G(Fe3+) values in the FBX dosimeter at low dose-rates

1985 ◽  
Vol 36 (12) ◽  
pp. 985-987 ◽  
Author(s):  
B.L. Gupta ◽  
U. Madhvanath
Keyword(s):  
Low Dose ◽  
Dose Rates

Ovarian Dysfunction in Fetally Irradiated Beagles

1977 ◽  
Vol 35 ◽  
pp. 658-659
Author(s):  
T. M. Seed ◽  
M. H. Sanderson ◽  
D. L. Gutzeit ◽  
T. E. Fritz ◽  
D. V. Tolle ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Low Dose ◽  
Long Term Effects ◽  
Ovarian Dysfunction ◽  
Dose Rates ◽  
Highly Sensitive ◽  
Microscopic Evaluation ◽  
Ovarian Pathology ◽  
Normal Offspring

The developing mammalian fetus is thought to be highly sensitive to ionizing radiation. However, dose, dose-rate relationships are not well established, especially the long term effects of protracted, low-dose exposure. A previous report (1) has indicated that bred beagle bitches exposed to daily doses of 5 to 35 R 60Co gamma rays throughout gestation can produce viable, seemingly normal offspring. Puppies irradiated in utero are distinguishable from controls only by their smaller size, dental abnormalities, and, in adulthood, by their inability to bear young.We report here our preliminary microscopic evaluation of ovarian pathology in young pups continuously irradiated throughout gestation at daily (22 h/day) dose rates of either 0.4, 1.0, 2.5, or 5.0 R/day of gamma rays from an attenuated 60Co source. Pups from non-irradiated bitches served as controls. Experimental animals were evaluated clinically and hematologically (control + 5.0 R/day pups) at regular intervals.

scholarly journals Serum Metabolomic Alterations Associated with Cesium-137 Internal Emitter Delivered in Various Dose Rates

Metabolites ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 270
Author(s):  
Heng-Hong Li ◽  
Yun-Tien Lin ◽  
Evagelia C. Laiakis ◽  
Maryam Goudarzi ◽  
Waylon Weber ◽  
...  
Keyword(s):  
Dose Rate ◽  
Cumulative Dose ◽  
Low Dose ◽  
Biological Effects ◽  
Serum Samples ◽  
Dose Rates ◽  
Sphingosine 1 Phosphate ◽  
Cesium 137 ◽  
Dose Rate Effect ◽  
Medium Dose

Our laboratory and others have use radiation metabolomics to assess responses in order to develop biomarkers reflecting exposure and level of injury. To expand the types of exposure and compare to previously published results, metabolomic analysis has been carried out using serum samples from mice exposed to 137Cs internal emitters. Animals were injected intraperitoneally with 137CsCl solutions of varying radioactivity, and the absorbed doses were calculated. To determine the dose rate effect, serum samples were collected at 2, 3, 5, 7, and 14 days after injection. Based on the time for each group receiving the cumulative dose of 4 Gy, the dose rate for each group was determined. The dose rates analyzed were 0.16 Gy/day (low), 0.69 Gy/day (medium), and 1.25 Gy/day (high). The results indicated that at a cumulative dose of 4 Gy, the low dose rate group had the least number of statistically significantly differential spectral features. Some identified metabolites showed common changes for different dose rates. For example, significantly altered levels of oleamide and sphingosine 1-phosphate were seen in all three groups. On the other hand, the intensity of three amino acids, Isoleucine, Phenylalanine and Arginine, significantly decreased only in the medium dose rate group. These findings have the potential to be used in assessing the exposure and the biological effects of internal emitters.

Electron-beam radiation effects on the structure and properties of polypropylene at low dose rates

2018 ◽  
Vol 29 (6) ◽  
Author(s):  
Heng-Ti Wang ◽  
Hai-Qing Jiang ◽  
Rong-Fang Shen ◽  
Xiao-Jun Ding ◽  
Cong Zhang ◽  
...  
Keyword(s):  
Electron Beam ◽  
Radiation Effects ◽  
Low Dose ◽  
Structure And Properties ◽  
Beam Radiation ◽  
Dose Rates ◽  
Electron Beam Radiation

scholarly journals A systems biology approach reveals neuronal and muscle developmental defects after chronic exposure to ionising radiation in zebrafish

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Sophia Murat El Houdigui ◽  
Christelle Adam-Guillermin ◽  
Giovanna Loro ◽  
Caroline Arcanjo ◽  
Sandrine Frelon ◽  
...  
Keyword(s):  
Chronic Exposure ◽  
Nuclear Power ◽  
Muscle Development ◽  
Low Dose ◽  
Neuromuscular Junctions ◽  
Biological Effects ◽  
Cardiac Activity ◽  
Developmental Defects ◽  
Dose Rates ◽  
Larval Behaviour

AbstractContamination of the environment after the Chernobyl and Fukushima Daiichi nuclear power plant (NPP) disasters led to the exposure of a large number of humans and wild animals to radioactive substances. However, the sub-lethal consequences induced by these absorbed radiological doses remain understudied and the long-term biological impacts largely unknown. We assessed the biological effects of chronic exposure to ionizing radiation (IR) on embryonic development by exposing zebrafish embryo from fertilization and up to 120 hours post-fertilization (hpf) at dose rates of 0.5 mGy/h, 5 mGy/h and 50 mGy/h, thereby encompassing the field of low dose rates defined at 6 mGy/h. Chronic exposure to IR altered larval behaviour in a light-dark locomotor test and affected cardiac activity at a dose rate as low as 0.5 mGy/h. The multi-omics analysis of transcriptome, proteome and transcription factor binding sites in the promoters of the deregulated genes, collectively points towards perturbations of neurogenesis, muscle development, and retinoic acid (RA) signaling after chronic exposure to IR. Whole-mount RNA in situ hybridization confirmed the impaired expression of the transcription factors her4.4 in the central nervous system and myogenin in the developing muscles of exposed embryos. At the organ level, the assessment of muscle histology by transmission electron microscopy (TEM) demonstrated myofibers disruption and altered neuromuscular junctions in exposed larvae at 5 mGy/h and 50 mGy/h. The integration of these multi-level data demonstrates that chronic exposure to low dose rates of IR has an impact on neuronal and muscle progenitor cells, that could lead to motility defects in free swimming larvae at 120 hpf. The mechanistic understanding of these effects allows us to propose a model where deregulation of RA signaling by chronic exposure to IR has pleiotropic effects on neurogenesis and muscle development.

Evidence for dose and dose rate effects in human and animal radiation studies

2018 ◽  
Vol 47 (3-4) ◽  
pp. 97-112 ◽  
Author(s):  
M.P. Little
Keyword(s):  
Dose Rate ◽  
Dose Response ◽  
Low Dose ◽  
Atomic Bomb ◽  
Dose Range ◽  
Quadratic Model ◽  
Linear Quadratic ◽  
Dose Rates ◽  
Atomic Bomb Survivors ◽  
Linear Quadratic Model

For stochastic effects such as cancer, linear-quadratic models of dose are often used to extrapolate from the experience of the Japanese atomic bomb survivors to estimate risks from low doses and low dose rates. The low dose extrapolation factor (LDEF), which consists of the ratio of the low dose slope (as derived via fitting a linear-quadratic model) to the slope of the straight line fitted to a specific dose range, is used to derive the degree of overestimation (if LDEF > 1) or underestimation (if LDEF < 1) of low dose risk by linear extrapolation from effects at higher doses. Likewise, a dose rate extrapolation factor (DREF) can be defined, consisting of the ratio of the low dose slopes at high and low dose rates. This paper reviews a variety of human and animal data for cancer and non-cancer endpoints to assess evidence for curvature in the dose response (i.e. LDEF) and modifications of the dose response by dose rate (i.e. DREF). The JANUS mouse data imply that LDEF is approximately 0.2–0.8 and DREF is approximately 1.2–2.3 for many tumours following gamma exposure, with corresponding figures of approximately 0.1–0.9 and 0.0–0.2 following neutron exposure. This paper also cursorily reviews human data which allow direct estimates of low dose and low dose rate risk.

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