Physics From the News — Fukushima Daiichi: Radiation Doses and Dose Rates

2011 ◽  
Vol 49 (6) ◽  
pp. 330-330
Author(s):  
A. A. Bartlett
Keyword(s):  
Radiation Doses ◽  
Dose Rates ◽  
Fukushima Daiichi

scholarly journals Intraoperative 2D C-arm and 3D O-arm in children: a comparative phantom study

2018 ◽  
Vol 12 (5) ◽  
pp. 550-557 ◽  
Author(s):  
M. Prod’homme ◽  
M. Sans-Merce ◽  
N. Pitteloud ◽  
J. Damet ◽  
P. Lascombes
Keyword(s):  
Radiation Exposure ◽  
Scattered Radiation ◽  
Intraoperative Imaging ◽  
Radiation Doses ◽  
Organ Doses ◽  
Thermoluminescent Dosimeters ◽  
Dose Rates ◽  
Absorbed Doses ◽  
Entrance Dose ◽  
Student’S T

Purpose Exposure to ionizing radiation is a concern for children during intraoperative imaging. We aimed to assess the radiation exposure to the paediatric patient with 2D and 3D imaging. Methods To evaluate the radiation exposure, patient absorbed doses to the organs were measured in an anthropomorphic phantom representing a five-year-old child, using thermoluminescent dosimeters. For comparative purposes, organ doses were measured using a C-arm for one minute of fluoroscopy and one acquisition with an O-arm. The cone-beam was centred on the pelvis. Direct and scattered irradiations were measured and compared (Student’s t-test). Skin entrance dose rates were also evaluated. Results All radiation doses were expressed in µGy. Direct radiation doses of pelvic organs were between 631.22 and 1691.87 for the O-arm and between 214.08 and 737.51 for the C-arm, and were not significant (p = 0.07). Close scattered radiation on abdominal organs were between 25.11 and 114.85 for the O-arm and between 8.03 and 55.34 for the C-arm, and were not significant (p = 0.07). Far scattered radiation doses on thorax, neck and head varied from 0.86 to 6.42 for the O-arm and from 0.04 to 3.08 for the C-arm, and were significant (p = 0.02). The dose rate at the skin entrance was 328.58 µGy.s−1 for the O-arm and 1.90 with the C-arm. Conclusion During imaging of the pelvis, absorbed doses for a 3D O-arm acquisition were higher than with one minute fluoroscopy with the C-arm. Further clinical studies comparing effective doses are needed to assess ionizing risks of the intraoperative imaging systems in children.

Release rate estimation of both long- and short-lived radionuclides for the Fukushima Daiichi nuclear accident based on local-scale observations

2020 ◽  
Author(s):  
Sheng Fang ◽  
Xinpeng Li ◽  
Shuhan Zhuang
Keyword(s):  
Release Rate ◽  
Source Term ◽  
A Priori ◽  
Regional Scale ◽  
Local Scale ◽  
Gamma Dose ◽  
Nuclear Accident ◽  
Dose Rates ◽  
Gamma Dose Rates ◽  
Fukushima Daiichi

<p>Many efforts have been devoted to estimate the release rate of the radionuclide emission in the Fukushima Daiichi nuclear accident using regional scale observations. Because of the radioactive decay, regional scale observations may not provide information of short-lived radionuclides, which contributes the majority of radiation exposure in the early stage. In this study, the local-scale gamma dose rates data were used to estimate the atmospheric release rates of both long- and short-lived radio nuclides.The proposed method uses reactor physics to obtain an a priori radionuclide composition and a reverse source term estimate as an a priori release rate. A weighted additive model is developed, which uses the local-scale gamma dose rates to handle the conflicts between the two priors and to simultaneously incorporate them into the source inversion. The proposed method is validated against both the local-scale gamma dose rates and the regional concentration measurements of Cs-137. The results prove that the retrieved a posteriori source term combines the advantages of both priors and substantially improves the predictions of the on-site gamma dose rates. Given a detailed priori release rate, this approach also improves the regional predictions of both airborne and deposited Cs-137 concentrations.</p>

Radiolysis of dilute aqueous thiourea solutions

1966 ◽  
Vol 292 (1428) ◽  
pp. 122-133 ◽  
Keyword(s):  
Aqueous Solution ◽  
Dose Rate ◽  
Direct Effect ◽  
Indirect Effect ◽  
Radiation Doses ◽  
Limited Extent ◽  
Γ Radiation ◽  
Low Concentration ◽  
Dose Rates ◽  
Rapid Destruction

Thiourea, when present at low concentration, can act as a radiation protector to macromolecules (biological or polymeric) in aqueous solution. Previous work has shown that much of this protection occurs against the indirect effect. Thiourea can also protect against the direct effect, though to a more limited extent. In this paper the reactions of dilute aqueous thiourea solutions have been followed at a range of γ radiation doses and dose rates, and in the absence and presence of oxygen. The rapid destruction of thiourea confirms that the effect is primarily indirect, and almost independent of concentration, and dose rate over the range 10 to 500 mg/1. The breakdown products of thiourea can react further. In the presence of oxygen the loss of thiourea is more rapid, and different products are formed.

scholarly journals Radiation dose rates now and in the future for residents neighboring restricted areas of the Fukushima Daiichi Nuclear Power Plant

2014 ◽  
Vol 111 (10) ◽  
pp. E914-E923 ◽  
Author(s):  
Kouji H. Harada ◽  
Tamon Niisoe ◽  
Mie Imanaka ◽  
Tomoyuki Takahashi ◽  
Katsumi Amako ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Radiation Dose ◽  
Radiation Exposure ◽  
Dose Rate ◽  
Nuclear Power ◽  
Solid Cancer ◽  
External Dose ◽  
Dose Rates ◽  
Fukushima Daiichi

Radiation dose rates were evaluated in three areas neighboring a restricted area within a 20- to 50-km radius of the Fukushima Daiichi Nuclear Power Plant in August–September 2012 and projected to 2022 and 2062. Study participants wore personal dosimeters measuring external dose equivalents, almost entirely from deposited radionuclides (groundshine). External dose rate equivalents owing to the accident averaged 1.03, 2.75, and 1.66 mSv/y in the village of Kawauchi, the Tamano area of Soma, and the Haramachi area of Minamisoma, respectively. Internal dose rates estimated from dietary intake of radiocesium averaged 0.0058, 0.019, and 0.0088 mSv/y in Kawauchi, Tamano, and Haramachi, respectively. Dose rates from inhalation of resuspended radiocesium were lower than 0.001 mSv/y. In 2012, the average annual doses from radiocesium were close to the average background radiation exposure (2 mSv/y) in Japan. Accounting only for the physical decay of radiocesium, mean annual dose rates in 2022 were estimated as 0.31, 0.87, and 0.53 mSv/y in Kawauchi, Tamano, and Haramachi, respectively. The simple and conservative estimates are comparable with variations in the background dose, and unlikely to exceed the ordinary permissible dose rate (1 mSv/y) for the majority of the Fukushima population. Health risk assessment indicates that post-2012 doses will increase lifetime solid cancer, leukemia, and breast cancer incidences by 1.06%, 0.03% and 0.28% respectively, in Tamano. This assessment was derived from short-term observation with uncertainties and did not evaluate the first-year dose and radioiodine exposure. Nevertheless, this estimate provides perspective on the long-term radiation exposure levels in the three regions.

Radiation doses deriving from patients treated with 166Ho-ferric hydroxide

2003 ◽  
Vol 42 (06) ◽  
pp. 251-254
Author(s):  
C. Pirich ◽  
P. John ◽  
S. Ofluoglu ◽  
H. Sinzinger ◽  
E. Havlik ◽  
...  
Keyword(s):  
Radiation Exposure ◽  
Radiation Protection ◽  
Ferric Hydroxide ◽  
Medical Personnel ◽  
Whole Body ◽  
Radiation Doses ◽  
Annual Dose ◽  
Tracer Injection ◽  
Dose Rates ◽  
Protection Devices

Summary Aim: To estimate radiation doses deriving from patients treated with 166Ho ferric hydroxide. Methods: For radiation synoviorthesis about 900 ± 100 MBq 166Ho ferric hydroxide was injected into the knee joint of 16 patients. To estimate the radiation exposure of persons in the neighbourhood of the patients measurements of the dose rates were performed at 0.5 m, 1 m and 2 m distance of the treated joint 10 min after tracer injection. Measurements were carried out with and without radiation protection devices of the syringe. Results: The initial values of the dose rate were 11.9 μSv/h at 0.5 m, 3.5 μSv/h at 1 m and 1 μSv/h at 2 m distance, respectively. The whole body doses were 2.9 μSv for the physician and 4.6 μSv for the technologist. The finger doses for the technologist and the physician were ranging from 65 to 111 μSv. After discharge at home other persons might receive 118 μSv. Conclusion: Our results, under very strict assumptions, clearly demonstrate that the calculated radiation exposure to medical and non medical personnel is well below the maximum annual dose limit. The use of any additional radiation protection device as syringe shielding does not significantly lower radiation exposure.

CHANGES OF ABSORBED DOSE RATE IN AIR BY CAR-BORNE SURVEY IN NAMIE TOWN, FUKUSHIMA PREFECTURE AFTER THE FUKUSHIMA DAIICHI NUCLEAR POWER PLANT ACCIDENT

2019 ◽  
Vol 184 (3-4) ◽  
pp. 527-530 ◽  
Author(s):  
Y Shiroma ◽  
M Hosoda ◽  
K Iwaoka ◽  
M Hegedűs ◽  
H Kudo ◽  
...  
Keyword(s):  
Power Plant ◽  
Dose Rate ◽  
Nuclear Power ◽  
Absorbed Dose ◽  
Local Distribution ◽  
Absorbed Dose Rate ◽  
Distribution Maps ◽  
Dose Rates ◽  
Fdnpp Accident ◽  
Fukushima Daiichi

Abstract The latest car-borne survey was carried out by Hirosaki University in order to grasp the local distribution of the absorbed dose rate in air after the evacuation order was lifted on Namie Town in 2017. The car-borne survey of absorbed dose rate in air was carried out on most of the roads which were accessible by car in Namie Town using a 3-in × 3-in NaI(Tl) scintillation spectrometer. The range of the absorbed dose rate in air was calculated to be 0.041–11 μGy h−1. The distribution maps of the absorbed dose rate in air were drawn based on the data obtained during the surveys in 2011, 2015 and 2017. The comparison of these absorbed dose rates in air suggests that the elevated absorbed dose rate in air in Namie Town caused by the FDNPP accident may be decreasing faster than natural decline which includes weathering effect and physical decay due to the artificial decontamination.

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