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NUNDO: a numerical model of a human torso phantom and its application to effective dose equivalent calculations for astronauts at the ISS.

Puchalska M, Bilski P, Berger T, Hajek M, Horwacik T, Körner C, Olko P, Shurshakov V, Reitz G - Radiat Environ Biophys (2014)

Bottom Line: The present work reports the first successful attempt of the experimental determination of the effective dose equivalent in space, both for extra-vehicular activity (EVA) and intra-vehicular activity (IVA).It was found that the effective dose equivalent rate during an EVA approaches 700 μSv/d, while during an IVA about 20 % lower values were observed.It is shown that the individual dose based on a personal dosimeter reading for an astronaut during IVA results in an overestimate of the effective dose equivalent of about 15 %, whereas under an EVA conditions the overestimate is more than 200 %.

View Article: PubMed Central - PubMed

Affiliation: Institute of Nuclear Physics, Polish Academy of Sciences, 31-342, Kraków, Poland, monika.puchalska@chalmers.se.

ABSTRACT
The health effects of cosmic radiation on astronauts need to be precisely quantified and controlled. This task is important not only in perspective of the increasing human presence at the International Space Station (ISS), but also for the preparation of safe human missions beyond low earth orbit. From a radiation protection point of view, the baseline quantity for radiation risk assessment in space is the effective dose equivalent. The present work reports the first successful attempt of the experimental determination of the effective dose equivalent in space, both for extra-vehicular activity (EVA) and intra-vehicular activity (IVA). This was achieved using the anthropomorphic torso phantom RANDO(®) equipped with more than 6,000 passive thermoluminescent detectors and plastic nuclear track detectors, which have been exposed to cosmic radiation inside the European Space Agency MATROSHKA facility both outside and inside the ISS. In order to calculate the effective dose equivalent, a numerical model of the RANDO(®) phantom, based on computer tomography scans of the actual phantom, was developed. It was found that the effective dose equivalent rate during an EVA approaches 700 μSv/d, while during an IVA about 20 % lower values were observed. It is shown that the individual dose based on a personal dosimeter reading for an astronaut during IVA results in an overestimate of the effective dose equivalent of about 15 %, whereas under an EVA conditions the overestimate is more than 200 %. A personal dosemeter can therefore deliver quite good exposure records during IVA, but may overestimate the effective dose equivalent received during an EVA considerably.

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Continuous TLD dose distribution models combined with the numerical voxel phantom NUNDO for a MTR-1, b MTR-2A and c MTR-2B. Mean organ dose rates are calculated from these distributions (Tables 3, 4)
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Related In: Results  -  Collection


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Fig2: Continuous TLD dose distribution models combined with the numerical voxel phantom NUNDO for a MTR-1, b MTR-2A and c MTR-2B. Mean organ dose rates are calculated from these distributions (Tables 3, 4)

Mentions: The average TLD organ dose rate calculated by folding the TLD 3D dose distribution model with the NUNDO voxel phantom (Fig. 2) is given by DTLD. DTLD-low represents the average absorbed organ dose rate measured by TLDs for LET <10 keV/μm, and the DPNTD-high represents the absorbed dose rate measured by PNTDs for LET >10 keV/μm. DT is the total average organ dose rate given by the sum of DTLD-low and DPNTD-high. The total daily organ dose equivalent rate () and the mean quality factor (QT) are based on the combination of TLD measurements and PNTD data. (see Reitz et al. 2009 for further details).Fig. 2


NUNDO: a numerical model of a human torso phantom and its application to effective dose equivalent calculations for astronauts at the ISS.

Puchalska M, Bilski P, Berger T, Hajek M, Horwacik T, Körner C, Olko P, Shurshakov V, Reitz G - Radiat Environ Biophys (2014)

Continuous TLD dose distribution models combined with the numerical voxel phantom NUNDO for a MTR-1, b MTR-2A and c MTR-2B. Mean organ dose rates are calculated from these distributions (Tables 3, 4)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4206298&req=5

Fig2: Continuous TLD dose distribution models combined with the numerical voxel phantom NUNDO for a MTR-1, b MTR-2A and c MTR-2B. Mean organ dose rates are calculated from these distributions (Tables 3, 4)
Mentions: The average TLD organ dose rate calculated by folding the TLD 3D dose distribution model with the NUNDO voxel phantom (Fig. 2) is given by DTLD. DTLD-low represents the average absorbed organ dose rate measured by TLDs for LET <10 keV/μm, and the DPNTD-high represents the absorbed dose rate measured by PNTDs for LET >10 keV/μm. DT is the total average organ dose rate given by the sum of DTLD-low and DPNTD-high. The total daily organ dose equivalent rate () and the mean quality factor (QT) are based on the combination of TLD measurements and PNTD data. (see Reitz et al. 2009 for further details).Fig. 2

Bottom Line: The present work reports the first successful attempt of the experimental determination of the effective dose equivalent in space, both for extra-vehicular activity (EVA) and intra-vehicular activity (IVA).It was found that the effective dose equivalent rate during an EVA approaches 700 μSv/d, while during an IVA about 20 % lower values were observed.It is shown that the individual dose based on a personal dosimeter reading for an astronaut during IVA results in an overestimate of the effective dose equivalent of about 15 %, whereas under an EVA conditions the overestimate is more than 200 %.

View Article: PubMed Central - PubMed

Affiliation: Institute of Nuclear Physics, Polish Academy of Sciences, 31-342, Kraków, Poland, monika.puchalska@chalmers.se.

ABSTRACT
The health effects of cosmic radiation on astronauts need to be precisely quantified and controlled. This task is important not only in perspective of the increasing human presence at the International Space Station (ISS), but also for the preparation of safe human missions beyond low earth orbit. From a radiation protection point of view, the baseline quantity for radiation risk assessment in space is the effective dose equivalent. The present work reports the first successful attempt of the experimental determination of the effective dose equivalent in space, both for extra-vehicular activity (EVA) and intra-vehicular activity (IVA). This was achieved using the anthropomorphic torso phantom RANDO(®) equipped with more than 6,000 passive thermoluminescent detectors and plastic nuclear track detectors, which have been exposed to cosmic radiation inside the European Space Agency MATROSHKA facility both outside and inside the ISS. In order to calculate the effective dose equivalent, a numerical model of the RANDO(®) phantom, based on computer tomography scans of the actual phantom, was developed. It was found that the effective dose equivalent rate during an EVA approaches 700 μSv/d, while during an IVA about 20 % lower values were observed. It is shown that the individual dose based on a personal dosimeter reading for an astronaut during IVA results in an overestimate of the effective dose equivalent of about 15 %, whereas under an EVA conditions the overestimate is more than 200 %. A personal dosemeter can therefore deliver quite good exposure records during IVA, but may overestimate the effective dose equivalent received during an EVA considerably.

Show MeSH
Related in: MedlinePlus