affected patients.Fragments of uranium (U), copper (Cu), iron (Fe) and volcanic ash with effective diameters ranging from (approximately) 100 to 700 μm were selected. The fragments were positioned at two different locations on an anatomical torso phantom and images were produced with standard-dose CT, non-diagnostic CT and digital radiography. Capsules with radionuclides of (137)Cs, (60)Co and (99m)Tc were also positioned in the phantom and the effective doses were estimated for radionuclide exposures as well as for standard-dose CT, non-diagnostic CT and digital radiography. For standard-dose CT and digital radiography, U, Cu and Fe fragments were detected in sizes down to 100-180, 250-300 and 300-400 μm respectively. For the non-diagnostic CT the results were 180-250 μm (for U), 300-400 μm (for Cu) and 400-500 μm (for Fe). The effective dose from the standard-dose CT, non-diagnostic CT and digital radiography was 5.6, 1.9 and 0.76 mSv. Corresponding doses from (137)Co, (60)Co and (99m)Tc positioned at the site of fragments were in the range of 0.07-0.1, 0.32-0.45 and 0.08-0.09 mSv per MBq during 24 h. We conclude that, for a number of gamma emitters with activity levels on the order of magnitude of megabecquerel, imaging using ionising radiation can be justified since the effective dose from the radionuclides will exceed the dose from the radiological examination.
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