| 1. |
- Bernhardsson, Christian, et al.
(författare)
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Advancements in prospective dosimetry with NaCl read-out by optically stimulated luminescence
- 2017
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Ingår i: Medical Physics in the Baltic States : Proceedings of the 13th International Conference on Medical Physics - Proceedings of the 13th International Conference on Medical Physics. - 1822-5721. ; , s. 26-29
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Konferensbidrag (refereegranskat)abstract
- In this paper we present the recent improvements for optically stimulated luminescence dosimetry using ordinary salt (NaCl). It is shown that the dosimetric properties of NaCl may be improved by compressing the salt grains to solid pellets. With a linear dose response in, at least, the region <100 mGy, a zero background signal (when pre-bleached) and a minimum measurable dose of 10-20 μGy and high reproducibility, this opens for new applications of prospective OSL dosimetry with NaCl.
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| 2. |
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| 3. |
- Bernhardsson, Christian, et al.
(författare)
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Household salt (NaCl) for optically stimulated luminescence dosimetry: an overview
- 2021
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Ingår i: Medical Physics in the Baltic States : Proceedings of the 15th International Conference on Medical Physics - Proceedings of the 15th International Conference on Medical Physics. - 1822-5721. ; , s. 90-94
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Konferensbidrag (refereegranskat)abstract
- This brief overview of the use of household salt (NaCl) in optically stimulated luminescence (OSL) dosimetry is focusing on the use of NaCl pellets. It is suggested that the most optimal use of household NaCl, in general prospective dosimetry, is to compress the salt grains to pellets and read the radiation induced signal using OSL rather than TL. A summary of the main OSL dosimetric properties is provided for two Swedish household salts, and compared to the OSL properties of 100 different salts from all over the world.
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| 4. |
- Endesfelder, David, et al.
(författare)
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RENEB/EURADOS field exercise 2019 : robust dose estimation under outdoor conditions based on the dicentric chromosome assay
- 2021
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Ingår i: International Journal of Radiation Biology. - : Informa UK Limited. - 0955-3002 .- 1362-3095. ; 97:9, s. 1181-1198
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Biological and/or physical assays for retrospective dosimetry are valuable tools to recover the exposure situation and to aid medical decision making. To further validate and improve such biological and physical assays, in 2019, EURADOS Working Group 10 and RENEB performed a field exercise in Lund, Sweden, to simulate various real-life exposure scenarios.Materials and methods: For the dicentric chromosome assay (DCA), blood tubes were located at anthropomorphic phantoms positioned in different geometries and were irradiated with a 1.36 TBq 192Ir-source. For each exposure condition, dose estimates were provided by at least one laboratory and for four conditions by 17 participating RENEB laboratories. Three radio-photoluminescence glass dosimeters were placed at each tube to assess reference doses.Results: The DCA results were homogeneous between participants and matched well with the reference doses (≥95% of estimates within ±0.5 Gy of the reference). For samples close to the source systematic underestimation could be corrected by accounting for exposure time. Heterogeneity within and between tubes was detected for reference doses as well as for DCA doses estimates.Conclusions: The participants were able to successfully estimate the doses and to provide important information on the exposure scenarios under conditions closely resembling a real-life situation.
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| 5. |
- 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
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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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| 6. |
- Waldner, Lovisa, et al.
(författare)
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NaCl pellets for prospective dosimetry using optically stimulated luminescence : Signal integrity and long-term versus short-term exposure
- 2020
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 59:4, s. 693-702
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Tidskriftsartikel (refereegranskat)abstract
- Optically stimulated luminescence (OSL) signal properties of pellets from three types of NaCl (two household salts and one analytical grade salt) were investigated for their use in prospective dosimetry. Special attention was given to the OSL signal behaviour with time. The readout protocol was optimised in terms of preheat temperature, and the OSL signal yield of the NaCl pellet with time as well as the fading of the OSL signal with time was investigated. The effects of acute and chronic irradiations were compared. Irradiations and readout were performed using a Risø TL/OSL reader (TL/OSL-DA-15, DTU Nutech, Denmark). The optimal preheat temperature was determined to be 100 ºC, yielding OSL signals similar to a 1 h pause before OSL signal readout. There was no OSL signal fading observed as a function of time, but a decrease in the OSL signal yield of the NaCl pellets with time resulted in an apparent inverse fading when converting the OSL signal to an absorbed dose. For chronic radiation exposures of up to five weeks, the sensitivity of the NaCl pellets was found to be stable. The results of this study show that the use of NaCl pellets for prospective dosimetry is a promising, cost-effective, and accessible complement to commercially available alternatives for accurate absorbed dose determinations.
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| 7. |
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| 8. |
- Waldner, Lovisa, et al.
(författare)
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Physical and dosimetric properties of NaCl pellets made in-house for the use in prospective optically stimulated luminescence dosimetry applications
- 2018
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Ingår i: Radiation Measurements. - : Elsevier BV. - 1350-4487. ; 119, s. 52-57
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, NaCl pellets are produced in-house from ordinary household salt using simple and accessible methods, for the purpose of suggesting a cost-effective and available tool for various optically stimulated luminescence dosimetry applications. First, the pellets are investigated in terms of optimal configuration by varying combinations of grain sizes and compression forces. Then, the pellets with the optimal configuration are further investigated in terms of dosimetric properties such as signal-dose response, dose estimation, reproducibility, radiation induced sensitisation, detection limits and signal stability over time. The radiation induced OSL signals are read at room temperature and dose estimations are performed using one calibration dose. The optimal pellet configuration, for the three salts investigated, was achieved with 100–400 μm sized salt grains and a compression force of 3.0 ± 0.5 tons. With the proposed NaCl pellets, readout and calibration procedure, it is possible to achieve a linear dose response in the dose range from 0 to 300 mGy. When using a calibration dose for signal normalisation the reproducibility of the radiation induced OSL signal is within 1.5% and when using the most optimal calibration dose for each salt the estimated dose is within 3% of the given dose. The detection limits for the salts investigated are, in terms of minimum detectable dose, between 5 and 21 μGy. Considering these findings and the overall cost of manufacturing NaCl pellets i.e. the worldwide availability, the proposed method opens for radiation protection measurements that have so far been too expensive or impossible.
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