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![Thoron decay scheme [1, 2].](profile/Uwe_Oeh/publication/260319413/figure/fig1/AS:669537787711493@1536641656452/Thoron-decay-scheme-1-2.png)
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![Figure 1: Thoron decay scheme [1, 2].](profile/Uwe_Oeh/publication/260319413/figure/fig1/AS:669537787711493@1536641656452/Thoron-decay-scheme-1-2_Q320.jpg)
The lung dose contributed from thoron (220 Rn) and its progeny was usually neglected in the dose assessment because of the generally low concentrations. Recently, increased concentrations of 220 Rn and its progeny were measured in the traditional residential dwellings in China, in dwellings in India and in other countries. The potential alpha energ...
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... ( 220 Rn) is a radioactive noble gas formed by the decay of 224 Ra in the 232 Th decay series. 220 Rn has a half-life of 55.6 s, much shorter in comparison to 3.8 d of radon ( 222 Rn). 220 Rn decays through the short-lived daughters 216 Po, 212 Pb, 212 Bi, 212 Po and 208 Tl to the stable nuclide 208 Pb (Fig. 1). The main energies and yields of 220 Rn and its decay products are presented in Table 1. The lung and other organ doses contributed from 220 Rn and its progeny were usually neglected in the dose assessment because of generally low concentrations. Recently, increased concentrations of 220 Rn and its progeny were measured in the ...
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... In the biokinetic modeling, the most key organs and tissues are involved according to the human biokinetic models, including the radionuclide-specific systemic models (ICRP, 1995;1993b;1980), the human respiratory tract model (ICRP, 1994b) and the human alimentary tract model (ICRP, 1979). The developed biokinetic model structure is shown in Figure 3 and this model has been successfully applied in the estimation of the dose conversion inhalation factors of radon and thoron progeny for the public population of different age and sex (Li et al., 2008;Bi et al., 2010;Brudecki et al., 2014). In this present work, we used these dose conversion factors to calculate the age dependent doses for different human organs at different age groups and sex. ...
In the assessment of health effects due to inhalation of radon and thoron progeny aerosols, particle size is one of the most influential parameters. Therefore, the present work aimed at deposition of inhaled particles in different body organs (bone surfaces, spleen, breast, stomach, kidneys, lungs, liver, and ET airways) from radon and thoron progeny concentration were calculated taking into account eight age and sex groups for the inhibitors of Reasi district, Jammu & Kashmir, India. The estimated age dependent mean doses for different body organs due to inhalation of radon progeny through air for all age groups varied between 1.05E-08 and 0.08 n Svy − 1 and due to inhalation of thoron progeny varied between 7.72E-08 and 6.52E-04 Svy − 1 which were found to be well within the recommended limit of 1000 µSvy − 1 (ICRP 2010). The percentage contribution of thoron progeny dose is negligible for spleen, brain, stomach ULI, and LLI, respectively and contributes only 1–4% to bone surfaces, kidneys, and liver for all age groups. However, The percentage contribution of radon progeny dose is negligible for all body organs except lungs and ET airways, respectively. A good positive correlation has been observed between all radon and thoron progeny concentrations.
... The SAAM II software (Epsilon group, USA) was used in the modeling. This method has been successfully used many times in previous studies (Li et al. 2008;Brudecki et al. 2014Brudecki et al. , 2017aBrudecki et al. , 2017bBrudecki et al. , 2018aBrudecki et al. , 2018bBrudecki et al. , 2019Brudecki et al. , 2020. ...
This paper presents results of measurements of 99m Tc activity concentration in air and nuclear medical personnel blood during ventilation–perfusion SPECT lung scans. 99m Tc activity measurements were conducted at the Nuclear Medicine Department, John Paul II Hospital, Krakow. Technicians and nurses who perform examinations were equipped with personal aspirators enabling air sampling to determine the radiation exposure at their workplaces. Measurements allowed to evaluate the concentration of 99m Tc in 14 air samples and it ranged from 7800 ± 600 to 10,000 ± 1000 Bq m ⁻³ for air samples collected by technicians and from 390 ± 30 to 600 ± 40 Bq m ⁻³ for air samples collected by nurses. In addition 99m Tc concentrations in blood of medical personnel were determined in 24 samples. For technicians the maximum 99m Tc blood concentration levels reached 920 ± 70 Bq L ⁻¹ and 1300 ± 100 Bq L ⁻¹ . In the case of nurses, the maximum estimated activity concentrations were about ten times lower, namely 71 ± 7 Bq L ⁻¹ and 39 ± 3 Bq L ⁻¹ . Although the intakes appear to be relatively high, the resulting annual effective doses are about 34 µSv for technicians and only 2 µSv for nurses.
... However, the summation effective dose rate ERn (Sv.h -1 ) received from radon decay products is: Tables 3 and 6, it is clear that the values of ERn based on the HRTM due to the processing of the studied minerals are almost twice that obtained epidemiologically. This difference is explained considering that the radiation weighting factor used for alpha particles is 20 in the biokintic models while the relative biological effectiveness of alpha particles based on the epidemiology is closer to 10 than 20 [12,[16][17][18]. Figure (4 biokinetic models with the activity A (kBq) of the processed radioactive minerals. The slopes of the two lines represent the additive effective dose rate ESRn (Sv.h -1 .kBq ...
The additive effective dose rates from the radioactive gases radon and thoron and their decay products were evaluated at the laboratories of the minerals; ilmenite, zircon, monazite and rutile. Two types of concentration-effective dose conversion factors were employed; factors resulted from epidemiological studies and those obtained by the Human Respiratory Tract Model (HRTM). Based on HRTM, the additive effective dose rates from radon and thoron gases were found to be 5.84x10-9 and 1.58x10-9 (Sv.h-1 .kBq-1), respectively. No significant difference found between the additive effective doses received from thoron gas estimated by the two methods while the value of the additive effective dose rate estimated for radon gas by HRTM factors is almost twice that obtained by the epidemiological factor. The additive effective dose rates received from the radioactive gases radon and thoron and their individual progenies are constants and they are used to estimate the effective dose rates at the environments of these gases directly from the known activity of the processed mineral. On the average, the additive effective dose rate received from each of the three radon decay products 218 Po, 214 Pb and 214 Bi is 1.95x10-9 (Sv.h-1 .kBq-1) at the common ventilation rate 1 (h-1).
... Finally, doses were calculated based on the time-integrated 99m Tc activity (model of technetium biokinetics and computer simulations), radiation-weighted coefficients (SECALL program, Oak Ridge National Laboratory, Oak Ridge, TN, USA) and tissue-weighting factors according to the ICRP methodology (ICRP 2007). More details on the applied methodology of absorbed dose calculations are given in Li et al. (2008) and Brudecki et al. (2014Brudecki et al. ( , 2017aBrudecki et al. ( , b, 2018a. ...
This paper presents the results of measurements of 99mTc activity concentrations in indoor air in a nuclear medicine department and resulting estimated 99mTc intake by medical personnel. 99mTc air activity measurements were conducted at the Nuclear Medicine Department, John Paul II Hospital, Krakow, Poland, during ventilation–perfusion SPECT lung scans. Technetium from the air was collected by means of a mobile aerosol sampler with a Petryanov filter operating at an average flow rate of 10 dm3 min−1. Measured activities ranged from 99 ± 11 to 6.1 ± 0.5 kBq m−3. The resulting daily average intake of 99mTc by medical staff was estimated to be 5.4 kBq, 4.4 kBq, 3.0 kBq and 2.5 kBq, respectively, for male technicians, female technicians, male nurses and female nurses. Corresponding annual effective doses were 1.6 µSv for technicians and 1 µSv for nurses. The highest equivalent dose values were determined for extrathoracic (ET) airways: 5 µSv and 10 µSv for nurses and technicians, respectively. It is concluded that estimated annual absorbed doses are over three orders of magnitude lower than the dose limit established in the Polish Atomic Law Act and in recommendations of the International Commission on Radiological Protection for medical staff.
... To describe the behaviour of the inhaled 131 I in the human body and iodine accumulation in organs and tissues, the systemic biokinetic compartment model by Leggett (2010), the HRTM, and GITM were combined together into a onecompartment model. Such a solution has already been successfully applied for calculation of doses due to inhalation of indoor short-lived radon (both 222 Rn and 220 Rn) progenies for members of the public (Lie et al. 2008;Brudecki et al. 2014). The model is based on three subsystems for extrathyroidal inorganic iodine, thyroidal iodine, and extrathyroidal organic iodine. ...
A general method for calculating doses absorbed from isotopes released in nuclear accidents is presented. As an example, this method was used to calculate doses for inhabitants of Southern Poland due to inhalation of ¹³¹I released due to the Fukushima nuclear plant accident. ¹³¹I activity measurements in the air of that region provided the basis for the study. The proposed model is based on a complex biokinetic model for iodine merging the Leggett model developed in 2010 with the human respiratory tract and gastrointestinal tract models recommended by the International Commission on Radiological Protection (ICRP). This model is described here, and it is demonstrated that resulting dose estimates are consistent with those obtained using the ICRP methodology. Using the developed model, total doses were calculated for six age groups of both genders, for gaseous and aerosol fractions alike. The committed effective dose, H50, for an adult man reached 16 nSv, which is lower than 0.001% of the background dose. The dose for the thyroid of an adult reached 0.33 μSv, which corresponds to circa 0.0007% of the dose to the population of Southern Poland after the Chernobyl nuclear plant accident.
... A low fraction unattached (<0.02) is assumed for most DCFs (UNSCEAR, 2006), but it is known that the DCF increases very rapidly when the unattached fraction increase (Nikezic et al., 2010;Porstend€ orfer, 2001). For example, unattached TnP with an activity median thermodynamic diameter (AMTD) of 1.5 nm would give a 7.7 times higher dose coefficient when calculating the effective dose as compared with attached thoron progeny of an activity median aerodynamic diameter (AMAD) of 300 nm (Li et al., 2010). Considering that a portion of the radionuclides in the investigated area may originate from air ventilated from the mines or flowing out through the drainage pipe, as indicated by the in situ measurements, a higher fraction of unattached TnP could be anticipated to be associated with air from the mines. ...
Radon (222Rn), thoron (220Rn) and their decay products may reach high levels in areas of high natural background radiation, with increased risk associated with mining areas. Historically, the focus has mostly been placed upon radon and progeny (RnP), but recently there have been reports of significant contributions to dose from thoron progeny (TnP). However, few direct measurements of TnP exist under outdoor conditions. Therefore, we assessed the outdoor activity concentrations of radon, thoron and TnP in an area of igneous bedrock with extreme levels of radionuclides in the thorium decay series. The area is characterized by decommissioned mines and waste rock deposits, which provide a large surface area for radon and thoron emanation and high porosity enhancing exhalation. Extreme levels of thorium and thoron have previously been reported from this area and to improve dose rate estimates we also measured TnP using filter sampling and time-integrating alpha track detectors. We found high to extreme levels of thoron and TnP and the associated dose rates relevant for inhalation were up to 8 μSvh−1 at 100 cm height. Taking gamma irradiation and RnP into account, significant combined doses may result from occupancies in this area. This applies to recreational use of the area and especially previous and planned road-works, which in the worst case could involve doses as large as 23.4 mSv y−1. However, radon and thoron levels were much more intense on a hot September day than during time-integrated measurements made the subsequent colder and wetter month, especially along the ground. This may be explained by cold air observed flowing out from inside the mines through a drainage pipe adjacent to the measurement stations. During warm periods, activity concentrations may therefore be due to both local exhalation from the ground and air ventilating from the mines. However, a substantially lower level of TnP was measured on the September day using filter sampling, as compared to what was measured with time-integrative alpha track detectors. A possible explanation could be reduced filter efficiency related to the attached progeny of some aerosol sizes, but a more likely cause is an upwards bias on TnP detectors associated with assumed deposition velocity, which may be different in outdoor conditions with wind or a larger fraction of unattached progeny. There is thus a need for better instrumentation when dealing with outdoor TnP.
... During inhalation, the deposition of unattached and attached atoms of 212 Pb depends on the particle size. The unattached atoms pass the upper respiratory tract, therefore deposited in the alveoli, and then are subject to somatic transport processes (Steinhäusler, 1996;Tschiersch et al., 2007;Li et al., 2008) while the attached atoms are likely to pass the upper respiratory tract and to leave the alveoli during exhalation (James et al., 1991). Therefore, for estimation of the dose equivalent (for the epithelium of the bronchi) by inhalation the activity size distribution and the actual concentration of unattached and attached 212 Pb is an important parameter. ...
... Note that the systemic models for different progeny are independent, and accordingly, the structure and parameters of biokinetic models for different progeny are therefore different. This general compartment model has already been successfully applied for the estimation of doses due to inhalation of thoron progeny for the public population of different age and sex (Li et al. 2008a;Bi et al. 2010) and for adults exposed to radon progeny (Al- Jundi et al. 2011). This general inhalation biokinetic model was also used to predict the retention and excretion after inhalation of aerosols of depleted uranium (Li et al. 2008b). ...
The main contribution of radiation dose to the human lungs from natural exposure originates from short-lived radon progeny. In the present work, the inhalation doses from indoor short-lived radon progeny, i.e., (218)Po, (214)Pb, (214)Bi, and (214)Po, to different age groups of members of the public were calculated. In the calculations, the age-dependent systemic biokinetic models of polonium, bismuth, and lead published by the International Commission on Radiological Protection (ICRP) were adopted. In addition, the ICRP human respiratory tract and gastrointestinal tract models were applied to determine the deposition fractions in different regions of the lungs during inhalation and exhalation, and the absorption fractions of radon progeny in the alimentary tract. Based on the calculated contribution of each progeny to equivalent dose and effective dose, the dose conversion factor was estimated, taking into account the unattached fraction of aerosols, attached aerosols in the nucleation, accumulation and coarse modes, and the potential alpha energy concentration fraction in indoor air. It turned out that for each progeny, the equivalent doses to extrathoracic airways and the lungs are greater than those to other organs. The contribution of (214)Po to effective dose is much smaller compared to that of the other short-lived radon progeny and can thus be neglected in the dose assessment. In fact, 90 % of the effective dose from short-lived radon progeny arises from (214)Pb and (214)Bi, while the rest is from (218)Po. The dose conversion factors obtained in the present study are 17 and 18 mSv per working level month (WLM) for adult female and male, respectively. This compares to values ranging from 6 to 20 mSv WLM(-1) calculated by other investigators. The dose coefficients of each radon progeny calculated in the present study can be used to estimate the radiation doses for the population, especially for small children and women, in specific regions of the world exposed to radon progeny by measuring their concentrations, aerosol sizes, and unattached fractions.
... Volunteer studies in which subjects have Table 3.4. Summary of calculated effective dose conversion coefficients (mSv WLM 21 ) for thoron progeny indoors based on adult male breathing conditions (ICRP, 2010;Li et al., 2010) References ...
... Science of the Total Environment 435-436 (2012) 578-579 To illustrate this diverging behavior of both nuclides, we calculated with the room model of Porstendörfer (1994) attached and unattached radon and thoron indoor decay product concentrations under different filtration rate φ and aerosol concentration c, whereas the attachment rate to aerosol particles β = 7.9 · 10 −7 cm 3 /s and the air exchange rate aer = 0.3 h −1 were kept constant. Resulting inhalation doses were calculated with dose coefficients DC taken from Kendall and Smith (2002) and Li et al. (2008). Assuming the initial room conditions are given as φ 0 = 0 and c 0 = 8000 cm −3 , then the relative dose R is expressed as the ratio ...
