scholarly journals Dosimetric Comparison of Exposure Pathways to Human Organs and Tissues in Radon Therapy

2021 ◽  
Vol 18 (20) ◽  
pp. 10870
Author(s):  
Werner Hofmann ◽  
Herbert Lettner ◽  
Alexander Hubmer
Keyword(s):  
Thermal Bath ◽  
Basal Cells ◽  
Radon Progeny ◽  
Organ Doses ◽  
Red Bone Marrow ◽  
Therapeutic Applications ◽  
Human Organs ◽  
Exposure Pathways ◽  
Therapeutic Benefits ◽  
Skin Doses

Three therapeutic applications are presently prescribed in the radon spas in Gastein, Austria: exposure to radon in a thermal bath, exposure to radon vapor in an exposure chamber (vapor bath), and exposure to radon in the thermal gallery, a former mine. The radiological exposure pathways to human organs and tissues in these therapeutic radon applications are inhalation of radon and radon progeny via the lungs, radon transfer from water or air through the skin, and radon-progeny deposition on the skin in water or air. The objectives of the present study were to calculate radon and radon-progeny doses for selected organs and tissues for the different exposure pathways and therapeutic applications. Doses incurred in red bone marrow, liver, kidneys, and Langerhans cells in the skin may be correlated with potential therapeutic benefits, while doses to the lungs and the basal cells of the skin indicate potential carcinogenic effects. The highest organ doses among the three therapeutic applications were produced in the thermal gallery by radon progeny via inhalation, with lung doses of 5.0 mSv, and attachment to the skin, with skin doses of 4.4 mSv, while the radon contribution was less significant. For comparison, the primary exposure pathways in the thermal bath are the radon uptake through the skin, with lung doses of 334 μSv, and the radon-progeny attachment to the skin, with skin doses of 216 μSv, while the inhalation route can safely be neglected.

scholarly journals Comparative analysis of medical and dosimetric consequences of the 1957 accident and contamination of the Techa river from the perspective of protective measures efficiency

2020 ◽  
Vol 13 (1) ◽  
pp. 16-26
Author(s):  
A. V. Akleyev ◽  
M. O. Degteva ◽  
L. Yu. Krestinina
Keyword(s):  
Radiation Safety ◽  
Time Frame ◽  
Accidental Exposure ◽  
Organ Doses ◽  
Protective Measures ◽  
Red Bone Marrow ◽  
Counter Measures ◽  
Techa River ◽  
Mayak Production Association ◽  
Radioactive Trace

The paper deals with the evaluation of the efficiency of the implemented protective measures in the event of accidental exposure of the Urals region population due to radioactive contamination of the Techa River and the 1957 accident. Both of the accidents occurred in one and the same region within approximately the same time frame, and were caused by discharges of Mayak Production Association radioactive waste into the Techa River (1949–1956) and into the atmosphere (1957). Counter-measures that had been undertaken to provide radiation safety of the population differed both in nature and in timeline. Their efficiency was insufficient in the Techa River basin as they were delayed in time and were not implemented to a full extent. But countermeasures in the East Urals Radioactive Trace were much more effective according to medical and dosimetric criteria. As a result, residents of the Techa riverside settlements received much higher organ doses, including doses to red bone marrow, and health effects of accidental exposure were registered in them both soon after and long after the radiation exposure.

scholarly journals Estimation of lymphocyte radiation doses after the ingestion of radionuclides of different tropicity

2021 ◽  
Vol 14 (3) ◽  
pp. 18-28
Author(s):  
E. I. Tolstykh ◽  
M. O. Degteva ◽  
A. V. Akleyev
Keyword(s):  
Bone Marrow ◽  
T Lymphocytes ◽  
Residence Time ◽  
Chromosomal Aberrations ◽  
Lymphoid Organs ◽  
Published Data ◽  
Organ Doses ◽  
Red Bone Marrow ◽  
Circulating Lymphocytes ◽  
Dose Coefficients

Assessment of the lymphocyte doses is relevant for solving a number of radiobiological problems, including the risk assessment of hemoblastosis (leukemia, multiple myeloma, lymphoma etc.), as well as the use of circulating lymphocytes as “natural biodosimeters”. The latter is because the frequency of chromosomal aberrations occurring in lymphocytes following radiation exposure is proportional to the accumulated dose. Assessment of doses to the circulating lymphocytes requires due account of: first, the dose accumulated by the lymphocyte progenitors in the red bone marrow; and second, the dose accumulated during lymphocyte circulation through lymphoid organs. The models presented by International Commission on Radiological Protection (ICRP-67, ICRP-100) allow calculating the dose for specific lymphoid organs based on known level of radionuclide intakes. A recently developed model of circulating T-lymphocyte irradiation takes into account all sources of exposure and age-related dynamics of T-lymphocytes: (1) exposure of lymphocyte progenitors in red bone marrow: (2) exposure of T-lymphocytes in the lymphoid organs, taking into account the proportion of resident lymphocytes and the residence time of circulating lymphocytes in the specific lymphoid organs. The objective of the study is to assess the dose coefficients allowing for the transition from the ingestion of 141,144Ce, 95Zr, 103,106Ru, 95Nb to the doses accumulated in circulating T-lymphocytes. For calculations, we used the dose coefficients from ICRP publications for specific lymphoid organs, as well as published data on the residence time of circulating lymphocytes in lymphoid organs and tissues. As a result, it was shown that the doses in circulating T-lymphocytes are higher than those in the red bone marrow, but lower than the doses to the colon wall. The dose coefficients were age dependent; the maximum values were typical for newborns. The obtained dose coefficients for 141,144Ce, 95Zr, 95Nb and 103,106Ru can be used to estimate the tissue and organ doses based on data on the frequency of chromosomal aberrations in peripheral blood lymphocytes.

Gamma and beta doses in human organs due to radon progeny in human lung

2009 ◽  
Vol 135 (3) ◽  
pp. 197-202 ◽  
Author(s):  
V. M. Markovic ◽  
D. Krstic ◽  
D. Nikezic
Keyword(s):  
Human Lung ◽  
Radon Progeny ◽  
Human Organs

scholarly journals Evaluation of skin doses for cone-beam computed tomography in dentomaxillofacial imaging: A preclinical study

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254510
Author(s):  
Carolin Sophie Reidelbach ◽  
Jakob Neubauer ◽  
Maximilian Frederik Russe ◽  
Jan Kusterer ◽  
Wiebke Semper-Hogg
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Standard Dose ◽  
Repeated Measurements ◽  
Cone Beam ◽  
High Dose ◽  
Parotid Glands ◽  
Organ Doses ◽  
Significant Difference ◽  
Skin Doses

Purpose Evaluation of skin organ doses in six different cone-beam computed tomography scanners (CBCT) dedicated to dentomaxillofacial imaging. Our hypothesis is that the dose varies between different devices, protocols and skin areas. Materials and methods An anthropomorphic adult head and neck phantom was used to which a dosimeter (Waterproof Farmer® Chamber, PTW, Freiburg, Germany) was attached to anatomic landmarks of both parotid glands, both ocular lenses, the thyroid gland and the neurocranium. CBCT examinations were performed on six different CBCT devices dedicated to dentomaxillofacial imaging with standard settings and, if available, also in high dose settings. Measurements were repeated five times each. Results The measured mean skin doses ranged from 0.48 to 2.21 mGy. The comparison of the region based dose evaluation showed a high correlation between the single measurements. Furthermore, the distribution of doses between regions was similar in all devices, except that four devices showed side differences for the dose of the parotid region and one device showed side differences for the lens region. The directly exposed regions, such as the parotid glands, showed significant higher values than the more distant regions like the neurocranium. When comparing examination protocols, a significant difference between the standard dose and the high dose acquisitions could be detected. But also a significant dose difference between the different CBCTs could be shown. 3D Accuitomo 170 (Morita, Osaka, Japan) showed the highest absorbed mean dose value for standard settings with 2.21 mGy, especially at the directly exposed regions and their adjacent organs. The lowest mean value for standard settings was achieved with VGi evo (NewTom, Verona, Italy) with 0.48 mGy. Conclusion Repeated measurements of skin organ doses in six different CBCT scanners using a surface dosimeter showed side differences in distribution of dose in five devices for the parotid and lens region. Additionally, significant dose differences between the devices could be detected. Further studies should be performed to confirm these results.

PATIENT-SPECIFIC ORGAN DOSES FROM PEDIATRIC HEAD CT EXAMINATIONS

2020 ◽  
Vol 191 (1) ◽  
pp. 1-8
Author(s):  
W J Garzón ◽  
D F A Aldana ◽  
V F Cassola
Keyword(s):  
Absorbed Dose ◽  
Organ Dose ◽  
Patient Specific ◽  
Specific Information ◽  
Organ Doses ◽  
Red Bone Marrow ◽  
Head Ct ◽  
Absorbed Doses ◽  
Specific Organ ◽  
Conversion Coefficients

Abstract The aim of this work was to estimate patient’s organ absorbed doses from pediatric helical head computed tomography (CT) examinations using the Size-Specific Dose Estimate (SSDE) methodology and to determine organ dose to SSDE conversion coefficients for clinical routine. Patient-specific organ and tissue absorbed doses from 139 Head CT scans performed in pediatric patients from 0 to 15 years old in a Public Hospital in Tunja, Colombia were estimated. The calculations were made through Monte Carlo simulations, based on patient-specific information, dosimetric CT quantities (CTDIvol, DLP) and age-specific computational human phantoms matched to patients on the basis of gender and size. SSDE showed to be a good quantity for estimate patient-specific organ doses from pediatric head CT examinations when appropriate phantom’s attenuation-based size metrics are chosen to match for any patient size. Strong correlations between absorbed dose and SSDE were found for skin (R2 = 0.99), brain (R2 = 0.98) and eyes (R2 = 0.97), respectively. Besides, a good correlation between SSDE and absorbed dose to the red bone marrow (tissue extended outside the scan coverage) was observed (R2 = 0.94). SSDE-to-organ-dose conversion coefficients obtained in this study provide a practical way to estimate patient-specific organ head CT doses.

DIAGNOSIS OF CHRONIC RADIATION SYNDROME AT THE EARLY STAGE

2021 ◽  
Vol 65 (5) ◽  
pp. 21-28
Author(s):  
A. Akleev
Keyword(s):  
Dose Rate ◽  
Clinical Picture ◽  
Early Stage ◽  
Morphological Changes ◽  
Clinical Manifestations ◽  
Absorbed Dose ◽  
Postnatal Exposure ◽  
Organ Doses ◽  
Red Bone Marrow ◽  
Chronic Radiation

Purpose: To describe early symptoms of chronic radiation syndrome (CRS) which is of utmost importance for diagnosing this rare radiation pathology in man. Material and methods: The paper presents the findings of retrospective analysis of early clinical manifestations of chronic radiation syndrome (CRS) based on the data of a long-term medical follow up of the residents of the Techa riverside communities. Mean doses of postnatal exposure to red bone marrow in patients with CRS calculated with TRDS-2016D were 698.8±18.2 mGy, maximum doses were 3 603.9 mGy. Results: Clinical picture of the CRS at the early stage was characterized by a set of non-specific changes including hematological, immune, neurological, and endocrine ones, as well as impairment of functions of a number of internal organs. The above-mentioned CRS symptoms developed in a certain sequence and depended on dose rate and absorbed dose to the organs. Prior to the development of a full-scale CRS clinical picture patients had a decrease in olfactory and taste thresholds, in vibration sensitivity, and changes in systemic immunity. Impairment of hematopoiesis, nervous and endocrine systems were also noted even at the early stage of CRS. Initial CRS changes were moderate and transient. The analysis of early CRS symptoms allows assuming that early CRS stage is a dysregulation pathology that is caused initially by radiation-induced disorders of immunohematopoiesis, nervous and endocrine systems. Visceral changes at the early CRS stage are secondary and functional. If exposure is terminated, they are reversible. However, if exposure continues at doses high enough to cause morphological changes in organs and tissues (dystrophy, fibrosis, hypoplasia, etc.), CRS course worsens and becomes irreversible. Conclusion: It was demonstrated that CRS diagnosis at the early stage is very complicated. The key issue is to analyze the relationship of specific CRS symptoms development and dose rate and absorbed organ doses.

Determination of Entrance Skin Doses and Organ Doses for Medical X Ray Examinations

1999 ◽  
Vol 85 (1) ◽  
pp. 417-420 ◽  
Author(s):  
C.J. Tung ◽  
C.Y. Cheng ◽  
T.C. Chao ◽  
H.Y. Tsai
Keyword(s):  
Organ Doses ◽  
X Ray ◽  
Skin Doses

The structure of the gills of the axolotl, Ambystoma mexicanum

1987 ◽  
Vol 45 ◽  
pp. 824-825
Author(s):  
Mohinder S. Jarial
Keyword(s):  
Leydig Cells ◽  
Secretory Granules ◽  
Light And Electron Microscopy ◽  
Cell Types ◽  
Ambystoma Mexicanum ◽  
Basal Cells ◽  
Granular Cells ◽  
Gill Filaments ◽  
Mitotic Figures ◽  
Apical Membranes

The axolotl is a strictly aquatic salamander in which the larval external gills are retained throughout life. The external gills of the adult axolotl have been studied by light and electron microscopy for ultrastructural evidence of ionic transport. The thin epidermis of the gill filaments and gill stems is composed of 3 cell types: granular cells, the basal cells and a sparce population of intervening Leydig cells. The gill epidermis is devoid of muscles, and no mitotic figures were observed in any of its cells.The granular cells cover the gill surface as a continuous layer (Fig. 1, G) and contain secretory granules of different forms, located apically (Figs.1, 2, SG). Some granules are found intimately associated with the apical membrane while others fuse with it and release their contents onto the external surface (Fig. 3). The apical membranes of the granular cells exhibit microvilli which are covered by a PAS+ fuzzy coat, termed “glycocalyx” (Fig. 2, MV).

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