32 CFR 218.3 - Dose reconstruction methodology.

Code of Federal Regulations, 2014 CFR

2014-07-01

... effects of shot-specific parameters such as weapon type and yield, neutron and gamma output, source and... specific personnel activities. Due to the range of activities, times, geometries, shielding, and weapon... that could have led to atypical doses. Radiation dose from neutrons and dose commitments due to inhaled...

32 CFR 218.3 - Dose reconstruction methodology.

Code of Federal Regulations, 2012 CFR

2012-07-01

... effects of shot-specific parameters such as weapon type and yield, neutron and gamma output, source and... specific personnel activities. Due to the range of activities, times, geometries, shielding, and weapon... that could have led to atypical doses. Radiation dose from neutrons and dose commitments due to inhaled...

Population dose commitments due to radioactive releases from nuclear power plant sites in 1988

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, D.A.

Population radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1988. Fifty-year commitments for a one-year exposure from both liquid and atmospheric releases were calculated for four population groups (infant, child, teen-ager and adult) residing between 2 and 80 km from each of 71 reactor sites. This report tabulates the results of these calculations, showing the dose commitments for both water and airborne pathways for each age group and organ. Also included for each of the sites is a histogram showing the fraction of the total population within 2 to 80 km aroundmore » each site receiving various average dose commitments from the airborne pathways. The total collective dose commitments (from both liquid and airborne pathways) for each site ranged from a high of 16 person-rem to a low of 0.0011 person-rem for the sites with plants operating throughout the year with an arithmetic mean of 1.1 person-rem. The total population dose for all sites was estimated at 75 person-rem for the 150 million people considered at risk. The site average individual dose commitment from all pathways ranged from a low of 3 {times} 10{sup {minus}7} mrem to a high of 0.02 mrem. No attempt was made in this study to determine the maximum dose commitment received by any one individual from the radionuclides released at any of the sites. However, licensee calculation of doses to the maximally exposed individual at some sites indicated values of up to approximately 100 times average individual doses (on the order of a few millirem per year).« less

Population dose commitments due to radioactive releases from nuclear power plant sites in 1988. Volume 10

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, D.A.

Population radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1988. Fifty-year commitments for a one-year exposure from both liquid and atmospheric releases were calculated for four population groups (infant, child, teen-ager and adult) residing between 2 and 80 km from each of 71 reactor sites. This report tabulates the results of these calculations, showing the dose commitments for both water and airborne pathways for each age group and organ. Also included for each of the sites is a histogram showing the fraction of the total population within 2 to 80 km aroundmore » each site receiving various average dose commitments from the airborne pathways. The total collective dose commitments (from both liquid and airborne pathways) for each site ranged from a high of 16 person-rem to a low of 0.0011 person-rem for the sites with plants operating throughout the year with an arithmetic mean of 1.1 person-rem. The total population dose for all sites was estimated at 75 person-rem for the 150 million people considered at risk. The site average individual dose commitment from all pathways ranged from a low of 3 {times} 10{sup {minus}7} mrem to a high of 0.02 mrem. No attempt was made in this study to determine the maximum dose commitment received by any one individual from the radionuclides released at any of the sites. However, licensee calculation of doses to the maximally exposed individual at some sites indicated values of up to approximately 100 times average individual doses (on the order of a few millirem per year).« less

Assessment of radiation doses from residential smoke detectors that contain americium-241

NASA Astrophysics Data System (ADS)

Odonnell, F. R.; Etnier, E. L.; Holton, G. A.; Travis, C. C.

1981-10-01

External dose equivalents and internal dose commitments were estimated for individuals and populations from annual distribution, use, and disposal of 10 million ionization chamber smoke detectors that contain 110 kBq americium-241 each. Under exposure scenarios developed for normal distribution, use, and disposal using the best available information, annual external dose equivalents to average individuals were estimated to range from 4 fSv to 20 nSv for total body and from 7 fSv to 40 nSv for bone. Internal dose commitments to individuals under post disposal scenarios were estimated to range from 0.006 to 80 micro-Sv (0.0006 to 8 mrem) to total body and from 0.06 to 800 micro-Sv to bone. The total collective dose (the sum of external dose equivalents and 50-year internal dose commitments) for all individuals involved with distribution, use, or disposal of 10 million smoke detectors was estimated to be about 0.38 person-Sv (38 person-rem) to total body and 00 ft squared.

Age-specific inhalation radiation dose commitment factors for selected radionuclides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strenge, D.L.; Peloquin, R.A.; Baker, D.A.

Inhalation dose commitment factors are presented for selected radionuclides for exposure of individuals in four age groups: infant, child, teen and adult. Radionuclides considered are /sup 35/S, /sup 36/Cl, /sup 45/Ca, /sup 67/Ga, /sup 75/Se, /sup 85/Sr, /sup 109/Cd, /sup 113/Sn, /sup 125/I, /sup 133/Ba, /sup 170/Tm, /sup 169/Yb, /sup 182/Ta, /sup 192/Ir, /sup 198/Au, /sup 201/Tl, /sup 204/Tl, and /sup 236/Pu. The calculational method is based on the human metabolic model of ICRP as defined in Publication 2 (ICRP 1959) and as used in previous age-specific dose factor calculations by Hoenes and Soldat (1977). Dose commitment factors are presentedmore » for the following organs of reference: total body, bone, liver, kidney, thyroid, lung and lower large intestine.« less

Assessment of radiation doses from residential smoke detectors that contain americium-241

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Donnell, F.R.; Etnier, E.L.; Holton, G.A.

1981-10-01

External dose equivalents and internal dose commitments were estimated for individuals and populations from annual distribution, use, and disposal of 10 million ionization chamber smoke detectors that contain 110 kBq (3 ..mu..Ci) americium-241 each. Under exposure scenarios developed for normal distribution, use, and disposal using the best available information, annual external dose equivalents to average individuals were estimated to range from 4 fSv (0.4 prem) to 20 nSv (2 ..mu..rem) for total body and from 7 fSv to 40 nSv for bone. Internal dose commitments to individuals under post disposal scenarios were estimated to range from 0.006 to 80 ..mu..Svmore » (0.0006 to 8 mrem) to total body and from 0.06 to 800 ..mu..Sv to bone. The total collective dose (the sum of external dose equivalents and 50-year internal dose commitments) for all individuals involved with distribution, use, or disposal of 10 million smoke detectors was estimated to be about 0.38 person-Sv (38 person-rem) to total body and 00 ft/sup 2/).« less

Annual committed effective dose from olive oil (due to 238U, 232Th, and 222Rn) estimated for members of the Moroccan public from ingestion and skin application.

PubMed

Misdaq, M A; Touti, R

2012-03-01

Olive oil is traditionally refined and widely consumed by Moroccan rural populations. Uranium (238U), thorium (232Th), radon (222Rn), and thoron (220Rn) contents were measured in various locally produced olive oil samples collected in rural areas of Morocco. These radionuclides were also measured inside various bottled virgin olive oils consumed by the Moroccan populations. CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs) were used. Annual committed effective doses due to 238U, 232Th, and 222Rn from the ingestion of olive oil by the members of the general public were determined. The maximum total committed effective dose due to 238U, 232Th, and 222Rn from the ingestion of olive oil by adult members of Moroccan rural populations was found equal to 5.9 µSv y-1. The influence of pollution due to building material dusts and phosphates on the radiation dose to workers from the ingestion of olive oil was investigated, and it was found that the maximum total committed effective dose due to 238U, 232Th, and 222Rn was on the order of 0.22 mSy y-1. Committed effective doses to skin due to 238U, 232Th, and 222Rn from the application of olive oil masks by rural women were evaluated. The maximum total committed effective dose to skin due to 238U, 232Th, and 222Rn was found equal to 0.07 mSy y-1 cm-2.

10 CFR 835.2 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Reasonably Achievable,” which is the approach to radiation protection to manage and control exposures (both... (Sv)) (1 rem = 0.01 Sv) or a committed equivalent dose of 50 rems (0.5 Sv) to any individual organ or... radiological control. Background means radiation from: (1) Naturally occurring radioactive materials which have...

10 CFR 835.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Reasonably Achievable,” which is the approach to radiation protection to manage and control exposures (both... (Sv)) (1 rem = 0.01 Sv) or a committed equivalent dose of 50 rems (0.5 Sv) to any individual organ or... radiological control. Background means radiation from: (1) Naturally occurring radioactive materials which have...

10 CFR 835.2 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Reasonably Achievable,” which is the approach to radiation protection to manage and control exposures (both... (Sv)) (1 rem = 0.01 Sv) or a committed equivalent dose of 50 rems (0.5 Sv) to any individual organ or... radiological control. Background means radiation from: (1) Naturally occurring radioactive materials which have...

10 CFR 835.2 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Reasonably Achievable,” which is the approach to radiation protection to manage and control exposures (both... (Sv)) (1 rem = 0.01 Sv) or a committed equivalent dose of 50 rems (0.5 Sv) to any individual organ or... radiological control. Background means radiation from: (1) Naturally occurring radioactive materials which have...

10 CFR 835.2 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Reasonably Achievable,” which is the approach to radiation protection to manage and control exposures (both... (Sv)) (1 rem = 0.01 Sv) or a committed equivalent dose of 50 rems (0.5 Sv) to any individual organ or... radiological control. Background means radiation from: (1) Naturally occurring radioactive materials which have...

National survey on dose data analysis in computed tomography.

PubMed

Heilmaier, Christina; Treier, Reto; Merkle, Elmar Max; Alkhadi, Hatem; Weishaupt, Dominik; Schindera, Sebastian

2018-05-28

A nationwide survey was performed assessing current practice of dose data analysis in computed tomography (CT). All radiological departments in Switzerland were asked to participate in the on-line survey composed of 19 questions (16 multiple choice, 3 free text). It consisted of four sections: (1) general information on the department, (2) dose data analysis, (3) use of a dose management software (DMS) and (4) radiation protection activities. In total, 152 out of 241 Swiss radiological departments filled in the whole questionnaire (return rate, 63%). Seventy-nine per cent of the departments (n = 120/152) analyse dose data on a regular basis with considerable heterogeneity in the frequency (1-2 times per year, 45%, n = 54/120; every month, 35%, n = 42/120) and method of analysis. Manual analysis is carried out by 58% (n = 70/120) compared with 42% (n = 50/120) of departments using a DMS. Purchase of a DMS is planned by 43% (n = 30/70) of the departments with manual analysis. Real-time analysis of dose data is performed by 42% (n = 21/50) of the departments with a DMS; however, residents can access the DMS in clinical routine only in 20% (n = 10/50) of the departments. An interdisciplinary dose team, which among other things communicates dose data internally (63%, n = 76/120) and externally, is already implemented in 57% (n = 68/120) departments. Swiss radiological departments are committed to radiation safety. However, there is high heterogeneity among them regarding the frequency and method of dose data analysis as well as the use of DMS and radiation protection activities. • Swiss radiological departments are committed to and interest in radiation safety as proven by a 63% return rate of the survey. • Seventy-nine per cent of departments analyse dose data on a regular basis with differences in the frequency and method of analysis: 42% use a dose management software, while 58% currently perform manual dose data analysis. Of the latter, 43% plan to buy a dose management software. • Currently, only 25% of the departments add radiation exposure data to the final CT report.

Radiation doses to individuals due to ²³⁸U, ²³²Th and ²²²Rn from the immersion in thermal waters and to radon progeny from the inhalation of air inside thermal stations.

PubMed

Misdaq, M A; Ghilane, M; Ouguidi, J; Outeqablit, K

2012-11-01

In Morocco, thermal waters have been used for decades for the treatment of various diseases. To explore the exposure pathway of (238)U, (232)Th and (222)Rn to the skin of bathers from the immersion in thermal waters, these radionuclides were measured inside waters collected from different Moroccan thermal springs, by means of CR-39 and LR-115 type II solid-state nuclear track detectors (SSNTDs), and corresponding annual committed effective doses to skin were determined. Accordingly, to assess radiation dose due to radon short-lived decay products from the inhalation of air by individuals, concentrations of these radionuclides were measured in indoor air of two thermal stations by evaluating mean critical angles of etching of the CR-39 and LR-115 II SSNTDs. Committed effective doses due to the short-lived radon decay products (218)Po and (214)Po by bathers and working personnel inside the thermal stations studied were determined.

Estimates of internal-dose equivalent from inhalation and ingestion of selected radionuclides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dunning, D.E.

1982-01-01

This report presents internal radiation dose conversion factors for radionuclides of interest in environmental assessments of nuclear fuel cycles. This volume provides an updated summary of estimates of committed dose equivalent for radionuclides considered in three previous Oak Ridge National Laboratory (ORNL) reports. Intakes by inhalation and ingestion are considered. The International Commission on Radiological Protection (ICRP) Task Group Lung Model has been used to simulate the deposition and retention of particulate matter in the respiratory tract. Results corresponding to activity median aerodynamic diameters (AMAD) of 0.3, 1.0, and 5.0 ..mu..m are given. The gastorintestinal (GI) tract has been representedmore » by a four-segment catenary model with exponential transfer of radioactivity from one segment to the next. Retention of radionuclides in systemic organs is characterized by linear combinations of decaying exponential functions, recommended in ICRP Publication 30. The first-year annual dose rate, maximum annual dose rate, and fifty-year dose commitment per microcurie intake of each radionuclide is given for selected target organs and the effective dose equivalent. These estimates include contributions from specified source organs plus the systemic activity residing in the rest of the body; cross irradiation due to penetrating radiations has been incorporated into these estimates. 15 references.« less

PB-210 concentrations in cigarettes tobaccos and radiation doses to the smokers.

PubMed

Tahir, S N A; Alaamer, A S

2008-01-01

Cigarette smoking is a source of radiation exposure due to the concentrations of natural radionuclides in the tobacco leaves. From the health point of view, measurement of (210)Pb and (210)Po contents in cigarette tobacco is important to assess the radiological effects associated with the tobacco smoking for the smokers. In the present study, activity concentrations of (210)Pb, which is a (210)Po precursor in the (238)U-decay series, were measured in cigarette tobaccos. Samples of nine different commonly sold brands of cigarette tobaccos were analysed by employing a planar high purity germanium (HPGe) low background detector. Activity concentrations of (210)Pb were measured from its gamma peak at 47 keV. Mean activity concentration of (210)Pb was measured to be 13 +/- 4 Bq kg(-1) from all samples analysed. The annual committed effective dose for a smoker and the collective committed effective dose corresponding to annual cigarettes production were estimated to be 64 +/- 20 microSv and 0.6 x 10(2) man-Sv, respectively.

Impact of the new nuclear decay data of ICRP publication 107 on inhalation dose coefficients for workers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manabe, K.; Endo, Akira; Eckerman, Keith F

2010-03-01

The impact a revision of nuclear decay data had on dose coefficients was studied using data newly published in ICRP Publication 107 (ICRP 107) and existing data from ICRP Publication 38 (ICRP 38). Committed effective dose coefficients for occupational inhalation of radionuclides were calculated using two sets of decay data with the dose and risk calculation software DCAL for 90 elements, 774 nuclides and 1572 cases. The dose coefficients based on ICRP 107 increased by over 10 % compared with those based on ICRP 38 in 98 cases, and decreased by over 10 % in 54 cases. It was foundmore » that the differences in dose coefficients mainly originated from changes in the radiation energy emitted per nuclear transformation. In addition, revisions of the half-lives, radiation types and decay modes also resulted in changes in the dose coefficients.« less

Circulating Hematopoietic Stem and Progenitor Cells in Aging Atomic Bomb Survivors.

PubMed

Kyoizumi, Seishi; Kubo, Yoshiko; Misumi, Munechika; Kajimura, Junko; Yoshida, Kengo; Hayashi, Tomonori; Imai, Kazue; Ohishi, Waka; Nakachi, Kei; Young, Lauren F; Shieh, Jae-Hung; Moore, Malcolm A; van den Brink, Marcel R M; Kusunoki, Yoichiro

2016-01-01

It is not yet known whether hematopoietic stem and progenitor cells (HSPCs) are compromised in the aging population of atomic bomb (A-bomb) survivors after their exposure nearly 70 years ago. To address this, we evaluated age- and radiation-related changes in different subtypes of circulating HSPCs among the CD34-positive/lineage marker-negative (CD34(+)Lin(-)) cell population in 231 Hiroshima A-bomb survivors. We enumerated functional HSPC subtypes, including: cobblestone area-forming cells; long-term culture-initiating cells; erythroid burst-forming units; granulocyte and macrophage colony-forming units; and T-cell and natural killer cell progenitors using cell culture. We obtained the count of each HSPC subtype per unit volume of blood and the proportion of each HSPC subtype in CD34(+)Lin(-) cells to represent the lineage commitment trend. Multivariate analyses, using sex, age and radiation dose as variables, showed significantly decreased counts with age in the total CD34(+)Lin(-) cell population and all HSPC subtypes. As for the proportion, only T-cell progenitors decreased significantly with age, suggesting that the commitment to the T-cell lineage in HSPCs continuously declines with age throughout the lifetime. However, neither the CD34(+)Lin(-) cell population, nor HSPC subtypes showed significant radiation-induced dose-dependent changes in counts or proportions. Moreover, the correlations of the proportions among HSPC subtypes in the survivors properly revealed the hierarchy of lineage commitments. Taken together, our findings suggest that many years after exposure to radiation and with advancing age, the number and function of HSPCs in living survivors as a whole may have recovered to normal levels.

Circulating Hematopoietic Stem and Progenitor Cells in Aging Atomic Bomb Survivors

PubMed Central

Kyoizumi, Seishi; Kubo, Yoshiko; Misumi, Munechika; Kajimura, Junko; Yoshida, Kengo; Hayashi, Tomonori; Imai, Kazue; Ohishi, Waka; Nakachi, Kei; Young, Lauren F.; Shieh, Jae-Hung; Moore, Malcolm A.; van den Brink, Marcel R. M.; Kusunoki, Yoichiro

2016-01-01

It is not yet known whether hematopoietic stem and progenitor cells (HSPCs) are compromised in the aging population of atomic bomb (A-bomb) survivors after their exposure nearly 70 years ago. To address this, we evaluated age- and radiation-related changes in different subtypes of circulating HSPCs among the CD34-positive/lineage marker-negative (CD34+Lin− ) cell population in 231 Hiroshima A-bomb survivors. We enumerated functional HSPC subtypes, including: cobblestone area-forming cells; long-term culture-initiating cells; erythroid burst-forming units; granulocyte and macrophage colony-forming units; and T-cell and natural killer cell progenitors using cell culture. We obtained the count of each HSPC subtype per unit volume of blood and the proportion of each HSPC subtype in CD34+Lin− cells to represent the lineage commitment trend. Multivariate analyses, using sex, age and radiation dose as variables, showed significantly decreased counts with age in the total CD34+Lin− cell population and all HSPC subtypes. As for the proportion, only T-cell progenitors decreased significantly with age, suggesting that the commitment to the T-cell lineage in HSPCs continuously declines with age throughout the lifetime. However, neither the CD34+Lin− cell population, nor HSPC subtypes showed significant radiation-induced dose-dependent changes in counts or proportions. Moreover, the correlations of the proportions among HSPC subtypes in the survivors properly revealed the hierarchy of lineage commitments. Taken together, our findings suggest that many years after exposure to radiation and with advancing age, the number and function of HSPCs in living survivors as a whole may have recovered to normal levels. PMID:26720799

Fukushima radionuclides in the NW Pacific, and assessment of doses for Japanese and world population from ingestion of seafood

PubMed Central

Povinec, Pavel P.; Hirose, Katsumi

2015-01-01

Variations of Fukushima-derived radionuclides (90Sr, 134Cs and 137Cs) in seawater and biota offshore Fukushima and in the NW Pacific Ocean were investigated and radiation doses to the Japanese and world population from ingestion of seafood contaminated by Fukushima radionuclides were estimated and compared with those from other sources of anthropogenic and natural radionuclides. The total effective dose commitment from ingestion of radionuclides in fish, shellfish and seaweed caught in coastal waters off Fukushima was estimated to be 0.6 ± 0.4 mSv/y. The individual effective dose commitment from consumption of radioactive-contaminated fish caught in the open Pacific Ocean was estimated to be 0.07 ± 0.05 mSv/y. These doses are comparable or much lower than doses delivered from the consumption of natural 210Po in fish and in shellfish (0.7 mSv/y). The estimated individual doses have been below the levels when any health damage of the Japanese and world population could be expected. PMID:25761420

Fukushima radionuclides in the NW Pacific, and assessment of doses for Japanese and world population from ingestion of seafood.

PubMed

Povinec, Pavel P; Hirose, Katsumi

2015-03-12

Variations of Fukushima-derived radionuclides ((90)Sr, (134)Cs and (137)Cs) in seawater and biota offshore Fukushima and in the NW Pacific Ocean were investigated and radiation doses to the Japanese and world population from ingestion of seafood contaminated by Fukushima radionuclides were estimated and compared with those from other sources of anthropogenic and natural radionuclides. The total effective dose commitment from ingestion of radionuclides in fish, shellfish and seaweed caught in coastal waters off Fukushima was estimated to be 0.6 ± 0.4 mSv/y. The individual effective dose commitment from consumption of radioactive-contaminated fish caught in the open Pacific Ocean was estimated to be 0.07 ± 0.05 mSv/y. These doses are comparable or much lower than doses delivered from the consumption of natural (210)Po in fish and in shellfish (0.7 mSv/y). The estimated individual doses have been below the levels when any health damage of the Japanese and world population could be expected.

Environmental consequences of postulate plutonium releases from Atomics International's Nuclear Materials Development Facility (NMDF), Santa Susana, California, as a result of severe natural phenomena

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jamison, J.D.; Watson, E.C.

1982-02-01

Potential environmental consequences in terms of radiation dose to people are presented for postulated plutonium releases caused by severe natural phenomena at the Atomics International's Nuclear Materials Development Facility (NMDF), in the Santa Susana site, California. The severe natural phenomena considered are earthquakes, tornadoes, and high straight-line winds. Plutonium deposition values are given for significant locations around the site. All important potential exposure pathways are examined. The most likely 50-year committed dose equivalents are given for the maximum-exposed individual and the population within a 50-mile radius of the plant. The maximum plutonium deposition values likely to occur offsite are alsomore » given. The most likely calculated 50-year collective committed dose equivalents are all much lower than the collective dose equivalent expected from 50 years of exposure to natural background radiation and medical x-rays. The most likely maximum residual plutonium contamination estimated to be deposited offsite following the earthquake, and the 150-mph and 170-mph tornadoes are above the Environmental Protection Agency's (EPA) proposed guideline for plutonium in the general environment of 0.2 ..mu..Ci/m/sup 2/. The deposition values following the 110-mph and the 130-mph tornadoes are below the EPA proposed guideline.« less

Environmental consequences of postulated plutonium releases from General Electric Company Vallecitos Nuclear Center, Vallecitos, California, as a result of severe natural phenomena

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jamison, J.D.; Watson, E.C.

1980-11-01

Potential environmental consequences in terms of radiation dose to people are presented for postulated plutonium releases caused by severe natural phenomena at the General Electric Company Vallecitos Nuclear Center, Vallecitos, California. The severe natural phenomena considered are earthquakes, tornadoes, and high straight-line winds. Maximum plutonium deposition values are given for significant locations around the site. All important potential exposure pathways are examined. The most likely 50-year committed dose equivalents are given for the maximum-exposed individual and the population within a 50-mile radius of the plant. The maximum plutonium deposition values likely to occur offsite are also given. The most likelymore » calculated 50-year collective committed dose equivalents are all much lower than the collective dose equivalent expected from 50 years of exposure to natural background radiation and medical x-rays. The most likely maximum residual plutonium contamination estimated to be deposited offsite following the earthquakes, and the 180-mph and 230-mph tornadoes are above the Environmental Protection Agency's (EPA) proposed guideline for plutonium in the general environment of 0.2 ..mu..Ci/m/sup 2/. The deposition values following the 135-mph tornado are below the EPA proposed guidelines.« less

Occupational radiation exposure experience: Paducah Gaseous Diffusion Plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, R.C.

1975-01-01

The potential for significant uranium exposure in gaseous diffusion plants is very low. The potential for significant radiation exposure in uranium hexafluoride manufacturing is very real. Exposures can be controlled to low levels only through the cooperation and commitment of facility management and operating personnel. Exposure control can be adequately monitored by a combination of air analyses, urinalyses, and measurements of internal deposition as obtained by the IVRML. A program based on control of air-borne uranium exposure has maintained the internal dose of the Paducah Gaseous Diffusion Plant workman to less than one-half the RPG dose to the lung (15more » rem/year) and probably to less than one-fourth that dose. (auth)« less

Requirements for radiation emergency urine bioassay techniques for the public and first responders.

PubMed

Li, Chunsheng; Vlahovich, Slavica; Dai, Xiongxin; Richardson, Richard B; Daka, Joseph N; Kramer, Gary H

2010-11-01

Following a radiation emergency, the affected public and the first responders may need to be quickly assessed for internal contamination by the radionuclides involved. Urine bioassay is one of the most commonly used methods for assessing radionuclide intake and radiation dose. This paper attempts to derive the sensitivity requirements (from inhalation exposure) for the urine bioassay techniques for the top 10 high-risk radionuclides that might be used in a terrorist attack. The requirements are based on a proposed reference dose to adults of 0.1 Sv (CED, committed effective dose). In addition, requirements related to sample turnaround time and field deployability of the assay techniques are also discussed. A review of currently available assay techniques summarized in this paper reveals that method development for ²⁴¹Am, ²²⁶Ra, ²³⁸Pu, and ⁹⁰Sr urine bioassay is needed.

Daily radionuclide ingestion and internal radiation doses in Aomori prefecture, Japan.

PubMed

Ohtsuka, Yoshihito; Kakiuchi, Hideki; Akata, Naofumi; Takaku, Yuichi; Hisamatsu, Shun'ichi

2013-10-01

To assess internal annual dose in the general public in Aomori Prefecture, Japan, 80 duplicate cooked diet samples, equivalent to the food consumed over a 400-d period by one person, were collected from 100 volunteers in Aomori City and the village of Rokkasho during 2006–2010 and were analyzed for 11 radionuclides. To obtain average rates of ingestion of radionuclides, the volunteers were selected from among office, fisheries, agricultural, and livestock farm workers. Committed effective doses from ingestion of the diet over a 1-y period were calculated from the analytical results and from International Commission on Radiological Protection dose coefficients; for 40K, an internal effective dose rate from the literature was used. Fisheries workers had significantly higher combined internal annual dose than the other workers, possibly because of high rates of ingestion of marine products known to have high 210Po concentrations. The average internal dose rate, weighted by the numbers of households in each worker group in Aomori Prefecture, was estimated at 0.47 mSv y-1. Polonium-210 contributed 49% of this value. The sum of committed effective dose rates for 210Po, 210Pb, 228Ra, and 14C and the effective dose rate of 40K accounted for approximately 99% of the average internal dose rate.

New Stochastic Annual Limits on Intake for Selected Radionuclides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carbaugh, Eugene H.

Annual limits on intake (ALI) have historically been tabulated by the International Commission on Radiological Protection (e.g., ICRP 1979, 1961) and also by the Environmental Protection Agency (EPA 1988). These compilations have been rendered obsolete by more recent ICRP dosimetry methods, and, rather than provide new ALIs, the ICRP has opted instead to provide committed dose coefficients from which an ALI can be determined by a user for a specific set of conditions. The U.S. Department of Energy historically has referenced compilations of ALIs and has defined their method of calculation in its radiation protection regulation (10 CFDR 835), butmore » has never provided a specific compilation. Under June 2007 amendments to 10 CFR 835, ALIs can be calculated by dividing an appropriate dose limit, either 5-rem (0.05 Sv) effective dose or 50 rem (0.5 Sv) equivalent dose to an individual organ or tissue, by an appropriate committed dose coefficient. When based on effective dose, the ALI is often referred to as a stochastic annual limit on intake (SALI), and when based on the individual organ or tissue equivalent limit, it has often been called a deterministic annual limit on intake (DALI).« less

Ultralow Dose MSCT Imaging in Dental Implantology

PubMed Central

Widmann, Gerlig; Al-Ekrish, Asma'a A.

2018-01-01

Introduction: The Council Directive 2013/59 Euratom has a clear commitment for keeping medical radiation exposure as low as reasonably achievable and demands a regular review and use of diagnostic reference levels. Methods: In dental implantology, the range of effective doses for cone beam computed tomography (CBCT) shows a broad overlap with multislice computed tomography (MSCT). More recently, ultralow dose imaging with new generations of MSCT scanners may impart radiation doses equal to or lower than CBCT. Dose reductions in MSCT have been further facilitated by the introduction of iterative image reconstruction technology (IRT), which provides substantial noise reduction over the current standard of filtered backward projection (FBP). Aim: The aim of this article is to review the available literature on ultralow dose CT imaging and IRTs in dental implantology imaging and to summarize their influence on spatial and contrast resolution, image noise, tissue density measurements, and validity of linear measurements of the jaws. Conclusion: Application of ultralow dose MSCT with IRT technology in dental implantology offers the potential for very large dose reductions compared with standard dose imaging. Yet, evaluation of various diagnostic tasks related to dental implantology is still needed to confirm the results obtained with various IRTs and ultra-low doses so far. PMID:29492174

Cancer Risks Associated with External Radiation From Diagnostic Imaging Procedures

PubMed Central

Linet, Martha S.; Slovis, Thomas L.; Miller, Donald L.; Kleinerman, Ruth; Lee, Choonsik; Rajaraman, Preetha; de Gonzalez, Amy Berrington

2012-01-01

The 600% increase in medical radiation exposure to the US population since 1980 has provided immense benefit, but potential future cancer risks to patients. Most of the increase is from diagnostic radiologic procedures. The objectives of this review are to summarize epidemiologic data on cancer risks associated with diagnostic procedures, describe how exposures from recent diagnostic procedures relate to radiation levels linked with cancer occurrence, and propose a framework of strategies to reduce radiation from diagnostic imaging in patients. We briefly review radiation dose definitions, mechanisms of radiation carcinogenesis, key epidemiologic studies of medical and other radiation sources and cancer risks, and dose trends from diagnostic procedures. We describe cancer risks from experimental studies, future projected risks from current imaging procedures, and the potential for higher risks in genetically susceptible populations. To reduce future projected cancers from diagnostic procedures, we advocate widespread use of evidence-based appropriateness criteria for decisions about imaging procedures, oversight of equipment to deliver reliably the minimum radiation required to attain clinical objectives, development of electronic lifetime records of imaging procedures for patients and their physicians, and commitment by medical training programs, professional societies, and radiation protection organizations to educate all stakeholders in reducing radiation from diagnostic procedures. PMID:22307864

Determination of the uncertainties in radiation doses from ingestion of strontium-90

NASA Astrophysics Data System (ADS)

Apostoaei, Andrei Iulian

Quantification of the uncertainties in the internal dosimetry is important because it can impact the outcome of dose reconstruction, risk assessment or epidemiological studies. This research focused on determination of the uncertainties in the dose factors from a single ingestion of 90Sr by adults, and analyzed the changes with age and the effect of gender. The uncertainties in the estimated dose factors are a factor of 6 for the bone surface, 5 for the red bone marrow, 2.5 for bladder and stomach, 2.2 for the small intestine, 2.1 for the upper large intestine and 2.7 for the lower large intestine. For the rest of the organs the uncertainty is a factor of 3. Only four parameters of the biokinetic model showed an age-dependency within the adult age group: the fractional transfers of strontium from plasma to cortical and trabecular bone, and the removal rates from the cortical and trabecular bone, respectively. When age-dependent biokinetic parameters were used, the estimated dose-factors are very close to the dose factors obtained using age-independent kinetics (within 40%). Thus, the dose factors based on age-independent parameters should suffice for most practical purposes. The dose factors and the associated uncertainties were also calculated as a function of age-at-exposure and attained age. These age dependent curves can be used for estimating doses from continuous intakes, or doses delivered over a limited portion of time. In addition to the committed dose, an expected dose is also estimated in this work. The expected dose is calculated using the dose rate weighted by the probability of surviving up to the age when the dose-rate is delivered. For exposure at young ages the expected dose and the committed dose are similar, but the committed dose decreases to zero when exposure occurs close to age 70, while the expected dose has elevated values pass age 70. No gender differences were found for bone surface, for red bone marrow, and the large intestine. The doses to the soft tissues for females are larger by 20% than the doses for males, because of the differences in the whole-body mass between males and females.

Use of Transportable Radiation Detection Instruments to Assess Internal Contamination from Intakes of Radionuclides Part II: Calibration Factors and ICAT Computer Program.

PubMed

Anigstein, Robert; Olsher, Richard H; Loomis, Donald A; Ansari, Armin

2016-12-01

The detonation of a radiological dispersion device or other radiological incidents could result in widespread releases of radioactive materials and intakes of radionuclides by affected individuals. Transportable radiation monitoring instruments could be used to measure radiation from gamma-emitting radionuclides in the body for triaging individuals and assigning priorities to their bioassay samples for in vitro assessments. The present study derived sets of calibration factors for four instruments: the Ludlum Model 44-2 gamma scintillator, a survey meter containing a 2.54 × 2.54-cm NaI(Tl) crystal; the Captus 3000 thyroid uptake probe, which contains a 5.08 × 5.08-cm NaI(Tl) crystal; the Transportable Portal Monitor Model TPM-903B, which contains two 3.81 × 7.62 × 182.9-cm polyvinyltoluene plastic scintillators; and a generic instrument, such as an ionization chamber, that measures exposure rates. The calibration factors enable these instruments to be used for assessing inhaled or ingested intakes of any of four radionuclides: Co, I, Cs, and Ir. The derivations used biokinetic models embodied in the DCAL computer software system developed by the Oak Ridge National Laboratory and Monte Carlo simulations using the MCNPX radiation transport code. The three physical instruments were represented by MCNP models that were developed previously. The affected individuals comprised children of five ages who were represented by the revised Oak Ridge National Laboratory pediatric phantoms, and adult men and adult women represented by the Adult Reference Computational Phantoms described in Publication 110 of the International Commission on Radiological Protection. These calibration factors can be used to calculate intakes; the intakes can be converted to committed doses by the use of tabulated dose coefficients. These calibration factors also constitute input data to the ICAT computer program, an interactive Microsoft Windows-based software package that estimates intakes of radionuclides and cumulative and committed effective doses, based on measurements made with these instruments. This program constitutes a convenient tool for assessing intakes and doses without consulting tabulated calibration factors and dose coefficients.

USE OF TRANSPORTABLE RADIATION DETECTION INSTRUMENTS TO ASSESS INTERNAL CONTAMINATION FROM INTAKES OF RADIONUCLIDES PART II: CALIBRATION FACTORS AND ICAT COMPUTER PROGRAM

PubMed Central

Anigstein, Robert; Olsher, Richard H.; Loomis, Donald A.; Ansari, Armin

2017-01-01

The detonation of a radiological dispersion device or other radiological incidents could result in widespread releases of radioactive materials and intakes of radionuclides by affected individuals. Transportable radiation monitoring instruments could be used to measure radiation from gamma-emitting radionuclides in the body for triaging individuals and assigning priorities to their bioassay samples for in vitro assessments. The present study derived sets of calibration factors for four instruments: the Ludlum Model 44-2 gamma scintillator, a survey meter containing a 2.54 × 2.54-cm NaI(Tl) crystal; the Captus 3000 thyroid uptake probe, which contains a 5.08 × 5.08-cm NaI(Tl) crystal; the Transportable Portal Monitor Model TPM-903B, which contains two 3.81 × 7.62 × 182.9-cm polyvinyltoluene plastic scintillators; and a generic instrument, such as an ionization chamber, that measures exposure rates. The calibration factors enable these instruments to be used for assessing inhaled or ingested intakes of any of four radionuclides: 60Co, 131I, 137Cs, and 192Ir. The derivations used biokinetic models embodied in the DCAL computer software system developed by the Oak Ridge National Laboratory and Monte Carlo simulations using the MCNPX radiation transport code. The three physical instruments were represented by MCNP models that were developed previously. The affected individuals comprised children of five ages who were represented by the revised Oak Ridge National Laboratory pediatric phantoms, and adult men and adult women represented by the Adult Reference Computational Phantoms described in Publication 110 of the International Commission on Radiological Protection. These calibration factors can be used to calculate intakes; the intakes can be converted to committed doses by the use of tabulated dose coefficients. These calibration factors also constitute input data to the ICAT computer program, an interactive Microsoft Windows-based software package that estimates intakes of radionuclides and cumulative and committed effective doses, based on measurements made with these instruments. This program constitutes a convenient tool for assessing intakes and doses without consulting tabulated calibration factors and dose coefficients. PMID:27798478

Combined exposure to X-irradiation followed by N-ethyl-N-nitrosourea treatment alters the frequency and spectrum of Ikaros point mutations in murine T-cell lymphoma.

PubMed

Kakinuma, Shizuko; Nishimura, Mayumi; Amasaki, Yoshiko; Takada, Mayumi; Yamauchi, Kazumi; Sudo, Satomi; Shang, Yi; Doi, Kazutaka; Yoshinaga, Shinji; Shimada, Yoshiya

2012-09-01

Ionizing radiation is a well-known carcinogen, but its potency may be influenced by other environmental carcinogens, which is of practical importance in the assessment of risk. Data are scarce, however, on the combined effect of radiation with other environmental carcinogens and the underlying mechanisms involved. We studied the mode and mechanism of the carcinogenic effect of radiation in combination with N-ethyl-N-nitrosourea (ENU) using doses approximately equal to the corresponding thresholds. B6C3F1 mice exposed to fractionated X-irradiation (Kaplan's method) followed by ENU developed T-cell lymphomas in a dose-dependent manner. Radiation doses above an apparent threshold acted synergistically with ENU to promote lymphoma development, whereas radiation doses below that threshold antagonized lymphoma development. Ikaros, which regulates the commitment and differentiation of lymphoid lineage cells, is a critical tumor suppressor gene frequently altered in both human and mouse lymphomas and shows distinct mutation spectra between X-ray- and ENU-induced lymphomas. In the synergistically induced lymphomas, we observed a low frequency of LOH and an inordinate increase of Ikaros base substitutions characteristic of ENU-induced point mutations, G:C to A:T at non-CpG, A:T to G:C, G:C to T:A and A:T to T:A. This suggests that radiation doses above an apparent threshold activate the ENU mutagenic pathway. This is the first report on the carcinogenic mechanism elicited by combined exposure to carcinogens below and above threshold doses based on the mutation spectrum of the causative gene. These findings constitute a basis for assessing human cancer risk following exposure to multiple carcinogens. Copyright © 2012 Elsevier B.V. All rights reserved.

Ionizing Radiation Dose Due to the Use of Agricultural Fertilizers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Umisedo, Nancy K.; Okuno, Emico; Medina, Nilberto H.

2008-08-07

The transference of radionuclides from the fertilizers to/and from soils to the foodstuffs can represent an increment in the internal dose when the vegetables are consumed by the human beings. This work evaluates the contribution of fertilizers to the increase of radiation level in the environment and of dose to the people. Samples of fertilizers, soils and vegetables produced in farms located in the neighbourhood of Sao Paulo city in the State of Sao Paulo, Brazil were analysed through gamma spectroscopy. The values of specific activity of {sup 40}K, {sup 238}U and {sup 232}Th show that there is no significantmore » transference of natural radionuclides from fertilizers to the final product of the food chain. The annual committed effective dose due to the ingestion of {sup 40}K contained in the group of consumed vegetables analysed in this work resulted in the very low value of 0.882 {mu}Sv.« less

Field and bioassay indicators for internal dose intervention therapy.

PubMed

Carbaugh, Eugene H

2007-05-01

Guidance is presented that is used at the U.S. Department of Energy Hanford Site to identify the potential need for medical intervention in response to intakes of radioactivity. The guidance, based on ICRP Publication 30 models and committed effective dose equivalents of 20 mSv and 200 mSv, is expressed as numerical workplace measurements and derived first-day bioassay results for large intakes. It is used by facility radiation protection staff and on-call dosimetry support staff during the first few days following an intake.

Field and Bioassay Indicators for Internal Dose Intervention Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carbaugh, Eugene H.

2007-05-01

Guidance is presented that is used at the U.S. Department of Energy Hanford Site to identify the potential need for medical intervention in response to intakes of radioactivity. The guidance, based on ICRP Publication 30 models and committed effective dose equivalents of 20 mSv and 200 mSv, is expressed as numerical workplace measurements and derived first-day bioassay results for large intakes. It is used by facility radiation protection staff and on-call dosimetry support staff during the first few days following an intake.

Hanford Site Composite Analysis Technical Approach Description: Groundwater Pathway Dose Calculation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morgans, D. L.; Lindberg, S. L.

The purpose of this technical approach document (TAD) is to document the assumptions, equations, and methods used to perform the groundwater pathway radiological dose calculations for the revised Hanford Site Composite Analysis (CA). DOE M 435.1-1, states, “The composite analysis results shall be used for planning, radiation protection activities, and future use commitments to minimize the likelihood that current low-level waste disposal activities will result in the need for future corrective or remedial actions to adequately protect the public and the environment.”

131I INTERNAL CONTAMINATION AND COMMITTED DOSE ASSESSMENT AMONG NUCLEAR MEDICINE MEDICAL PERSONNEL.

PubMed

Brudecki, K; Kluczewska-Galka, A; Mróz, T; Jarzab, B; Zagrodzki, P; Janowski, P

2018-05-01

This study presents 131I thyroid activity measurements of 56 employees of the Department of Nuclear Medicine and Endocrine Oncology, Centre for Oncology in Gliwice. The research instrument was a whole-body spectrometer. In 44 out of 56 examined staff members, the determined 131I activity was found to be above the detection limit. The measured activities ranged from 6 ± 2 to 457 ± 118 Bq. The maximum estimated committed effective dose reached was 1.5 mSv/y. The results were compared with previous measurements conducted in another Polish nuclear medical unit. From this comparison, we can see that radiological safety among nuclear medicine personnel can be improved by appropriate work organisation. Reducing exposure of workers can be achieved by properly organised turnovers concerning the most vulnerable worksites. In addition, to lower the radiation risk, it is essential to comply strictly with the isolation regime for the patients.

MPC and ALI: their basis and their comparison

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kennedy, W.E. Jr.; Watson, E.C.

Radiation protection regulations in the United States have evolved from the recommendations of the International Commission on Radiological Protection (ICRP) and the National Council on Radiation Protection and Measurements (NCRP). In 1959, the ICRP issued Publication 2 which contained specific recommendations on dose rate limits, permissible body burdens, metabolic data for radionuclides, and maximum permissible concentrations (MPC) in air or water. Over the next 20 years, new information became available concerning the effects of radiation, the uptake and retention of radionuclides, and the radioactive decay schemes of parent radionuclides. To include this newer information, the ICRP issued Publication 30 inmore » 1978 to supersede Publication 2. One of the secondary limits defined in Publication 30 is the annual limit of intake (ALI). Radionuclide specific ALI values are intended to replace MPC values in determining whether or not ambient air and water concentrations are sufficiently low to maintain the dose to workers within accepted dose rate limits. In this paper, we discuss the derivation of MPC and ALI values, compare inhalation committed dose equivalent factors derived from ICRP Publications 2 and 30, and discuss the practical implications of using either MPC or ALI in determining compliance with occupational exposure limits. 6 references.« less

ALARA implementation throughout project life cycle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haynes, M.J.

1995-03-01

A strength of radiation protection programs generally has been endorsement and application of the ALARA principle. In Ontario Hydro, which currently operates 20 commercial size nuclear units, great strides have been made in the last three decades in reducing occupational radiation exposure per unit of electricity generated. This paper will discuss specific applications of elements of the overall ALARA program which have most contributed to dose reduction as the nuclear program has expanded. This includes such things as management commitment, ALARA application in the design phase and major rehabilitation work, the benefits of the self protection concept, a specific examplemore » of elimination (or reduction) of the source term and the importance of dose targets. Finally, it is concluded that the major opportunities for further improvements may lie in the area of information management.« less

Radon and Thoron Measured in Petrol and Gas-oil Exhaust Fumes by Using CR-39 and LR-115 II Nuclear Track Detectors: Radiation Doses to the Respiratory Tract of Mechanic Workers.

PubMed

Misdaq, M A; Chaouqi, A; Ouguidi, J; Touti, R; Mortassim, A

2015-06-01

Mechanic workers are exposed to exhaust fumes when controlling vehicle engines in motion inside repair shops. To assess radiation doses due to radon short-lived progeny from the inhalation of exhaust fumes by mechanic workers, concentrations of these radionuclides were measured in petrol (gasoline) and gas-oil exhaust fumes by evaluating mean critical angles of etching of the CR-39 and LR-115 type II SSNTDs for alpha particles emitted by the radon and thoron decay series. Committed effective doses due to ²¹⁸Po and ²¹⁴Po short-lived radon decay products from the inhalation of petrol and gas-oil exhaust fumes by workers were evaluated. A maximum value of 1.35 mSv y⁻¹ due to radon short-lived decay products from the inhalation of gas-oil exhaust fumes by mechanic workers was found, which is lower than the (3-10 mSv y⁻¹) dose limit interval for workers.

Report on the PWR-radiation protection/ALARA Committee

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malone, D.J.

1995-03-01

In 1992, representatives from several utilities with operational Pressurized Water Reactors (PWR) formed the PWR-Radiation Protection/ALARA Committee. The mission of the Committee is to facilitate open communications between member utilities relative to radiation protection and ALARA issues such that cost effective dose reduction and radiation protection measures may be instituted. While industry deregulation appears inevitable and inter-utility competition is on the rise, Committee members are fully committed to sharing both positive and negative experiences for the benefit of the health and safety of the radiation worker. Committee meetings provide current operational experiences through members providing Plant status reports, and informationmore » relative to programmatic improvements through member presentations and topic specific workshops. The most recent Committee workshop was facilitated to provide members with defined experiences that provide cost effective ALARA performance.« less

Environmental consequences of postulated plutonium releases from Westinghouse PFDL, Cheswick, Pennsylvania, as a result of severe natural phenomena

DOE Office of Scientific and Technical Information (OSTI.GOV)

McPherson, R.B.; Watson, E.C.

1979-06-01

Potential environmental consequences in terms of radiation dose to people are presented for postulated accidents due to earthquakes, tornadoes, high straight-line winds, and floods. Maximum plutonium deposition values are given for significant locations around the site. All important potential exposure pathways are examined. The most likely calculated 50-year collective committed dose equivalents are all much lower than the collective dose equivalent expected from 50 years of exposure to natural background radiation and medical x-rays except Earthquake No. 4 and the 260-mph tornado. The most likely maximum residual plutonium contamination estimated to be deposited offsite following Earthquake No. 4, and themore » 200-mph and 260-mph tornadoes are above the Environmental Protection Agency's (EPA) proposed guideline for plutonium in the general environment of 0.2 ..mu..Ci/m/sup 2/. The deposition values following the other severe natural phenomena are below the EPA proposed guideline.« less

Air concentrations of /sup 239/Pu and /sup 240/Pu and potential radiation doses to persons living near Pu-contaminated areas in Palomares, Spain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iranzo, E.; Salvador, S.; Iranzo, C.E.

1987-04-01

On 17 January 1966, an accident during a refueling operation resulted in the destruction of an air force KC-135 tanker and a B-52 bomber carrying four thermonuclear weapons. Two weapons, whose parachutes opened, were found intact. The others experienced non-nuclear explosion with some burning and release of the fissile fuel at impact. Joint efforts by the United States and Spain resulted in remedial action and a long-term program to monitor the effectiveness of the cleanup. Air concentrations of /sup 239/Pu and /sup 240/Pu have been continuously monitored since the accident. The average annual air concentration for each location was usedmore » to estimate committed dose equivalents for individuals living and working around the air sampling stations. The average annual /sup 239/Pu and /sup 240/Pu air concentrations during the 15-y period corresponding to 1966-1980 and the potential committed dose equivalents for various tissues due to the inhalation of the /sup 239/Pu and /sup 240/Pu average annual air concentration during this period are shown and discussed in the report.« less

Mapping radon-prone areas using γ-radiation dose rate and geological information.

PubMed

García-Talavera, M; García-Pérez, A; Rey, C; Ramos, L

2013-09-01

Identifying radon-prone areas is key to policies on the control of this environmental carcinogen. In the current paper, we present the methodology followed to delineate radon-prone areas in Spain. It combines information from indoor radon measurements with γ-radiation and geological maps. The advantage of the proposed approach is that it lessens the requirement for a high density of measurements by making use of commonly available information. It can be applied for an initial definition of radon-prone areas in countries committed to introducing a national radon policy or to improving existing radon maps in low population regions.

Radiation-Induced Second Cancer Risk Estimates From Radionuclide Therapy

NASA Astrophysics Data System (ADS)

Bednarz, Bryan; Besemer, Abigail

2017-09-01

The use of radionuclide therapy in the clinical setting is expected to increase significantly over the next decade. There is an important need to understand the radiation-induced second cancer risk associated with these procedures. In this study the radiation-induced cancer risk in five radionuclide therapy patients was investigated. These patients underwent serial SPECT imaging scans following injection as part of a clinical trial testing the efficacy of a 131Iodine-labeled radiopharmaceutical. Using these datasets the committed absorbed doses to multiple sensitive structures were calculated using RAPID, which is a novel Monte Carlo-based 3D dosimetry platform developed for personalized dosimetry. The excess relative risk (ERR) for radiation-induced cancer in these structures was then derived from these dose estimates following the recommendations set forth in the BEIR VII report. The radiation-induced leukemia ERR was highest among all sites considered reaching a maximum value of approximately 4.5. The radiation-induced cancer risk in the kidneys, liver and spleen ranged between 0.3 and 1.3. The lifetime attributable risks (LARs) were also calculated, which ranged from 30 to 1700 cancers per 100,000 persons and were highest for leukemia and the liver for both males and females followed by radiation-induced spleen and kidney cancer. The risks associated with radionuclide therapy are similar to the risk associated with external beam radiation therapy.

Dose commitments due to radioactive releases from nuclear power plant sites: Methodology and data base. Supplement 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, D.A.

1996-06-01

This manual describes a dose assessment system used to estimate the population or collective dose commitments received via both airborne and waterborne pathways by persons living within a 2- to 80-kilometer region of a commercial operating power reactor for a specific year of effluent releases. Computer programs, data files, and utility routines are included which can be used in conjunction with an IBM or compatible personal computer to produce the required dose commitments and their statistical distributions. In addition, maximum individual airborne and waterborne dose commitments are estimated and compared to 10 CFR Part 50, Appendix 1, design objectives. Thismore » supplement is the last report in the NUREG/CR-2850 series.« less

Is it useful to assess annual effective doses that are less than 100 mSv?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strom, Daniel J.; Cameron, John R.

It is useful to assess annual effective doses less than 100 mSv. Beyond the''score-keeping'' needs of regulatory compliance, there are at least seven other valid reasons for performing personnel monitoring, many of which fall into the category of''no news is good news,'' or more aptly,''null news, as long as you can prove it, is good news.'' These are performance measures for contractual compliance, diagnosis of problems with radiation protection programs, health surveillance and occupational epidemiology, prevention of and support for litigation, demonstration of management commitment and safety, worker counseling, ensuring peace of mind. Furthermore, it is shown that there ismore » very reasonable expectation that detriment may be associated with doses smaller than 100 mSv per year.« less

10 CFR Appendix B to Part 20 - Annual Limits on Intake (ALIs) and Derived Air Concentrations (DACs) of Radionuclides for...

Code of Federal Regulations, 2014 CFR

2014-01-01

...) a committed effective dose equivalent of 5 rems (stochastic ALI) or (2) a committed dose equivalent of 50 rems to an organ or tissue (non-stochastic ALI). The stochastic ALIs were derived to result in... equivalent to the whole body of 5 rems. The derivation includes multiplying the committed dose equivalent to...

10 CFR Appendix B to Part 20 - Annual Limits on Intake (ALIs) and Derived Air Concentrations (DACs) of Radionuclides for...

Code of Federal Regulations, 2011 CFR

2011-01-01

...) a committed effective dose equivalent of 5 rems (stochastic ALI) or (2) a committed dose equivalent of 50 rems to an organ or tissue (non-stochastic ALI). The stochastic ALIs were derived to result in... equivalent to the whole body of 5 rems. The derivation includes multiplying the committed dose equivalent to...

10 CFR Appendix B to Part 20 - Annual Limits on Intake (ALIs) and Derived Air Concentrations (DACs) of Radionuclides for...

Code of Federal Regulations, 2012 CFR

2012-01-01

...) a committed effective dose equivalent of 5 rems (stochastic ALI) or (2) a committed dose equivalent of 50 rems to an organ or tissue (non-stochastic ALI). The stochastic ALIs were derived to result in... equivalent to the whole body of 5 rems. The derivation includes multiplying the committed dose equivalent to...

10 CFR Appendix B to Part 20 - Annual Limits on Intake (ALIs) and Derived Air Concentrations (DACs) of Radionuclides for...

Code of Federal Regulations, 2010 CFR

2010-01-01

...) a committed effective dose equivalent of 5 rems (stochastic ALI) or (2) a committed dose equivalent of 50 rems to an organ or tissue (non-stochastic ALI). The stochastic ALIs were derived to result in... equivalent to the whole body of 5 rems. The derivation includes multiplying the committed dose equivalent to...

10 CFR Appendix B to Part 20 - Annual Limits on Intake (ALIs) and Derived Air Concentrations (DACs) of Radionuclides for...

Code of Federal Regulations, 2013 CFR

2013-01-01

...) a committed effective dose equivalent of 5 rems (stochastic ALI) or (2) a committed dose equivalent of 50 rems to an organ or tissue (non-stochastic ALI). The stochastic ALIs were derived to result in... equivalent to the whole body of 5 rems. The derivation includes multiplying the committed dose equivalent to...

Concentrations of Radiocesium in Local Foods Collected in Kawauchi Village after the Accident at the Fukushima Dai-ichi Nuclear Power Station

NASA Astrophysics Data System (ADS)

Orita, Makiko; Nakashima, Kanami; Hayashida, Naomi; Endo, Yuuko; Yamashita, Shunichi; Takamura, Noboru

2016-06-01

We evaluated the current concentrations of radiocesium in local foods collected in Kawauchi Village, which is located less than 30 km from Fukushima Daiichi Nuclear Power Station, to minimize public anxiety regarding internal radiation exposure through the consumption of locally produced foods after the 2011 Fukushima accident. The number of samples exceeding the regulatory radiocesium limit (100 Bq/kg for general foods) was five out of 4,080 vegetables (0.1%), 652 of 1,986 (32.8%) among edible wild plants and fungi, and eight of 647 (1.2%) in fruits. Our study confirmed that the internal radiation doses of ingesting these foods are acceptably low compared to the public dose limit, ranging from 24.4 to 42.7 μSv for males and from 21.7 to 43.4 μSv for females, although the potential for radiation exposure still exists. Long-term comprehensive follow-up should take place to clarify trends in radiocesium concentrations in local foods and the committed effective doses found in Fukushima-area residents. By constructing a system that allows residents to access information on radiocesium concentration in foods, a risk communication model between specialists and residents could be developed in the recovery phase after the Fukushima accident.

Concentrations of Radiocesium in Local Foods Collected in Kawauchi Village after the Accident at the Fukushima Dai-ichi Nuclear Power Station

PubMed Central

Orita, Makiko; Nakashima, Kanami; Hayashida, Naomi; Endo, Yuuko; Yamashita, Shunichi; Takamura, Noboru

2016-01-01

We evaluated the current concentrations of radiocesium in local foods collected in Kawauchi Village, which is located less than 30 km from Fukushima Daiichi Nuclear Power Station, to minimize public anxiety regarding internal radiation exposure through the consumption of locally produced foods after the 2011 Fukushima accident. The number of samples exceeding the regulatory radiocesium limit (100 Bq/kg for general foods) was five out of 4,080 vegetables (0.1%), 652 of 1,986 (32.8%) among edible wild plants and fungi, and eight of 647 (1.2%) in fruits. Our study confirmed that the internal radiation doses of ingesting these foods are acceptably low compared to the public dose limit, ranging from 24.4 to 42.7 μSv for males and from 21.7 to 43.4 μSv for females, although the potential for radiation exposure still exists. Long-term comprehensive follow-up should take place to clarify trends in radiocesium concentrations in local foods and the committed effective doses found in Fukushima-area residents. By constructing a system that allows residents to access information on radiocesium concentration in foods, a risk communication model between specialists and residents could be developed in the recovery phase after the Fukushima accident. PMID:27334847

Internal Radiation Exposure Dose in Iwaki City, Fukushima Prefecture after the Accident at Fukushima Dai-ichi Nuclear Power Plant

PubMed Central

Orita, Makiko; Hayashida, Naomi; Nukui, Hiroshi; Fukuda, Naoko; Kudo, Takashi; Matsuda, Naoki; Fukushima, Yoshiko; Takamura, Noboru

2014-01-01

As a result of the accident at the Fukushima Daiichi Nuclear Power Plant (FNPP) on 11 March 2011, a huge amount of radionuclides, including radiocesium, was released and spread over a wide area of eastern Japan. Although three years have passed since the accident, residents around the FNPP are anxious about internal radiation exposure due to radiocesium. In this study, we screened internal radiation exposure doses in Iwaki city of Fukushima prefecture, using a whole-body counter. The first screening was conducted from October 2012 to February 2013, and the second screening was conducted from May to November 2013. Study participants were employees of ALPINE and their families who underwent examination. A total of 2,839 participants (1,366 men and 1,473 women, 1–86 years old) underwent the first screening, and 2,092 (1,022 men and 1,070 women, 1–86 years old) underwent the second screening. The results showed that 99% of subjects registered below 300 Bq per body in the first screening, and all subjects registered below 300 Bq per body in the second screening. The committed effective dose ranged from 0.01–0.06 mSv in the first screening and 0.01–0.02 mSv in the second screening. Long-term follow-up studies are needed to avoid unnecessary chronic internal exposure and to reduce anxiety among the residents by communicating radiation health risks. PMID:25478794

Internal radiation exposure dose in Iwaki city, Fukushima prefecture after the accident at Fukushima Dai-ichi Nuclear Power Plant.

PubMed

Orita, Makiko; Hayashida, Naomi; Nukui, Hiroshi; Fukuda, Naoko; Kudo, Takashi; Matsuda, Naoki; Fukushima, Yoshiko; Takamura, Noboru

2014-01-01

As a result of the accident at the Fukushima Daiichi Nuclear Power Plant (FNPP) on 11 March 2011, a huge amount of radionuclides, including radiocesium, was released and spread over a wide area of eastern Japan. Although three years have passed since the accident, residents around the FNPP are anxious about internal radiation exposure due to radiocesium. In this study, we screened internal radiation exposure doses in Iwaki city of Fukushima prefecture, using a whole-body counter. The first screening was conducted from October 2012 to February 2013, and the second screening was conducted from May to November 2013. Study participants were employees of ALPINE and their families who underwent examination. A total of 2,839 participants (1,366 men and 1,473 women, 1-86 years old) underwent the first screening, and 2,092 (1,022 men and 1,070 women, 1-86 years old) underwent the second screening. The results showed that 99% of subjects registered below 300 Bq per body in the first screening, and all subjects registered below 300 Bq per body in the second screening. The committed effective dose ranged from 0.01-0.06 mSv in the first screening and 0.01-0.02 mSv in the second screening. Long-term follow-up studies are needed to avoid unnecessary chronic internal exposure and to reduce anxiety among the residents by communicating radiation health risks.

Capstone Depleted Uranium Aerosol Biokinetics, Concentrations, and Doses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guilmette, Raymond A.; Miller, Guthrie; Parkhurst, MaryAnn

2009-02-26

One of the principal goals of the Capstone Depleted Uranium (DU) Aerosol Study was to quantify and characterize DU aerosols generated inside armored vehicles by perforation with a DU penetrator. This study consequently produced a database in which the DU aerosol source terms were specified both physically and chemically for a variety of penetrator-impact geometries and conditions. These source terms were used to calculate radiation doses and uranium concentrations for various scenarios as part of the Capstone DU Human Health Risk Assessment (HHRA). This paper describes the scenario-related biokinetics of uranium, and summarizes intakes, chemical concentrations to the organs, andmore » E(50) and HT(50) for organs and tissues based on exposure scenarios for personnel in vehicles at the time of perforation as well as for first responders. For a given exposure scenario (duration time and breathing rates), the range of DU intakes among the target vehicles and shots was not large, about a factor of 10, with the lowest being from a ventilated operational Abrams tank and the highest being for an unventilated Abrams with DU penetrator perforating DU armor. The ranges of committed effective doses were more scenario-dependent than were intakes. For example, the largest range, a factor of 20, was shown for scenario A, a 1-min exposure, whereas, the range was only a factor of two for the first-responder scenario (E). In general, the committed effective doses were found to be in the tens of mSv. The risks ascribed to these doses are discussed separately.« less

Dosimetric assessment from 212Pb inhalation at a thorium purification plant.

PubMed

Campos, M P; Pecequilo, B R S

2004-01-01

At the Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, Brazil, there is a facility (thorium purification plant) where materials with high thorium concentrations are manipulated. In order to estimate afterwards the lung cancer risk for the workers, the thoron daughter (212Pb) levels were assessed and the committed effective and lung committed equivalent doses for workers in place. A total of 28 air filter samples were measured by total alpha counting through the modified Kusnetz method, to determine the 212Pb concentraion. The committed effective dose and lung committed equivalent dose due to 212Pb inhalation were derived from compartmental analysis following the ICRP 66 lung compartmental model, and ICRP 67 lead metabolic model.

Measurement of 238U and 232Th in Petrol, Gas-oil and Lubricant Samples by Using Nuclear Track Detectors and Resulting Radiation Doses to the Skin of Mechanic Workers.

PubMed

Misdaq, M A; Chaouqi, A; Ouguidi, J; Touti, R; Mortassim, A

2015-10-01

Workers in repair shops of vehicles (cars, buses, truck, etc.) clean carburetors, check fuel distribution, and perform oil changes and greasing. To explore the exposure pathway of (238)U and (232)Th and its decay products to the skin of mechanic workers, these radionuclides were measured inside petrol, gas-oil, and lubricant material samples by means of CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs), and corresponding annual committed equivalent doses to skin were determined. The maximum total equivalent effective dose to skin due to the (238)U and (232)Th series from the application of different petrol, gas-oil, and lubricant samples by mechanic workers was found equal to 1.2 mSv y(-1) cm(-2).

Evaluation of annual committed effective doses to members of the public in Morocco due to 238U and 232Th in various food materials.

PubMed

Misdaq, M A; Bourzik, W

2004-12-01

Uranium (238U) and thorium (232Th) concentrations were measured in different foods widely consumed in Morocco by using CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs). Annual committed effective doses due to 238U and 232Th intakes from the ingestion of the studied food materials were evaluated for different age groups of individuals, using the ICRP ingestion dose coefficients. The influence of the 238U and 232Th intakes and ages of individuals on the committed effective dose was investigated. Total annual intakes of 238U and 232Th for a typical food basket for adult members of the Moroccan population were estimated to be 451 +/- 27 Bq y(-1) and 359 +/- 20 Bq y(-1), corresponding to committed effective doses of (20 +/- 1) x 10(-6) Sv y(-1) and (83 +/- 5) x 10(-6) Sv y(-1), respectively.

Determination of in vitro lung solubility and intake-to-dose conversion factor for tritiated lanthanum nickel aluminum alloy.

PubMed

Farfán, Eduardo B; Labone, Thomas R; Staack, Gregory C; Cheng, Yung-Sung; Zhou, Yue; Varallo, Thomas P

2012-09-01

A sample of tritiated lanthanum nickel aluminum alloy (LaNi4.25Al0.75 or LANA.75) similar to that used at the Savannah River Site Tritium Facilities was analyzed to estimate the particle size distribution of this metal tritide powder and the rate at which this material dissolves in the human respiratory tract after it is inhaled. This information is used to calculate the committed effective dose received by a worker after inhaling the material. These doses, which were calculated using the same methodology given in the U.S. Department of Energy Tritium Handbook, are presented as inhalation intake-to-dose conversion factors (DCF). The DCF for this metal tritide was determined to be 9.4 × 10 Sv Bq, which is less than the DCF for tritiated water. Therefore, the radiation worker bioassay programs designed for tritiated water are adequate to monitor for intakes of this material.

40 CFR Appendix B to Part 191 - Calculation of Annual Committed Effective Dose

Code of Federal Regulations, 2013 CFR

2013-07-01

... the proportion of the stochastic risk resulting from irradiation of the tissue or organ to the total... of HE. III. Annual Committed Tissue or Organ Equivalent Dose For internal irradiation from...

40 CFR Appendix B to Part 191 - Calculation of Annual Committed Effective Dose

Code of Federal Regulations, 2012 CFR

2012-07-01

... the proportion of the stochastic risk resulting from irradiation of the tissue or organ to the total... of HE. III. Annual Committed Tissue or Organ Equivalent Dose For internal irradiation from...

40 CFR Appendix B to Part 191 - Calculation of Annual Committed Effective Dose

Code of Federal Regulations, 2014 CFR

2014-07-01

... the proportion of the stochastic risk resulting from irradiation of the tissue or organ to the total... of HE. III. Annual Committed Tissue or Organ Equivalent Dose For internal irradiation from...

40 CFR Appendix B to Part 191 - Calculation of Annual Committed Effective Dose

Code of Federal Regulations, 2010 CFR

2010-07-01

... the proportion of the stochastic risk resulting from irradiation of the tissue or organ to the total... of HE. III. Annual Committed Tissue or Organ Equivalent Dose For internal irradiation from...

40 CFR Appendix B to Part 191 - Calculation of Annual Committed Effective Dose

Code of Federal Regulations, 2011 CFR

2011-07-01

... the proportion of the stochastic risk resulting from irradiation of the tissue or organ to the total... of HE. III. Annual Committed Tissue or Organ Equivalent Dose For internal irradiation from...

A comprehensive dose reconstruction methodology for former rocketdyne/atomics international radiation workers.

PubMed

Boice, John D; Leggett, Richard W; Ellis, Elizabeth Dupree; Wallace, Phillip W; Mumma, Michael; Cohen, Sarah S; Brill, A Bertrand; Chadda, Bandana; Boecker, Bruce B; Yoder, R Craig; Eckerman, Keith F

2006-05-01

Incomplete radiation exposure histories, inadequate treatment of internally deposited radionuclides, and failure to account for neutron exposures can be important uncertainties in epidemiologic studies of radiation workers. Organ-specific doses from lifetime occupational exposures and radionuclide intakes were estimated for an epidemiologic study of 5,801 Rocketdyne/Atomics International (AI) radiation workers engaged in nuclear technologies between 1948 and 1999. The entire workforce of 46,970 Rocketdyne/AI employees was identified from 35,042 Kardex work histories cards, 26,136 electronic personnel listings, and 14,189 radiation folders containing individual exposure histories. To obtain prior and subsequent occupational exposure information, the roster of all workers was matched against nationwide dosimetry files from the Department of Energy, the Nuclear Regulatory Commission, the Landauer dosimetry company, the U.S. Army, and the U.S. Air Force. Dosimetry files of other worker studies were also accessed. Computation of organ doses from radionuclide intakes was complicated by the diversity of bioassay data collected over a 40-y period (urine and fecal samples, lung counts, whole-body counts, nasal smears, and wound and incident reports) and the variety of radionuclides with documented intake including isotopes of uranium, plutonium, americium, calcium, cesium, cerium, zirconium, thorium, polonium, promethium, iodine, zinc, strontium, and hydrogen (tritium). Over 30,000 individual bioassay measurements, recorded on 11 different bioassay forms, were abstracted. The bioassay data were evaluated using ICRP biokinetic models recommended in current or upcoming ICRP documents (modified for one inhaled material to reflect site-specific information) to estimate annual doses for 16 organs or tissues taking into account time of exposure, type of radionuclide, and excretion patterns. Detailed internal exposure scenarios were developed and annual internal doses were derived on a case-by-case basis for workers with committed equivalent doses indicated by screening criteria to be greater than 10 mSv to the organ with the highest internal dose. Overall, 5,801 workers were monitored for radiation at Rocketdyne/AI: 5,743 for external exposure and 2,232 for internal intakes of radionuclides; 41,169 workers were not monitored for radiation. The mean cumulative external dose based on Rocketdyne/AI records alone was 10.0 mSv, and the dose distribution was highly skewed with most workers experiencing low cumulative doses and only a few with high doses (maximum 500 mSv). Only 45 workers received greater than 200 mSv while employed at Rocketdyne/AI. However, nearly 32% (or 1,833) of the Rocketdyne/AI workers had been monitored for radiation at other nuclear facilities and incorporation of these doses increased the mean dose to 13.5 mSv (maximum 1,005 mSv) and the number of workers with >200 mSv to 69. For a small number of workers (n=292), lung doses from internal radionuclide intakes were relatively high (mean 106 mSv; maximum 3,560 mSv) and increased the overall population mean dose to 19.0 mSv and the number of workers with lung dose>200 mSv to 109. Nearly 10% of the radiation workers (584) were monitored for neutron exposures (mean 1.2 mSv) at Rocketdyne/AI, and another 2% were monitored for neutron exposures elsewhere. Interestingly, 1,477 workers not monitored for radiation at Rocketdyne/AI (3.6%) were found to have worn dosimeters at other nuclear facilities (mean external dose of 2.6 mSv, maximum 188 mSv). Without considering all sources of occupational exposure, an incorrect characterization of worker exposure would have occurred with the potential to bias epidemiologic results. For these pioneering workers in the nuclear industry, 26.5% of their total occupational dose (collective dose) was received at other facilities both prior to and after employment at Rocketdyne/AI. In addition, a small number of workers monitored for internal radionuclides contributed disproportionately to the number of workers with high lung doses. Although nearly 12% of radiation workers had been monitored for neutron exposures during their career, the cumulative dose levels were small in comparison with other external and internal exposure. Risk estimates based on nuclear worker data must be interpreted cautiously if internally deposited radionuclides and occupational doses received elsewhere are not considered.

Probabilistic dose assessment of normal operations and accident conditions for an assured isolation facility in Texas

NASA Astrophysics Data System (ADS)

Arno, Matthew Gordon

Texas is investigating building a long-term waste storage facility, also known as an Assured Isolation Facility. This is an above-ground low-level radioactive waste storage facility that is actively maintained and from which waste may be retrieved. A preliminary, scoping-level analysis has been extended to consider more complex scenarios of radiation streaming and skyshine by using the computer code Monte Carlo N-Particle (MCNP) to model the facility in greater detail. Accidental release scenarios have been studied in more depth to better assess the potential dose to off-site individuals. Using bounding source term assumptions, the projected radiation doses and dose rates are estimated to exceed applicable limits by an order of magnitude. By altering the facility design to fill in the hollow cores of the prefabricated concrete slabs used in the roof over the "high-gamma rooms," where the waste with the highest concentration of gamma emitting radioactive material is stored, dose rates outside the facility decrease by an order of magnitude. With the modified design, the annual dose at the site fenceline is estimated at 86 mrem, below the 100 mrem annual limit for exposure of the public. Within the site perimeter, the dose rates are lowered sufficiently such that it is not necessary to categorize many workers and contractor personnel as radiation workers, saving on costs as well as being advisable under ALARA principles. A detailed analysis of bounding accidents incorporating information on the local meteorological conditions indicate that the maximum committed effective dose equivalent from the passage of a plume of material released in an accident at any of the cities near the facility is 59 :rem in the city of Eunice, NM based on the combined day and night meteorological conditions. Using the daytime meteorological conditions, the maximum dose at any city is 7 :rem, also in the city of Eunice. The maximum dose at the site boundary was determined to be 230 mrem using the combined day and night meteorological conditions and 33 mrem using the daytime conditions.

Committed effective dose determination in southern Brazilian cereal flours.

PubMed

Scheibel, V; Appoloni, C R

2013-01-01

The health impact of radionuclide ingestion from foodstuffs was evaluated by the committed effective doses determined in eight commercial samples of South-Brazilian cereal flours (soy, wheat, cornmeal, cassava, rye, oat, barley and rice flours). The radioactivity traces of (228)Th, (228)Ra, (226)Ra, (40)K, (7)Be and (137)Cs were measured by gamma-ray spectrometry employing an HPGe detector of 66 % relative efficiency. The efficiency curve has taken into account the differences in densities and chemical composition between the matrix and the certified sample. The highest concentration levels of (228)Th and (40)K were 3.5±0.4 and 1469±17 Bq kg(-1) for soy flour, respectively, within the 95 % confidence level. The lower limit of detection for (137)Cs ranged from 0.04 to 0.4 Bq kg(-1). The highest committed effective dose was 0.36 μSv.y(-1) for (228)Ra in cassava flour (adults). All committed effective doses determined at the present work were lower than the International Atomic Energy Agency dose limit of 1 mSv.y(-1), to the public exposure.

Strategic effects of future environmental policy commitments: climate change, solar radiation management and correlated air pollutants.

PubMed

Qu, Jingwen; Silva, Emilson Caputo Delfino

2015-03-15

We study the effects of environmental policy commitments in a futuristic world in which solar radiation management (SRM) can be utilized to reduce climate change damages. Carbon and sulfur dioxide emissions (correlated pollutants) can be reduced through tradable permits. We show that if nations simultaneously commit to carbon permit policies, national SRM levels rise with carbon quotas. Alternatively, if they simultaneously commit to SRM policies, the global temperature falls with each unit increase in the global SRM level. A nation always wishes to be a leader in policymaking, but prefers carbon to SRM policymaking. The globe prefers SRM policy commitments. Copyright © 2014 Elsevier Ltd. All rights reserved.

WORKER INHALATION DOSE COEFFICIENTS FOR RADIONUCLIDES NOT PREVIOUSLY IDENTIFIED IN ICRP PUBLICATION 68

DOE Office of Scientific and Technical Information (OSTI.GOV)

McLaughlin, David A; Schwahn, Scott O

2011-01-01

While inhalation dose coefficients are provided for about 800 radionuclides in International Commission on Radiological Protection (ICRP) Publication 68, many radionuclides of practical dosimetric interest for facilities such as high-energy proton accelerators are not specifically addressed, nor are organ-specific dose coefficients tabulated. The ICRP Publication 68 methodology is used, along with updated radiological decay data and metabolic data, to identify committed equivalent dose coefficients [hT(50)] and committed effective dose coefficients [e(50)] for radionuclides produced at the Oak Ridge National Laboratory s Spallation Neutron Source.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mayr, Nina A., E-mail: ninamayr@uw.edu; Hu, Kenneth S.; Liao, Zhongxing

In this era of globalization and rapid advances in radiation oncology worldwide, the American Society for Radiation Oncology (ASTRO) is committed to help decrease profound regional disparities through the work of the International Education Subcommittee (IES). The IES has expanded its base, reach, and activities to foster educational advances through a variety of educational methods with broad scope, in addition to committing to the advancement of radiation oncology care for cancer patients around the world, through close collaboration with our sister radiation oncology societies and other educational, governmental, and organizational groups.

Radiological Risk Assessment of Capstone Depleted Uranium Aerosols

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hahn, Fletcher; Roszell, Laurie E.; Daxon, Eric G.

2009-02-26

Assessment of the health risk from exposure to aerosols of depleted uranium (DU) is an important outcome of the Capstone aerosol studies that established exposure ranges to personnel in armored combat vehicles perforated by DU munitions. Although the radiation exposure from DU is low, there is concern that DU deposited in the body may increase cancer rates. Radiation doses to various organs of the body resulting from the inhalation of DU aerosols measured in the Capstone studies were calculated using International Commission on Radiological Protection (ICRP) models. Organs and tissues with the highest calculated committed equivalent 50-yr doses were lungmore » and extrathoracic tissues (nose and nasal passages, pharynx, larynx, mouth and thoracic lymph nodes). Doses to the bone surface and kidney were about 5 to 10% of the doses to the extrathoracic tissues. The methodologies of the ICRP International Steering Committee on Radiation Standards (ISCORS) were used for determining the whole body cancer risk. Organ-specific risks were estimated using ICRP and U.S. Environmental Protection Agency (EPA) methodologies. Risks for crewmembers and first responders were determined for selected scenarios based on the time interval of exposure and for vehicle and armor type. The lung was the organ with the highest cancer mortality risk, accounting for about 97% of the risks summed from all organs. The highest mean lifetime risk for lung cancer for the scenario with the longest exposure time interval (2 h) was 0.42%. This risk is low compared with the natural or background risk of 7.35%. These risks can be significantly reduced by using an existing ventilation system (if operable) and by reducing personnel time in the vehicle immediately after perforation.« less

Estimates of radiological risk from depleted uranium weapons in war scenarios.

PubMed

Durante, Marco; Pugliese, Mariagabriella

2002-01-01

Several weapons used during the recent conflict in Yugoslavia contain depleted uranium, including missiles and armor-piercing incendiary rounds. Health concern is related to the use of these weapons, because of the heavy-metal toxicity and radioactivity of uranium. Although chemical toxicity is considered the more important source of health risk related to uranium, radiation exposure has been allegedly related to cancers among veterans of the Balkan conflict, and uranium munitions are a possible source of contamination in the environment. Actual measurements of radioactive contamination are needed to assess the risk. In this paper, a computer simulation is proposed to estimate radiological risk related to different exposure scenarios. Dose caused by inhalation of radioactive aerosols and ground contamination induced by Tomahawk missile impact are simulated using a Gaussian plume model (HOTSPOT code). Environmental contamination and committed dose to the population resident in contaminated areas are predicted by a food-web model (RESRAD code). Small values of committed effective dose equivalent appear to be associated with missile impacts (50-y CEDE < 5 mSv), or population exposure by water-independent pathways (50-y CEDE < 80 mSv). The greatest hazard is related to the water contamination in conditions of effective leaching of uranium in the groundwater (50-y CEDE < 400 mSv). Even in this worst case scenario, the chemical toxicity largely predominates over radiological risk. These computer simulations suggest that little radiological risk is associated to the use of depleted uranium weapons.

A bioassay experience and lessons learned on the internal contamination of (131)I during a maintenance period in a Korean nuclear power plant.

PubMed

Kim, Hee Geun; Kong, Tae Young

2012-08-01

During a maintenance period at a Korean nuclear power plant, internal exposure of radiation workers occurred by the inhalation of (131)I that was released into the reactor building from a primary system opening due to defective fuels. The internal activity in radiation workers contaminated by (131)I was immediately measured using a whole body counter (WBC). A whole body counting was performed again a few days later, considering the factors of equilibrium in the body. The intake and the committed effective dose were estimated based on the WBC results. The intake was also calculated by hand, based on both the entrance records to the reactor building, and the counted results of the air concentration for (131)I were compared with the whole body counting results.

Environmental analysis burial of offsite low-level waste at SRP

NASA Astrophysics Data System (ADS)

Poe, W. L.; Moyer, R. A.

1980-12-01

The environmental effects of receipt and burial of low level naval waste are assessed. This low level waste was sent to the NRC-licensed burial ground operated by Chem-Nuclear Systems, Inc., at Barnwell, South Carolina. The DOE announced that DOE-generated low level waste would no longer be buried at commercial waste burial sites. The SRP was selected to receive the Naval waste described in this analysis. Receipt and burial of these wastes will have a negligible effect on SRP's environment and increase only sightly the environmental effects of the SRP operations discussed in the EIS on SRP waste management operations. The environmental effects of burial of this waste at Chem-Nuclear Burial Ground or at the SRP Burial Ground are described in this environmental analysis to permit assessment of incremental effects caused by the decision to bury this Naval waste in the SRP Burial Ground rather than in the Barnwell Burial Ground. The radiological effects from burial of this waste in either the SRP or Chem-Nuclear Burial Ground are very small when compared to those from natural background radiation or to the annual population dose commitment from operation of SRP. The environmental effects of burial at SRP to dose commitments normally received by the population surrounding SRP are compared.

Assessment of ²¹⁰Po in Italian diet.

PubMed

Meli, Maria Assunta; Desideri, Donatella; Roselli, Carla; Feduzi, Laura

2014-07-15

This research was dedicated to the study, in the Italian daily diet, of the background activity concentration of (210)Po, a radionuclide with a high radiotoxicity. (210)Po was determined by alpha spectrometry. For food products of vegetable origin, the (210)Po activity concentration follows the trend: leafy vegetable>flour>rice>fruits>pasta>other vegetables>fruit vegetable; for those of animal origin: eggs>cheese>milk. The (210)Po activity concentration was also compared with that found by the same authors in meat, sea food, water and beverages in a previous study. The committed effective doses to individuals of three population groups (infants, children and adults) were 379, 222 and 151 μSv y(-1), respectively. The intake of foods of marine origin contributed about 67% of the total dose due to (210)Po ingestion. The effective dose, from (210)Po ingested by total diet, accounts for only 5-12% of the natural radiation exposure in Italy. Copyright © 2014 Elsevier Ltd. All rights reserved.

Estimation of Radionuclide Concentrations and Average Annual Committed Effective Dose due to Ingestion for the Population in the Red River Delta, Vietnam.

PubMed

Van, Tran Thi; Bat, Luu Tam; Nhan, Dang Duc; Quang, Nguyen Hao; Cam, Bui Duy; Hung, Luu Viet

2018-02-16

Radioactivity concentrations of nuclides of the 232 Th and 238 U radioactive chains and 40 K, 90 Sr, 137 Cs, and 239+240 Pu were surveyed for raw and cooked food of the population in the Red River delta region, Vietnam, using α-, γ-spectrometry, and liquid scintillation counting techniques. The concentration of 40 K in the cooked food was the highest compared to those of other radionuclides ranging from (23 ± 5) (rice) to (347 ± 50) Bq kg -1 dw (tofu). The 210 Po concentration in the cooked food ranged from its limit of detection (LOD) of 5 mBq kg -1  dw (rice) to (4.0 ± 1.6) Bq kg -1  dw (marine bivalves). The concentrations of other nuclides of the 232 Th and 238 U chains in the food were low, ranging from LOD of 0.02 Bq kg -1  dw to (1.1 ± 0.3) Bq kg -1  dw. The activity concentrations of 90 Sr, 137 Cs, and 239+240 Pu in the food were minor compared to that of the natural radionuclides. The average annual committed effective dose to adults in the study region was estimated and it ranged from 0.24 to 0.42 mSv a -1 with an average of 0.32 mSv a -1 , out of which rice, leafy vegetable, and tofu contributed up to 16.2%, 24.4%, and 21.3%, respectively. The committed effective doses to adults due to ingestion of regular diet in the Red River delta region, Vietnam are within the range determined in other countries worldwide. This finding suggests that Vietnamese food is safe for human consumption with respect to radiation exposure.

Protracted exposure to fallout: the Rongelap and Utirik experience.

PubMed

Lessard, E T; Miltenberger, R P; Cohn, S H; Musolino, S V; Conard, R A

1984-03-01

From June 1946 to August 1958, the U.S. Department of Defense and the U.S. Atomic Energy Commission (AEC) conducted nuclear weapons tests in the Northern Marshall Islands. On 1 March 1954, BRAVO, an above-ground test in the Castle series, produced high levels of radioactive material, some of which subsequently fell on Rongelap and Utirik Atolls due to an unexpected wind shift. On 3 March 1954, the inhabitants of these atolls were moved out of the affected area. They later returned to Utirik in June 1954 and to Rongelap in June 1957. Comprehensive environmental and personnel radiological monitoring programs were initiated in the mid 1950s by Brookhaven National Laboratory to ensure that body burdens of the exposed Marshallese subjects remained within AEC guidelines. Their body-burden histories and calculated activity ingestion rate patterns post-return are presented along with estimates of internal committed effective dose equivalents. External exposure data are also included. In addition, relationships between body burden or urine-activity concentration and declining continuous intake were developed. The implications of these studies are: (1) the dietary intake of 137Cs was a major component contributing to the committed effective dose equivalent for the years after the initial contamination of the atolls; (2) for persons whose diet included fish, 65Zn was a major component of committed effective dose equivalent during the first years post-return; (3) a decline in the daily activity ingestion rate greater than that resulting from radioactive decay of the source was estimated for 137Cs, 65Zn, 90Sr and 60Co; (4) the relative impact of each nuclide on the estimate of committed effective dose equivalent was dependent upon the time interval between initial contamination and rehabilitation; and (5) the internal committed effective dose equivalent exceeded the external dose equivalent by a factor of 1.1 at Utirik and 1.5 at Rongelap during the rehabitation period. Few reliable 239Pu measurements on human excreta were made. An analysis of the tentative data leads to the conclusion that a reliable estimate of committed effective dose equivalent requires further research.

Cancer Risk Assessment for Space Radiation

NASA Technical Reports Server (NTRS)

Richmond, Robert C.; Cruz, Angela; Bors, Karen; Curreri, Peter A. (Technical Monitor)

2001-01-01

Predicting the occurrence of human cancer following exposure to any agent causing genetic damage is a difficult task. This is because the uncertainty of uniform exposure to the damaging agent, and the uncertainty of uniform processing of that damage within a complex set of biological variables, degrade the confidence of predicting the delayed expression of cancer as a relatively rare event within any given clinically normal individual. The radiation health research priorities for enabling long-duration human exploration of space were established in the 1996 NRC Report entitled 'Radiation Hazards to Crews of Interplanetary Missions: Biological Issues and Research Strategies'. This report emphasized that a 15-fold uncertainty in predicting radiation-induced cancer incidence must be reduced before NASA can commit humans to extended interplanetary missions. That report concluded that the great majority of this uncertainty is biologically based, while a minority is physically based due to uncertainties in radiation dosimetry and radiation transport codes. Since that report, the biologically based uncertainty has remained large, and the relatively small uncertainty associated with radiation dosimetry has increased due to the considerations raised by concepts of microdosimetry. In a practical sense, however, the additional uncertainties introduced by microdosimetry are encouraging since they are in a direction of lowered effective dose absorbed through infrequent interactions of any given cell with the high energy particle component of space radiation. Additional information is contained in the original extended abstract.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Podonsky, Glenn S.

The U.S. Department of Energy (DOE) Office of Analysis within the Office of Health, Safety and Security (HSS) publishes the annual DOE Occupational Radiation Exposure Report to provide an overview of the status of radiation protection practices at DOE (including the National Nuclear Security Administration [NNSA]). The DOE 2012 Occupational Radiation Exposure Report provides an evaluation of DOE-wide performance regarding compliance with Title 10, Code of Federal Regulations (C.F.R.), Part 835, Occupational Radiation Protection dose limits and as low as reasonably achievable (ALARA) process requirements. In addition, the report provides data to DOE organizations responsible for developing policies for protectionmore » of individuals from the adverse health effects of radiation. The report provides a summary and an analysis of occupational radiation exposure information from the monitoring of individuals involved in DOE activities. Over the past 5-year period, the occupational radiation exposure information is analyzed in terms of aggregate data, dose to individuals, and dose by site. As an indicator of the overall amount of radiation dose received during the conduct of operations at DOE, the report includes information on collective total effective dose (TED). The TED is comprised of the effective dose (ED) from external sources, which includes neutron and photon radiation, and the internal committed effective dose (CED), which results from the intake of radioactive material into the body. The collective ED from photon exposure decreased by 23% between 2011 and 2012, while the neutron dose increased by 5%. The internal dose components of the collective TED decreased by 7%. Over the past 5-year period, 99.99% of the individuals receiving measurable TED have received doses below the 2 roentgen equivalent in man (rems) (20 millisievert [mSv]) TED administrative control level (ACL), which is well below the DOE regulatory limit of 5 rems (50 mSv) TED annually. The occupational radiation exposure records show that in 2012, DOE facilities continued to comply with DOE dose limits and ACLs and worked to minimize exposure to individuals. The DOE collective TED decreased 17.1% from 2011 to 2012. The collective TED decreased at three of the five sites with the largest collective TED. u Idaho Site – Collective dose reductions were achieved as a result of continuing improvements at the Advanced Mixed Waste Treatment Project (AMWTP) through the planning of drum movements that reduced the number of times a container is handled; placement of waste containers that created highradiation areas in a centralized location; and increased worker awareness of high-dose rate areas. In addition, Idaho had the largest decrease in the total number of workers with measurable TED (1,143 fewer workers). u Hanford Site (Hanford) – An overall reduction of decontamination and decommissioning (D&D) activities at the Plutonium Finishing Plant (PFP) and Transuranic (TRU) retrieval activities resulted in collective dose reductions. u Savannah River Site (SRS) – Reductions were achieved through ALARA initiatives employed site wide. The Solid Waste Management Facility used extended specialty tools, cameras and lead shield walls to facilitate removal of drums. These tools and techniques reduce exposure time through improved efficiency, increase distance from the source of radiation by remote monitoring, shield the workers to lower the dose rate, and reduce the potential for contamination and release of material through repacking of waste. Overall, from 2011 to 2012, there was a 19% decrease in the number of workers with measurable dose. Furthermore, due to a slight decrease in both the DOE workforce (7%) and monitored workers (10%), the ratio of workers with measurable doses to monitored workers decreased to 13%. Another primary indicator of the level of radiation exposure covered in this report is the average measurable dose, which normalizes the collective dose over the population of workers who actually received a measurable dose. The average measurable TED increased by 3% from 2011 to 2012. Additional analyses show that the dose distribution in 2012 was similar to the distribution in 2011. In 2012, 13% of the monitored workers received a measurable TED and the average measurable TED, 0.069 rem, was less than 2% of the DOE limit. From 2011 to 2012, the collective TED and the number of individuals with measurable TED decreased 17.1% and 19%, respectively. These decreases were mainly due to an overall reduction of D&D activities at the PFP and TRU retrieval activities at Hanford; a 78% decrease in the number of targeted waste drums that were processed at the Idaho Site’s Accelerated Retrieval Project (ARP) from 5,566 drums in 2011 to a total of 1,211 drums processed in 2012; and ALARA initiatives employed site wide at SRS. In addition, the decreases were the result of decreased American Recovery and Reinvestment Act (ARRA) activities and continuing D&D, particularly at the DOE sites that comprise the majority of DOE collective dose. Over the past 5 years, the size of the monitored workforce has remained at a fairly stable level (within 12%), while the collective dose has varied up to 37%. No reported doses exceeded the DOE occupational limit of 5 rems TED in 2012 and no reported doses exceeded the DOE ACL of 2 rems TED.« less

Natural radioactivity measurements and dosimetric evaluations in soil samples with a high content of NORM

NASA Astrophysics Data System (ADS)

Caridi, F.; Marguccio, S.; Durante, G.; Trozzo, R.; Fullone, F.; Belvedere, A.; D'Agostino, M.; Belmusto, G.

2017-01-01

In this article natural radioactivity measurements and dosimetric evaluations in soil samples contaminated by Naturally Occurring Radioactive Materials (NORM) are made, in order to assess any possible radiological hazard for the population and for workers professionally exposed to ionizing radiations. Investigated samples came from the district of Crotone, Calabria region, South of Italy. The natural radioactivity investigation was performed by high-resolution gamma-ray spectrometry. From the measured gamma spectra, activity concentrations were determined for 226Ra , 234-mPa , 224Ra , 228Ac and 40K and compared with their clearance levels for NORM. The total effective dose was calculated for each sample as due to the committed effective dose for inhalation and to the effective dose from external irradiation. The sum of the total effective doses estimated for all investigated samples was compared to the action levels provided by the Italian legislation (D.Lgs.230/95 and subsequent modifications) for the population members (0.3mSv/y) and for professionally exposed workers (1mSv/y). It was found to be less than the limit of no radiological significance (10μSv/y).

Radiological risk assessment of Capstone depleted uranium aerosols.

PubMed

Hahn, Fletcher F; Roszell, Laurie E; Daxon, Eric G; Guilmette, Raymond A; Parkhurst, Mary Ann

2009-03-01

Assessment of the health risk from exposure to aerosols of depleted uranium (DU) is an important outcome of the Capstone aerosol studies that established exposure ranges to personnel in armored combat vehicles perforated by DU munitions. Although the radiation exposure from DU is low, there is concern that DU deposited in the body may increase cancer rates. Radiation doses to various organs of the body resulting from the inhalation of DU aerosols measured in the Capstone studies were calculated using International Commission on Radiological Protection (ICRP) models. Organs and tissues with the highest calculated committed equivalent 50-y doses were lung and extrathoracic tissues (nose and nasal passages, pharynx, larynx, mouth, and thoracic lymph nodes). Doses to the bone surface and kidney were about 5 to 10% of the doses to the extrathoracic tissues. Organ-specific risks were estimated using ICRP and U.S. Environmental Protection Agency (EPA) methodologies. Risks for crewmembers and first responders were determined for selected scenarios based on the time interval of exposure and for vehicle and armor type. The lung was the organ with the highest cancer mortality risk, accounting for about 97% of the risks summed from all organs. The highest mean lifetime risk for lung cancer for the scenario with the longest exposure time interval (2 h) was 0.42%. This risk is low compared with the natural or background risk of 7.35%. These risks can be significantly reduced by using an existing ventilation system (if operable) and by reducing personnel time in the vehicle immediately after perforation.

Clinical imaging guidelines part 2: Risks, benefits, barriers, and solutions.

PubMed

Malone, James; del Rosario-Perez, Maria; Van Bladel, Lodewijk; Jung, Seung Eun; Holmberg, Ola; Bettmann, Michael A

2015-02-01

A recent international meeting was convened by two United Nations bodies to focus on international collaboration on clinical appropriateness/referral guidelines for use in medical imaging. This paper, the second of 4 from this technical meeting, addresses barriers to the successful development/deployment of clinical imaging guidelines and means of overcoming them. It reflects the discussions of the attendees, and the issues identified are treated under 7 headings: ■ Practical Strategy for Development and Deployment of Guidelines; ■ Governance Arrangements and Concerns with Deployment of Guidelines; ■ Finance, Sustainability, Reimbursement, and Related Issues; ■ Identifying Benefits and Radiation Risks from Radiological Examinations; ■ Information Given to Patients and the Public, and Consent Issues; ■ Special Concerns Related to Pregnancy; and ■ The Research Agenda. Examples of topics identified include the observation that guideline development is a global task and there is no case for continuing it as the project of the few professional organizations that have been brave enough to make the long-term commitment required. Advocacy for guidelines should include the expectations that they will facilitate: (1) better health care delivery; (2) lower cost of that delivery; with (3) reduced radiation dose and associated health risks. Radiation protection issues should not be isolated; rather, they should be integrated with the overall health care picture. The type of dose/radiation risk information to be provided with guidelines should include the uncertainty involved and advice on application of the precautionary principle with patients. This principle may be taken as an extension of the well-established medical principle of "first do no harm." Copyright © 2015. Published by Elsevier Inc.

NCI–RTOG Translational Program Strategic Guidelines for the Early-Stage Development of Radiosensitizers

PubMed Central

2013-01-01

The addition of chemotherapeutic agents to ionizing radiation has improved survival in many malignancies. Cure rates may be further improved by adding novel targeted agents to current radiotherapy or radiochemotherapy regimens. Despite promising laboratory data, progress in the clinical development of new drugs with radiation has been limited. To define and address the problems involved, a collaborative effort between individuals within the translational research program of the Radiation Oncology Therapy Group and the National Cancer Institute was established. We discerned challenges to drug development with radiation including: 1) the limited relevance of preclinical work, 2) the pharmaceutical industry’s diminished interest, and 3) the important individual skills and institutional commitments required to ensure a successful program. The differences between early-phase trial designs with and without radiation are noted as substantial. The traditional endpoints for early-phase clinical trials—acute toxicity and maximum-tolerated dose—are of limited value when combining targeted agents with radiation. Furthermore, response rate is not a useful surrogate marker of activity in radiation combination trials.Consequently, a risk-stratified model for drug-dose escalation with radiation is proposed, based upon the known and estimated adverse effects. The guidelines discuss new clinical trial designs, such as the time-to-event continual reassessment method design for phase I trials, randomized phase II “screening” trials, and the use of surrogate endpoints, such as pathological response. It is hoped that by providing a clear pathway, this article will accelerate the rate of drug development with radiation. PMID:23231975

The influence of particle size distribution on dose conversion factors for radon progeny in the underground excavations of hard coal mine.

PubMed

Skubacz, Krystian; Wojtecki, Łukasz; Urban, Paweł

2016-10-01

In Polish underground mines, hazards caused by enhanced natural radioactivity occur. The sources of radiation exposure are short-lived radon decay products, mine waters containing radium 226 Ra and 228 Ra and the radioactive sediments that can precipitate out of these waters. For miners, the greatest exposure is usually due to short-lived radon decay products. The risk assessment is based on the measurement of the total potential alpha energy concentration (PAEC) and the evaluation of the related dose by using the dose conversion factor as recommended by relevant legal requirements. This paper presents the results of measurements of particle size distributions of ambient aerosols in an underground hard coal mine, the assessment of the radioactive particle size distribution of the short-lived radon decay products and the corresponding values of dose conversion factors. The measurements of the ambient airborne particle size distribution were performed in the range from a few nanometers to about 20 μm. The study therefore included practically the whole class of respirable particles. The results showed that the high concentration of ultrafine and fine aerosols measured can significantly affect the value of the dose conversion factors, and consequently the corresponding committed effective dose, to which the miners can be exposed. Copyright © 2016 Elsevier Ltd. All rights reserved.

In vitro and in vivo assessment of direct effects of simulated solar and galactic cosmic radiation on human hematopoietic stem/progenitor cells.

PubMed

Rodman, C; Almeida-Porada, G; George, S K; Moon, J; Soker, S; Pardee, T; Beaty, M; Guida, P; Sajuthi, S P; Langefeld, C D; Walker, S J; Wilson, P F; Porada, C D

2017-06-01

Future deep space missions to Mars and near-Earth asteroids will expose astronauts to chronic solar energetic particles (SEP) and galactic cosmic ray (GCR) radiation, and likely one or more solar particle events (SPEs). Given the inherent radiosensitivity of hematopoietic cells and short latency period of leukemias, space radiation-induced hematopoietic damage poses a particular threat to astronauts on extended missions. We show that exposing human hematopoietic stem/progenitor cells (HSC) to extended mission-relevant doses of accelerated high-energy protons and iron ions leads to the following: (1) introduces mutations that are frequently located within genes involved in hematopoiesis and are distinct from those induced by γ-radiation; (2) markedly reduces in vitro colony formation; (3) markedly alters engraftment and lineage commitment in vivo; and (4) leads to the development, in vivo, of what appears to be T-ALL. Sequential exposure to protons and iron ions (as typically occurs in deep space) proved far more deleterious to HSC genome integrity and function than either particle species alone. Our results represent a critical step for more accurately estimating risks to the human hematopoietic system from space radiation, identifying and better defining molecular mechanisms by which space radiation impairs hematopoiesis and induces leukemogenesis, as well as for developing appropriately targeted countermeasures.

In vitro and in vivo assessment of direct effects of simulated solar and galactic cosmic radiation on human hematopoietic stem/progenitor cells

DOE PAGES

Rodman, C.; Almeida-Porada, G.; George, S. K.; ...

2016-11-24

Future deep space missions to Mars and near-Earth asteroids will expose astronauts to chronic solar energetic particles (SEP) and galactic cosmic ray (GCR) radiation,and likely one or more solar particle events (SPEs).Given the inherent radiosensitivity of hematopoietic cells and short latency period of leukemias, space radiation-induced hematopoietic damage poses a particular threat to astronauts on extended missions.We show that exposing human hematopoietic stem/progenitor cells(HSC) toextended mission-relevant doses of accelerated high-energyprotons andiron ions leads to the following: (1) introduces mutations that are frequently located within genes involved in hematopoiesis and are distinct from those induced by γ-radiation; (2) markedly reduces inmore » vitro colony formation; (3)markedly alters engraftment and lineage commitment in vivo; and (4) leads to the development, in vivo, ofwhat appears to be T-ALL. Sequential exposure to protons and iron ions (as typically occurs in deep space) proved far more deleterious to HSC genome integrity and function than either particle species alone.Our results represent a critical step for more accurately estimating risks to the human hematopoietic system from space radiation, identifying and better defining molecular mechanisms by which space radiation impairs hematopoiesis and induces leukemogenesis, as well as for developing appropriately targeted countermeasures.« less

In vitro and in vivo assessment of direct effects of simulated solar and galactic cosmic radiation on human hematopoietic stem/progenitor cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodman, C.; Almeida-Porada, G.; George, S. K.

Future deep space missions to Mars and near-Earth asteroids will expose astronauts to chronic solar energetic particles (SEP) and galactic cosmic ray (GCR) radiation,and likely one or more solar particle events (SPEs).Given the inherent radiosensitivity of hematopoietic cells and short latency period of leukemias, space radiation-induced hematopoietic damage poses a particular threat to astronauts on extended missions.We show that exposing human hematopoietic stem/progenitor cells(HSC) toextended mission-relevant doses of accelerated high-energyprotons andiron ions leads to the following: (1) introduces mutations that are frequently located within genes involved in hematopoiesis and are distinct from those induced by γ-radiation; (2) markedly reduces inmore » vitro colony formation; (3)markedly alters engraftment and lineage commitment in vivo; and (4) leads to the development, in vivo, ofwhat appears to be T-ALL. Sequential exposure to protons and iron ions (as typically occurs in deep space) proved far more deleterious to HSC genome integrity and function than either particle species alone.Our results represent a critical step for more accurately estimating risks to the human hematopoietic system from space radiation, identifying and better defining molecular mechanisms by which space radiation impairs hematopoiesis and induces leukemogenesis, as well as for developing appropriately targeted countermeasures.« less

Analysis of 238U, 232Th, 222Rn, and 220Rn in different medical drug preparations by using CR-39 and LR-115 typE II SSNTDs and resulting radiation doses to adult patients.

PubMed

Misdaq, M A; Karime, M

2009-01-01

Uranium (238U) and thorium (232Th) concentrations as well as radon (222Rn) and thoron (220Rn) alpha activities per unit volume have been measured inside 18 medical drugs (4 liquid and 14 solid materials), widely prescribed by doctors to the Moroccan adult patients, by using CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs). The measured 238U, 232Th, 222Rn, and 220Rn concentrations ranged from (4.7 +/- 0.1) mBq L-1 to (14.3 +/- 0.7) mBq L-1, (0.32 +/- 0.02) mBq L-1 to (2.7 +/- 0.2) mBq L-1, (4.7 +/- 0.2) Bq L-1 to (14.3 +/- 0.7) Bq L-1, and (0.32 +/- 0.02) Bq L-1 to (2.7 +/- 0.2) Bq L-1 for the medical drug samples studied, respectively. These radionuclides were also measured inside the preparations of the solid medical drugs studied. The influence of the drinking water nature and pollution on the concentrations of these radionuclides inside the considered medical drug preparations was investigated. Annual committed equivalent doses due to 238U, 232Th, and 222Rn were evaluated in the human body compartments of adult patients from the ingestion of the medical drug preparations studied. The maximum total committed effective dose due to 238U, 232Th, and 222Rn from the ingestion of the studied medical drug preparations, prepared from unpolluted waters, by adult patients was found equal to 1.44 microSv y.

Cancer Risk Assessment for Space Radiation

NASA Technical Reports Server (NTRS)

Richmond, Robert C.; Curreri, Peter A. (Technical Monitor)

2002-01-01

Predicting the occurrence of human cancer following exposure to any agent causing genetic damage is a difficult task. This is because the uncertainty of uniform exposure to the damaging agent, and the uncertainty of uniform processing of that damage within a complex set of biological variables, degrade the confidence of predicting the delayed expression of cancer as a relatively rare event within any given clinically normal individual. The radiation health research priorities for enabling long-duration human exploration of space were established in the 1996 NRC Report entitled "Radiation Hazards to Crews of Interplanetary Missions: Biological Issues and Research Strategies". This report emphasized that a 15-fold uncertainty in predicting radiation-induced cancer incidence must be reduced before NASA can commit humans to extended interplanetary missions. That report concluded that the great majority of this uncertainty is biologically based, while a minority is physically based due to uncertainties in radiation dosimetry and radiation transport codes. Since that report, the biologically based uncertainty has remained large, and the relatively small uncertainty associated with radiation dosimetry has increased due to the considerations raised by concepts of microdosimetry. In a practical sense, however, the additional uncertainties introduced by microdosimetry are encouraging since they are in a direction of lowered effective dose absorbed through infrequent interactions of any given cell with the high energy particle component of space radiation. The biological uncertainty in predicting cancer risk for space radiation derives from two primary facts. 1) One animal tumor study has been reported that includes a relevant spectrum of particle radiation energies, and that is the Harderian gland model in mice. Fact #1: Extension of cancer risk from animal models, and especially from a single study in an animal model, to humans is inherently uncertain. 2) One human database is predominantly used for assessing cancer risk caused by space radiation, and that is the Japanese atomic bomb survivors. Fact #2: The atomic-bomb-survivor database, itself a remarkable achievement, contains uncertainties. These include the actual exposure to each individual, the radiation quality of that exposure, and the fact that the exposure was to acute doses of predominantly low-LET radiation, not to chronic exposures of high-LET radiation expected on long-duration interplanetary manned missions.

Mesenchymal stromal cells having inactivated RB1 survive following low irradiation and accumulate damaged DNA: Hints for side effects following radiotherapy.

PubMed

Alessio, Nicola; Capasso, Stefania; Di Bernardo, Giovanni; Cappabianca, Salvatore; Casale, Fiorina; Calarco, Anna; Cipollaro, Marilena; Peluso, Gianfranco; Galderisi, Umberto

2017-02-01

Following radiotherapy, bone sarcomas account for a significant percentage of recurring tumors. This risk is further increased in patients with hereditary retinoblastoma that undergo radiotherapy. We analyzed the effect of low and medium dose radiation on mesenchymal stromal cells (MSCs) with inactivated RB1 gene to gain insights on the molecular mechanisms that can induce second malignant neoplasm in cancer survivors. MSC cultures contain subpopulations of mesenchymal stem cells and committed progenitors that can differentiate into mesodermal derivatives: adipocytes, chondrocytes, and osteocytes. These stem cells and committed osteoblast precursors are the cell of origin in osteosarcoma, and RB1 gene mutations have a strong role in its pathogenesis. Following 40 and 2000 mGy X-ray exposure, MSCs with inactivated RB1 do not proliferate and accumulate high levels of unrepaired DNA as detected by persistence of gamma-H2AX foci. In samples with inactivated RB1 the radiation treatment did not increase apoptosis, necrosis or senescence versus untreated cells. Following radiation, CFU analysis showed a discrete number of cells with clonogenic capacity in cultures with silenced RB1. We extended our analysis to the other members of retinoblastoma gene family: RB2/P130 and P107. Also in the MSCs with silenced RB2/P130 and P107 we detected the presence of cells with unrepaired DNA following X-ray irradiation. Cells with unrepaired DNA may represent a reservoir of cells that may undergo neoplastic transformation. Our study suggests that, following radiotherapy, cancer patients with mutations of retinoblastoma genes may be under strict controls to evaluate onset of secondary neoplasms following radiotherapy.

Measurement of the concentration of radon gas in the Toirano's caves (Liguria).

PubMed

Bruzzone, Diego; Bussallino, Massimo; Castello, Gianrico; Maggiolo, Stefano; Rossi, Daniela

2006-01-01

The radioactive gas radon, intermediate term of the decay series of uranium and thorium, is the main contamination source of underground places and may be a risk for high concentration and long exposure time. European and Italian law requires radon concentration to be measured in workplaces and, if the "action level" of 500 Bq/m3 is reached, proper actions must be made in order to decrease the dose commitment. Considering natural showcaves or artificial cavities open to public, the exposition of the visitors is frequently small, due to the short residence time, but accompanying people, remaining underground for long time, may be subject to appreciable dose and the radon concentration should therefore be monitored. The high humidity in natural caves may impair the use of some measuring devices. Therefore, different detection methods were compared (ZnS scintillation counters, E-PERM electret ionisation chambers, cellulose nitrate alpha-track dosimeters) to select the best procedure for long-term investigation. The LR-115 (Kodak) alpha-track dosimeters were insensitive to humidity and permitted to monitor a great number of places at the same time. Measurements have been carried out in the speleological and archaeological site of the Toirano's Caves (Savona, Liguria, Italy) and several points were monitored for two years. Radon concentration strongly depends on the site and changes during the year, due to the difference between internal and external temperature. The maximum dose commitment during the visitors tour, considering the average yearly value of radon concentration, was found to be between 1.5 and 4 microSv. It was found that no risk exists for visitors, but the evaluation of the dose absorbed by the guides and their classification according to the radiation protection law requires a complete monitoring of the average yearly concentration of radon and of the total time spent by each worker into the cave.

A Comprehensive Quality Assurance Program for Personnel and Procedures in Radiation Oncology: Value of Voluntary Error Reporting and Checklists

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalapurakal, John A., E-mail: j-kalapurakal@northwestern.edu; Zafirovski, Aleksandar; Smith, Jeffery

Purpose: This report describes the value of a voluntary error reporting system and the impact of a series of quality assurance (QA) measures including checklists and timeouts on reported error rates in patients receiving radiation therapy. Methods and Materials: A voluntary error reporting system was instituted with the goal of recording errors, analyzing their clinical impact, and guiding the implementation of targeted QA measures. In response to errors committed in relation to treatment of the wrong patient, wrong treatment site, and wrong dose, a novel initiative involving the use of checklists and timeouts for all staff was implemented. The impactmore » of these and other QA initiatives was analyzed. Results: From 2001 to 2011, a total of 256 errors in 139 patients after 284,810 external radiation treatments (0.09% per treatment) were recorded in our voluntary error database. The incidence of errors related to patient/tumor site, treatment planning/data transfer, and patient setup/treatment delivery was 9%, 40.2%, and 50.8%, respectively. The compliance rate for the checklists and timeouts initiative was 97% (P<.001). These and other QA measures resulted in a significant reduction in many categories of errors. The introduction of checklists and timeouts has been successful in eliminating errors related to wrong patient, wrong site, and wrong dose. Conclusions: A comprehensive QA program that regularly monitors staff compliance together with a robust voluntary error reporting system can reduce or eliminate errors that could result in serious patient injury. We recommend the adoption of these relatively simple QA initiatives including the use of checklists and timeouts for all staff to improve the safety of patients undergoing radiation therapy in the modern era.« less

Radiation Protection

MedlinePlus

... Offices Regional Offices Labs and Research Centers Radiation Protection Contact Us Share Dose Calculator Use the Radiation ... the Office of Air and Radiation (OAR) Radiation Protection Radiation Sources and Doses Calculate Your Radiation Dose ...

Comparative transcriptome analysis of rice seedlings induced by different doses of heavy ion radiation

NASA Astrophysics Data System (ADS)

Zhao, Qian; Sun, Yeqing; Wang, Wei

2016-07-01

Highly ionizing radiation (HZE) in space is considered as a main factor causing biological effects on plant seeds. To investigate the different effects on genome-wide gene expression of low-dose and high-dose ion radiation, we carried out ground-base carbon particle HZE experiments with different cumulative doses (0Gy, 0.2Gy, 2Gy) to rice seeds and then performed comparative transcriptome analysis of the rice seedlings. We identified a total of 2551 and 1464 differentially expressed genes (DEGs) in low-dose and high-dose radiation groups, respectively. Gene ontology analyses indicated that low-dose and high-dose ion radiation both led to multiple physiological and biochemical activities changes in rice. By Gene Ontology analyses, the results showed that only one process-oxidation reduction process was enriched in the biological process category after high-dose ion radiation, while more processes such as response to biotic stimulus, heme binding, tetrapyrrole binding, oxidoreductase activity, catalytic activity and oxidoreductase activity were significantly enriched after low-dose ion radiation. The results indicated that the rice plants only focused on the process of oxidation reduction to response to high-dose ion radiation, whereas it was a coordination of multiple biological processes to response to low-dose ion radiation. To elucidate the transcriptional regulation of radiation stress-responsive genes, we identified several DEGs-encoding TFs. AP2/EREBP, bHLH, C2H2, MYB and WRKY TF families were altered significantly in response to ion radiation. Mapman analysis speculated that the biological effects on rice seedlings caused by the radiation stress might share similar mechanisms with the biotic stress. Our findings highlight important alterations in the expression of radiation response genes, metabolic pathways, and TF-encoding genes in rice seedlings exposed to low-dose and high-dose ion radiation.

Radiation Hormesis: Historical Perspective and Implications for Low-Dose Cancer Risk Assessment

PubMed Central

Vaiserman, Alexander M.

2010-01-01

Current guidelines for limiting exposure of humans to ionizing radiation are based on the linear-no-threshold (LNT) hypothesis for radiation carcinogenesis under which cancer risk increases linearly as the radiation dose increases. With the LNT model even a very small dose could cause cancer and the model is used in establishing guidelines for limiting radiation exposure of humans. A slope change at low doses and dose rates is implemented using an empirical dose and dose rate effectiveness factor (DDREF). This imposes usually unacknowledged nonlinearity but not a threshold in the dose-response curve for cancer induction. In contrast, with the hormetic model, low doses of radiation reduce the cancer incidence while it is elevated after high doses. Based on a review of epidemiological and other data for exposure to low radiation doses and dose rates, it was found that the LNT model fails badly. Cancer risk after ordinarily encountered radiation exposure (medical X-rays, natural background radiation, etc.) is much lower than projections based on the LNT model and is often less than the risk for spontaneous cancer (a hormetic response). Understanding the mechanistic basis for hormetic responses will provide new insights about both risks and benefits from low-dose radiation exposure. PMID:20585444

10 CFR 60.136 - Preclosure controlled area.

Code of Federal Regulations, 2010 CFR

2010-01-01

... limiting of a total effective dose equivalent of 0.05 Sv (5 rem), or the sum of the deep-dose equivalent and the committed dose equivalent to any individual organ or tissue (other than the lens of the eye) of 0.5 Sv (50 rem). The eye dose equivalent shall not exceed 0.15 Sv (15 rem), and the shallow dose...

10 CFR 60.136 - Preclosure controlled area.

Code of Federal Regulations, 2011 CFR

2011-01-01

... limiting of a total effective dose equivalent of 0.05 Sv (5 rem), or the sum of the deep-dose equivalent and the committed dose equivalent to any individual organ or tissue (other than the lens of the eye) of 0.5 Sv (50 rem). The eye dose equivalent shall not exceed 0.15 Sv (15 rem), and the shallow dose...

10 CFR 60.136 - Preclosure controlled area.

Code of Federal Regulations, 2013 CFR

2013-01-01

... limiting of a total effective dose equivalent of 0.05 Sv (5 rem), or the sum of the deep-dose equivalent and the committed dose equivalent to any individual organ or tissue (other than the lens of the eye) of 0.5 Sv (50 rem). The eye dose equivalent shall not exceed 0.15 Sv (15 rem), and the shallow dose...

10 CFR 60.136 - Preclosure controlled area.

Code of Federal Regulations, 2012 CFR

2012-01-01

... limiting of a total effective dose equivalent of 0.05 Sv (5 rem), or the sum of the deep-dose equivalent and the committed dose equivalent to any individual organ or tissue (other than the lens of the eye) of 0.5 Sv (50 rem). The eye dose equivalent shall not exceed 0.15 Sv (15 rem), and the shallow dose...

10 CFR 60.136 - Preclosure controlled area.

Code of Federal Regulations, 2014 CFR

2014-01-01

... limiting of a total effective dose equivalent of 0.05 Sv (5 rem), or the sum of the deep-dose equivalent and the committed dose equivalent to any individual organ or tissue (other than the lens of the eye) of 0.5 Sv (50 rem). The eye dose equivalent shall not exceed 0.15 Sv (15 rem), and the shallow dose...

Phosphoprotein profiles of candidate markers for early cellular responses to low-dose γ-radiation in normal human fibroblast cells

PubMed Central

Yim, Ji-Hye; Yun, Jung Mi; Kim, Ji Young; Lee, In Kyung; Nam, Seon Young

2017-01-01

Abstract Ionizing radiation causes biological damage that leads to severe health effects. However, the effects and subsequent health implications caused by exposure to low-dose radiation are unclear. The objective of this study was to determine phosphoprotein profiles in normal human fibroblast cell lines in response to low-dose and high-dose γ-radiation. We examined the cellular response in MRC-5 cells 0.5 h after exposure to 0.05 or 2 Gy. Using 1318 antibodies by antibody array, we observed ≥1.3-fold increases in a number of identified phosphoproteins in cells subjected to low-dose (0.05 Gy) and high-dose (2 Gy) radiation, suggesting that both radiation levels stimulate distinct signaling pathways. Low-dose radiation induced nucleic acid–binding transcription factor activity, developmental processes, and multicellular organismal processes. By contrast, high-dose radiation stimulated apoptotic processes, cell adhesion and regulation, and cellular organization and biogenesis. We found that phospho-BTK (Tyr550) and phospho-Gab2 (Tyr643) protein levels at 0.5 h after treatment were higher in cells subjected to low-dose radiation than in cells treated with high-dose radiation. We also determined that the phosphorylation of BTK and Gab2 in response to ionizing radiation was regulated in a dose-dependent manner in MRC-5 and NHDF cells. Our study provides new insights into the biological responses to low-dose γ-radiation and identifies potential candidate markers for monitoring exposure to low-dose ionizing radiation. PMID:28122968

Dynamics of body burdens and doses due to internal irradiation from intakes of long-lived radionuclides by residents of Ozyorsk situated near Mayak PA.

PubMed

Suslova, K G; Romanov, S A; Efimov, A V; Sokolova, A B; Sneve, M; Smith, G

2015-12-01

This paper presents and discusses new autopsy results and other historic data from earlier autopsies and environmental monitoring linked to releases from the Mayak PA facilities in the Chelyabinsk oblast in the southern Urals. The focus is on residents of the town of Ozyorsk located near to Mayak PA and the dynamics of body burdens and radiation doses from inhalation of plutonium alpha and americium-241, and ingestion of strontium-90 and caesium-137. It is demonstrated that accumulation and exposure from these radionuclides was mainly due to unplanned releases in the 1950s and 60s. The mean content of plutonium alpha at the time of autopsy of people commencing residence in Ozyorsk from 1949 to 1959 was about 3.5 Bq, falling to 0.2 Bq in those arriving after 1990. A reducing trend was also seen for (241)Am. The highest (90)Sr content in Ozyorsk residents was measured in 1967. The (137)Cs body content of residents arriving in Ozyorsk at any time was in almost all cases below the limit of detection. The committed effective dose from internal exposure to these long-lived radionuclides which would have been accumulated in Ozyorsk residents if present from 1949 to 2013 is estimated to be 13 mSv. This dose is primarily attributed to intakes during 1949 to 1959 when the annual effective dose rate was approximately 1 mSv y(-1). The current value is about 0.1 mSv y(-1). This dose is about 20 times higher than the dose from global man-made fallout, which is about 0.005 mSv y(-1) at present, but much lower than that from natural background radiation, i.e. about 2 mSv y(-1). The experience gained from this work and continuing activities can contribute to the development of improved international guidance in legacy situations, particularly as regards the provision and use of monitoring data to test and thereby build confidence in prognostic models for radiation conditions and potential future exposures. The scope includes evidence for the rate of reduction in radionuclide concentrations in environmental media and in their bioavailability, resuspension of long-lived alpha radionuclides, uptake of (90)Sr and (137)Cs in the food-chain, and confirmation of cumulative uptake via autopsy and whole body counting measurements. Continuing investigations will thus support decisions on future planned releases and contribute to planning of remediation of other areas affected by historic releases.

Acute Biological Effects of Simulating the Whole-Body Radiation Dose Distribution from a Solar Particle Event Using a Porcine Model

PubMed Central

Wilson, Jolaine M.; Sanzari, Jenine K.; Diffenderfer, Eric S.; Yee, Stephanie S.; Seykora, John T.; Maks, Casey; Ware, Jeffrey H.; Litt, Harold I.; Reetz, Jennifer A.; McDonough, James; Weissman, Drew; Kennedy, Ann R.; Cengel, Keith A.

2011-01-01

In a solar particle event (SPE), an unshielded astronaut would receive proton radiation with an energy profile that produces a highly inhomogeneous dose distribution (skin receiving a greater dose than internal organs). The novel concept of using megavoltage electron-beam radiation to more accurately reproduce both the total dose and the dose distribution of SPE protons and make meaningful RBE comparisons between protons and conventional radiation has been described previously. Here, Yucatan minipigs were used to determine the effects of a superficial, SPE-like proton dose distribution using megavoltage electrons. In these experiments, dose-dependent increases in skin pigmentation, ulceration, keratinocyte necrosis and pigment incontinence were observed. Five of 18 animals (one each exposed to 7.5 Gy and 12.5 Gy radiation and three exposed to 25 Gy radiation) developed symptomatic, radiation-associated pneumonopathy approximately 90 days postirradiation. The three animals from the highest dose group showed evidence of mycoplasmal pneumonia along with radiation pneumonitis. Moreover, delayed-type hypersensitivity was found to be altered, suggesting that superficial irradiation of the skin with ionizing radiation might cause immune dysfunction or dysregulation. In conclusion, using total doses, patterns of dose distribution, and dose rates that are compatible with potential astronaut exposure to SPE radiation, animals experienced significant toxicities that were qualitatively different from toxicities previously reported in pigs for homogeneously delivered radiation at similar doses. PMID:21859326

Scattered radiation doses absorbed by technicians at different distances from X-ray exposure: Experiments on prosthesis.

PubMed

Chiang, Hsien-Wen; Liu, Ya-Ling; Chen, Tou-Rong; Chen, Chun-Lon; Chiang, Hsien-Jen; Chao, Shin-Yu

2015-01-01

This work aimed to investigate the spatial distribution of scattered radiation doses induced by exposure to the portable X-ray, the C-arm machine, and to simulate the radiologist without a shield of lead clothing, radiation doses absorbed by medical staff at 2 m from the central exposure point. With the adoption of the Rando Phantom, several frequently X-rayed body parts were exposed to X-ray radiation, and the scattered radiation doses were measured by ionization chamber dosimeters at various angles from the patient. Assuming that the central point of the X-ray was located at the belly button, five detection points were distributed in the operation room at 1 m above the ground and 1-2 m from the central point horizontally. The radiation dose measured at point B was the lowest, and the scattered radiation dose absorbed by the prosthesis from the X-ray's vertical projection was 0.07 ±0.03 μGy, which was less than the background radiation levels. The Fluke biomedical model 660-5DE (400 cc) and 660-3DE (4 cc) ion chambers were used to detect air dose at a distance of approximately two meters from the central point. The AP projection radiation doses at point B was the lowest (0.07±0.03 μGy) and the radiation doses at point D was the highest (0.26±0.08 μGy) .Only taking the vertical projection into account, the radiation doses at point B was the lowest (0.52 μGy), and the radiation doses at point E was the highest (4 μGy).The PA projection radiation at point B was the lowest (0.36 μGy) and the radiation doses at point E was the highest(2.77 μGy), occupying 10-32% of the maximum doses. The maximum dose in five directions was nine times to the minimum dose. When the PX and the C-arm machine were used, the radiation doses at a distance of 2 m were attenuated to the background radiation level. The radiologist without a lead shield should stand at point B of patient's feet. Accordingly, teaching materials on radiation safety for radiological interns and clinical technicians were formulated.

10 CFR 20.1004 - Units of radiation dose.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Units of radiation dose. 20.1004 Section 20.1004 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION General Provisions § 20.1004 Units of radiation dose. (a) Definitions. As used in this part, the units of radiation dose are: Gray...

10 CFR 20.1301 - Dose limits for individual members of the public.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Section 20.1301 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Radiation..., exclusive of the dose contributions from background radiation, from any medical administration the....75, to receive a radiation dose greater than 0.1 rem (1 mSv) if— (1) The radiation dose received does...

10 CFR 20.1301 - Dose limits for individual members of the public.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Section 20.1301 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Radiation..., exclusive of the dose contributions from background radiation, from any medical administration the....75, to receive a radiation dose greater than 0.1 rem (1 mSv) if— (1) The radiation dose received does...

10 CFR 20.1301 - Dose limits for individual members of the public.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Section 20.1301 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Radiation..., exclusive of the dose contributions from background radiation, from any medical administration the....75, to receive a radiation dose greater than 0.1 rem (1 mSv) if— (1) The radiation dose received does...

10 CFR 20.1301 - Dose limits for individual members of the public.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Section 20.1301 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Radiation..., exclusive of the dose contributions from background radiation, from any medical administration the....75, to receive a radiation dose greater than 0.1 rem (1 mSv) if— (1) The radiation dose received does...

10 CFR 20.1301 - Dose limits for individual members of the public.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Section 20.1301 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Radiation..., exclusive of the dose contributions from background radiation, from any medical administration the....75, to receive a radiation dose greater than 0.1 rem (1 mSv) if— (1) The radiation dose received does...

10 CFR 20.1004 - Units of radiation dose.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Units of radiation dose. 20.1004 Section 20.1004 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION General Provisions § 20.1004 Units of radiation dose. (a) Definitions. As used in this part, the units of radiation dose are: Gray...

10 CFR 20.1004 - Units of radiation dose.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Units of radiation dose. 20.1004 Section 20.1004 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION General Provisions § 20.1004 Units of radiation dose. (a) Definitions. As used in this part, the units of radiation dose are: Gray...

10 CFR 20.1004 - Units of radiation dose.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Units of radiation dose. 20.1004 Section 20.1004 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION General Provisions § 20.1004 Units of radiation dose. (a) Definitions. As used in this part, the units of radiation dose are: Gray...

10 CFR 20.1004 - Units of radiation dose.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Units of radiation dose. 20.1004 Section 20.1004 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION General Provisions § 20.1004 Units of radiation dose. (a) Definitions. As used in this part, the units of radiation dose are: Gray...

When will we be committed to crossing 1.5 and 2 °C temperature thresholds?

NASA Astrophysics Data System (ADS)

Armour, K.; Proistosescu, C.; Roe, G.; Huybers, P. J.

2017-12-01

The zero-emissions climate commitment is a key metric for science and policy. It is the future warming we face given only to-date emissions, independent of future human influence on climate. Following a cessation of emissions, future global temperature change depends on (i) the atmospheric lifetimes of aerosols and greenhouse gases (GHGs), and (ii) the physical climate response to radiative forcing (Armour and Roe 2011). The cooling effect of aerosols diminishes within weeks; GHG concentrations get drawn down on timescales ranging from months to millennia; and ocean heat uptake diminishes as climate equilibrates with the residual CO2 forcing. Whether global temperature increases, stays stable, or declines following emission cessation depends on these competing factors. There is substantial uncertainty in the zero-emissions commitment due to a combination of (i) correlated uncertainties in aerosol radiative forcing and climate sensitivity, (ii) uncertainty in the atmospheric lifetime of CO2, and (iii) uncertainty in how climate sensitivity will evolve in the future. Here we quantify climate commitment in a Bayesian framework of an idealized model constrained by observations of global warming and energy imbalance, combined with estimates of global radiative forcing. At present, our committed warming is 1.2°C (median), with a 25% chance that it already exceeds 1.5°C and a 5% chance that it exceeds 2°C; the range comes primarily from uncertainty in the degree to which aerosols currently mask GHG forcing. We further quantify how climate commitment, and its uncertainty, changes with emissions scenario and over time. Under high emissions (RCP8.5), we will reach a >50% risk of a 2°C zero-emission climate commitment by the year 2035, about two decades before that temperature would be reached if emissions continued unabated. Committed warming is substantially reduced for lower-emissions scenarios, depending on the mix of aerosol and GHG mitigation. For the next few decades the primary uncertainty in climate commitment comes from correlated uncertainties in aerosol forcing and climate sensitivity; later in the century it comes from uncertainties in the carbon cycle (setting the lifetime and residual concentration of CO2) and in how climate sensitivity changes over time.

Phosphoproteomics profiling of human skin fibroblast cells reveals pathways and proteins affected by low doses of ionizing radiation.

PubMed

Yang, Feng; Waters, Katrina M; Miller, John H; Gritsenko, Marina A; Zhao, Rui; Du, Xiuxia; Livesay, Eric A; Purvine, Samuel O; Monroe, Matthew E; Wang, Yingchun; Camp, David G; Smith, Richard D; Stenoien, David L

2010-11-30

High doses of ionizing radiation result in biological damage; however, the precise relationships between long-term health effects, including cancer, and low-dose exposures remain poorly understood and are currently extrapolated using high-dose exposure data. Identifying the signaling pathways and individual proteins affected at the post-translational level by radiation should shed valuable insight into the molecular mechanisms that regulate dose-dependent responses to radiation. We have identified 7117 unique phosphopeptides (2566 phosphoproteins) from control and irradiated (2 and 50 cGy) primary human skin fibroblasts 1 h post-exposure. Semi-quantitative label-free analyses were performed to identify phosphopeptides that are apparently altered by radiation exposure. This screen identified phosphorylation sites on proteins with known roles in radiation responses including TP53BP1 as well as previously unidentified radiation-responsive proteins such as the candidate tumor suppressor SASH1. Bioinformatic analyses suggest that low and high doses of radiation affect both overlapping and unique biological processes and suggest a role for MAP kinase and protein kinase A (PKA) signaling in the radiation response as well as differential regulation of p53 networks at low and high doses of radiation. Our results represent the most comprehensive analysis of the phosphoproteomes of human primary fibroblasts exposed to multiple doses of ionizing radiation published to date and provide a basis for the systems-level identification of biological processes, molecular pathways and individual proteins regulated in a dose dependent manner by ionizing radiation. Further study of these modified proteins and affected networks should help to define the molecular mechanisms that regulate biological responses to radiation at different radiation doses and elucidate the impact of low-dose radiation exposure on human health.

Phosphoproteomics Profiling of Human Skin Fibroblast Cells Reveals Pathways and Proteins Affected by Low Doses of Ionizing Radiation

PubMed Central

Yang, Feng; Waters, Katrina M.; Miller, John H.; Gritsenko, Marina A.; Zhao, Rui; Du, Xiuxia; Livesay, Eric A.; Purvine, Samuel O.; Monroe, Matthew E.; Wang, Yingchun; Camp, David G.; Smith, Richard D.; Stenoien, David L.

2010-01-01

Background High doses of ionizing radiation result in biological damage; however, the precise relationships between long-term health effects, including cancer, and low-dose exposures remain poorly understood and are currently extrapolated using high-dose exposure data. Identifying the signaling pathways and individual proteins affected at the post-translational level by radiation should shed valuable insight into the molecular mechanisms that regulate dose-dependent responses to radiation. Principal Findings We have identified 7117 unique phosphopeptides (2566 phosphoproteins) from control and irradiated (2 and 50 cGy) primary human skin fibroblasts 1 h post-exposure. Semi-quantitative label-free analyses were performed to identify phosphopeptides that are apparently altered by radiation exposure. This screen identified phosphorylation sites on proteins with known roles in radiation responses including TP53BP1 as well as previously unidentified radiation-responsive proteins such as the candidate tumor suppressor SASH1. Bioinformatic analyses suggest that low and high doses of radiation affect both overlapping and unique biological processes and suggest a role for MAP kinase and protein kinase A (PKA) signaling in the radiation response as well as differential regulation of p53 networks at low and high doses of radiation. Conclusions Our results represent the most comprehensive analysis of the phosphoproteomes of human primary fibroblasts exposed to multiple doses of ionizing radiation published to date and provide a basis for the systems-level identification of biological processes, molecular pathways and individual proteins regulated in a dose dependent manner by ionizing radiation. Further study of these modified proteins and affected networks should help to define the molecular mechanisms that regulate biological responses to radiation at different radiation doses and elucidate the impact of low-dose radiation exposure on human health. PMID:21152398

Real-time colour pictorial radiation monitoring during coronary angiography: effect on patient peak skin and total dose during coronary angiography.

PubMed

Wilson, Sharon M; Prasan, Ananth M; Virdi, Amy; Lassere, Marissa; Ison, Glenn; Ramsay, David R; Weaver, James C

2016-10-10

The aim of this study was to evaluate whether a real-time (RT) colour pictorial radiation dose monitoring system reduces patient skin and total radiation dose during coronary angiography and intervention. Patient demographics, procedural variables and radiation parameters were recorded before and after institution of the RT skin dose recording system. Peak skin dose as well as traditionally available measures of procedural radiation dose were compared. A total of 1,077 consecutive patients underwent coronary angiography, of whom 460 also had PCI. Institution of the RT skin dose recording system resulted in a 22% reduction in peak skin dose after accounting for confounding variables. Radiation dose reduction was most pronounced in those having PCI but was also seen over a range of subgroups including those with prior coronary artery bypass surgery, high BMI, and with radial arterial access. This was associated with a significant reduction in the number of patients placed at risk of skin damage. Similar reductions in parameters reflective of total radiation dose were also demonstrated after institution of RT radiation monitoring. Institution of an RT skin dose recording reduced patient peak skin and total radiation dose during coronary angiography and intervention. Consideration should be given to widespread adoption of this technology.

Protection from radiation-induced apoptosis by the radioprotector amifostine (WR-2721) is radiation dose dependent.

PubMed

Ormsby, Rebecca J; Lawrence, Mark D; Blyth, Benjamin J; Bexis, Katrina; Bezak, Eva; Murley, Jeffrey S; Grdina, David J; Sykes, Pamela J

2014-02-01

The radioprotective agent amifostine is a free radical scavenger that can protect cells from the damaging effects of ionising radiation when administered prior to radiation exposure. However, amifostine has also been shown to protect cells from chromosomal mutations when administered after radiation exposure. As apoptosis is a common mechanism by which cells with mutations are removed from the cell population, we investigated whether amifostine stimulates apoptosis when administered after radiation exposure. We chose to study a relatively low dose which is the maximum radiation dose for radiation emergency workers (0.25 Gy) and a high dose relevant to radiotherapy exposures (6 Gy). Mice were administered 400 mg/kg amifostine 30 min before, or 3 h after, whole-body irradiation with 0.25 or 6 Gy X-rays and apoptosis was analysed 3 or 7 h later in spleen and bone marrow. We observed a significant increase in radiation-induced apoptosis in the spleen of mice when amifostine was administered before or after 0.25 Gy X-rays. In contrast, when a high dose of radiation was used (6 Gy), amifostine caused a reduction in radiation-induced apoptosis 3 h post-irradiation in spleen and bone marrow similar to previously published studies. This is the first study to investigate the effect of amifostine on radiation-induced apoptosis at a relatively low radiation dose and the first to demonstrate that while amifostine can reduce apoptosis from high doses of radiation, it does not mediate the same effect in response to low-dose exposures. These results suggest that there may be a dose threshold at which amifostine protects from radiation-induced apoptosis and highlight the importance of examining a range of radiation doses and timepoints.

Radiation dose-reduction strategies in thoracic CT.

PubMed

Moser, J B; Sheard, S L; Edyvean, S; Vlahos, I

2017-05-01

Modern computed tomography (CT) machines have the capability to perform thoracic CT for a range of clinical indications at increasingly low radiation doses. This article reviews several factors, both technical and patient-related, that can affect radiation dose and discusses current dose-reduction methods relevant to thoracic imaging through a review of current techniques in CT acquisition and image reconstruction. The fine balance between low radiation dose and high image quality is considered throughout, with an emphasis on obtaining diagnostic quality imaging at the lowest achievable radiation dose. The risks of excessive radiation dose reduction are also considered. Inappropriately low dose may result in suboptimal or non-diagnostic imaging that may reduce diagnostic confidence, impair diagnosis, or result in repeat examinations incurring incremental ionising radiation exposure. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

10 CFR 72.106 - Controlled area of an ISFSI or MRS.

Code of Federal Regulations, 2012 CFR

2012-01-01

... controlled area may not receive from any design basis accident the more limiting of a total effective dose equivalent of 0.05 Sv (5 rem), or the sum of the deep-dose equivalent and the committed dose equivalent to any individual organ or tissue (other than the lens of the eye) of 0.5 Sv (50 rem). The lens dose...

10 CFR 72.106 - Controlled area of an ISFSI or MRS.

Code of Federal Regulations, 2014 CFR

2014-01-01

... controlled area may not receive from any design basis accident the more limiting of a total effective dose equivalent of 0.05 Sv (5 rem), or the sum of the deep-dose equivalent and the committed dose equivalent to any individual organ or tissue (other than the lens of the eye) of 0.5 Sv (50 rem). The lens dose...

10 CFR 72.106 - Controlled area of an ISFSI or MRS.

Code of Federal Regulations, 2011 CFR

2011-01-01

... controlled area may not receive from any design basis accident the more limiting of a total effective dose equivalent of 0.05 Sv (5 rem), or the sum of the deep-dose equivalent and the committed dose equivalent to any individual organ or tissue (other than the lens of the eye) of 0.5 Sv (50 rem). The lens dose...

10 CFR 72.106 - Controlled area of an ISFSI or MRS.

Code of Federal Regulations, 2013 CFR

2013-01-01

... controlled area may not receive from any design basis accident the more limiting of a total effective dose equivalent of 0.05 Sv (5 rem), or the sum of the deep-dose equivalent and the committed dose equivalent to any individual organ or tissue (other than the lens of the eye) of 0.5 Sv (50 rem). The lens dose...

10 CFR 72.106 - Controlled area of an ISFSI or MRS.

Code of Federal Regulations, 2010 CFR

2010-01-01

... controlled area may not receive from any design basis accident the more limiting of a total effective dose equivalent of 0.05 Sv (5 rem), or the sum of the deep-dose equivalent and the committed dose equivalent to any individual organ or tissue (other than the lens of the eye) of 0.5 Sv (50 rem). The lens dose...

210Po in the diet at Seville (Spain) and its contribution to the dose by ingestion

PubMed Central

Díaz-Francés, I.; Mantero, J.; Díaz-Ruiz, J.; Manjón, G.; García-Tenorio, R.

2016-01-01

The activity concentrations of 210Po have been determined in a total of 24 representative diet samples from Seville (south of Spain), inferring from the obtained values the annual intakes of 210Po by ingestion of the affected population and the corresponding committed effective doses. The annual intakes of 210Po and, consequently, the corresponding doses of this radionuclide show a high variability in correspondence with the variability in the composition of the analysed samples over time, and their magnitude is comparable with the estimated ones in other regions/countries of the world with similar diet habits (countries where the marine products have a considerable weight in the diets). Committed effective doses by ingestion higher than 0.1 mSv y−1 have been estimated exclusively for 210Po, reflecting the importance of this radionuclide and this route of incorporation in the magnitude of the total doses received by the affected population from natural sources. PMID:25802464

[Personal dose monitoring of radiation workers in medical institutions at the municipal level and below in a city from 2011 to 2014].

PubMed

Wang, C; Mo, S F; Zhang, J B; Li, J R; Huang, R L; Tan, H Y

2017-08-20

Objective: To determine the personal dose level of radiation workers in medical institutions at the municipal level and below in a city, and to provide a scientific support for strengthening the radiation protection in the city's medical institutions. Methods: Information of the successful applicants for the "Radiation Worker Permit" from 174 medical institutions at the municipal level and below was collected from October 1, 2011 to December 31, 2014. The annual effective dose was calculated based on the personal dose monitoring report, and indicators including sex, permit application time, hospital level, type of occupational radiation, length of radiation work, blood test, and micronucleated lymphocyte rate were analyzed. Results: Of the 1 143 radiation worker permit applications submitted by medical institutions the municipal level and below in this city from 2011 to 2014, 1 123 provided at least one personal dose monitoring report. The annual effective dose of the radiation workers was 0-4.76 mSv (mean 0.31±0.40 mSv) , and the collective annual effective dose was 351.96 mSv. The annual effective dose was significantly different between radiation workers with different times of permit application, hospital levels, and types of occupational radiation ( P <0.05) . Interventional radiology workers had the highest annual effective dose (0.63 mSv) , and annual effective dose was significantly different between interventional radiology workers with different lengths of radiation work ( H =10.812, P <0.05) . Conclusion: The personal radiation dose of radiation workers in medical institutions at the municipal level and below in this city is maintained at a relatively low level, suggesting that the occupational environment is relatively safe for these workers. However, more focus should be placed on clinical interventional radiology workers.

10 CFR 20.1003 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... assessment of dose equivalent by the use of devices designed to be worn by an individual; (2) The assessment... equipment) means devices designed to be worn by a single individual for the assessment of dose equivalent... radionuclide in a year by the reference man that would result in a committed effective dose equivalent of 5...

10 CFR 20.1003 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... assessment of dose equivalent by the use of devices designed to be worn by an individual; (2) The assessment... equipment) means devices designed to be worn by a single individual for the assessment of dose equivalent... radionuclide in a year by the reference man that would result in a committed effective dose equivalent of 5...

10 CFR 20.1003 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... assessment of dose equivalent by the use of devices designed to be worn by an individual; (2) The assessment... equipment) means devices designed to be worn by a single individual for the assessment of dose equivalent... radionuclide in a year by the reference man that would result in a committed effective dose equivalent of 5...

10 CFR 20.1003 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... assessment of dose equivalent by the use of devices designed to be worn by an individual; (2) The assessment... equipment) means devices designed to be worn by a single individual for the assessment of dose equivalent... radionuclide in a year by the reference man that would result in a committed effective dose equivalent of 5...

10 CFR 20.1003 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... assessment of dose equivalent by the use of devices designed to be worn by an individual; (2) The assessment... equipment) means devices designed to be worn by a single individual for the assessment of dose equivalent... radionuclide in a year by the reference man that would result in a committed effective dose equivalent of 5...

Radiation exposure from work-related medical X-rays at the Portsmouth Naval Shipyard.

PubMed

Daniels, Robert D; Kubale, Travis L; Spitz, Henry B

2005-03-01

Previous analyses suggest that worker radiation dose may be significantly increased by routine occupational X-ray examinations. Medical exposures are investigated for 570 civilian workers employed at the Portsmouth Naval Shipyard (PNS) at Kittery, Maine. The research objective was to determine the radiation exposure contribution of work-related chest X-rays (WRX) relative to conventional workplace radiation sources. Methods were developed to estimate absorbed doses to the active (hematopoietic) bone marrow from X-ray examinations and workplace exposures using data extracted from worker dosimetry records (8,468) and health records (2,453). Dose distributions were examined for radiation and non-radiation workers. Photofluorographic chest examinations resulted in 82% of the dose from medical sources. Radiation workers received 26% of their collective dose from WRX and received 66% more WRX exposure than non-radiation workers. WRX can result in a significant fraction of the total dose, especially for radiation workers who were more likely to be subjected to routine medical monitoring. Omission of WRX from the total dose is a likely source of bias that can lead to dose category misclassification and may skew the epidemiologic dose-response assessment for cancers induced by the workplace.

Evaluation of Gamma Radiation-Induced Biochemical Changes in Skin for Dose Assesment: A Study on Small Experimental Animals.

PubMed

Kumar Soni, Sandeep; Basu, Mitra; Agrawal, Priyanka; Bhatnagar, Aseem; Chhillar, Neelam

2018-05-24

Researchers have been evaluating several approaches to assess acute radiation injury/toxicity markers owing to radiation exposure. Keeping in mind this background, we assumed that whole-body irradiation in single fraction in graded doses can affect the antioxidant profile in skin that could be used as an acute radiation injury/toxicity marker. Sprague-Dawley rats were treated with CO-60 gamma radiation (dose: 1-5 Gy; dose rate: 0.85 Gy/minute). Skin samples were collected (before and after radiation up to 72 hours) and analyzed for glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), and lipid peroxidation (LPx). Intra-group comparison showed significant differences in GSH, GPx, SOD, and CAT, and they declined in a dose-dependent manner from 1 to 5 Gy (P value0.05). This study suggests that skin antioxidants were sensitive toward radiation even at a low radiation dose, which can be used as a predictor of radiation injury and altered in a dose-dependent manner. These biochemical parameters may have wider application in the evaluation of radiation-induced skin injury and dose assessment. (Disaster Med Public Health Preparedness. 2018;page 1 of 6).

ICRP Publication 137: Occupational Intakes of Radionuclides: Part 3.

PubMed

Paquet, F; Bailey, M R; Leggett, R W; Lipsztein, J; Marsh, J; Fell, T P; Smith, T; Nosske, D; Eckerman, K F; Berkovski, V; Blanchardon, E; Gregoratto, D; Harrison, J D

2017-12-01

The 2007 Recommendations of the International Commission on Radiological Protection (ICRP, 2007) introduced changes that affect the calculation of effective dose, and implied a revision of the dose coefficients for internal exposure, published previously in the Publication 30 series (ICRP, 1979, 1980, 1981, 1988) and Publication 68 (ICRP, 1994). In addition, new data are now available that support an update of the radionuclide-specific information given in Publications 54 and 78 (ICRP, 1988a, 1997b) for the design of monitoring programmes and retrospective assessment of occupational internal doses. Provision of new biokinetic models, dose coefficients, monitoring methods, and bioassay data was performed by Committee 2, Task Group 21 on Internal Dosimetry, and Task Group 4 on Dose Calculations. A new series, the Occupational Intakes of Radionuclides (OIR) series, will replace the Publication 30 series and Publications 54, 68, and 78. OIR Part 1 has been issued (ICRP, 2015), and describes the assessment of internal occupational exposure to radionuclides, biokinetic and dosimetric models, methods of individual and workplace monitoring, and general aspects of retrospective dose assessment. OIR Part 2 (ICRP, 2016), this current publication and upcoming publications in the OIR series (Parts 4 and 5) provide data on individual elements and their radioisotopes, including information on chemical forms encountered in the workplace; a list of principal radioisotopes and their physical half-lives and decay modes; the parameter values of the reference biokinetic model; and data on monitoring techniques for the radioisotopes encountered most commonly in workplaces. Reviews of data on inhalation, ingestion, and systemic biokinetics are also provided for most of the elements. Dosimetric data provided in the printed publications of the OIR series include tables of committed effective dose per intake (Sv Bq−1 intake) for inhalation and ingestion, tables of committed effective dose per content (Sv Bq−1 measurement) for inhalation, and graphs of retention and excretion data per Bq intake for inhalation. These data are provided for all absorption types and for the most common isotope(s) of each element. The electronic annex that accompanies the OIR series of publications contains a comprehensive set of committed effective and equivalent dose coefficients, committed effective dose per content functions, and reference bioassay functions. Data are provided for inhalation, ingestion, and direct input to blood. This third publication in the series provides the above data for the following elements: ruthenium (Ru), antimony (Sb), tellurium (Te), iodine (I), caesium (Cs), barium (Ba), iridium (Ir), lead (Pb), bismuth (Bi), polonium (Po), radon (Rn), radium (Ra), thorium (Th), and uranium (U).

ICRP Publication 134: Occupational Intakes of Radionuclides: Part 2.

PubMed

Paquet, F; Bailey, M R; Leggett, R W; Lipsztein, J; Fell, T P; Smith, T; Nosske, D; Eckerman, K F; Berkovski, V; Ansoborlo, E; Giussani, A; Bolch, W E; Harrison, J D

2016-12-01

The 2007 Recommendations of the International Commission on Radiological Protection (ICRP, 2007) introduced changes that affect the calculation of effective dose, and implied a revision of the dose coefficients for internal exposure, published previously in the Publication 30 series (ICRP, 1979, 1980, 1981, 1988b) and Publication 68 (ICRP, 1994b). In addition, new data are available that support an update of the radionuclide-specific information given in Publications 54 and 78 (ICRP, 1988a, 1997b) for the design of monitoring programmes and retrospective assessment of occupational internal doses. Provision of new biokinetic models, dose coefficients, monitoring methods, and bioassay data was performed by Committee 2, Task Group 21 on Internal Dosimetry, and Task Group 4 on Dose Calculations. A new series, the Occupational Intakes of Radionuclides (OIR) series, will replace the Publication 30 series and Publications 54, 68, and 78. Part 1 of the OIR series has been issued (ICRP, 2015), and describes the assessment of internal occupational exposure to radionuclides, biokinetic and dosimetric models, methods of individual and workplace monitoring, and general aspects of retrospective dose assessment. The following publications in the OIR series (Parts 2–5) will provide data on individual elements and their radioisotopes, including information on chemical forms encountered in the workplace; a list of principal radioisotopes and their physical half-lives and decay modes; the parameter values of the reference biokinetic model; and data on monitoring techniques for the radioisotopes encountered most commonly in workplaces. Reviews of data on inhalation, ingestion, and systemic biokinetics are also provided for most of the elements. Dosimetric data provided in the printed publications of the OIR series include tables of committed effective dose per intake (Sv per Bq intake) for inhalation and ingestion, tables of committed effective dose per content (Sv per Bq measurement) for inhalation, and graphs of retention and excretion data per Bq intake for inhalation. These data are provided for all absorption types and for the most common isotope(s) of each element. The electronic annex that accompanies the OIR series of reports contains a comprehensive set of committed effective and equivalent dose coefficients, committed effective dose per content functions, and reference bioassay functions. Data are provided for inhalation, ingestion, and direct input to blood. The present publication provides the above data for the following elements: hydrogen (H), carbon (C), phosphorus (P), sulphur (S), calcium (Ca), iron (Fe), cobalt (Co), zinc (Zn), strontium (Sr), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), and technetium (Tc).

40 CFR Appendix A to Part 197 - Calculation of Annual Committed Effective Dose Equivalent

Code of Federal Regulations, 2011 CFR

2011-07-01

... resulting from irradiation of the tissue or organ to the total risk when the whole body is irradiated... internal irradiation from incorporated radionuclides, the total absorbed dose will be spread out in time...

40 CFR Appendix A to Part 197 - Calculation of Annual Committed Effective Dose Equivalent

Code of Federal Regulations, 2012 CFR

2012-07-01

... resulting from irradiation of the tissue or organ to the total risk when the whole body is irradiated... internal irradiation from incorporated radionuclides, the total absorbed dose will be spread out in time...

40 CFR Appendix A to Part 197 - Calculation of Annual Committed Effective Dose Equivalent

Code of Federal Regulations, 2014 CFR

2014-07-01

... resulting from irradiation of the tissue or organ to the total risk when the whole body is irradiated... internal irradiation from incorporated radionuclides, the total absorbed dose will be spread out in time...

40 CFR Appendix A to Part 197 - Calculation of Annual Committed Effective Dose Equivalent

Code of Federal Regulations, 2013 CFR

2013-07-01

... resulting from irradiation of the tissue or organ to the total risk when the whole body is irradiated... internal irradiation from incorporated radionuclides, the total absorbed dose will be spread out in time...

40 CFR Appendix A to Part 197 - Calculation of Annual Committed Effective Dose Equivalent

Code of Federal Regulations, 2010 CFR

2010-07-01

... resulting from irradiation of the tissue or organ to the total risk when the whole body is irradiated... internal irradiation from incorporated radionuclides, the total absorbed dose will be spread out in time...

AREA RADIATION MONITOR

DOEpatents

Manning, F.W.; Groothuis, S.E.; Lykins, J.H.; Papke, D.M.

1962-06-12

S>An improved area radiation dose monitor is designed which is adapted to compensate continuously for background radiation below a threshold dose rate and to give warning when the dose integral of the dose rate of an above-threshold radiation excursion exceeds a selected value. This is accomplished by providing means for continuously charging an ionization chamber. The chamber provides a first current proportional to the incident radiation dose rate. Means are provided for generating a second current including means for nulling out the first current with the second current at all values of the first current corresponding to dose rates below a selected threshold dose rate value. The second current has a maximum value corresponding to that of the first current at the threshold dose rate. The excess of the first current over the second current, which occurs above the threshold, is integrated and an alarm is given at a selected integrated value of the excess corresponding to a selected radiation dose. (AEC)

Integrated molecular analysis indicates undetectable change in DNA damage in mice after continuous irradiation at ~ 400-fold natural background radiation.

PubMed

Olipitz, Werner; Wiktor-Brown, Dominika; Shuga, Joe; Pang, Bo; McFaline, Jose; Lonkar, Pallavi; Thomas, Aline; Mutamba, James T; Greenberger, Joel S; Samson, Leona D; Dedon, Peter C; Yanch, Jacquelyn C; Engelward, Bevin P

2012-08-01

In the event of a nuclear accident, people are exposed to elevated levels of continuous low dose-rate radiation. Nevertheless, most of the literature describes the biological effects of acute radiation. DNA damage and mutations are well established for their carcinogenic effects. We assessed several key markers of DNA damage and DNA damage responses in mice exposed to low dose-rate radiation to reveal potential genotoxic effects associated with low dose-rate radiation. We studied low dose-rate radiation using a variable low dose-rate irradiator consisting of flood phantoms filled with 125Iodine-containing buffer. Mice were exposed to 0.0002 cGy/min (~ 400-fold background radiation) continuously over 5 weeks. We assessed base lesions, micronuclei, homologous recombination (HR; using fluorescent yellow direct repeat mice), and transcript levels for several radiation-sensitive genes. We did not observe any changes in the levels of the DNA nucleobase damage products hypoxanthine, 8-oxo-7,8-dihydroguanine, 1,N6-ethenoadenine, or 3,N4-ethenocytosine above background levels under low dose-rate conditions. The micronucleus assay revealed no evidence that low dose-rate radiation induced DNA fragmentation, and there was no evidence of double strand break-induced HR. Furthermore, low dose-rate radiation did not induce Cdkn1a, Gadd45a, Mdm2, Atm, or Dbd2. Importantly, the same total dose, when delivered acutely, induced micronuclei and transcriptional responses. These results demonstrate in an in vivo animal model that lowering the dose-rate suppresses the potentially deleterious impact of radiation and calls attention to the need for a deeper understanding of the biological impact of low dose-rate radiation.

CANCER RISKS ATTRIBUTABLE TO LOW DOSES OF IONIZING RADIATION - ASSESSING WHAT WE REALLY KNOW?

EPA Science Inventory

Cancer Risks Attributable to Low Doses of Ionizing Radiation - What Do We Really Know?

Abstract
High doses of ionizing radiation clearly produce deleterious consequences in humans including, but not exclusively, cancer induction. At very low radiation doses the situatio...

[Estimation of dietary intake of radioactive materials by total diet methods].

PubMed

Uekusa, Yoshinori; Nabeshi, Hiromi; Tsutsumi, Tomoaki; Hachisuka, Akiko; Matsuda, Rieko; Teshima, Reiko

2014-01-01

Radioactive contamination in foods is a matter of great concern after the Tokyo Electric Power Company's Fukushima Daiichi nuclear power plant disaster caused by the Great East Japan Earthquake. In order to estimate human intake and annual committed effective dose of radioactive materials, market basket and duplicate diet samples from various areas in Japan were analyzed for cesium-134 ((134)Cs), -137 ((137)Cs), and natural radionuclide potassium-40 ((40)K) by γ-ray spectroscopy. Dietary intake of radioactive cesium around Fukushima area was somewhat higher than in other areas. However, maximum committed effective doses obtained by the market basket and duplicate diet samples were 0.0094 and 0.027 mSv/year, respectively, which are much lower than the maximum permissible dose (1 mSv/year) in foods in Japan.

Exposure of the Heart in Breast Cancer Radiation Therapy: A Systematic Review of Heart Doses Published During 2003 to 2013.

PubMed

Taylor, Carolyn W; Wang, Zhe; Macaulay, Elizabeth; Jagsi, Reshma; Duane, Frances; Darby, Sarah C

2015-11-15

Breast cancer radiation therapy cures many women, but where the heart is exposed, it can cause heart disease. We report a systematic review of heart doses from breast cancer radiation therapy that were published during 2003 to 2013. Eligible studies were those reporting whole-heart dose (ie, dose averaged over the whole heart). Analyses considered the arithmetic mean of the whole-heart doses for the CT plans for each regimen in each study. We termed this "mean heart dose." In left-sided breast cancer, mean heart dose averaged over all 398 regimens reported in 149 studies from 28 countries was 5.4 Gy (range, <0.1-28.6 Gy). In regimens that did not include the internal mammary chain (IMC), average mean heart dose was 4.2 Gy and varied with the target tissues irradiated. The lowest average mean heart doses were from tangential radiation therapy with either breathing control (1.3 Gy; range, 0.4-2.5 Gy) or treatment in the lateral decubitus position (1.2 Gy; range, 0.8-1.7 Gy), or from proton radiation therapy (0.5 Gy; range, 0.1-0.8 Gy). For intensity modulated radiation therapy mean heart dose was 5.6 Gy (range, <0.1-23.0 Gy). Where the IMC was irradiated, average mean heart dose was around 8 Gy and varied little according to which other targets were irradiated. Proton radiation therapy delivered the lowest average mean heart dose (2.6 Gy, range, 1.0-6.0 Gy), and tangential radiation therapy with a separate IMC field the highest (9.2 Gy, range, 1.9-21.0 Gy). In right-sided breast cancer, the average mean heart dose was 3.3 Gy based on 45 regimens in 23 studies. Recent estimates of typical heart doses from left breast cancer radiation therapy vary widely between studies, even for apparently similar regimens. Maneuvers to reduce heart dose in left tangential radiation therapy were successful. Proton radiation therapy delivered the lowest doses. Inclusion of the IMC doubled typical heart dose. Copyright © 2015 Elsevier Inc. All rights reserved.

No adaptive response is induced by chronic low-dose radiation from Ra-226 in the CHSE/F fish embryonic cell line and the HaCaT human epithelial cell line

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, Xiaopei, E-mail: shix22@mcmaster.ca; Mothersi

Purpose: To determine whether chronic low-dose α-particle radiation from Ra-226 over multiple cell generations can lead to an adaptive response in CHSE/F fish embryonic cells or HaCaT human epithelial cells receiving subsequent acute high-dose γ-ray radiation. Methods: CHSE/F and HaCaT cells were exposed to very low doses of Ra-226 in medium for multiple generations prior to being challenged by a higher dose γ-ray radiation. The clonogenic assay was used to test the clonogenic survival of cells with or without being pretreated by radiation from Ra-226. Results: In general, pretreatment with chronic radiation has no significant influence on the reaction ofmore » cells to the subsequent challenge radiation. Compared to unprimed cells, the change in clonogenic survival of primed cells after receiving challenge radiation is mainly due to the influence of the chronic exposure, and there's little adaptive response induced. However at several dose points, pretreatment of CHSE/F fish cells with chronic radiation resulted in a radiosensitive response to a challenge dose of γ-ray radiation, and pretreatment of HaCaT cells resulted in no effect except for a slightly radioresistant response to the challenge radiation which was not significant. Conclusion: The results suggest that chronic low-dose radiation is not effective enough to induce adaptive response. There was a difference between human and fish cells and it may be important to consider results from multiple species before making conclusions about effects of chronic or low doses of radiation in the environment. The term “radiosensitive” or “adaptive” make no judgment about whether such responses are ultimately beneficial or harmful. - Highlights: • No obvious adaptive response is induced by chronic low-dose radiation from Ra-226. • Priming radiation from Ra-226 sensitized CHSE/F cells to the challenge radiation. • Linear model is inconsistent with current work using chronic low-dose radiation.« less

Phosphoproteomics profiling of human skin fibroblast cells reveals pathways and proteins affected by low doses of ionizing radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Feng; Waters, Katrina M.; Miller, John H.

2010-11-30

Background: High doses of ionizing radiation result in biological damage, however the precise relationships between long term health effects, including cancer, and low dose exposures remain poorly understood and are currently extrapolated using high dose exposure data. Identifying the signaling pathways and individual proteins affected at the post-translational level by radiation should shed valuable insight into the molecular mechanisms that regulate dose dependent responses to radiation. Principle Findings: We have identified 6845 unique phosphopeptides (2566 phosphoproteins) from control and irradiated (2 and 50 cGy) primary human skin fibroblasts one hour post-exposure. Dual statistical analyses based on spectral counts and peakmore » intensities identified 287 phosphopeptides (from 231 proteins) and 244 phosphopeptides (from 182 proteins) that varied significantly following exposure to 2 and 50 cGy respectively. This screen identified phosphorylation sites on proteins with known roles in radiation responses including TP53BP1 as well as previously unidentified radiation responsive proteins such as the candidate tumor suppressor SASH1. Bioinformatics analyses suggest that low and high doses of radiation affect both overlapping and unique biological processes and suggest a role of MAP kinase and protein kinase A (PKA) signaling in the radiation response as well as differential regulation of p53 networks at low and high doses of radiation. Conlcusions: Our results represent the most comprehensive analysis of the phosphoproteomes of human primary fibroblasts exposed to multiple doses of ionizing radiation published to date and provides a basis for the systems level identification of biological processes, molecular pathways and individual proteins regulated in a dose dependent manner by ionizing radiation. Further study of these modified proteins and affected networks should help to define the molecular mechanisms that regulate biological responses to radiation at different radiation doses and elucidate the impact of low dose radiation exposure on human health.« less

42 CFR 81.4 - Definition of terms used in this part.

Code of Federal Regulations, 2011 CFR

2011-10-01

...]. (e) Equivalent dose means the absorbed dose in a tissue or organ multiplied by a radiation weighting... dose means the portion of the equivalent dose that is received from radiation sources outside of the... pattern and level of radiation exposure. (h) Internal dose means the portion of the equivalent dose that...

Internal exposure to (210)Po and (40)K from ingestion of cooked daily foodstuffs for adults in Japanese cities.

PubMed

Sugiyama, Hideo; Terada, Hiroshi; Isomura, Kimio; Iijima, Ikuyo; Kobayashi, Jun; Kitamura, Kiyoshi

2009-10-01

The isotope (210)Po was suspected of being involved in the death of a former Russian intelligence agent in 2006 in the UK. Although human exposure to this natural radionuclide in foods is estimated to be high, few studies are available. UNSCEAR Report 2000 does not contain data on (210)Po concentrations of foodstuffs in Japan. We analyzed samples of the everyday Japanese diet cooked with foodstuffs purchased at supermarkets in 7 major domestic cities in 2007-2008. (210)Po was quantified by alpha spectrometry and natural radionuclides such as (40)K by gamma spectrometry. The daily intake and committed effective dose of (210)Po, (40)K, and other natural radionuclides for Japanese adults were calculated. Daily intake was 0.34-1.84 (mean +/- sigma : 0.66 +/- 0.53) and 68.5-94.2 (81.5 +/- 8.5) Bq/d and the committed effective dose was 0.15-0.81 (0.29 +/- 0.24) and 0.16-0.21 (0.18 +/- 0.02) mSv for (210)Po and (40)K, respectively, comprising a high percentage of the total exposure. The total of the mean committed effective dose for the two nuclides (0.47 mSv) was higher than the annual effective dose from ingestion of foods reported by UNSCEAR 2000 (0.29 mSv). The mean committed effective dose of (40)K in the 7 major Japanese cities was comparable to the global average (0.17 mSv). The dietary exposure of Japanese adults can be characterized by a higher (210)Po contribution than in other countries. Of the total daily dietary (210)Po exposure (13 food categories excluding water) for adults in Yokohama, about 70% was from fish/shellfish and 20% from vegetables/mushrooms/seaweeds, reflecting preferences of Japanese to eat a considerable amount of fish/shellfish containing high (210)Po concentrations.

An environmental dose experiment

NASA Astrophysics Data System (ADS)

Peralta, Luis

2017-11-01

Several radiation sources worldwide contribute to the delivered dose to the human population. This radiation also acts as a natural background when detecting radiation, for instance from radioactive sources. In this work a medium-sized plastic scintillation detector is used to evaluate the dose delivered by natural radiation sources. Calibration of the detector involved the use of radioactive sources and Monte Carlo simulation of the energy deposition per disintegration. A measurement of the annual dose due to background radiation to the body was then estimated. A dose value compatible with the value reported by the United Nations Scientific Committee on the Effects of Atomic Radiation was obtained.

Typical doses and dose rates in studies pertinent to radiation risk inference at low doses and low dose rates

PubMed Central

Rühm, Werner; Azizova, Tamara; Bouffler, Simon; Cullings, Harry M; Grosche, Bernd; Little, Mark P; Shore, Roy S; Walsh, Linda; Woloschak, Gayle E

2018-01-01

Abstract In order to quantify radiation risks at exposure scenarios relevant for radiation protection, often extrapolation of data obtained at high doses and high dose rates down to low doses and low dose rates is needed. Task Group TG91 on ‘Radiation Risk Inference at Low-dose and Low-dose Rate Exposure for Radiological Protection Purposes’ of the International Commission on Radiological Protection is currently reviewing the relevant cellular, animal and human studies that could be used for that purpose. This paper provides an overview of dose rates and doses typically used or present in those studies, and compares them with doses and dose rates typical of those received by the A-bomb survivors in Japan. PMID:29432579

42 CFR 81.6 - Use of radiation dose information.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 1 2011-10-01 2011-10-01 false Use of radiation dose information. 81.6 Section 81... Probability of Causation § 81.6 Use of radiation dose information. Determining probability of causation will require the use of radiation dose information provided to DOL by the National Institute for Occupational...

42 CFR 81.6 - Use of radiation dose information.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 42 Public Health 1 2013-10-01 2013-10-01 false Use of radiation dose information. 81.6 Section 81... Probability of Causation § 81.6 Use of radiation dose information. Determining probability of causation will require the use of radiation dose information provided to DOL by the National Institute for Occupational...

42 CFR 81.6 - Use of radiation dose information.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 42 Public Health 1 2012-10-01 2012-10-01 false Use of radiation dose information. 81.6 Section 81... Probability of Causation § 81.6 Use of radiation dose information. Determining probability of causation will require the use of radiation dose information provided to DOL by the National Institute for Occupational...

42 CFR 81.6 - Use of radiation dose information.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 1 2014-10-01 2014-10-01 false Use of radiation dose information. 81.6 Section 81... Probability of Causation § 81.6 Use of radiation dose information. Determining probability of causation will require the use of radiation dose information provided to DOL by the National Institute for Occupational...

Acute Hematological Effects in Mice Exposed to the Expected Doses, Dose-rates, and Energies of Solar Particle Event-like Proton Radiation.

PubMed

Sanzari, Jenine K; Cengel, Keith A; Wan, X Steven; Rusek, Adam; Kennedy, Ann R

2014-07-01

NASA has funded several projects that have provided evidence for the radiation risk in space. One radiation concern arises from solar particle event (SPE) radiation, which is composed of energetic electrons, protons, alpha particles and heavier particles. SPEs are unpredictable and the accompanying SPE radiation can place astronauts at risk of blood cell death, contributing to a weakened immune system and increased susceptibility to infection. The doses, dose rates, and energies of the proton radiation expected to occur during a SPE have been simulated at the NASA Space Radiation Laboratory, Brookhaven National Laboratory, delivering total body doses to mice. Hematological values were evaluated at acute time points, up to 24 hrs. post-radiation exposure.

Acute hematological effects in mice exposed to the expected doses, dose-rates, and energies of solar particle event-like proton radiation

NASA Astrophysics Data System (ADS)

Sanzari, Jenine K.; Cengel, Keith A.; Steven Wan, X.; Rusek, Adam; Kennedy, Ann R.

2014-07-01

NASA has funded several projects that have provided evidence for the radiation risk in space. One radiation concern arises from solar particle event (SPE) radiation, which is composed of energetic electrons, protons, alpha particles and heavier particles. SPEs are unpredictable and the accompanying SPE radiation can place astronauts at risk of blood cell death, contributing to a weakened immune system and increased susceptibility to infection. The doses, dose rates, and energies of the proton radiation expected to occur during an SPE have been simulated at the NASA Space Radiation Laboratory, Brookhaven National Laboratory, delivering total body doses to mice. Hematological values were evaluated at acute time points, up to 24 hours post-radiation exposure.

Tolerance doses of cutaneous and mucosal tissues in ring-necked parakeets (Psittacula krameri) for external beam megavoltage radiation.

PubMed

Barron, Heather W; Roberts, Royce E; Latimer, Kenneth S; Hernandez-Divers, Stephen; Northrup, Nicole C

2009-03-01

Currently used dosages for external-beam megavoltage radiation therapy in birds have been extrapolated from mammalian patients and often appear to provide inadequate doses of radiation for effective tumor control. To determine the tolerance doses of cutaneous and mucosal tissues of normal birds in order to provide more effective radiation treatment for tumors that have been shown to be radiation responsive in other species, ingluvial mucosa and the skin over the ingluvies of 9 ring-necked parakeets (Psittacula krameri) were irradiated in 4-Gy fractions to a total dose of either 48, 60, or 72 Gy using an isocentric cobalt-60 teletherapy unit. Minimal radiation-induced epidermal changes were present in the high-dose group histologically. Neither dose-related acute nor chronic radiation effects could be detected in any group grossly in cutaneous or mucosal tissue over a 9-month period. Radiation doses of 72 Gy in 4-Gy fractions were well tolerated in the small number of ring-necked parakeets in this initial tolerance dose study.

Polonium in size fractionated mainstream cigarette smoke, predicted deposition and associated internal radiation dose.

PubMed

Tiwari, M; Sahu, S K; Bhangare, R C; Pandit, G G

2016-10-01

In this study, size fractionated mass and 210 Po activity concentrations in mainstream cigarette smoke (MCS) were monitored for three popular cigarette brands. Size segregated collection of MCS was carried out using a cascade type impactor, while mass and 210 Po activity concentration were analyzed gravimetrically and alpha spectrometry (following the radiochemical separation) respectively. Multiple-Path Particle Dosimetry (MPPD V2.11) model is used for prediction of deposition fraction calculations for the MCS deposition in different compartment of human respiratory tract. The activity concentration of 210 Po is founds 10.56 ± 2.46 mBq per cigarette for the tested cigarette brands. 210 Po size distribution indicates most of this associates with fine fraction (Dp < 2.23 μm) of cigarette smoke. The committed annual effective dose to smokers (smoking on an average 20 cigarette a day), considering the 210 Po and 210 Pb concentrations (assuming it is in secular equilibrium with 210 Po) in MCS, was estimated between 0.22 and 0.40 mSv, with mean value of 0.30 mSv for tested cigarette brands. Considering the risk factor of fatal cancer due to radiation exposure of lung (exposure time of 30 years); the average collective estimated fatal cancer risk is estimated as 1.5 × 10 -4 due to 210 Po and 210 Pb exposure to smokers. Copyright © 2016. Published by Elsevier Ltd.

MO-G-18A-01: Radiation Dose Reducing Strategies in CT, Fluoroscopy and Radiography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mahesh, M; Gingold, E; Jones, A

2014-06-15

Advances in medical x-ray imaging have provided significant benefits to patient care. According to NCRP 160, there are more than 400 million x-ray procedures performed annually in the United States alone that contributes to nearly half of all the radiation exposure to the US population. Similar growth trends in medical x-ray imaging are observed worldwide. Apparent increase in number of medical x-ray imaging procedures, new protocols and the associated radiation dose and risk has drawn considerable attention. This has led to a number of technological innovations such as tube current modulation, iterative reconstruction algorithms, dose alerts, dose displays, flat panelmore » digital detectors, high efficient digital detectors, storage phosphor radiography, variable filters, etc. that are enabling users to acquire medical x-ray images at a much lower radiation dose. Along with these, there are number of radiation dose optimization strategies that users can adapt to effectively lower radiation dose in medical x-ray procedures. The main objectives of this SAM course are to provide information and how to implement the various radiation dose optimization strategies in CT, Fluoroscopy and Radiography. Learning Objectives: To update impact of technological advances on dose optimization in medical imaging. To identify radiation optimization strategies in computed tomography. To describe strategies for configuring fluoroscopic equipment that yields optimal images at reasonable radiation dose. To assess ways to configure digital radiography systems and recommend ways to improve image quality at optimal dose.« less

Radiation doses for pediatric nuclear medicine studies: comparing the North American consensus guidelines and the pediatric dosage card of the European Association of Nuclear Medicine.

PubMed

Grant, Frederick D; Gelfand, Michael J; Drubach, Laura A; Treves, S Ted; Fahey, Frederic H

2015-04-01

Estimated radiation dose is important for assessing and communicating the risks and benefits of pediatric nuclear medicine studies. Radiation dose depends on the radiopharmaceutical, the administered activity, and patient factors such as age and size. Most radiation dose estimates for pediatric nuclear medicine have not been based on administered activities of radiopharmaceuticals recommended by established practice guidelines. The dosage card of the European Association of Nuclear Medicine (EANM) and the North American consensus guidelines each provide recommendations of administered activities of radiopharmaceuticals in children, but there are substantial differences between these two guidelines. For 12 commonly performed pediatric nuclear medicine studies, two established pediatric radiopharmaceutical administration guidelines were used to calculate updated radiation dose estimates and to compare the radiation exposure resulting from the recommendations of each of the guidelines. Estimated radiation doses were calculated for 12 common procedures in pediatric nuclear medicine using administered activities recommended by the dosage card of the EANM (version 1.5.2008) and the 2010 North American consensus guidelines for radiopharmaceutical administered activities in pediatrics. Based on standard models and nominal age-based weights, radiation dose was estimated for typical patients at ages 1, 5, 10 and 15 years and adult. The resulting effective doses were compared, with differences greater than 20% considered significant. Following either the EANM dosage card or the 2010 North American guidelines, the highest effective doses occur with radiopharmaceuticals labeled with fluorine-18 and iodine-123. In 24% of cases, following the North American consensus guidelines would result in a substantially higher radiation dose. The guidelines of the EANM dosage card would lead to a substantially higher radiation dose in 39% of all cases, and in 62% of cases in which patients were age 5 years or younger. For 12 commonly performed pediatric nuclear medicine studies, updated radiation dose estimates can guide efforts to reduce radiation exposure and provide current information for discussing radiation exposure and risk with referring physicians, patients and families. There can be substantial differences in radiation exposure for the same procedure, depending upon which of these two guidelines is followed. This discordance identifies opportunities for harmonization of the guidelines, which may lead to further reduction in nuclear medicine radiation doses in children.

77 FR 75417 - Renewal of the Veterans' Advisory Board on Dose Reconstruction

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-20

...-discretionary federal advisory committee that shall provide review and oversight of the Radiation Dose... administration of the Radiation Dose Reconstruction Program as it considers appropriate as a result of the audits.... Conduct periodic, random audits of dose reconstructions under the Radiation Dose Reconstruction Program...

Radiation-Induced Carcinogenesis: Mechanistically Based Differences between Gamma-Rays and Neutrons, and Interactions with DMBA

PubMed Central

Shuryak, Igor; Brenner, David J.; Ullrich, Robert L.

2011-01-01

Different types of ionizing radiation produce different dependences of cancer risk on radiation dose/dose rate. Sparsely ionizing radiation (e.g. γ-rays) generally produces linear or upwardly curving dose responses at low doses, and the risk decreases when the dose rate is reduced (direct dose rate effect). Densely ionizing radiation (e.g. neutrons) often produces downwardly curving dose responses, where the risk initially grows with dose, but eventually stabilizes or decreases. When the dose rate is reduced, the risk increases (inverse dose rate effect). These qualitative differences suggest qualitative differences in carcinogenesis mechanisms. We hypothesize that the dominant mechanism for induction of many solid cancers by sparsely ionizing radiation is initiation of stem cells to a pre-malignant state, but for densely ionizing radiation the dominant mechanism is radiation-bystander-effect mediated promotion of already pre-malignant cell clone growth. Here we present a mathematical model based on these assumptions and test it using data on the incidence of dysplastic growths and tumors in the mammary glands of mice exposed to high or low dose rates of γ-rays and neutrons, either with or without pre-treatment with the chemical carcinogen 7,12-dimethylbenz-alpha-anthracene (DMBA). The model provides a mechanistic and quantitative explanation which is consistent with the data and may provide useful insight into human carcinogenesis. PMID:22194850

Radioactivity Risk Assessment of Radon and Gamma Dose at One Uranium Tailings Pond in China

NASA Astrophysics Data System (ADS)

Lou, Yalong; Liu, Yong; Peng, Guowen; Zhao, Guodong; Zhang, Yan; Yang, Zhu

2018-01-01

A year-long monitoring of gamma radiation effective dose rate and radon concentration had been done in the reservoir area of one uranium tailings pond in Hunan province (The monitoring area included indoor and outdoor area of residential buildings and workshops, tailings dam slope). Afterwards, the annual effective radiation dose of the people in that radiation environment had been calculated based on the results of monitoring, as well as a radiation risk assessment. According to the assessment, gamma radiation effective dose rate and radon concentration in the monitoring area were low, and the annual effective radiation dose was far below the international standard (30mSv), which showed that the radiation would not put the people’s health at risk. However, the annual effective radiation dose of gamma was far above that of radon in the area of uranium tailings pond; therefore, it’s advisable to take quarantine measures in in the area of uranium tailings pond to keep the surrounding residents away from unnecessary ionizing radiation.

Review of reconstruction of radiation incident air kerma by measurement of absorbed dose in tooth enamel with EPR.

PubMed

Wieser, A

2012-03-01

Electron paramagnetic resonance dosimetry with tooth enamel has been proved to be a reliable method to determine retrospectively exposures from photon fields with minimal detectable doses of 100 mGy or lower, which is lower than achievable with cytogenetic dose reconstruction methods. For risk assessment or validating dosimetry systems for specific radiation incidents, the relevant dose from the incident has to be calculated from the total absorbed dose in enamel by subtracting additional dose contributions from the radionuclide content in teeth, natural external background radiation and medical exposures. For calculating organ doses or evaluating dosimetry systems the absorbed dose in enamel from a radiation incident has to be converted to air kerma using dose conversion factors depending on the photon energy spectrum and geometry of the exposure scenario. This paper outlines the approach to assess individual dose contributions to absorbed dose in enamel and calculate individual air kerma of a radiation incident from the absorbed dose in tooth enamel.

Acute Hematological Effects in Mice Exposed to the Expected Doses, Dose-rates, and Energies of Solar Particle Event-like Proton Radiation

PubMed Central

Sanzari, Jenine K.; Cengel, Keith A.; Wan, X. Steven; Rusek, Adam; Kennedy, Ann R.

2014-01-01

NASA has funded several projects that have provided evidence for the radiation risk in space. One radiation concern arises from solar particle event (SPE) radiation, which is composed of energetic electrons, protons, alpha particles and heavier particles. SPEs are unpredictable and the accompanying SPE radiation can place astronauts at risk of blood cell death, contributing to a weakened immune system and increased susceptibility to infection. The doses, dose rates, and energies of the proton radiation expected to occur during a SPE have been simulated at the NASA Space Radiation Laboratory, Brookhaven National Laboratory, delivering total body doses to mice. Hematological values were evaluated at acute time points, up to 24 hrs. post-radiation exposure. PMID:25202654

Utilization of ICU Data to Improve 30 and 60 Day HENRE Mortality Models, Revision 1

DTIC Science & Technology

2017-05-12

Acute Radiation Syndrome , Mortality, Burn Combined Injury, Lethality, Small Intestine, Ordinary...a large dose of radiation in a short period of time (high dose rate) causes acute radiation syndrome (ARS). Depending on the radiation dose, an...individual may experience the hematopoietic acute radiation syndrome (H-ARS) or the gastrointestinal acute radiation syndrome (GI-ARS) (reviewed in

Dose reduction potential of iterative reconstruction algorithms in neck CTA-a simulation study.

PubMed

Ellmann, Stephan; Kammerer, Ferdinand; Allmendinger, Thomas; Brand, Michael; Janka, Rolf; Hammon, Matthias; Lell, Michael M; Uder, Michael; Kramer, Manuel

2016-10-01

This study aimed to determine the degree of radiation dose reduction in neck CT angiography (CTA) achievable with Sinogram-affirmed iterative reconstruction (SAFIRE) algorithms. 10 consecutive patients scheduled for neck CTA were included in this study. CTA images of the external carotid arteries either were reconstructed with filtered back projection (FBP) at full radiation dose level or underwent simulated dose reduction by proprietary reconstruction software. The dose-reduced images were reconstructed using either SAFIRE 3 or SAFIRE 5 and compared with full-dose FBP images in terms of vessel definition. 5 observers performed a total of 3000 pairwise comparisons. SAFIRE allowed substantial radiation dose reductions in neck CTA while maintaining vessel definition. The possible levels of radiation dose reduction ranged from approximately 34 to approximately 90% and depended on the SAFIRE algorithm strength and the size of the vessel of interest. In general, larger vessels permitted higher degrees of radiation dose reduction, especially with higher SAFIRE strength levels. With small vessels, the superiority of SAFIRE 5 over SAFIRE 3 was lost. Neck CTA can be performed with substantially less radiation dose when SAFIRE is applied. The exact degree of radiation dose reduction should be adapted to the clinical question, in particular to the smallest vessel needing excellent definition.

Effects of Chronic Low-Dose Radiation on Human Neural Progenitor Cells

NASA Astrophysics Data System (ADS)

Katsura, Mari; Cyou-Nakamine, Hiromasa; Zen, Qin; Zen, Yang; Nansai, Hiroko; Amagasa, Shota; Kanki, Yasuharu; Inoue, Tsuyoshi; Kaneki, Kiyomi; Taguchi, Akashi; Kobayashi, Mika; Kaji, Toshiyuki; Kodama, Tatsuhiko; Miyagawa, Kiyoshi; Wada, Youichiro; Akimitsu, Nobuyoshi; Sone, Hideko

2016-01-01

The effects of chronic low-dose radiation on human health have not been well established. Recent studies have revealed that neural progenitor cells are present not only in the fetal brain but also in the adult brain. Since immature cells are generally more radiosensitive, here we investigated the effects of chronic low-dose radiation on cultured human neural progenitor cells (hNPCs) derived from embryonic stem cells. Radiation at low doses of 31, 124 and 496 mGy per 72 h was administered to hNPCs. The effects were estimated by gene expression profiling with microarray analysis as well as morphological analysis. Gene expression was dose-dependently changed by radiation. By thirty-one mGy of radiation, inflammatory pathways involving interferon signaling and cell junctions were altered. DNA repair and cell adhesion molecules were affected by 124 mGy of radiation while DNA synthesis, apoptosis, metabolism, and neural differentiation were all affected by 496 mGy of radiation. These in vitro results suggest that 496 mGy radiation affects the development of neuronal progenitor cells while altered gene expression was observed at a radiation dose lower than 100 mGy. This study would contribute to the elucidation of the clinical and subclinical phenotypes of impaired neuronal development induced by chronic low-dose radiation.

Weldon Spring Site environmental report for calendar year 1993. Weldon Springs Site Remedial Action Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1994-05-01

This Site Environmental Report for Calendar Year 1993 describes the environmental monitoring programs at the Weldon Spring Site Remedial Action Project (WSSRAP). The objectives of these programs are to assess actual or potential exposure to contaminant effluents from the project area by providing public use scenarios and dose estimates, to demonstrate compliance with Federal and State permitted levels, and to summarize trends and/or changes in contaminant concentrations from environmental monitoring program. In 1993, the maximum committed dose to a hypothetical individual at the chemical plant site perimeter was 0.03 mrem (0.0003 mSv). The maximum committed dose to a hypothetical individualmore » at the boundary of the Weldon Spring Quarry was 1.9 mrem (0.019 mSv). These scenarios assume an individual walking along the perimeter of the site-once a day at the chemical plant/raffinate pits and twice a day at the quarry-250 days per year. This hypothetical individual also consumes fish, sediment, and water from lakes and other bodies of water in the area. The collective dose, based on an effected population of 112,000 was 0.12 person-rem (0.0012 person-Sv). This calculation is based on recreational use of the August A. Busch Memorial Conservation Area and the Missouri Department of Conservation recreational trail (the Katy Trail) near the quarry. These estimates are below the U.S. Department of Energy requirement of 100 mrem (I mSv) annual committed effective dose equivalent for all exposure pathways. Results from air monitoring for the National Emission Standards for Hazardous Air Pollutants (NESHAPs) program indicated that the estimated dose was 0.38 mrem, which is below the U.S. Environmental Protection Agency (EPA) standard of 10 mrem per year.« less

Exposure of the Heart in Breast Cancer Radiation Therapy: A Systematic Review of Heart Doses Published During 2003 to 2013

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, Carolyn W., E-mail: carolyn.taylor@ctsu.ox.ac.uk; Wang, Zhe; Macaulay, Elizabeth

Purpose: Breast cancer radiation therapy cures many women, but where the heart is exposed, it can cause heart disease. We report a systematic review of heart doses from breast cancer radiation therapy that were published during 2003 to 2013. Methods and Materials: Eligible studies were those reporting whole-heart dose (ie, dose averaged over the whole heart). Analyses considered the arithmetic mean of the whole-heart doses for the CT plans for each regimen in each study. We termed this “mean heart dose.” Results: In left-sided breast cancer, mean heart dose averaged over all 398 regimens reported in 149 studies from 28more » countries was 5.4 Gy (range, <0.1-28.6 Gy). In regimens that did not include the internal mammary chain (IMC), average mean heart dose was 4.2 Gy and varied with the target tissues irradiated. The lowest average mean heart doses were from tangential radiation therapy with either breathing control (1.3 Gy; range, 0.4-2.5 Gy) or treatment in the lateral decubitus position (1.2 Gy; range, 0.8-1.7 Gy), or from proton radiation therapy (0.5 Gy; range, 0.1-0.8 Gy). For intensity modulated radiation therapy mean heart dose was 5.6 Gy (range, <0.1-23.0 Gy). Where the IMC was irradiated, average mean heart dose was around 8 Gy and varied little according to which other targets were irradiated. Proton radiation therapy delivered the lowest average mean heart dose (2.6 Gy, range, 1.0-6.0 Gy), and tangential radiation therapy with a separate IMC field the highest (9.2 Gy, range, 1.9-21.0 Gy). In right-sided breast cancer, the average mean heart dose was 3.3 Gy based on 45 regimens in 23 studies. Conclusions: Recent estimates of typical heart doses from left breast cancer radiation therapy vary widely between studies, even for apparently similar regimens. Maneuvers to reduce heart dose in left tangential radiation therapy were successful. Proton radiation therapy delivered the lowest doses. Inclusion of the IMC doubled typical heart dose.« less

Thyroid Dysfunction and Autoimmune Thyroid Diseases Among Atomic Bomb Survivors Exposed in Childhood.

PubMed

Imaizumi, Misa; Ohishi, Waka; Nakashima, Eiji; Sera, Nobuko; Neriishi, Kazuo; Yamada, Michiko; Tatsukawa, Yoshimi; Takahashi, Ikuno; Fujiwara, Saeko; Sugino, Keizo; Ando, Takao; Usa, Toshiro; Kawakami, Atsushi; Akahoshi, Masazumi; Hida, Ayumi

2017-07-01

The risk of thyroid cancer increases and persists for decades among individuals exposed to ionizing radiation in childhood, although the long-term effects of childhood exposure to medium to low doses of radiation on thyroid dysfunction and autoimmune thyroid diseases have remained unclear. To evaluate radiation dose responses for the prevalence of thyroid dysfunction and autoimmune thyroid disease among atomic bomb survivors exposed in childhood. Hiroshima and Nagasaki atomic bomb survivors who were younger than 10 years old at exposure underwent thyroid examinations at the Radiation Effects Research Foundation between 2007 and 2011, which was 62 to 66 years after the bombing. Data from 2668 participants (mean age, 68.2 years; 1455 women) with known atomic bomb thyroid radiation doses (mean dose, 0.182 Gy; dose range, 0 to 4.040 Gy) were analyzed. Dose-response relationships between atomic bomb radiation dose and the prevalence of hypothyroidism, hyperthyroidism (Graves' disease), and positive for antithyroid antibodies. Prevalences were determined for hypothyroidism (129 cases, 7.8%), hyperthyroidism (32 cases of Graves' disease, 1.2%), and positive for antithyroid antibodies (573 cases, 21.5%). None of these was associated with thyroid radiation dose. Neither thyroid antibody-positive nor -negative hypothyroidism was associated with thyroid radiation dose. Additional analyses using alternative definitions of hypothyroidism and hyperthyroidism found that radiation dose responses were not significant. Radiation effects on thyroid dysfunction and autoimmune thyroid diseases were not observed among atomic bomb survivors exposed in childhood, at 62 to 66 years earlier. The cross-sectional design and survival bias were limitations of this study. Copyright © 2017 Endocrine Society

γ-H2AX Kinetic Profile in Mouse Lymphocytes Exposed to the Internal Emitters Cesium-137 and Strontium-90

PubMed Central

Turner, Helen C.; Shuryak, Igor; Weber, Waylon; Doyle-Eisele, Melanie; Melo, Dunstana; Guilmette, Raymond; Amundson, Sally A.; Brenner, David J.

2015-01-01

In the event of a dirty bomb scenario or an industrial nuclear accident, a significant dose of volatile radionuclides such as 137Cs and 90Sr may be dispersed into the atmosphere as a component of fallout and inhaled or ingested by hundreds and thousands of people. To study the effects of prolonged exposure to ingested radionuclides, we have performed long-term (30 day) internal-emitter mouse irradiations using soluble-injected 137CsCl and 90SrCl2 radioisotopes. The effect of ionizing radiation on the induction and repair of DNA double strand breaks (DSBs) in peripheral mouse lymphocytes in vivo was determined using the γ-H2AX biodosimetry marker. Using a serial sacrifice experimental design, whole-body radiation absorbed doses for 137Cs (0 to 10 Gy) and 90Sr (0 to 49 Gy) were delivered over 30 days following exposure to each radionuclide. The committed absorbed doses of the two internal emitters as a function of time post exposure were calculated based on their retention parameters and their derived dose coefficients for each specific sacrifice time. In order to measure the kinetic profile for γ-H2AX, peripheral blood samples were drawn at 5 specific timed dose points over the 30-day study period and the total γ-H2AX nuclear fluorescence per lymphocyte was determined using image analysis software. A key finding was that a significant γ-H2AX signal was observed in vivo several weeks after a single radionuclide exposure. A mechanistically-motivated model was used to analyze the temporal kinetics of γ-H2AX fluorescence. Exposure to either radionuclide showed two peaks of γ-H2AX: one within the first week, which may represent the death of mature, differentiated lymphocytes, and the second at approximately three weeks, which may represent the production of new lymphocytes from damaged progenitor cells. The complexity of the observed responses to internal irradiation is likely caused by the interplay between continual production and repair of DNA damage, cell cycle effects and apoptosis. PMID:26618801

γ-H2AX Kinetic Profile in Mouse Lymphocytes Exposed to the Internal Emitters Cesium-137 and Strontium-90.

PubMed

Turner, Helen C; Shuryak, Igor; Weber, Waylon; Doyle-Eisele, Melanie; Melo, Dunstana; Guilmette, Raymond; Amundson, Sally A; Brenner, David J

2015-01-01

In the event of a dirty bomb scenario or an industrial nuclear accident, a significant dose of volatile radionuclides such as 137Cs and 90Sr may be dispersed into the atmosphere as a component of fallout and inhaled or ingested by hundreds and thousands of people. To study the effects of prolonged exposure to ingested radionuclides, we have performed long-term (30 day) internal-emitter mouse irradiations using soluble-injected 137CsCl and 90SrCl2 radioisotopes. The effect of ionizing radiation on the induction and repair of DNA double strand breaks (DSBs) in peripheral mouse lymphocytes in vivo was determined using the γ-H2AX biodosimetry marker. Using a serial sacrifice experimental design, whole-body radiation absorbed doses for 137Cs (0 to 10 Gy) and 90Sr (0 to 49 Gy) were delivered over 30 days following exposure to each radionuclide. The committed absorbed doses of the two internal emitters as a function of time post exposure were calculated based on their retention parameters and their derived dose coefficients for each specific sacrifice time. In order to measure the kinetic profile for γ-H2AX, peripheral blood samples were drawn at 5 specific timed dose points over the 30-day study period and the total γ-H2AX nuclear fluorescence per lymphocyte was determined using image analysis software. A key finding was that a significant γ-H2AX signal was observed in vivo several weeks after a single radionuclide exposure. A mechanistically-motivated model was used to analyze the temporal kinetics of γ-H2AX fluorescence. Exposure to either radionuclide showed two peaks of γ-H2AX: one within the first week, which may represent the death of mature, differentiated lymphocytes, and the second at approximately three weeks, which may represent the production of new lymphocytes from damaged progenitor cells. The complexity of the observed responses to internal irradiation is likely caused by the interplay between continual production and repair of DNA damage, cell cycle effects and apoptosis.

Multidisciplinary European Low Dose Initiative (MELODI): strategic research agenda for low dose radiation risk research.

PubMed

Kreuzer, M; Auvinen, A; Cardis, E; Durante, M; Harms-Ringdahl, M; Jourdain, J R; Madas, B G; Ottolenghi, A; Pazzaglia, S; Prise, K M; Quintens, R; Sabatier, L; Bouffler, S

2018-03-01

MELODI (Multidisciplinary European Low Dose Initiative) is a European radiation protection research platform with focus on research on health risks after exposure to low-dose ionising radiation. It was founded in 2010 and currently includes 44 members from 18 countries. A major activity of MELODI is the continuous development of a long-term European Strategic Research Agenda (SRA) on low-dose risk for radiation protection. The SRA is intended to identify priorities for national and European radiation protection research programs as a basis for the preparation of competitive calls at the European level. Among those key priorities is the improvement of health risk estimates for exposures close to the dose limits for workers and to reference levels for the population in emergency situations. Another activity of MELODI is to ensure the availability of European key infrastructures for research activities, and the long-term maintenance of competences in radiation research via an integrated European approach for training and education. The MELODI SRA identifies three key research topics in low dose or low dose-rate radiation risk research: (1) dose and dose rate dependence of cancer risk, (2) radiation-induced non-cancer effects and (3) individual radiation sensitivity. The research required to improve the evidence base for each of the three key topics relates to three research lines: (1) research to improve understanding of the mechanisms contributing to radiogenic diseases, (2) epidemiological research to improve health risk evaluation of radiation exposure and (3) research to address the effects and risks associated with internal exposures, differing radiation qualities and inhomogeneous exposures. The full SRA and associated documents can be downloaded from the MELODI website ( http://www.melodi-online.eu/sra.html ).

The effect of radiation dose on the onset and progression of radiation-induced brain necrosis in the rat model.

PubMed

Hartl, Brad A; Ma, Htet S W; Hansen, Katherine S; Perks, Julian; Kent, Michael S; Fragoso, Ruben C; Marcu, Laura

2017-07-01

To provide a comprehensive understanding of how the selection of radiation dose affects the temporal and spatial progression of radiation-induced necrosis in the rat model. Necrosis was induced with a single fraction of radiation exposure, at doses ranging between 20 and 60 Gy, to the right hemisphere of 8-week-old Fischer rats from a linear accelerator. The development and progression of necrosis in the rats was monitored and quantified every other week with T1- and T2-weighted gadolinium contrast-enhanced MRI studies. The time to onset of necrosis was found to be dose-dependent, but after the initial onset, the necrosis progression rate and total volume generated was constant across different doses ranging between 30 and 60 Gy. Radiation doses less than 30 Gy did not develop necrosis within 33 weeks after treatment, indicating a dose threshold existing between 20 and 30 Gy. The highest dose used in this study led to the shortest time to onset of radiation-induced necrosis, while producing comparable disease progression dynamics after the onset. Therefore, for the radiation-induced necrosis rat model using a linear accelerator, the most optimum results were generated from a dose of 60 Gy.

Method for inserting noise in digital mammography to simulate reduction in radiation dose

NASA Astrophysics Data System (ADS)

Borges, Lucas R.; de Oliveira, Helder C. R.; Nunes, Polyana F.; Vieira, Marcelo A. C.

2015-03-01

The quality of clinical x-ray images is closely related to the radiation dose used in the imaging study. The general principle for selecting the radiation is ALARA ("as low as reasonably achievable"). The practical optimization, however, remains challenging. It is well known that reducing the radiation dose increases the quantum noise, which could compromise the image quality. In order to conduct studies about dose reduction in mammography, it would be necessary to acquire repeated clinical images, from the same patient, with different dose levels. However, such practice would be unethical due to radiation related risks. One solution is to simulate the effects of dose reduction in clinical images. This work proposes a new method, based on the Anscombe transformation, which simulates dose reduction in digital mammography by inserting quantum noise into clinical mammograms acquired with the standard radiation dose. Thus, it is possible to simulate different levels of radiation doses without exposing the patient to new levels of radiation. Results showed that the achieved quality of simulated images generated with our method is the same as when using other methods found in the literature, with the novelty of using the Anscombe transformation for converting signal-independent Gaussian noise into signal-dependent quantum noise.

²¹⁰Po in the diet at Seville (Spain) and its contribution to the dose by ingestion.

PubMed

Díaz-Francés, I; Mantero, J; Díaz-Ruiz, J; Manjón, G; García-Tenorio, R

2016-02-01

The activity concentrations of (210)Po have been determined in a total of 24 representative diet samples from Seville (south of Spain), inferring from the obtained values the annual intakes of (210)Po by ingestion of the affected population and the corresponding committed effective doses. The annual intakes of (210)Po and, consequently, the corresponding doses of this radionuclide show a high variability in correspondence with the variability in the composition of the analysed samples over time, and their magnitude is comparable with the estimated ones in other regions/countries of the world with similar diet habits (countries where the marine products have a considerable weight in the diets). Committed effective doses by ingestion higher than 0.1 mSv y(-1) have been estimated exclusively for (210)Po, reflecting the importance of this radionuclide and this route of incorporation in the magnitude of the total doses received by the affected population from natural sources. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Statistical analysis of radiation dose derived from ingestion of foods

NASA Astrophysics Data System (ADS)

Dougherty, Ward L.

2001-09-01

This analysis undertook the task of designing and implementing a methodology to determine an individual's probabilistic radiation dose from ingestion of foods utilizing Crystal Ball. A dietary intake model was determined by comparing previous existing models. Two principal radionuclides were considered-Lead210 (Pb-210) and Radium 226 (Ra-226). Samples from three different local grocery stores-Publix, Winn Dixie, and Albertsons-were counted on a gamma spectroscopy system with a GeLi detector. The same food samples were considered as those in the original FIPR database. A statistical analysis, utilizing the Crystal Ball program, was performed on the data to assess the most accurate distribution to use for these data. This allowed a determination of a radiation dose to an individual based on the above-information collected. Based on the analyses performed, radiation dose for grocery store samples was lower for Radium-226 than FIPR debris analyses, 2.7 vs. 5.91 mrem/yr. Lead-210 had a higher dose in the grocery store sample than the FIPR debris analyses, 21.4 vs. 518 mrem/yr. The output radiation dose was higher for all evaluations when an accurate estimation of distributions for each value was considered. Radium-226 radiation dose for FIPR and grocery rose to 9.56 and 4.38 mrem/yr. Radiation dose from ingestion of Pb-210 rose to 34.7 and 854 mrem/yr for FIPR and grocery data, respectively. Lead-210 was higher than initial doses for many reasons: Different peak examined, lower edge of detection limit, and minimum detectable concentration was considered. FIPR did not utilize grocery samples as a control because they calculated radiation dose that appeared unreasonably high. Consideration of distributions with the initial values allowed reevaluation of radiation does and showed a significant difference to original deterministic values. This work shows the value and importance of considering distributions to ensure that a person's radiation dose is accurately calculated. Probabilistic dose methodology was proved to be a more accurate and realistic method of radiation dose determination. This type of methodology provides a visual presentation of dose distribution that can be a vital aid in risk methodology.

Perception of Radiation Risk by Japanese Radiation Specialists Evaluated as a Safe Dose Before the Fukushima Nuclear Accident.

PubMed

Miura, Miwa; Ono, Koji; Yamauchi, Motohiro; Matsuda, Naoki

2016-06-01

From October to December 2010, just before the radiological accident at the Fukushima Daiichi nuclear power plant, 71 radiation professionals from radiation facilities in Japan were asked what they considered as a "safe dose" of radiation for themselves, their partners, parents, children, siblings, and friends. Although the 'safe dose' they noted varied widely, from less than 1 mSv y to more than 100 mSv y, the average dose was 35.6 mSv y, which is around the middle point between the legal exposure dose limits for the annual average and for any single year. Similar results were obtained from other surveys of members of the Japan Radioisotope Association (36.9 mSv y) and of the Oita Prefectural Hospital (36.8 mSv y). Among family members and friends, the minimum average "safe" dose was 8.5 mSv y for children, for whom 50% of the responders claimed a "safe dose" of less than 1 mSv. Gender, age and specialty of the radiation professional also affected their notion of a "safe dose." These findings suggest that the perception of radiation risk varies widely even for radiation professionals and that the legal exposure dose limits derived from regulatory science may act as an anchor of safety. The different levels of risk perception for different target groups among radiation professionals appear similar to those in the general population. The gap between these characteristics of radiation professionals and the generally accepted picture of radiation professionals might have played a role in the state of confusion after the radiological accident.

Gamma-radiation effects on luminescence properties of Eu3+ activated LaPO4 phosphor

NASA Astrophysics Data System (ADS)

Vujčić, Ivica; Gavrilović, Tamara; Sekulić, Milica; Mašić, Slobodan; Putić, Slaviša; Papan, Jelena; Dramićanin, Miroslav D.

2018-05-01

Eu3+ activated LaPO4 phosphors were prepared by a high-temperature solid-state method and irradiated to different high-doses gamma-radiation in the 0-4 MGy range. No effects of high-doses of high-energy radiation on phosphor's morphology and structure were observed, as documented by electron microscopy and X-ray diffraction measurements. On the other hand, photoluminescence measurements showed that emission properties of phosphor were affected by gamma-radiation; changes in radiative properties being prominent for absorbed radiation doses up to 250 kGy after which no additional changes are observed. Judd-Ofelt analysis of emission spectra is performed to thoroughly investigate radiative properties of phosphors. Analysis showed that radiative transition probability of Eu3+ emission decreases while non-radiative probability increases upon gamma-irradiation. Quantum efficiency of emission is decreased from about 46% to 35% when Eu3+ doped LaPO4 powders are exposed to gamma-radiation of 250 kGy dose, showing no additional decrease for higher gamma-radiation doses.

Role of genetic background in induced instability

NASA Technical Reports Server (NTRS)

Kadhim, Munira A.; Nelson, G. A. (Principal Investigator)

2003-01-01

Genomic instability is effectively induced by ionizing radiation. Recently, evidence has accumulated supporting a relationship between genetic background and the radiation-induced genomic instability phenotype. This is possibly due to alterations in proteins responsible for maintenance of genomic integrity or altered oxidative metabolism. Studies in human cell lines, human primary cells, and mouse models have been performed predominantly using high linear energy transfer (LET) radiation, or high doses of low LET radiation. The interplay between genetics, radiation response, and genomic instability has not been fully determined at low doses of low LET radiation. However, recent studies using low doses of low LET radiation suggest that the relationship between genetic background and radiation-induced genomic instability may be more complicated than these same relationships at high LET or high doses of low LET radiation. The complexity of this relationship at low doses of low LET radiation suggests that more of the population may be at risk than previously recognized and may have implications for radiation risk assessment.

Time- and dose-dependent effects of total-body ionizing radiation on muscle stem cells

PubMed Central

Masuda, Shinya; Hisamatsu, Tsubasa; Seko, Daiki; Urata, Yoshishige; Goto, Shinji; Li, Tao-Sheng; Ono, Yusuke

2015-01-01

Exposure to high levels of genotoxic stress, such as high-dose ionizing radiation, increases both cancer and noncancer risks. However, it remains debatable whether low-dose ionizing radiation reduces cellular function, or rather induces hormetic health benefits. Here, we investigated the effects of total-body γ-ray radiation on muscle stem cells, called satellite cells. Adult C57BL/6 mice were exposed to γ-radiation at low- to high-dose rates (low, 2 or 10 mGy/day; moderate, 50 mGy/day; high, 250 mGy/day) for 30 days. No hormetic responses in proliferation, differentiation, or self-renewal of satellite cells were observed in low-dose radiation-exposed mice at the acute phase. However, at the chronic phase, population expansion of satellite cell-derived progeny was slightly decreased in mice exposed to low-dose radiation. Taken together, low-dose ionizing irradiation may suppress satellite cell function, rather than induce hormetic health benefits, in skeletal muscle in adult mice. PMID:25869487

COMPREHENSIVE DATA CONCERNING COSMIC RADIATION DOSES AT GROUND LEVEL AND IN-FLIGHTS FOR TURKEY.

PubMed

Parmaksız, A

2016-12-01

Cosmic radiation doses of individuals living in 81 cities in Turkey were estimated by using CARI-6 software. Annual cosmic radiation doses of individuals were found to be between 308 and 736 µSv y -1 at ground level. The population-weighted annual effective dose from cosmic radiation was determined to be 387 µSv y -1 for Turkey. Cosmic radiation doses on-board for 137 (60 domestic and 77 international) flights varied from 1.2 to 83 µSv. It was estimated that six or over long-route round-trip air travels may cause cosmic radiation dose above the permissible limit for member of the public, i.e. 1 mSv y -1 According to the assumption of flights throughout 800 h on each route, cosmic radiation doses were found to be between 1.0 and 4.8 mSv for aircrew. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Geosciences help to protect human health: estimation of the adsorbed radiation doses while flight journeys, as important step to radiation risk assessment

NASA Astrophysics Data System (ADS)

Chernov, Anatolii; Shabatura, Olexandr

2016-04-01

Estimation of the adsorbed radiation dose while flight journeys is a complex problem, which should be solved to get correct evaluation of equivalent effective doses and radiation risk assessment. Direct measurements of the adsorbed dose in the aircrafts during regional flights (3-10 hours) has shown that the radiation in the plane may increase 10-15 times (to 2-4 mSv/h) compared to the values on the surface of the Earth (0.2-0.5 mSv/h). Results of instrumental research confirmed by the other investigations. It is a fact that adsorbed doses per year while flight journeys are less than doses from medical tests. However, while flight journeys passengers get the same doses as nuclear power plant staff, people in zones of natural radiation anomalies and so should be evaluated. According to the authors' research, flight journeys are safe enough, when solar activity is normal and if we fly under altitude of 18 km (as usual, while intercontinental flights). Most of people travel by plane not so often, but if flight is lasting in dangerous periods of solar activity (powerful solar winds and magnetic field storms), passengers and flight crew can adsorb great amount of radiation doses. People, who spend more than 500 hours in flight journeys (pilots, business oriented persons', government representatives, etc.) get amount of radiation, which can negatively influence on health and provoke diseases, such as cancer. Authors consider that problem actual and researches are still going on. It is revealed, that radiation can be calculated, using special equations. Great part of radiation depends on very variable outer-space component and less variable solar. Accurate calculations of doses will be possible, when we will take into account all features of radiation distribution (time, season of year and exact time of the day, duration of flight), technical features of aircraft and logistics of flight (altitude, latitude). Results of first attempts of radiation doses modelling confirmed instrumental evaluation of doses, which passengers get while flight journeys. Further researches of radiation doses while flight journeys are going on. That example of researches shows that geoscience and social interests and problems are closely connected. Human society could not develop properly and safely without cooperation with geological science. As we see, geophysical methods can be used to count variations of natural radiation in spatial and time dimensions, which influence on level of radiation in aircrafts. As a result of such researches important conclusions to reduce radiation risks and collective doses of adsorbed radiation can be done. Geophysicists work hard on solving different problems of monitoring and analysis of natural surroundings to protect humanity and create safe, well-organized living surroundings. Key words: Solar radiation, flight journeys, dose of adsorbed radiation.

Estimation of background radiation doses for the Peninsular Malaysia's population by ESR dosimetry of tooth enamel.

PubMed

Rodzi, Mohd; Zhumadilov, Kassym; Ohtaki, Megu; Ivannikov, Alexander; Bhattacharjee, Deborshi; Fukumura, Akifumi; Hoshi, Masaharu

2011-08-01

Background radiation dose is used in dosimetry for estimating occupational doses of radiation workers or determining radiation dose of an individual following accidental exposure. In the present study, the absorbed dose and the background radiation level are determined using the electron spin resonance (ESR) method on tooth samples. The effect of using different tooth surfaces and teeth exposed with single medical X-rays on the absorbed dose are also evaluated. A total of 48 molars of position 6-8 were collected from 13 district hospitals in Peninsular Malaysia. Thirty-six teeth had not been exposed to any excessive radiation, and 12 teeth had been directly exposed to a single X-ray dose during medical treatment prior to extraction. There was no significant effect of tooth surfaces and exposure with single X-rays on the measured absorbed dose of an individual. The mean measured absorbed dose of the population is 34 ± 6.2 mGy, with an average tooth enamel age of 39 years. From the slope of a regression line, the estimated annual background dose for Peninsular Malaysia is 0.6 ± 0.3 mGy y(-1). This value is slightly lower than the yearly background dose for Malaysia, and the radiation background dose is established by ESR tooth measurements on samples from India and Russia.

Enhancement of Structured Reporting - an Integration Reporting Module with Radiation Dose Collection Supporting.

PubMed

Lee, Ming-Che; Chuang, Kei-Shih; Hsu, Tien-Cheng; Lee, Chien-Ding

2016-11-01

Collection of radiation dose derived from radiological examination is necessary not only for radiation protection, but also for fulfillment of structured reports. However, the material regarding of radiation dose cannot be directly utilized by the Radiological Information System (RIS) since it is generated and only stored in the Picture Archiving and Communication System (PACS). In this paper, an integration reporting module is proposed to facilitate handling of dose information and structured reporting by providing two functionalities. First, a gateway is established to automatically collect the related information from PACS for further analyzing and monitoring the accumulated radiation. Second, the designated structured reporting patterns with corresponding radiation dose measurements can be acquired by radiologists as necessary. In the design, the radiation dose collection gateway and the well-established pattern are collocated to achieve that there is no need to do manual entry for structured reporting, thus increasing productivity and medical quality.

THE CHALLENGE OF CIEMAT INTERNAL DOSIMETRY SERVICE FOR ACCREDITATION ACCORDING TO ISO/IEC 17025 STANDARD, FOR IN VIVO AND IN VITRO MONITORING AND DOSE ASSESSMENT OF INTERNAL EXPOSURES.

PubMed

Lopez, M A; Martin, R; Hernandez, C; Navarro, J F; Navarro, T; Perez, B; Sierra, I

2016-09-01

The accreditation of an Internal Dosimetry Service (IDS) according to ISO/IEC 17025 Standard is a challenge. The aim of this process is to guarantee the technical competence for the monitoring of radionuclides incorporated in the body and for the evaluation of the associated committed effective dose E(50). This publication describes the main accreditation issues addressed by CIEMAT IDS regarding all the procedures involving good practice in internal dosimetry, focussing in the difficulties to ensure the traceability in the whole process, the appropriate calculation of detection limit of measurement techniques, the validation of methods (monitoring and dose assessments), the description of all the uncertainty sources and the interpretation of monitoring data to evaluate the intake and the committed effective dose. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Estimation of the total effective dose from low-dose CT scans and radiopharmaceutical administrations delivered to patients undergoing SPECT/CT explorations.

PubMed

Montes, Carlos; Tamayo, Pilar; Hernandez, Jorge; Gomez-Caminero, Felipe; García, Sofia; Martín, Carlos; Rosero, Angela

2013-08-01

Hybrid imaging, such as SPECT/CT, is used in routine clinical practice, allowing coregistered images of the functional and structural information provided by the two imaging modalities. However, this multimodality imaging may mean that patients are exposed to a higher radiation dose than those receiving SPECT alone. The study aimed to determine the radiation exposure of patients who had undergone SPECT/CT examinations and to relate this to the Background Equivalent Radiation Time (BERT). 145 SPECT/CT studies were used to estimate the total effective dose to patients due to both radiopharmaceutical administrations and low-dose CT scans. The CT contribution was estimated by the Dose-Length Product method. Specific conversion coefficients were calculated for SPECT explorations. The radiation dose from low-dose CTs ranged between 0.6 mSv for head and neck CT and 2.6 mSv for whole body CT scan, representing a maximum of 1 year of background radiation exposure. These values represent a decrease of 80-85% with respect to the radiation dose from diagnostic CT. The radiation exposure from radiopharmaceutical administration varied from 2.1 mSv for stress myocardial perfusion SPECT to 26 mSv for gallium SPECT in patients with lymphoma. The BERT ranged from 1 to 11 years. The contribution of low-dose CT scans to the total radiation dose to patients undergoing SPECT/CT examinations is relatively low compared with the effective dose from radiopharmaceutical administration. When a CT scan is only acquired for anatomical localization and attenuation correction, low-dose CT scan is justified on the basis of its lower dose.

Air contamination measurements for the evaluation of internal dose to workers in nuclear medicine departments

NASA Astrophysics Data System (ADS)

De Massimi, B.; Bianchini, D.; Sarnelli, A.; D'Errico, V.; Marcocci, F.; Mezzenga, E.; Mostacci, D.

2017-11-01

Radionuclides handled in nuclear medicine departments are often characterized by high volatility and short half-life. It is generally difficult to monitor directly the intake of these short-lived radionuclides in hospital staff: this makes measuring air contamination of utmost interest. The aim of the present work is to provide a method for the evaluation of internal doses to workers in nuclear medicine, by means of an air activity sampling detector, to ensure that the limits prescribed by the relevant legislation are respected. A continuous air sampling system measures isotope concentration with a Nal(TI) detector. Energy efficiency of the system was assessed with GEANT4 and with known activities of 18F. Air is sampled in a number of areas of the nuclear medicine department of the IRST-IRCCS hospital (Meldola- Italy). To evaluate committed doses to hospital staff involved (doctors, technicians, nurses) different exposure situations (rooms, times, radionuclides etc) were considered. After estimating the intake, the committed effective dose has been evaluated, for the different radionuclides, using the dose coefficients mandated by the Italian legislation. Error propagation for the estimated intake and personal dose has been evaluated, starting from measurement statistics.

Guidance on the Use of Hand-Held Survey Meters for Radiological Triage: Time-Dependent Detector Count Rates Corresponding to 50, 250, and 500 mSv Effective Dose for Adult Males and Adult Females

PubMed Central

Bolch, Wesley E.; Hurtado, Jorge L.; Lee, Choonsik; Manger, Ryan; Hertel, Nolan; Dickerson, William

2013-01-01

In June of 2006, the Radiation Studies Branch of the Centers for Disease Control and Prevention held a workshop to explore rapid methods of facilitating radiological triage of large numbers of potentially contaminated individuals following detonation of a radiological dispersal device. Two options were discussed. The first was the use of traditional gamma-cameras in nuclear medicine departments operated as make-shift whole-body counters. Guidance on this approach is currently available from the CDC. This approach is feasible if a manageable number of individuals were involved, transportation to the relevant hospitals was quickly provided, and the medical staff at each facility had been previously trained in this non-traditional use of their radiopharmaceutical imaging devices. If, however, substantially large numbers of individuals (100s to 1000s) needed radiological screening, other options must be given to first responders, first receivers, and health physicists providing medical management. In this study, the second option of the workshop was investigated – the use of commercially available portable survey meters (either NaI or GM based) for assessing potential ranges of effective dose (<50, 50–250, 250–500, and >500 mSv). Two hybrid computational phantoms were used to model an adult male and an adult female subject internally contaminated with either 241Am, 60Cs, 137Cs, 131I, and 192Ir following an acute inhalation or ingestion intake. As a function of time following the exposure, the net count rates corresponding to committed effective doses of 50, 250, and 500 mSv were estimated via Monte Carlo radiation transport simulation for each of four different detectors types, positions, and screening distances. Measured count rates can be compared to these values and an assignment of one of four possible effective dose ranges could be made. The method implicitly assumes that all external contamination has been removed prior to screening, and that the measurements be conducted in a low-background, and possibly mobile, facility positioned at the triage location. Net count rate data are provided in both tabular and graphical format within a series of eight handbooks available at the CDC website http://emergency.cdc.gov/radiation. PMID:22420020

Guidance on the Use of Hand-Held Survey Meters for radiological Triage: Time-Dependent Detector Count Rates Corresponding to 50, 250, and 500 mSv Effective Dose for Adult Males and Adult Females

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolch, W.E.; Hurtado, J.L.; Lee, C.

2012-01-01

In June 2006, the Radiation Studies Branch of the Centers for Disease Control and Prevention held a workshop to explore rapid methods of facilitating radiological triage of large numbers of potentially contaminated individuals following detonation of a radiological dispersal device. Two options were discussed. The first was the use of traditional gamma cameras in nuclear medicine departments operated as makeshift wholebody counters. Guidance on this approach is currently available from the CDC. This approach would be feasible if a manageable number of individuals were involved, transportation to the relevant hospitals was quickly provided, and the medical staff at each facilitymore » had been previously trained in this non-traditional use of their radiopharmaceutical imaging devices. If, however, substantially larger numbers of individuals (100 s to 1,000 s) needed radiological screening, other options must be given to first responders, first receivers, and health physicists providing medical management. In this study, the second option of the workshop was investigated by the use of commercially available portable survey meters (either NaI or GM based) for assessing potential ranges of effective dose (G50, 50Y250, 250Y500, and 9500 mSv). Two hybrid computational phantoms were used to model an adult male and an adult female subject internally contaminated with 241Am, 60Cs, 137Cs, 131I, or 192Ir following an acute inhalation or ingestion intake. As a function of time following the exposure, the net count rates corresponding to committed effective doses of 50, 250, and 500 mSv were estimated via Monte Carlo radiation transport simulation for each of four different detector types, positions, and screening distances. Measured net count rates can be compared to these values, and an assignment of one of four possible effective dose ranges could be made. The method implicitly assumes that all external contamination has been removed prior to screening and that the measurements be conducted in a low background, and possibly mobile, facility positioned at the triage location. Net count rate data are provided in both tabular and graphical format within a series of eight handbooks available at the CDC website (http://www.bt.cdc.gov/radiation/clinicians/evaluation).« less

Radiation Dose to Post-Chernobyl Cleanup Workers

Cancer.gov

Radiation dose calculation for post-Chernobyl Cleanup Workers in Ukraine - both external radiation exposure due to fallout and internal doses due to inhalation (I131 intake) or ingestion of contaminated foodstuffs.

Knowledge of medical imaging radiation dose and risk among doctors.

PubMed

Brown, Nicholas; Jones, Lee

2013-02-01

The growth of computed tomography (CT) and nuclear medicine (NM) scans has revolutionised healthcare but also greatly increased population radiation doses. Overuse of diagnostic radiation is becoming a feature of medical practice, leading to possible unnecessary radiation exposures and lifetime-risks of developing cancer. Doctors across all medical specialties and experience levels were surveyed to determine their knowledge of radiation doses and potential risks associated with some diagnostic imaging. A survey relating to knowledge and understanding of medical imaging radiation was distributed to doctors at 14 major Queensland public hospitals, as well as fellows and trainees in radiology, emergency medicine and general practice. From 608 valid responses, only 17.3% correctly estimated the radiation dose from CT scans and almost 1 in 10 incorrectly believed that CT radiation is not associated with any increased lifetime risk of developing cancer. There is a strong inverse relationship between a clinician's experience and their knowledge of CT radiation dose and risks, even among radiologists. More than a third (35.7%) of doctors incorrectly believed that typical NM imaging either does not use ionising radiation or emits doses equal to or less than a standard chest radiograph. Knowledge of CT and NM radiation doses is poor across all specialties, and there is a significant inverse relationship between experience and awareness of CT dose and risk. Despite having a poor understanding of these concepts, most doctors claim to consider them prior to requesting scans and when discussing potential risks with patients. © 2012 The Authors. Journal of Medical Imaging and Radiation Oncology © 2012 The Royal Australian and New Zealand College of Radiologists.

The c-Abl signaling network in the radioadaptive response

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chi-Min, Yuan

2014-01-28

The radioadaptive response, or radiation hormesis, i.e. a low dose of radiation can protect cells and organisms from the effects of a subsequent higher dose, is a widely recognized phenomenon. Mechanisms underlying such radiation hormesis, however, remain largely unclear. Preliminary studies indicate an important role of c-Abl signaling in mediating the radioadaptive response. We propose to investigate how c-Abl regulates the crosstalk between p53 and NFκB in response to low doses irradiation. We found in our recent study that low dose IR induces a reciprocal p53 suppression and NFκB activation, which induces HIF-a and subsequently a metabolic reprogramming resulting inmore » a transition from oxidative phosphorylation to glycolysis. Of importance is that this glycolytic switch is essential for the radioadaptive response. This low-dose radiationinduced HIF1α activation was in sharp contrast with the high-dose IR-induced p53 activation and HIF1α inhibition. HIF1α and p53 seem to play distinct roles in mediating the radiation dose-dependent metabolic response. The induction of HIF1α-mediated glycolysis is restricted to a low dose range of radiation, which may have important implications in assessing the level of radiation exposure and its potential health risk. Our results support a dose-dependent metabolic response to IR. When IR doses are below the threshold of causing detectable DNA damage (<0.2Gy) and thus little p53 activation, HIF1α is induced resulting in induction of glycolysis and increased radiation resistance. When the radiation dose reaches levels eliciting DNA damage, p53 is activated and diminishes the activity of HIF1α and glycolysis, leading to the induction of cell death. Our work challenges the LNT model of radiation exposure risk and provides a metabolic mechanism of radioadaptive response. The study supports a need for determining the p53 and HIF1α activity as a potential reliable biological readout of radiation exposure in humans. The exquisite sensitivity of cellular metabolism to low doses of radiation could also serve as a valuable biomarker for estimating the health effects of low-level radiation exposure.« less

Dose and Fractionation in Radiation Therapy of Curative Intent for Non-Small Cell Lung Cancer: Meta-Analysis of Randomized Trials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramroth, Johanna; Cutter, David J.; Darby, Sarah C.

Purpose: The optimum dose and fractionation in radiation therapy of curative intent for non-small cell lung cancer remains uncertain. We undertook a published data meta-analysis of randomized trials to examine whether radiation therapy regimens with higher time-corrected biologically equivalent doses resulted in longer survival, either when given alone or when given with chemotherapy. Methods and Materials: Eligible studies were randomized comparisons of 2 or more radiation therapy regimens, with other treatments identical. Median survival ratios were calculated for each comparison and pooled. Results: 3795 patients in 25 randomized comparisons of radiation therapy dose were studied. The median survival ratio, highermore » versus lower corrected dose, was 1.13 (95% confidence interval [CI] 1.04-1.22) when radiation therapy was given alone and 0.83 (95% CI 0.71-0.97) when it was given with concurrent chemotherapy (P for difference=.001). In comparisons of radiation therapy given alone, the survival benefit increased with increasing dose difference between randomized treatment arms (P for trend=.004). The benefit increased with increasing dose in the lower-dose arm (P for trend=.01) without reaching a level beyond which no further survival benefit was achieved. The survival benefit did not differ significantly between randomized comparisons where the higher-dose arm was hyperfractionated and those where it was not. There was heterogeneity in the median survival ratio by geographic region (P<.001), average age at randomization (P<.001), and year trial started (P for trend=.004), but not for proportion of patients with squamous cell carcinoma (P=.2). Conclusions: In trials with concurrent chemotherapy, higher radiation therapy doses resulted in poorer survival, possibly caused, at least in part, by high levels of toxicity. Where radiation therapy was given without chemotherapy, progressively higher radiation therapy doses resulted in progressively longer survival, and no upper dose level was found above which there was no further benefit. These findings support the consideration of further radiation therapy dose escalation trials, making use of modern treatment methods to reduce toxicity.« less

Acute Radiation Syndrome

MedlinePlus

... on Specific Types of Emergencies Acute Radiation Syndrome (ARS): A Fact Sheet for the Public Language: English ( ... radiation dose. People exposed to radiation will get ARS only if: The radiation dose was high The ...

Estimation of Effective Doses for Radiation Cancer Risks on ISS, Lunar, and Mars Missions with Space Radiation Measurement

NASA Technical Reports Server (NTRS)

Kim, M.Y.; Cucinotta, F.A.

2005-01-01

Radiation protection practices define the effective dose as a weighted sum of equivalent dose over major sites for radiation cancer risks. Since a crew personnel dosimeter does not make direct measurement of effective dose, it has been estimated with skin-dose measurements and radiation transport codes for ISS and STS missions. The Phantom Torso Experiment (PTE) of NASA s Operational Radiation Protection Program has provided the actual flight measurements of active and passive dosimeters which were placed throughout the phantom on STS-91 mission for 10 days and on ISS Increment 2 mission. For the PTE, the variation in organ doses, which is resulted by the absorption and the changes in radiation quality with tissue shielding, was considered by measuring doses at many tissue sites and at several critical body organs including brain, colon, heart, stomach, thyroid, and skins. These measurements have been compared with the organ dose calculations obtained from the transport models. Active TEPC measurements of lineal energy spectra at the surface of the PTE also provided the direct comparison of galactic cosmic ray (GCR) or trapped proton dose and dose equivalent. It is shown that orienting the phantom body as actual in ISS is needed for the direct comparison of the transport models to the ISS data. One of the most important observations for organ dose equivalent of effective dose estimates on ISS is the fractional contribution from trapped protons and GCR. We show that for most organs over 80% is from GCR. The improved estimation of effective doses for radiation cancer risks will be made with the resultant tissue weighting factors and the modified codes.

Airborne Dust, "The Good Guy or the Bad Guy": How Much do We Know?

NASA Technical Reports Server (NTRS)

Tsay, Si-Chee

2010-01-01

Processes in generating, transporting, and dissipating the airborne dust particles are global phenomena -African dust regularly reaching the Alps; Asian dust seasonally crossing the Pacific into North America, and ultimately the Atlantic into Europe. One of the vital biogeochemical roles dust storms play in Earth's ecosystem is routinely mobilizing mineral dust, as a source of iron, from deserts into oceans for fertilizing the growth of phytoplankton -the basis of the oceanic food chain. Similarly, these dust-laden airs also supply crucial nutrients for the soil of tropical rain forests, the so-called womb of life that hosts 50-90% of the species on Earth. With massive amounts of dust lifted from desert regions and injected into the atmosphere, however, these dust storms often affect daily activities in dramatic ways: pushing grit through windows and doors, forcing people to stay indoors, causing breathing problems, reducing visibility and delaying flights, and by and large creating chaos. Thus, both increasing and decreasing concentrations of doses result in harmful biological effects; so do the airborne dust particles to our Living Earth. Since 1997 NASA has been successfully launching a series of satellites - the Earth Observing System - to intensively study, and gain a better understanding of, the Earth as an integrated system. Through participation in many satellite remote-sensing/retrieval and validation projects over the years, we have gradually developed and refined the SMART (Surface-sensing Measurements for Atmospheric Radiative Transfer) and COMMIT (Chemical, Optical & Microphysical Measurements of In-situ Troposphere) mobile observatories, a suite of surface remote sensing and in-situ instruments that proved to be vital in providing high temporal measurements, which complement the satellite observations. In this talk, we will present SMART-COMMIT which has played key roles, serving as network or supersite, in major international research projects such as the Joint Aerosol Monsoon Experiment (JAMEX), a core element of the Asian Monsoon Years (AMY, 2008-2012). SMART-COMMIT deployments during 2008 AMY/JAMEX were conducted in northwestern China to characterize the properties of dust-laden aerosols. In 2009, SMART-COMMIT also participated in the JAMEX/RAJO-MEGHA (Radiation, Aerosol Joint Observations-Monsoon Experiment in the Gangetic-Himalayan Area; Sanskrit for Dust-Cloud) to study the aerosol properties, solar absorption and the associated atmospheric warming, and the climatic impact of elevated aerosols during the premonsoon season in South Asia. To fully characterize the properties of airborne dust in the field is an important but challenging task. In this seminar, we will present our recent measurements and retrievals of airborne dust properties.

Measurements of the neutron dose equivalent for various radiation qualities, treatment machines and delivery techniques in radiation therapy

NASA Astrophysics Data System (ADS)

Hälg, R. A.; Besserer, J.; Boschung, M.; Mayer, S.; Lomax, A. J.; Schneider, U.

2014-05-01

In radiation therapy, high energy photon and proton beams cause the production of secondary neutrons. This leads to an unwanted dose contribution, which can be considerable for tissues outside of the target volume regarding the long term health of cancer patients. Due to the high biological effectiveness of neutrons in regards to cancer induction, small neutron doses can be important. This study quantified the neutron doses for different radiation therapy modalities. Most of the reports in the literature used neutron dose measurements free in air or on the surface of phantoms to estimate the amount of neutron dose to the patient. In this study, dose measurements were performed in terms of neutron dose equivalent inside an anthropomorphic phantom. The neutron dose equivalent was determined using track etch detectors as a function of the distance to the isocenter, as well as for radiation sensitive organs. The dose distributions were compared with respect to treatment techniques (3D-conformal, volumetric modulated arc therapy and intensity-modulated radiation therapy for photons; spot scanning and passive scattering for protons), therapy machines (Varian, Elekta and Siemens linear accelerators) and radiation quality (photons and protons). The neutron dose equivalent varied between 0.002 and 3 mSv per treatment gray over all measurements. Only small differences were found when comparing treatment techniques, but substantial differences were observed between the linear accelerator models. The neutron dose equivalent for proton therapy was higher than for photons in general and in particular for double-scattered protons. The overall neutron dose equivalent measured in this study was an order of magnitude lower than the stray dose of a treatment using 6 MV photons, suggesting that the contribution of the secondary neutron dose equivalent to the integral dose of a radiotherapy patient is small.

Measurements of the neutron dose equivalent for various radiation qualities, treatment machines and delivery techniques in radiation therapy.

PubMed

Hälg, R A; Besserer, J; Boschung, M; Mayer, S; Lomax, A J; Schneider, U

2014-05-21

In radiation therapy, high energy photon and proton beams cause the production of secondary neutrons. This leads to an unwanted dose contribution, which can be considerable for tissues outside of the target volume regarding the long term health of cancer patients. Due to the high biological effectiveness of neutrons in regards to cancer induction, small neutron doses can be important. This study quantified the neutron doses for different radiation therapy modalities. Most of the reports in the literature used neutron dose measurements free in air or on the surface of phantoms to estimate the amount of neutron dose to the patient. In this study, dose measurements were performed in terms of neutron dose equivalent inside an anthropomorphic phantom. The neutron dose equivalent was determined using track etch detectors as a function of the distance to the isocenter, as well as for radiation sensitive organs. The dose distributions were compared with respect to treatment techniques (3D-conformal, volumetric modulated arc therapy and intensity-modulated radiation therapy for photons; spot scanning and passive scattering for protons), therapy machines (Varian, Elekta and Siemens linear accelerators) and radiation quality (photons and protons). The neutron dose equivalent varied between 0.002 and 3 mSv per treatment gray over all measurements. Only small differences were found when comparing treatment techniques, but substantial differences were observed between the linear accelerator models. The neutron dose equivalent for proton therapy was higher than for photons in general and in particular for double-scattered protons. The overall neutron dose equivalent measured in this study was an order of magnitude lower than the stray dose of a treatment using 6 MV photons, suggesting that the contribution of the secondary neutron dose equivalent to the integral dose of a radiotherapy patient is small.

Exposure of luminous marine bacteria to low-dose gamma-radiation.

PubMed

Kudryasheva, N S; Petrova, A S; Dementyev, D V; Bondar, A A

2017-04-01

The study addresses biological effects of low-dose gamma-radiation. Radioactive 137 Cs-containing particles were used as model sources of gamma-radiation. Luminous marine bacterium Photobacterium phosphoreum was used as a bioassay with the bioluminescent intensity as the physiological parameter tested. To investigate the sensitivity of the bacteria to the low-dose gamma-radiation exposure (≤250 mGy), the irradiation conditions were varied as follows: bioluminescence intensity was measured at 5, 10, and 20°С for 175, 100, and 47 h, respectively, at different dose rates (up to 4100 μGy/h). There was no noticeable effect of gamma-radiation at 5 and 10°С, while the 20°С exposure revealed authentic bioluminescence inhibition. The 20°С results of gamma-radiation exposure were compared to those for low-dose alpha- and beta-radiation exposures studied previously under comparable experimental conditions. In contrast to ionizing radiation of alpha and beta types, gamma-emission did not initiate bacterial bioluminescence activation (adaptive response). As with alpha- and beta-radiation, gamma-emission did not demonstrate monotonic dose-effect dependencies; the bioluminescence inhibition efficiency was found to be related to the exposure time, while no dose rate dependence was found. The sequence analysis of 16S ribosomal RNA gene did not reveal a mutagenic effect of low-dose gamma radiation. The exposure time that caused 50% bioluminescence inhibition was suggested as a test parameter for radiotoxicity evaluation under conditions of chronic low-dose gamma irradiation. Copyright © 2017 Elsevier Ltd. All rights reserved.

The radiation dosimeter on-board the FY-4 Satellite

NASA Astrophysics Data System (ADS)

Zhang, B.; Sun, Y.; Zhang, S.; Zhang, X.; Sun, Y.; Jing, T.

2017-12-01

The total radiation dose effect can lead to a decrease in the performance of satellite devices or materials. Accurately obtaining the total radiation dose during satellite operation could help to analyze the abnormality of payloads in orbit and optimize the design of radiation shielding. The radiation dosimeter is one of the space environmental monitoring devices on the "FY-4" satellite, which is a new generation of geostationary meteorological satellite. The dosimeter consists of 8 detectors, which are installed in different locations of the satellite, to obtain the total radiation dose with different shielding thickness and different orientations. To measure a total radiation dose up to 2000krad(Si), 100nm ion implantation RADFET was used. To improve the sensitivity of the dosimeter, the bias voltage of RADFET is set to 15V, and a 10V, 15-bit A/D is adopted to digitalize the RADFET's threshold voltage, which is increased as the total radiation dose grows. In addition, the temperature effect of RADFET is corrected from the measured temperature on orbit. The preliminary monitoring results show that the radiation dose is less than 35rad (Si) per day at 0.87 mm shielding thickness of equivalent aluminum in the geostationary orbit, and the dose in Y direction of the satellite is less than those in the X and Z directions. The radiation dose at the thickness of 3.87 mm equivalent aluminum is less than 1rad(Si)/day. It is found that the daily total dose measured by the dosimeter has a strong correlation with the flux of high energy electrons.

Radiation dose distributions due to sudden ejection of cobalt device.

PubMed

Abdelhady, Amr

2016-09-01

The evaluation of the radiation dose during accident in a nuclear reactor is of great concern from the viewpoint of safety. One of important accident must be analyzed and may be occurred in open pool type reactor is the rejection of cobalt device. The study is evaluating the dose rate levels resulting from upset withdrawal of co device especially the radiation dose received by the operator in the control room. Study of indirect radiation exposure to the environment due to skyshine effect is also taken into consideration in order to evaluate the radiation dose levels around the reactor during the ejection trip. Microshield, SHLDUTIL, and MCSky codes were used in this study to calculate the radiation dose profiles during cobalt device ejection trip inside and outside the reactor building. Copyright © 2016 Elsevier Ltd. All rights reserved.

Non-Malignant Thyroid Diseases Following a Wide Range of Radiation Exposures

PubMed Central

Ron, Elaine; Brenner, Alina

2013-01-01

Background The thyroid gland is one of the most radiosensitive human organs. While it is well known that radiation exposure increases the risk of thyroid cancer, less is known about its effects in relation to non-malignant thyroid diseases. Objectives The aim of this review is to evaluate the effects of high and low dose radiation on benign structural and functional diseases of the thyroid. Methods We examined the results of major studies from cancer patients treated with high-dose radiotherapy or thyrotoxicosis patients treated with high doses of iodine-131, patients treated with moderate to high dose radiotherapy for benign diseases, persons exposed to low doses from environmental radiation and survivors of the atomic bombings who were exposed to a range of doses. We evaluated radiation effects on structural (tumors, nodules), functional (hyper- and hypothyroidism), and autoimmune thyroid diseases. Results Following a wide range of doses of ionizing radiation, an increased risk of thyroid adenomas and nodules was observed in a variety of populations and settings. The dose response appeared to be linear at low to moderate doses, but in one study there was some suggestion of a reduction in risk above 5 Gy. The elevated risk for benign tumors continues for decades following exposure. Considerably less consistent findings are available regarding functional thyroid diseases including autoimmune diseases. In general, associations for these outcomes were fairly weak and significant radiation effects were most often observed following high doses, particularly for hypothyroidism. Conclusions A significant radiation dose-response relation was demonstrated for benign nodules and follicular adenomas. The effects of radiation on functional thyroid diseases are less clear, partly due to the greater difficulties studying these diseases. PMID:21128812

SCCT guidelines on radiation dose and dose-optimization strategies in cardiovascular CT

PubMed Central

Halliburton, Sandra S.; Abbara, Suhny; Chen, Marcus Y.; Gentry, Ralph; Mahesh, Mahadevappa; Raff, Gilbert L.; Shaw, Leslee J.; Hausleiter, Jörg

2012-01-01

Over the last few years, computed tomography (CT) has developed into a standard clinical test for a variety of cardiovascular conditions. The emergence of cardiovascular CT during a period of dramatic increase in radiation exposure to the population from medical procedures and heightened concern about the subsequent potential cancer risk has led to intense scrutiny of the radiation burden of this new technique. This has hastened the development and implementation of dose reduction tools and prompted closer monitoring of patient dose. In an effort to aid the cardiovascular CT community in incorporating patient-centered radiation dose optimization and monitoring strategies into standard practice, the Society of Cardiovascular Computed Tomography has produced a guideline document to review available data and provide recommendations regarding interpretation of radiation dose indices and predictors of risk, appropriate use of scanner acquisition modes and settings, development of algorithms for dose optimization, and establishment of procedures for dose monitoring. PMID:21723512

Method for microbeam radiation therapy

DOEpatents

Slatkin, D.N.; Dilmanian, F.A.; Spanne, P.O.

1994-08-16

A method is disclosed of performing radiation therapy on a patient, involving exposing a target, usually a tumor, to a therapeutic dose of high energy electromagnetic radiation, preferably X-ray radiation. The dose is in the form of at least two non-overlapping microbeams of radiation, each microbeam having a width of less than about 1 millimeter. Target tissue exposed to the microbeams receives a radiation dose during the exposure that exceeds the maximum dose that such tissue can survive. Non-target tissue between the microbeams receives a dose of radiation below the threshold amount of radiation that can be survived by the tissue, and thereby permits the non-target tissue to regenerate. The microbeams may be directed at the target from one direction, or from more than one direction in which case the microbeams overlap within the target tissue enhancing the lethal effect of the irradiation while sparing the surrounding healthy tissue. No Drawings

Radiation treatment of pharmaceuticals

NASA Astrophysics Data System (ADS)

Dám, A. M.; Gazsó, L. G.; Kaewpila, S.; Maschek, I.

1996-03-01

Product specific doses were calculated for pharmaceuticals to be radiation treated. Radio-pasteurization dose were determined for some heat sensitive pharmaceutical basic materials (pancreaton, neopancreatin, neopancreatin USP, duodenum extract). Using the new recommendation (ISO standards, Method 1) dose calculations were performed and radiation sterilization doses were determined for aprotinine and heparine Na.

Entrance radiation doses during paediatric cardiac catheterisations performed for diagnosis or the treatment of congenital heart disease.

PubMed

Papadopoulou, D; Yakoumakis, Em; Sandilos, P; Thanopoulos, V; Makri, Tr; Gialousis, G; Houndas, D; Yakoumakis, N; Georgiou, Ev

2005-01-01

The purpose of this study was to estimate the radiation exposure of children, during cardiac catheterisations for the diagnosis or treatment of congenital heart disease. Radiation doses were estimated for 45 children aged from 1 d to 13 y old. Thermoluminescent dosemeters (TLDs) were used to estimate the posterior entrance dose (DP), the lateral entrance dose (DLAT), the thyroid dose and the gonads dose. A dose-area product (DAP) meter was also attached externally to the tube of the angiographic system and gave a direct value in mGy cm2 for each procedure. Posterior and lateral entrance dose values during cardiac catheterisations ranged from 1 to 197 mGy and from 1.1 to 250.3 mGy, respectively. Radiation exposure to the thyroid and the gonads ranged from 0.3 to 8.4 mGy to 0.1 and 0.7 mGy, respectively. Finally, the DAP meter values ranged between 360 and 33,200 mGy cm2. Radiation doses measured in this study are comparable with those reported to previous studies. Moreover, strong correlation was found between the DAP values and the entrance radiation dose measured with TLDs.

Do changes in biomarkers from space radiation reflect dose or risk?

NASA Astrophysics Data System (ADS)

Brooks, A.

The space environment is made up of many different kinds of radiation so that the proper use of biomarkers is essential to estimate radiation risk. This presentation will evaluate differences between biomarkers of dose and risk and demonstrate why they should not be confused following radiation exposures in deep space. Dose is a physical quantity, while risk is a biological quantity. Many examples exist w ereh dose or changes in biomarkers of dose are inappropriately used as predictors of risk. Without information on the biology of the system, the biomarkers of dose provide little help in predicting risk in tissues or radiation exposure types where no excess risk can be demonstrated. Many of these biomarkers of dose only reflect changes in radiation dose or exposure. However, these markers are often incorrectly used to predict risk. For example, exposure of the trachea or of the deep lung to high-LET alpha particles results in similar changes in the biomarker chromosome damage in these two tissues. Such an observation would predict that the risk for cancer induction would be similar in these two tissues. It has been noted , however, that there has never been a tracheal tumor observed in rats that inhaled radon, but with the same exposure, large numbers of tumors were produced in the deep lung. The biology of the different tissues is the major determinant of the risk rather than the radiation dose. Recognition of this fact has resulted in the generation of tissue weighting factors for use in radiation protection. When tissue weighting factors are used the values derived are still called "dose". It is important to recognize that tissue specific observations have been corrected to reflect risk, and therefore should no longer be viewed as dose. The relative biological effectiveness (RBE) is also used to estimate radiation risk. The use of biomarkers to derive RBE is a difficult since it involves the use of a biological response to a standard low-LET reference radiation. Following low-LET radiation exposure, the biological response often does not increase as a linear function of dose. Thus, the RBE and the subsequent risk predicted is dependent on the dose where the two radiation types are compared. To avoid this problem the standard procedure is to use the dose and dose-rate response and compare the linear components of the two r diation exposures. Important riska comparisons are often done at very low doses, where the reference radiation may either increase or decrease as a function of dose. Since the low-LET exposure often does not produce a significant change above the background level of damage, the derived RBE factors can become very large.Studies using micronuclei as biomarkers following exposure to mono-energetic neutrons, x-rays and gamma rays delivered at very low doses (up to 0.10 Gy) demonstrated the differences in the shape of each dose-response relationship and the problems associated with the RBE. These studies show that RBE may not accurately reflect the hazards or risk associated with space radiation exposure. As additional measures of biological change are developed, it may become possible to base risk on biological change and not on changes in radiation doses. Research funded through grants # DE-FG03-99ER62787 from DOE Office of Biological and Environmental Research and RO1 CA74053-01 from NIH/NASA to Washington State University Tri-Cities.

Commentary 2 to Cox and Little: radiation-induced oncogenic transformation: the interplay between dose, dose protraction, and radiation quality

NASA Technical Reports Server (NTRS)

Brenner, D. J.; Hall, E. J.

1992-01-01

There is now a substantial body of evidence for end points such as oncogenic transformation in vitro, and carcinogenesis and life shortening in vivo, suggesting that dose protraction leads to an increase in effectiveness relative to a single, acute exposure--at least for radiations of medium linear energy transfer (LET) such as neutrons. Table I contains a summary of the pertinent data from studies in which the effect is seen. [table: see text] This phenomenon has come to be known as the "inverse dose rate effect," because it is in marked contrast to the situation at low LET, where protraction in delivery of a dose of radiation, either by fractionation or low dose rate, results in a decreased biological effect; additionally, at medium and high LET, for radiobiological end points such as clonogenic survival, the biological effectiveness is independent of protraction. The quantity and quality of the published reports on the "inverse dose rate effect" leaves little doubt that the effect is real, but the available evidence indicates that the magnitude of the effect is due to a complex interplay between dose, dose rate, and radiation quality. Here, we first summarize the available data on the inverse dose rate effect and suggest that it follows a consistent pattern in regard to dose, dose rate, and radiation quality; second, we describe a model that predicts these features; and, finally, we describe the significance of the effect for radiation protection.

SU-E-J-274: Responses of Medulloblastoma Cells to Radiation Dosimetric Parameters in Intensity-Modulated Radiation Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, J; Molecular Imaging Program at Stanford, Stanford, CA; Bio-X Program, Stanford, CA

2015-06-15

Purpose: To evaluate radiation responses of the medulloblastoma cell line Daoy in intensity-modulated radiation therapy (IMRT), quantitative variations to variable radiation dosimetic parameters were tracked by bioluminescent images (BLIs). Methods: The luciferase and green fluorescent protein positive Daoy cells were cultured on dishes. The medulloblastoma cells irradiated to different dose rate, interval of fractionated doses, field margin and misalignment, and dose uniformity in IMRT were monitored using bioluminescent images. The cultured cells were placed into a dedicated acrylic phantom to deliver intensity-modulated fluences and calculate accurate predicted dose distribution. The radiation with dose rate from 0.5 Gy/min to 15 Gy/minmore » was irradiated by adjusting monitor unit per minute and source-to-surface distances. The intervals of fractionated dose delivery were changed considering the repair time of double strand breaks (DSB) revealed by straining of gamma-H2AX.The effect of non-uniform doses on the cells were visualized by registering dose distributions and BLIs. The viability according to dosimetric parameters was correlated with bioluminescent intensities for cross-check of radiation responses. Results: The DSB and cell responses due to the first fractionated dose delivery significantly affected final tumor control rather than other parameters. The missing tumor volumes due to the smaller field margin than the tumor periphery or field misalignment caused relapse of cell responses on BLIs. The dose rate and gradient had effect on initial responses but could not bring out the distinguishable killing effect on cancer cells. Conclusion: Visualized and quantified bioluminescent images were useful to correlate the dose distributions with spatial radiation effects on cells. This would derive the effective combination of dose delivery parameters and fractionation. Radiation responses in particular IMRT configuration could be reflected to image based-dose re-optimization.« less

Absorbed Dose and Dose Equivalent Calculations for Modeling Effective Dose

NASA Technical Reports Server (NTRS)

Welton, Andrew; Lee, Kerry

2010-01-01

While in orbit, Astronauts are exposed to a much higher dose of ionizing radiation than when on the ground. It is important to model how shielding designs on spacecraft reduce radiation effective dose pre-flight, and determine whether or not a danger to humans is presented. However, in order to calculate effective dose, dose equivalent calculations are needed. Dose equivalent takes into account an absorbed dose of radiation and the biological effectiveness of ionizing radiation. This is important in preventing long-term, stochastic radiation effects in humans spending time in space. Monte carlo simulations run with the particle transport code FLUKA, give absorbed and equivalent dose data for relevant shielding. The shielding geometry used in the dose calculations is a layered slab design, consisting of aluminum, polyethylene, and water. Water is used to simulate the soft tissues that compose the human body. The results obtained will provide information on how the shielding performs with many thicknesses of each material in the slab. This allows them to be directly applicable to modern spacecraft shielding geometries.

Patient Dose Management: Focus on Practical Actions

PubMed Central

2016-01-01

Medical radiation is a very important part of modern medicine, and should be only used when needed and optimized. Justification and optimization of radiation examinations must be performed. The first step of reduction of medical exposure is to know the radiation dose in currently performed examinations. This review covers radiation units, how various imaging modalities report dose, and the current status of radiation dose reports and legislation. Also, practical tips that can be applied to clinical practice are introduced. Afterwards, the importance of radiology exposure related education is emphasized and the current status of education for medical personal and the public is explained, and appropriate education strategies are suggested. Commonly asked radiation dose related example questions and answers are provided in detail to allow medical personnel to answer patients. Lastly, we talk about computerized programs that can be used in medical facilities for managing patient dose. While patient dose monitoring and management should be used to decrease and optimize overall radiation dose, it should not be used to assess individual cancer risk. One must always remember that medically justified examinations should always be performed, and unneeded examinations should be avoided in the first place. PMID:26908988

Space dosimetry with the application of a 3D silicon detector telescope: response function and inverse algorithm.

PubMed

Pázmándi, Tamás; Deme, Sándor; Láng, Edit

2006-01-01

One of the many risks of long-duration space flights is the excessive exposure to cosmic radiation, which has great importance particularly during solar flares and higher sun activity. Monitoring of the cosmic radiation on board space vehicles is carried out on the basis of wide international co-operation. Since space radiation consists mainly of charged heavy particles (protons, alpha and heavier particles), the equivalent dose differs significantly from the absorbed dose. A radiation weighting factor (w(R)) is used to convert absorbed dose (Gy) to equivalent dose (Sv). w(R) is a function of the linear energy transfer of the radiation. Recently used equipment is suitable for measuring certain radiation field parameters changing in space and over time, so a combination of different measurements and calculations is required to characterise the radiation field in terms of dose equivalent. The objectives of this project are to develop and manufacture a three-axis silicon detector telescope, called Tritel, and to develop software for data evaluation of the measured energy deposition spectra. The device will be able to determine absorbed dose and dose equivalent of the space radiation.

Appropriate Use of Effective Dose in Radiation Protection and Risk Assessment.

PubMed

Fisher, Darrell R; Fahey, Frederic H

2017-08-01

Effective dose was introduced by the ICRP for the single, over-arching purpose of setting limits for radiation protection. Effective dose is a derived quantity or mathematical construct and not a physical, measurable quantity. The formula for calculating effective dose to a reference model incorporates terms to account for all radiation types, organ and tissue radiosensitivities, population groups, and multiple biological endpoints. The properties and appropriate applications of effective dose are not well understood by many within and outside the health physics profession; no other quantity in radiation protection has been more confusing or misunderstood. According to ICRP Publication 103, effective dose is to be used for "prospective dose assessment for planning and optimization in radiological protection, and retrospective demonstration of compliance for regulatory purposes." In practice, effective dose has been applied incorrectly to predict cancer risk among exposed persons. The concept of effective dose applies generally to reference models only and not to individual subjects. While conceived to represent a measure of cancer risk or heritable detrimental effects, effective dose is not predictive of future cancer risk. The formula for calculating effective dose incorporates committee-selected weighting factors for radiation quality and organ sensitivity; however, the organ weighting factors are averaged across all ages and both genders and thus do not apply to any specific individual or radiosensitive subpopulations such as children and young women. Further, it is not appropriate to apply effective dose to individual medical patients because patient-specific parameters may vary substantially from the assumptions used in generalized models. Also, effective dose is not applicable to therapeutic uses of radiation, as its mathematical underpinnings pertain only to observed late (stochastic) effects of radiation exposure and do not account for short-term adverse tissue reactions. The weighting factors incorporate substantial uncertainties, and linearity of the dose-response function at low dose is uncertain and highly disputed. Since effective dose is not predictive of future cancer incidence, it follows that effective dose should never be used to estimate future cancer risk from specific sources of radiation exposure. Instead, individual assessments of potential detriment should only be based on organ or tissue radiation absorbed dose, together with best scientific understanding of the corresponding dose-response relationships.

Seasonal influenza vaccine dose distribution in 195 countries (2004-2013): Little progress in estimated global vaccination coverage.

PubMed

Palache, Abraham; Oriol-Mathieu, Valerie; Fino, Mireli; Xydia-Charmanta, Margarita

2015-10-13

Seasonal influenza is an important disease which results in 250,000-500,000 annual deaths worldwide. Global targets for vaccination coverage rates (VCRs) in high-risk groups are at least 75% in adults ≥65 years and increased coverage in other risk groups. The International Federation of Pharmaceutical Manufacturers and Associations Influenza Vaccine Supply (IFPMA IVS) International Task Force developed a survey methodology in 2008, to assess the global distribution of influenza vaccine doses as a proxy for VCRs. This paper updates the previous survey results on absolute numbers of influenza vaccine doses distributed between 2004 and 2013 inclusive, and dose distribution rates per 1000 population, and provides a qualitative assessment of the principal enablers and barriers to seasonal influenza vaccination. The two main findings from the quantitative portion of the survey are the continued negative trend for dose distribution in the EURO region and the perpetuation of appreciable differences in scale of dose distribution between WHO regions, with no observed convergence in the rates of doses distributed per 1000 population over time. The main findings from the qualitative portion of the survey were that actively managing the vaccination program in real-time and ensuring political commitment to vaccination are important enablers of vaccination, whereas insufficient access to vaccination and lack of political commitment to seasonal influenza vaccination programs are likely contributing to vaccination target failures. In all regions of the world, seasonal influenza vaccination is underutilized as a public health tool. The survey provides evidence of lost opportunity to protect populations against potentially serious influenza-associated disease. We call on the national and international public health communities to re-evaluate their political commitment to the prevention of the annual influenza disease burden and to develop a systematic approach to improve vaccine distribution equitably. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Proteomic and Epigenetic Analysis of Rice after Seed Spaceflight and Ground-Base Ion Radiations

NASA Astrophysics Data System (ADS)

Wang, Wei; Sun, Yeqing; Peng, Yuming; Zhao, Qian; Wen, Bin; Yang, Jun

Highly ionizing radiation (HZE) in space is considered as main factor causing biological effects to plant seeds. In previous work, we compared the proteomic profiles of rice plants growing after seed spaceflights to ground controls by two-dimensional difference gel electrophoresis (2-D DIGE) with mass spectrometry and found that the protein expression profiles were changed and differentially expressed proteins participated in most of the biological processes of rice. To further evaluate the dosage effects of space radiation and compare between low- and high-dose ion effects, we carried out three independent ground-base ionizing radiation experiments with different cumulative doses (low-dose range: 2~1000mGy, high-dose range: 2000~20000mGy) to rice seeds and performed proteomic analysis of seedlings. We found that protein expression profiles showed obvious boundaries between low- and high-dose radiation groups. Rates of differentially expressed proteins presented a dose-dependent effect, it reached the highest value at 2000mGy dosage point in all three radiation experiments coincidently; while proteins responded to low-dose radiations preferred to change their expressions at the minimum dosage (2mGy). Proteins participating in rice biological processes also responded differently between low- and high-dose radiations: proteins involved in energy metabolism and photosynthesis tended to be regulated after low-dose radiations while stress responding, protein folding and cell redox homeostasis related proteins preferred to change their expressions after high-dose radiations. By comparing the proteomic profiles between ground-base radiations and spaceflights, it was worth noting that ground-base low-dose ion radiation effects shared similar biological effects as space environment. In addition, we discovered that protein nucleoside diphosphate kinase 1 (NDPK1) showed obvious increased regulation after spaceflights and ion radiations. NDPK1 catalyzes nucleotide metabolism and is reported to be involved in DNA repair process. Its expression sensitivity and specificity were confirmed by RT-PCR and western blot analysis, indicating its potential to be used as space radiation biomarker. Space radiations might induce epigenetic effects on rice plants, especially changes of DNA methylation. Early results suggested that there were correlations between DNA methylation polymorphic and genomic mutation rates. In addition, the 5-methylcytosine located in coding gene’s promoter and exon regions could regulate gene expressions thus influence protein expressions. So whether there is correlation between genome DNA methylation changes and protein expression profile alterations caused by space radiation is worth for further investigation. Therefore we used the same rice samples treated by carbon ion radiation with different doses (0, 10, 20,100, 200, 1000, 2000, 5000, 20000mGy) and applied methylation sensitive amplification polymorphism (MSAP) for scanning genome DNA methylation changes. Interestingly, DNA methylation polymorphism rates also presented a dose-dependent effect and showed the same changing trend as rates of differentially expressed proteins. Whether there are correlations between epigenetic and proteomic effects of space radiation is worth for further investigation.

[Dose rate-dependent cellular and molecular effects of ionizing radiation].

PubMed

Przybyszewski, Waldemar M; Wideł, Maria; Szurko, Agnieszka; Maniakowski, Zbigniew

2008-09-11

The aim of radiation therapy is to kill tumor cells while minimizing damage to normal cells. The ultimate effect of radiation can be apoptotic or necrotic cell death as well as cytogenetic damage resulting in genetic instability and/or cell death. The destructive effects of radiation arise from direct and indirect ionization events leading to peroxidation of macromolecules, especially those present in lipid-rich membrane structures as well as chromatin lipids. Lipid peroxidative end-products may damage DNA and proteins. A characteristic feature of radiation-induced peroxidation is an inverse dose-rate effect (IDRE), defined as an increase in the degree of oxidation(at constant absorbed dose) accompanying a lower dose rate. On the other hand, a low dose rate can lead to the accumulation of cells in G2, the radiosensitive phase of the cell cycle since cell cycle control points are not sensitive to low dose rates. Radiation dose rate may potentially be the main factor improving radiotherapy efficacy as well as affecting the intensity of normal tissue and whole-body side effects. A better understanding of dose rate-dependent biological effects may lead to improved therapeutic intervention and limit normal tissue reaction. The study reviews basic biological effects that depend on the dose rate of ionizing radiation.

Estimation of median human lethal radiation dose computed from data on occupants of reinforced concrete structures in Nagasaki, Japan.

PubMed

Levin, S G; Young, R W; Stohler, R L

1992-11-01

This paper presents an estimate of the median lethal dose for humans exposed to total-body irradiation and not subsequently treated for radiation sickness. The median lethal dose was estimated from calculated doses to young adults who were inside two reinforced concrete buildings that remained standing in Nagasaki after the atomic detonation. The individuals in this study, none of whom have previously had calculated doses, were identified from a detailed survey done previously. Radiation dose to the bone marrow, which was taken as the critical radiation site, was calculated for each individual by the Engineering Physics and Mathematics Division of the Oak Ridge National Laboratory using a new three-dimensional discrete-ordinates radiation transport code that was developed and validated for this study using the latest site geometry, radiation yield, and spectra data. The study cohort consisted of 75 individuals who either survived > 60 d or died between the second and 60th d postirradiation due to radiation injury, without burns or other serious injury. Median lethal dose estimates were calculated using both logarithmic (2.9 Gy) and linear (3.4 Gy) dose scales. Both calculations, which met statistical validity tests, support previous estimates of the median lethal dose based solely on human data, which cluster around 3 Gy.

Treatment planning systems for external whole brain radiation therapy: With and without MLC (multi leaf collimator) optimization

NASA Astrophysics Data System (ADS)

Budiyono, T.; Budi, W. S.; Hidayanto, E.

2016-03-01

Radiation therapy for brain malignancy is done by giving a dose of radiation to a whole volume of the brain (WBRT) followed by a booster at the primary tumor with more advanced techniques. Two external radiation fields given from the right and left side. Because the shape of the head, there will be an unavoidable hotspot radiation dose of greater than 107%. This study aims to optimize planning of radiation therapy using field in field multi-leaf collimator technique. A study of 15 WBRT samples with CT slices is done by adding some segments of radiation in each field of radiation and delivering appropriate dose weighting using a TPS precise plan Elekta R 2.15. Results showed that this optimization a more homogeneous radiation on CTV target volume, lower dose in healthy tissue, and reduced hotspots in CTV target volume. Comparison results of field in field multi segmented MLC technique with standard conventional technique for WBRT are: higher average minimum dose (77.25% ± 0:47%) vs (60% ± 3:35%); lower average maximum dose (110.27% ± 0.26%) vs (114.53% ± 1.56%); lower hotspot volume (5.71% vs 27.43%); and lower dose on eye lenses (right eye: 9.52% vs 18.20%); (left eye: 8.60% vs 16.53%).

New image-processing and noise-reduction software reduces radiation dose during complex endovascular procedures.

PubMed

Kirkwood, Melissa L; Guild, Jeffrey B; Arbique, Gary M; Tsai, Shirling; Modrall, J Gregory; Anderson, Jon A; Rectenwald, John; Timaran, Carlos

2016-11-01

A new proprietary image-processing system known as AlluraClarity, developed by Philips Healthcare (Best, The Netherlands) for radiation-based interventional procedures, claims to lower radiation dose while preserving image quality using noise-reduction algorithms. This study determined whether the surgeon and patient radiation dose during complex endovascular procedures (CEPs) is decreased after the implementation of this new operating system. Radiation dose to operators, procedure type, reference air kerma, kerma area product, and patient body mass index were recorded during CEPs on two Philips Allura FD 20 fluoroscopy systems with and without Clarity. Operator dose during CEPs was measured using optically stimulable, luminescent nanoDot (Landauer Inc, Glenwood, Ill) detectors placed outside the lead apron at the left upper chest position. nanoDots were read using a microStar ii (Landauer Inc) medical dosimetry system. For the CEPs in the Clarity group, the radiation dose to surgeons was also measured by the DoseAware (Philips Healthcare) personal dosimetry system. Side-by-side measurements of DoseAware and nanoDots allowed for cross-calibration between systems. Operator effective dose was determined using a modified Niklason algorithm. To control for patient size and case complexity, the average fluoroscopy dose rate and the dose per radiographic frame were adjusted for body mass index differences and then compared between the groups with and without Clarity by procedure. Additional factors, for example, physician practice patterns, that may have affected operator dose were inferred by comparing the ratio of the operator dose to procedural kerma area product with and without Clarity. A one-sided Wilcoxon rank sum test was used to compare groups for radiation doses, reference air kermas, and operating practices for each procedure type. The analysis included 234 CEPs; 95 performed without Clarity and 139 with Clarity. Practice patterns of operators during procedures with and without Clarity were not significantly different. For all cases, procedure radiation dose to the patient and the primary and assistant operators were significantly decreased in the Clarity group by 60% compared with the non-Clarity group. By procedure type, fluorography dose rates decreased from 44% for fenestrated endovascular repair and up to 70% with lower extremity interventions. Fluoroscopy dose rates also significantly decreased, from about 37% to 47%, depending on procedure type. The AlluraClarity system reduces the patient and primary operator's radiation dose by more than half during CEPs. This feature appears to be an effective tool in lowering the radiation dose while maintaining image quality. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Estimation of ²¹⁰Po and ²¹⁰Pb and its dose to human beings due to consumption of marine species of Ennore Creek, South India.

PubMed

Musthafa, M Saiyad; Krishnamoorthy, R

2012-10-01

A systemic study on the natural radionuclides such as (210)Po and (210)Pb in the environmental matrices and biota of Ennore Creek has been undertaken to establish a baseline data on the radiation profile of Ennore Creek environment. The environmental samples such as water, sediment, and biota (seaweeds, molluscs, crustaceans, and fishes) have been subjected to analyses. It has been observed that the concentration of (210)Po and (210)Pb in the water samples of Ennore Creek as 2.7 and 1.63 m Bq L(-1), respectively. The activity concentration of (210)Po and (210)Pb in the sediment sample was 17.9 and 28.9 Bq kg(-1), respectively. The bivalve mollusk Perna viridis have been identified to accumulate higher concentrations of (210)Po and (210)Pb suggesting that they could serve as bioindicator of radionuclides in the Ennore Creek environment. The committed effective dose for human beings was found at 81.13-216.8 and 2.1-297.2 μSv year(-1) for (210)Po and (210)Pb, respectively.

210Po and 238U isotope concentrations in commercial bottled mineral water samples in Spain and their dose contribution.

PubMed

Díaz-Francés, I; Mantero, J; Manjón, G; Díaz, J; García-Tenorio, R

2013-09-01

(210)Po is a naturally occurring radionuclide, belonging to the uranium series, which is present in minute amounts in the different environmental compartments (water, soil, biota). Through its route along the trophic chain, it can be incorporated in the human body via ingestion of waters and/or food. This radionuclide is highly radiotoxic, being one of the main contributors to the committed effective dose via ingestion by the general population. In this work, the contribution of this radionuclide to the committed effective dose received by the Spanish population via consumption of bottled mineral waters is evaluated. With this end, the (210)Po activity concentrations in a total of 32 different commercial bottled mineral waters have been determined by alpha-particle spectrometry. The determined contribution is also compared with the contributions of other natural radionuclides such as (234)U and (238)U.

Dose evaluation of organs at risk (OAR) cervical cancer using dose volume histogram (DVH) on brachytherapy

NASA Astrophysics Data System (ADS)

Arif Wibowo, R.; Haris, Bambang; Inganatul Islamiyah, dan

2017-05-01

Brachytherapy is one way to cure cervical cancer. It works by placing a radioactive source near the tumor. However, there are some healthy tissues or organs at risk (OAR) such as bladder and rectum which received radiation also. This study aims to evaluate the radiation dose of the bladder and rectum. There were 12 total radiation dose data of the bladder and rectum obtained from patients’ brachytherapy. The dose of cervix for all patients was 6 Gy. Two-dimensional calculation of the radiation dose was based on the International Commission on Radiation Units and Measurements (ICRU) points or called DICRU while the 3-dimensional calculation derived from Dose Volume Histogram (DVH) on a volume of 2 cc (D2cc). The radiation dose of bladder and rectum from both methods were analysed using independent t test. The mean DICRU of bladder was 4.33730 Gy and its D2cc was4.78090 Gy. DICRU and D2cc bladder did not differ significantly (p = 0.144). The mean DICRU of rectum was 3.57980 Gy and 4.58670 Gy for D2cc. The mean DICRU of rectum differed significantly from D2cc of rectum (p = 0.000). The three-dimensional method radiation dose of the bladder and rectum was higher than the two-dimensional method with ratios 1.10227 for bladder and 1.28127 for rectum. The radiation dose of the bladder and rectum was still below the tolerance dose. Two-dimensional calculation of the bladder and rectum dose was lower than three-dimension which was more accurate due to its calculation at the whole volume of the organs.

10 CFR 63.111 - Performance objectives for the geologic repository operations area through permanent closure.

Code of Federal Regulations, 2013 CFR

2013-01-01

... of the deep dose equivalent and the committed dose equivalent to any individual organ or tissue (other than the lens of the eye) of 0.5 Sv (50 rem). The lens dose equivalent may not exceed 0.15 Sv (15... TEDE (hereafter referred to as “dose”) to any real member of the public located beyond the boundary of...

10 CFR 63.111 - Performance objectives for the geologic repository operations area through permanent closure.

Code of Federal Regulations, 2012 CFR

2012-01-01

... of the deep dose equivalent and the committed dose equivalent to any individual organ or tissue (other than the lens of the eye) of 0.5 Sv (50 rem). The lens dose equivalent may not exceed 0.15 Sv (15... TEDE (hereafter referred to as “dose”) to any real member of the public located beyond the boundary of...

10 CFR 63.111 - Performance objectives for the geologic repository operations area through permanent closure.

Code of Federal Regulations, 2014 CFR

2014-01-01

... of the deep dose equivalent and the committed dose equivalent to any individual organ or tissue (other than the lens of the eye) of 0.5 Sv (50 rem). The lens dose equivalent may not exceed 0.15 Sv (15... TEDE (hereafter referred to as “dose”) to any real member of the public located beyond the boundary of...

10 CFR 63.111 - Performance objectives for the geologic repository operations area through permanent closure.

Code of Federal Regulations, 2011 CFR

2011-01-01

... of the deep dose equivalent and the committed dose equivalent to any individual organ or tissue (other than the lens of the eye) of 0.5 Sv (50 rem). The lens dose equivalent may not exceed 0.15 Sv (15... TEDE (hereafter referred to as “dose”) to any real member of the public located beyond the boundary of...

Reconstruction and analysis of erythemal UV radiation time series from Hradec Králové (Czech Republic) over the past 50 years

NASA Astrophysics Data System (ADS)

Čížková, Klára; Láska, Kamil; Metelka, Ladislav; Staněk, Martin

2018-02-01

This paper evaluates the variability of erythemal ultraviolet (EUV) radiation from Hradec Králové (Czech Republic) in the period 1964-2013. The EUV radiation time series was reconstructed using a radiative transfer model and additional empirical relationships, with the final root mean square error of 9.9 %. The reconstructed time series documented the increase in EUV radiation doses in the 1980s and the 1990s (up to 15 % per decade), which was linked to the steep decline in total ozone (10 % per decade). The changes in cloud cover were the major factor affecting the EUV radiation doses especially in the 1960s, 1970s, and at the beginning of the new millennium. The mean annual EUV radiation doses in the decade 2004-2013 declined by 5 %. The factors affecting the EUV radiation doses differed also according to the chosen integration period (daily, monthly, and annually): solar zenith angle was the most important for daily doses, cloud cover, and surface UV albedo for their monthly means, and the annual means of EUV radiation doses were most influenced by total ozone column. The number of days with very high EUV radiation doses increased by 22 % per decade, the increase was statistically significant in all seasons except autumn. The occurrence of the days with very high EUV doses was influenced mostly by low total ozone column (82 % of days), clear-sky or partly cloudy conditions (74 % of days) and by increased surface albedo (19 % of days). The principal component analysis documented that the occurrence of days with very high EUV radiation doses was much affected by the positive phase of North Atlantic Oscillation with an Azores High promontory reaching over central Europe. In the stratosphere, a strong Arctic circumpolar vortex and the meridional inflow of ozone-poor air from the southwest were favorable for the occurrence of days with very high EUV radiation doses. This is the first analysis of the relationship between the high EUV radiation doses and macroscale circulation patterns, and therefore more attention should be given also to other dynamical variables that may affect the solar UV radiation on the Earth surface.

Cellular response to low dose radiation: Role of phosphatidylinositol-3 kinase like kinases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balajee, A.S.; Meador, J.A.; Su, Y.

It is increasingly realized that human exposure either to an acute low dose or multiple chronic low doses of low LET radiation has the potential to cause different types of cancer. Therefore, the central theme of research for DOE and NASA is focused on understanding the molecular mechanisms and pathways responsible for the cellular response to low dose radiation which would not only improve the accuracy of estimating health risks but also help in the development of predictive assays for low dose radiation risks associated with tissue degeneration and cancer. The working hypothesis for this proposal is that the cellularmore » mechanisms in terms of DNA damage signaling, repair and cell cycle checkpoint regulation are different for low and high doses of low LET radiation and that the mode of action of phosphatidylinositol-3 kinase like kinases (PIKK: ATM, ATR and DNA-PK) determines the dose dependent cellular responses. The hypothesis will be tested at two levels: (I) Evaluation of the role of ATM, ATR and DNA-PK in cellular response to low and high doses of low LET radiation in simple in vitro human cell systems and (II) Determination of radiation responses in complex cell microenvironments such as human EpiDerm tissue constructs. Cellular responses to low and high doses of low LET radiation will be assessed from the view points of DNA damage signaling, DNA double strand break repair and cell cycle checkpoint regulation by analyzing the activities (i.e. post-translational modifications and kinetics of protein-protein interactions) of the key target proteins for PI-3 kinase like kinases both at the intra-cellular and molecular levels. The proteins chosen for this proposal are placed under three categories: (I) sensors/initiators include ATM ser1981, ATR, 53BP1, gamma-H2AX, MDC1, MRE11, Rad50 and Nbs1; (II) signal transducers include Chk1, Chk2, FANCD2 and SMC1; and (III) effectors include p53, CDC25A and CDC25C. The primary goal of this proposal is to elucidate the differences in cellular defense mechanisms between low and high doses of low LET radiation and to define the radiation doses where the cellular DNA damage signaling and repair mechanisms tend to shift. This information is critically important to address and advance some of the low dose research program objectives of DOE. The results of this proposed study will lead to a better understanding of the mechanisms for the cellular responses to low and high doses of low LET radiation. Further, systematic analysis of the role of PIKK signaling pathways as a function of radiation dose in tissue microenvironment will provide useful mechanistic information for improving the accuracy of radiation risk assessment for low doses. Knowledge of radiation responses in tissue microenvironment is important for the accurate prediction of ionizing radiation risks associated with cancer and tissue degeneration in humans.« less

Learning From Trials on Radiation Dose in Non-Small Cell Lung Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bradley, Jeffrey, E-mail: jbradley@wustl.edu; Hu, Chen

2016-11-15

In this issue of the International Journal of Radiation Oncology • Biology • Physics, Taylor et al present a meta-analysis of published data supporting 2 findings: (1) radiation dose escalation seems to benefit patients who receive radiation alone for non-small cell lung cancer; and (2) radiation dose escalation has a detrimental effect on overall survival in the setting of concurrent chemotherapy. The latter finding is supported by data but has perplexed the oncology community. Perhaps these findings are not perplexing at all. Perhaps it is simply another lesson in the major principle in radiation oncology, to minimize radiation dose to normalmore » tissues.« less

A Commentary on: "A History of the United States Department of Energy (DOE) Low Dose Radiation Research Program: 1998-2008".

PubMed

Brooks, Antone L

2015-04-01

This commentary provides a very brief overview of the book "A History of the United States Department of Energy (DOE) Low Dose Radiation Research Program: 1998-2008" ( http://lowdose.energy.gov ). The book summarizes and evaluates the research progress, publications and impact of the U.S. Department of Energy Low Dose Radiation Research Program over its first 10 years. The purpose of this book was to summarize the impact of the program's research on the current thinking and low-dose paradigms associated with the radiation biology field and to help stimulate research on the potential adverse and/or protective health effects of low doses of ionizing radiation. In addition, this book provides a summary of the data generated in the low dose program and a scientific background for anyone interested in conducting future research on the effects of low-dose or low-dose-rate radiation exposure. This book's exhaustive list of publications coupled with discussions of major observations should provide a significant resource for future research in the low-dose and dose-rate region. However, because of space limitations, only a limited number of critical references are mentioned. Finally, this history book provides a list of major advancements that were accomplished by the program in the field of radiation biology, and these bulleted highlights can be found in last part of chapters 4-10.

What is the optimal radiation dose for non-operable esophageal cancer? Dissecting the evidence in a meta-analysis.

PubMed

Chen, Yong; Zhu, Hui-Ping; Wang, Tao; Sun, Chang-Jiang; Ge, Xiao-Lin; Min, Ling-Feng; Zhang, Xian-Wen; Jia, Qing-Qing; Yu, Jie; Yang, Jian-Qi; Allgayer, Heike; Abba, Mohammed L; Zhang, Xi-Zhi; Sun, Xin-Chen

2017-10-24

The standard radiation dose 50.4 Gy with concurrent chemotherapy for localized inoperable esophageal cancer as supported by INT-0123 trail is now being challenged since a radiation dose above 50 Gy has been successfully administered with an observable dose-response relationship and insignificant untoward effects. Therefore, to ascertain the treatment benefits of different radiation doses, we performed a meta-analysis with 18 relative publications. According to our findings, a dose between 50 and 70 Gy appears optimal and patients who received ≥ 60 Gy radiation had a significantly better prognosis (pooled HR = 0.78, P = 0.004) as compared with < 60 Gy, especially in Asian countries (pooled HR = 0.75, P = 0.003). However, contradictory results of treatment benefit for ≥ 60 Gy were observed in two studies from Western countries, and the pooled treatment benefit of ≥ 60 Gy radiation was inconclusive (pooled HR = 0.86, P = 0.64). There was a marginal benefit in locoregional control in those treated with high dose (> 50.4/51 Gy) radiation when compared with those treated with low dose (≤ 50.4/51 Gy) radiation (pooled OR = 0.71, P = 0.06). Patients that received ≥ 60 Gy radiation had better locoregional control (OR = 0.29, P = 0.001), and for distant metastasis control, neither the > 50.4 Gy nor the ≥ 60 Gy treated group had any treatment benefit as compared to the groups that received ≤ 50.4 Gy and < 60 Gy group respectively. Taken together, a dose range of 50 to 70 Gy radiation with CCRT is recommended for non-operable EC patients. A dose of ≥ 60 Gy appears to be better in improving overall survival and locoregional control, especially in Asian countries, while the benefit of ≥ 60 Gy radiation in Western countries still remains controversial.

Radiation dose-rate meter using an energy-sensitive counter

DOEpatents

Kopp, Manfred K.

1988-01-01

A radiation dose-rate meter is provided which uses an energy-sensitive detector and combines charge quantization and pulse-rate measurement to monitor radiation dose rates. The charge from each detected photon is quantized by level-sensitive comparators so that the resulting total output pulse rate is proportional to the dose-rate.

Mutational influences of low-dose and high let ionizing radiation in drosophila melanogaster

NASA Astrophysics Data System (ADS)

Lei, Huang; Fanjun, Kong; Sun, Yeqing

For cosmic environment consists of a varying kinds of radiation particles including high Z and energy ions which was charactered with low-dose and high RBE, it is important to determine the possible biofuctions of high LET radiation on human beings. To analyse the possible effectes of mutational influences of low-dose and high-LET ionizing radiation, wild fruit flies drosophila melanogaster were irradiated by 12C6+ ions in two LET levels (63.3 and 30 keV/µum) with different low doses from 2mGy to 2000mGy (2, 20, 200, 2000mGy) in HIRFL (Heavy ion radiation facility laboratory, lanzhou, China).In the same LET value group, the average polymorphic frequency was elevated along with adding doses of irradation, the frequency in 2000 mGy dose samples was significantly higher than other samples (p<0.01).These results suggest that genomic DNA sequence could be effected by low-dose and high-LET ionizing radiation, the irradiation dose is an important element in genomic mutation frequency origination.

Gamma Low-Dose-Rate Ionizing Radiation Stimulates Adaptive Functional and Molecular Response in Human Aortic Endothelial Cells in a Threshold-, Dose-, and Dose Rate–Dependent Manner

PubMed Central

Vieira Dias, Juliana; Gloaguen, Celine; Kereselidze, Dimitri; Manens, Line; Tack, Karine; Ebrahimian, Teni G

2018-01-01

A central question in radiation protection research is whether low-dose and low-dose-rate (LDR) exposures to ionizing radiation play a role in progression of cardiovascular disease. The response of endothelial cells to different LDR exposures may help estimate risk of cardiovascular disease by providing the biological mechanism involved. We investigated the effect of chronic LDR radiation on functional and molecular responses of human aorta endothelial cells (HAoECs). Human aorta endothelial cells were continuously irradiated at LDR (6 mGy/h) for 15 days and analyzed at time points when the cumulative dose reached 0.05, 0.5, 1.0, and 2.0 Gy. The same doses were administered acutely at high-dose rate (HDR; 1 Gy/min). The threshold for the loss of angiogenic capacity for both LDR and HDR radiations was between 0.5 and 1.0 Gy. At 2.0 Gy, angiogenic capacity returned to normal only for HAoEC exposed to LDR radiation, associated with increased expression of antioxidant and anti-inflammatory genes. Pre-LDR, but not pre-HDR, radiation, followed by a single acute 2.0 Gy challenge dose sustained the expression of antioxidant and anti-inflammatory genes and stimulated angiogenesis. Our results suggest that dose rate is important in cellular response and that a radioadaptive response is involved for a 2.0 Gy dose at LDR. PMID:29531508

Gamma Low-Dose-Rate Ionizing Radiation Stimulates Adaptive Functional and Molecular Response in Human Aortic Endothelial Cells in a Threshold-, Dose-, and Dose Rate-Dependent Manner.

PubMed

Vieira Dias, Juliana; Gloaguen, Celine; Kereselidze, Dimitri; Manens, Line; Tack, Karine; Ebrahimian, Teni G

2018-01-01

A central question in radiation protection research is whether low-dose and low-dose-rate (LDR) exposures to ionizing radiation play a role in progression of cardiovascular disease. The response of endothelial cells to different LDR exposures may help estimate risk of cardiovascular disease by providing the biological mechanism involved. We investigated the effect of chronic LDR radiation on functional and molecular responses of human aorta endothelial cells (HAoECs). Human aorta endothelial cells were continuously irradiated at LDR (6 mGy/h) for 15 days and analyzed at time points when the cumulative dose reached 0.05, 0.5, 1.0, and 2.0 Gy. The same doses were administered acutely at high-dose rate (HDR; 1 Gy/min). The threshold for the loss of angiogenic capacity for both LDR and HDR radiations was between 0.5 and 1.0 Gy. At 2.0 Gy, angiogenic capacity returned to normal only for HAoEC exposed to LDR radiation, associated with increased expression of antioxidant and anti-inflammatory genes. Pre-LDR, but not pre-HDR, radiation, followed by a single acute 2.0 Gy challenge dose sustained the expression of antioxidant and anti-inflammatory genes and stimulated angiogenesis. Our results suggest that dose rate is important in cellular response and that a radioadaptive response is involved for a 2.0 Gy dose at LDR.

Spatial interpolation of gamma dose in radioactive waste storage facility

NASA Astrophysics Data System (ADS)

Harun, Nazran; Fathi Sujan, Muhammad; Zaidi Ibrahim, Mohd

2018-01-01

External radiation measurement for a radioactive waste storage facility in Malaysian Nuclear Agency is a part of Class G License requirement under Atomic Licensing Energy Board (AELB). The objectives of this paper are to obtain the distribution of radiation dose, create dose database and generate dose map in the storage facility. The radiation dose measurement is important to fulfil the radiation protection requirement to ensure the safety of the workers. There are 118 sampling points that had been recorded in the storage facility. The highest and lowest reading for external radiation recorded is 651 microSv/hr and 0.648 microSv/hour respectively. The calculated annual dose shows the highest and lowest reading is 1302 mSv/year and 1.3 mSv/year while the highest and lowest effective dose reading is 260.4 mSv/year and 0.26 mSv/year. The result shows that the ALARA concept along time, distance and shield principles shall be adopted to ensure the dose for the workers is kept below the dose limit regulated by AELB which is 20 mSv/year for radiation workers. This study is important for the improvement of planning and the development of shielding design for the facility.

Practical Advice on Calculating Confidence Intervals for Radioprotection Effects and Reducing Animal Numbers in Radiation Countermeasure Experiments

PubMed Central

Landes, Reid D.; Lensing, Shelly Y.; Kodell, Ralph L.; Hauer-Jensen, Martin

2014-01-01

The dose of a substance that causes death in P% of a population is called an LDP, where LD stands for lethal dose. In radiation research, a common LDP of interest is the radiation dose that kills 50% of the population by a specified time, i.e., lethal dose 50 or LD50. When comparing LD50 between two populations, relative potency is the parameter of interest. In radiation research, this is commonly known as the dose reduction factor (DRF). Unfortunately, statistical inference on dose reduction factor is seldom reported. We illustrate how to calculate confidence intervals for dose reduction factor, which may then be used for statistical inference. Further, most dose reduction factor experiments use hundreds, rather than tens of animals. Through better dosing strategies and the use of a recently available sample size formula, we also show how animal numbers may be reduced while maintaining high statistical power. The illustrations center on realistic examples comparing LD50 values between a radiation countermeasure group and a radiation-only control. We also provide easy-to-use spreadsheets for sample size calculations and confidence interval calculations, as well as SAS® and R code for the latter. PMID:24164553

Electron spin resonance analysis of tooth enamel does not indicate exposures to large radiation doses in a large proportion of distally-exposed A-bomb survivors.

PubMed

Hirai, Yuko; Kodama, Yoshiaki; Cullings, Harry M; Miyazawa, Chuzo; Nakamura, Nori

2011-01-01

The atomic bombs in Hiroshima and Nagasaki led to two different types of radiation exposure; one was direct and brief and the other was indirect and persistent. The latter (so-called exposure to residual radiation) resulted from the presence of neutron activation products in the soil, or from fission products present in the fallout. Compared with the doses from direct exposures, estimations of individual doses from residual radiation have been much more complicated, and estimates vary widely among researchers. The present report bases its conclusions on radiation doses recorded in tooth enamel from survivors in Hiroshima. Those survivors were present at distances of about 3 km or greater from the hypocenter at the time of the explosion, and have DS02 estimated doses (direct exposure doses) of less than 5 mGy (and are regarded as control subjects). Individual doses were estimated by measuring CO(2)(-) radicals in tooth enamel with the electron spin resonance (ESR; or electron paramagnetic resonance, EPR) method. The results from 56 molars donated by 49 survivors provided estimated doses which vary from -200 mGy to 500 mGy, and the median dose was 17 mGy (25% and 75% quartiles are -54 mGy and 137 mGy, respectively) for the buccal parts and 13 mGy (25% and 75% quartiles: -49 mGy and 87 mGy, respectively) for the lingual parts of the molars. Three molars had ESR-estimated doses of 300 to 400 mGy for both the buccal and lingual parts, which indicates possible exposures to excess doses of penetrating radiation, although the origin of such radiation remains to be determined. The results did not support claims that a large fraction of distally-exposed survivors received large doses (e.g. 1 Gy) of external penetrating radiation resulting from residual radiation.

Effects of a radiation dose reduction strategy for computed tomography in severely injured trauma patients in the emergency department: an observational study.

PubMed

Kim, Soo Hyun; Jung, Seung Eun; Oh, Sang Hoon; Park, Kyu Nam; Youn, Chun Song

2011-11-03

Severely injured trauma patients are exposed to clinically significant radiation doses from computed tomography (CT) imaging in the emergency department. Moreover, this radiation exposure is associated with an increased risk of cancer. The purpose of this study was to determine some effects of a radiation dose reduction strategy for CT in severely injured trauma patients in the emergency department. We implemented the radiation dose reduction strategy in May 2009. A prospective observational study design was used to collect data from patients who met the inclusion criteria during this one year study (intervention group) from May 2009 to April 2010. The prospective data were compared with data collected retrospectively for one year prior to the implementation of the radiation dose reduction strategy (control group). By comparison of the cumulative effective dose and the number of CT examinations in the two groups, we evaluated effects of a radiation dose reduction strategy. All the patients met the institutional adult trauma team activation criteria. The radiation doses calculated by the CT scanner were converted to effective doses by multiplication by a conversion coefficient. A total of 118 patients were included in this study. Among them, 33 were admitted before May 2009 (control group), and 85 were admitted after May 2009 (intervention group). There were no significant differences between the two groups regarding baseline characteristics, such as injury severity and mortality. Additionally, there was no difference between the two groups in the mean number of total CT examinations per patient (4.8 vs. 4.5, respectively; p = 0.227). However, the mean effective dose of the total CT examinations per patient significantly decreased from 78.71 mSv to 29.50 mSv (p < 0.001). The radiation dose reduction strategy for CT in severely injured trauma patients effectively decreased the cumulative effective dose of the total CT examinations in the emergency department. But not effectively decreased the number of CT examinations.

Radiation dose exposure in patients affected by lymphoma undergoing repeat CT examinations: how to manage the radiation dose variability.

PubMed

Paolicchi, Fabio; Bastiani, Luca; Guido, Davide; Dore, Antonio; Aringhieri, Giacomo; Caramella, Davide

2018-03-01

To assess the variability of radiation dose exposure in patients affected by lymphoma undergoing repeat CT (computed tomography) examinations and to evaluate the influence of different scan parameters on the overall radiation dose. A series of 34 patients (12 men and 22 women with a median age of 34.4 years) with lymphoma, after the initial staging CT underwent repeat follow-up CT examinations. For each patient and each repeat examination, age, sex, use of AEC system (Automated Exposure Control, i.e. current modulation), scan length, kV value, number of acquired scans (i.e. number of phases), abdominal size diameter and dose length product (DLP) were recorded. The radiation dose of just one venous phase was singled out from the DLP of the entire examination. All scan data were retrieved by our PACS (Picture Archiving and Communication System) by means of a dose monitoring software. Among the variables we considered, no significant difference of radiation dose was observed among patients of different ages nor concerning tube voltage. On the contrary the dose delivered to the patients varied depending on sex, scan length and usage of AEC. No significant difference was observed depending on the behaviour of technologists, while radiologists' choices had indirectly an impact on the radiation dose due to the different number of scans requested by each of them. Our results demonstrate that patients affected by lymphoma who undergo repeat whole body CT scanning may receive unnecessary overexposure. We quantified and analyzed the most relevant variables in order to provide a useful tool to manage properly CT dose variability, estimating the amount of additional radiation dose for every single significant variable. Additional scans, incorrect scan length and incorrect usage of AEC system are the most relevant cause of patient radiation exposure.

Effects of Radiation Exposure From Cardiac Imaging: How Good Are the Data?

PubMed Central

Einstein, Andrew J.

2012-01-01

Concerns about medical exposure to ionizing radiation have become heightened in recent years due to rapid growth in procedure volumes and the high radiation doses incurred from some procedures. This article summarizes the evidence base undergirding concerns about radiation exposure in cardiac imaging. After classifying radiation effects, explaining terminology used to quantify the radiation received by patients, and describing typical doses from cardiac imaging procedures, I address the major epidemiological studies having bearing on radiation effects at doses comparable to those received by patients undergoing cardiac imaging. These include studies of atomic bomb survivors, nuclear industry workers, and children exposed in utero to x-rays, all of which have evidenced increased cancer risks at low doses. Additional higher dose epidemiological studies of cohorts exposed to radiation in the context of medical treatment are described and found to be generally compatible with these cardiac-dose-level studies, albeit with exceptions. Using risk projection models developed by the US National Academies that incorporate these data and reflect several evidence-based assumptions, cancer risk from cardiac imaging can be estimated and compared to benefits from imaging. Several ongoing epidemiological studies will provide better understanding of radiation-associated cancer risks. PMID:22300689

An assessment of the radiological impact of the Windscale reactor fire, October 1957.

PubMed

Crick, M J; Linsley, G S

1984-11-01

On the 10th and 11 October 1957 a fire in the No 1 Pile at the Windscale establishment in Cumbria led to an uncontrolled release of activity to the atmosphere. The resultant cloud subsequently dispersed and radionuclides could be detected over England, Wales and parts of northern Europe. The extensive environmental measurements which were made during and after the release enabled a fairly accurate estimate to be made of the radiation doses to the most exposed individuals in the local population. Until recently, no estimates of the population dose resulting from the release had been published. This paper describes assessments which have been made by the NRPB of the population or collective dose from the release and of the possible associated health impact. In addition to the fission products that escaped, radionuclides were released from materials undergoing irradiation in the pile at the time of the fire. The assessment has included the results of a review of previously unpublished data which established the quantity of these nuclides released and considers their impact on both individual and population doses. The collective effective dose equivalent commitment from the release is estimated to have been 2.0 x 10(3) man Sv. The route of exposure which contributed the most to the collective dose was the inhalation pathway. Iodine-131 was the most important radionuclide, contributing nearly all of the collective dose to the thyroid and a large part of the collective effective dose. Polonium-210 and caesium-137 also made significant contributions; that from caesium-137 came in the longer term via external irradiation from ground deposits and the ingestion of contaminated foodstuffs. The methodology used in the study has been validated to a certain degree by comparing the predicted levels of individual thyroid activity and those measured directly in the weeks following the accident in London, Leeds and Cumbria.

[ESTIMATION OF IONIZING RADIATION EFFECTIVE DOSES IN THE INTERNATIONAL SPACE STATION CREWS BY THE METHOD OF CALCULATION MODELING].

PubMed

Mitrikas, V G

2015-01-01

Monitoring of the radiation loading on cosmonauts requires calculation of absorbed dose dynamics with regard to the stay of cosmonauts in specific compartments of the space vehicle that differ in shielding properties and lack means of radiation measurement. The paper discusses different aspects of calculation modeling of radiation effects on human body organs and tissues and reviews the effective dose estimates for cosmonauts working in one or another compartment over the previous period of the International space station operation. It was demonstrated that doses measured by a real or personal dosimeters can be used to calculate effective dose values. Correct estimation of accumulated effective dose can be ensured by consideration for time course of the space radiation quality factor.

Irradiation as a quarantine treatment for the solenopsis mealybug, Phenacoccus solenopsis

NASA Astrophysics Data System (ADS)

Huang, Fang; Li, Weidi; Li, Xiuqiong; Bei, Yawei; Lin, Wencai; Lu, Yaobin; Wang, Bingkui

2014-03-01

Phenacoccus solenopsis is an aggressively invasive species that targets agricultural and ornamental plants, thereby threatening the world cotton industry and other crops. P. solenopsis has been listed as a quarantine insect in Europe and China. The utilization of phytosanitary irradiation as a potential treatment for disinfesting agricultural commodities in trade has expanded rapidly in recent years. A reasonable dose of radiation to eliminate P. solenopsis needs to be determined, taking into account the side effects of radiation on agricultural products and the species-specific tolerance of the insect to radiation. We applied radiation ranging from 50 to 200 Gy to P. solenopsis to determine the optimal dose. Both the radiation dose and the developmental stage of the insect were independent variables. Higher doses of radiation or lesser mature insect stages provided more effective treatment. In nymphs, a radiation dose of 100 Gy caused extinction of the irradiated population by disrupting ovary development, while 150 Gy caused 100% mortality. In adults, all tested doses of irradiation did not affect longevity, but we were able to prevent reproduction with high (150 and 200 Gy) doses. In P. solenopsis, a 100 Gy dose of radiation could eliminate the irradiated population in two generations. The mortality curve showed a steep slope beyond 150 Gy; thus, if killing all of the insects in a shorter amount of time is necessary, 200 Gy may be a reasonable dose for the quarantine treatment of the solenopsis mealybug.

Low-dose ionizing radiation limitations to seed germination: Results from a model linking physiological characteristics and developmental-dynamics simulation strategy.

PubMed

Liu, Hui; Hu, Dawei; Dong, Chen; Fu, Yuming; Liu, Guanghui; Qin, Youcai; Sun, Yi; Liu, Dianlei; Li, Lei; Liu, Hong

2017-08-01

There is much uncertainty about the risks of seed germination after repeated or protracted environmental low-dose ionizing radiation exposure. The purpose of this study is to explore the influence mechanism of low-dose ionizing radiation on wheat seed germination using a model linking physiological characteristics and developmental-dynamics simulation. A low-dose ionizing radiation environment simulator was built to investigate wheat (Triticum aestivum L.) seeds germination process and then a kinetic model expressing the relationship between wheat seed germination dynamics and low-dose ionizing radiation intensity variations was developed by experimental data, plant physiology, relevant hypotheses and system dynamics, and sufficiently validated and accredited by computer simulation. Germination percentages were showing no differences in response to different dose rates. However, root and shoot lengths were reduced significantly. Plasma governing equations were set up and the finite element analysis demonstrated H 2 O, CO 2 , O 2 as well as the seed physiological responses to the low-dose ionizing radiation. The kinetic model was highly valid, and simultaneously the related influence mechanism of low-dose ionizing radiation on wheat seed germination proposed in the modeling process was also adequately verified. Collectively these data demonstrate that low-dose ionizing radiation has an important effect on absorbing water, consuming O 2 and releasing CO 2 , which means the risk for embryo and endosperm development was higher. Copyright © 2017 Elsevier Ltd. All rights reserved.

Differences in rates of decrease of environmental radiation dose rates by ground surface property in Fukushima City after the Fukushima Daiichi nuclear power plant accident.

PubMed

Kakamu, Takeyasu; Kanda, Hideyuki; Tsuji, Masayoshi; Kobayashi, Daisuke; Miyake, Masao; Hayakawa, Takehito; Katsuda, Shin-ichiro; Mori, Yayoi; Okouchi, Toshiyasu; Hazama, Akihiro; Fukushima, Tetsuhito

2013-01-01

After the Great East Japan Earthquake on 11 March 2011, the environmental radiation dose in Fukushima City increased. On 11 April, 1 mo after the earthquake, the environmental radiation dose rate at various surfaces in the same area differed greatly by surface property. Environmental radiation measurements continue in order to determine the estimated time to 50% reduction in environmental radiation dose rates by surface property in order to make suggestions for decontamination in Fukushima. The measurements were carried out from 11 April to 11 November 2011. Forty-eight (48) measurement points were selected, including four kinds of ground surface properties: grass (13), soil (5), artificial turf (7), and asphalt (23). Environmental radiation dose rate was measured at heights of 100 cm above the ground surface. Time to 50% reduction of environmental radiation dose rates was estimated for each ground surface property. Radiation dose rates on 11 November had decreased significantly compared with those on 11 April for all surface properties. Artificial turf showed the longest time to 50% reduction (544.32 d, standard error: 96.86), and soil showed the shortest (213.20 d, standard error: 35.88). The authors found the environmental radiation dose rate on artificial materials to have a longer 50% reduction time than that on natural materials. These results contribute to determining an order of priority for decontamination after nuclear disasters.

The Effects of Low Dose Irradiation on Inflammatory Response Proteins in a 3D Reconstituted Human Skin Tissue Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varnum, Susan M.; Springer, David L.; Chaffee, Mary E.

Skin responses to moderate and high doses of ionizing radiation include the induction of DNA repair, apoptosis, and stress response pathways. Additionally, numerous studies indicate that radiation exposure leads to inflammatory responses in skin cells and tissue. However, the inflammatory response of skin tissue to low dose radiation (<10 cGy) is poorly understood. In order to address this, we have utilized a reconstituted human skin tissue model (MatTek EpiDerm FT) and assessed changes in 23 cytokines twenty-four and forty eight hours following treatment of skin with either 3 or 10 cGy low-dose of radiation. Three cytokines, IFN-γ, IL-2, MIP-1α, weremore » significantly altered in response to low dose radiation. In contrast, seven cytokines were significantly altered in response to a high radiation dose of 200 cGy (IL-2, IL-10, IL-13, IFN-γ, MIP-1α, TNF α, and VEGF) or the tumor promoter 12-O-tetradecanoylphorbol 13-acetate (G-CSF, GM-CSF, IL-1α, IL-8, MIP-1α, MIP-1β, RANTES). Additionally, radiation induced inflammation appears to have a distinct cytokine response relative to the non-radiation induced stressor, TPA. Overall, these results indicate that there are subtle changes in the inflammatory protein levels following exposure to low dose radiation and this response is a sub-set of what is seen following a high dose in a human skin tissue model.« less

TH-E-209-00: Radiation Dose Monitoring and Protocol Management

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

Radiation dose monitoring solutions have opened up new opportunities for medical physicists to be more involved in modern clinical radiology practices. In particular, with the help of comprehensive radiation dose data, data-driven protocol management and informed case follow up are now feasible. Significant challenges remain however and the problems faced by medical physicists are highly heterogeneous. Imaging systems from multiple vendors and a wide range of vintages co-exist in the same department and employ data communication protocols that are not fully standardized or implemented making harmonization complex. Many different solutions for radiation dose monitoring have been implemented by imaging facilitiesmore » over the past few years. Such systems are based on commercial software, home-grown IT solutions, manual PACS data dumping, etc., and diverse pathways can be used to bring the data to impact clinical practice. The speakers will share their experiences with creating or tailoring radiation dose monitoring/management systems and procedures over the past few years, which vary significantly in design and scope. Topics to cover: (1) fluoroscopic dose monitoring and high radiation event handling from a large academic hospital; (2) dose monitoring and protocol optimization in pediatric radiology; and (3) development of a home-grown IT solution and dose data analysis framework. Learning Objectives: Describe the scope and range of radiation dose monitoring and protocol management in a modern radiology practice Review examples of data available from a variety of systems and how it managed and conveyed. Reflect on the role of the physicist in radiation dose awareness.« less

Mechanisms and biological importance of photon-induced bystander responses: do they have an impact on low-dose radiation responses

PubMed Central

Tomita, Masanori; Maeda, Munetoshi

2015-01-01

Abstract Elucidating the biological effect of low linear energy transfer (LET), low-dose and/or low-dose-rate ionizing radiation is essential in ensuring radiation safety. Over the past two decades, non-targeted effects, which are not only a direct consequence of radiation-induced initial lesions produced in cellular DNA but also of intra- and inter-cellular communications involving both targeted and non-targeted cells, have been reported and are currently defining a new paradigm in radiation biology. These effects include radiation-induced adaptive response, low-dose hypersensitivity, genomic instability, and radiation-induced bystander response (RIBR). RIBR is generally defined as a cellular response that is induced in non-irradiated cells that receive bystander signals from directly irradiated cells. RIBR could thus play an important biological role in low-dose irradiation conditions. However, this suggestion was mainly based on findings obtained using high-LET charged-particle radiations. The human population (especially the Japanese, who are exposed to lower doses of radon than the world average) is more frequently exposed to low-LET photons (X-rays or γ-rays) than to high-LET charged-particle radiation on a daily basis. There are currently a growing number of reports describing a distinguishing feature between photon-induced bystander response and high-LET RIBR. In particular, photon-induced bystander response is strongly influenced by irradiation dose, the irradiated region of the targeted cells, and p53 status. The present review focuses on the photon-induced bystander response, and discusses its impact on the low-dose radiation effect. PMID:25361549

The Effects of Gamma and Proton Radiation Exposure on Hematopoietic Cell Counts in the Ferret Model

PubMed Central

Sanzari, Jenine K.; Wan, X. Steven; Krigsfeld, Gabriel S.; Wroe, Andrew J.; Gridley, Daila S.; Kennedy, Ann R.

2014-01-01

Exposure to total-body radiation induces hematological changes, which can detriment one's immune response to wounds and infection. Here, the decreases in blood cell counts after acute radiation doses of γ-ray or proton radiation exposure, at the doses and dose-rates expected during a solar particle event (SPE), are reported in the ferret model system. Following the exposure to γ-ray or proton radiation, the ferret peripheral total white blood cell (WBC) and lymphocyte counts decreased whereas neutrophil count increased within 3 hours. At 48 hours after irradiation, the WBC, neutrophil, and lymphocyte counts decreased in a dose-dependent manner but were not significantly affected by the radiation type (γ-rays verses protons) or dose rate (0.5 Gy/minute verses 0.5 Gy/hour). The loss of these blood cells could accompany and contribute to the physiological symptoms of the acute radiation syndrome (ARS). PMID:25356435

Using RADFET for the real-time measurement of gamma radiation dose rate

NASA Astrophysics Data System (ADS)

Andjelković, Marko S.; Ristić, Goran S.; Jakšić, Aleksandar B.

2015-02-01

RADFETs (RADiation sensitive Field Effect Transistors) are integrating ionizing radiation dosimeters operating on the principle of conversion of radiation-induced threshold voltage shift into absorbed dose. However, one of the major drawbacks of RADFETs is the inability to provide the information on the dose rate in real-time using the conventional absorbed dose measurement technique. The real-time monitoring of dose rate and absorbed dose can be achieved with the current mode dosimeters such as PN and PIN diodes/photodiodes, but these dosimeters have some limitations as absorbed dose meters and hence they are often not a suitable replacement for RADFETs. In that sense, this paper investigates the possibility of using the RADFET as a real-time dose rate meter so that it could be applied for simultaneous online measurement of the dose rate and absorbed dose. A RADFET sample, manufactured by Tyndall National Institute, Cork, Ireland, was tested as a dose rate meter under gamma irradiation from a Co-60 source. The RADFET was configured as a PN junction, such that the drain, gate and source terminals were grounded, while the radiation-induced current was measured at the bulk terminal, whereby the bulk was successively biased with 0 , 10 , 20  and 30 V. In zero-bias mode the radiation-induced current was unstable, but in the biased mode the current response was stable for the investigated dose rates from 0.65  to 32.1 Gy h-1 and up to the total absorbed dose of 25 Gy. The current increased with the dose rate in accordance with the power law, whereas the sensitivity of the current read-out was linear with respect to the applied bias voltage. Comparison with previously analyzed PIN photodiodes has shown that the investigated RADFET is competitive with PIN photodiodes as a gamma radiation dose rate meter and therefore has the potential to be employed for the real-time monitoring of the dose rate and absorbed dose.

Estimation Of Organ Doses From Solar Particle Events For Future Space Exploration Missions

NASA Technical Reports Server (NTRS)

Kim, Myung-Hee; Cucinotta, Francis A.

2006-01-01

Radiation protection practices define the effective dose as a weighted sum of equivalent dose over major organ sites for radiation cancer risks. Since a crew personnel dosimeter does not make direct measurement of the effective dose, it has been estimated with skin-dose measurements and radiation transport codes for ISS and STS missions. If sufficient protection is not provided near solar maximum, the radiation risk can be significant due to exposure to sporadic solar particle events (SPEs) as well as to the continuous galactic cosmic radiation (GCR) on future exploratory-class and long-duration missions. For accurate estimates of overall fatal cancer risks from SPEs, the specific doses at various blood forming organs (BFOs) were considered, because proton fluences and doses vary considerably across marrow regions. Previous estimates of BFO doses from SPEs have used an average body-shielding distribution for the bone marrow based on the computerized anatomical man model (CAM). With the development of an 82-point body-shielding distribution at BFOs, the mean and variance of SPE doses in the major active marrow regions (head and neck, chest, abdomen, pelvis and thighs) will be presented. Consideration of the detailed distribution of bone marrow sites is one of many requirements to improve the estimation of effective doses for radiation cancer risks.

Patient radiation doses in interventional cardiology in the U.S.: Advisory data sets and possible initial values for U.S. reference levels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, Donald L.; Hilohi, C. Michael; Spelic, David C.

2012-10-15

Purpose: To determine patient radiation doses from interventional cardiology procedures in the U.S and to suggest possible initial values for U.S. benchmarks for patient radiation dose from selected interventional cardiology procedures [fluoroscopically guided diagnostic cardiac catheterization and percutaneous coronary intervention (PCI)]. Methods: Patient radiation dose metrics were derived from analysis of data from the 2008 to 2009 Nationwide Evaluation of X-ray Trends (NEXT) survey of cardiac catheterization. This analysis used deidentified data and did not require review by an IRB. Data from 171 facilities in 30 states were analyzed. The distributions (percentiles) of radiation dose metrics were determined for diagnosticmore » cardiac catheterizations, PCI, and combined diagnostic and PCI procedures. Confidence intervals for these dose distributions were determined using bootstrap resampling. Results: Percentile distributions (advisory data sets) and possible preliminary U.S. reference levels (based on the 75th percentile of the dose distributions) are provided for cumulative air kerma at the reference point (K{sub a,r}), cumulative air kerma-area product (P{sub KA}), fluoroscopy time, and number of cine runs. Dose distributions are sufficiently detailed to permit dose audits as described in National Council on Radiation Protection and Measurements Report No. 168. Fluoroscopy times are consistent with those observed in European studies, but P{sub KA} is higher in the U.S. Conclusions: Sufficient data exist to suggest possible initial benchmarks for patient radiation dose for certain interventional cardiology procedures in the U.S. Our data suggest that patient radiation dose in these procedures is not optimized in U.S. practice.« less

Maximizing Tumor Immunity With Fractionated Radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schaue, Doerthe, E-mail: dschaue@mednet.ucla.edu; Ratikan, Josephine A.; Iwamoto, Keisuke S.

Purpose: Technologic advances have led to increased clinical use of higher-sized fractions of radiation dose and higher total doses. How these modify the pathways involved in tumor cell death, normal tissue response, and signaling to the immune system has been inadequately explored. Here we ask how radiation dose and fraction size affect antitumor immunity, the suppression thereof, and how this might relate to tumor control. Methods and Materials: Mice bearing B16-OVA murine melanoma were treated with up to 15 Gy radiation given in various-size fractions, and tumor growth followed. The tumor-specific immune response in the spleen was assessed by interferon-{gamma}more » enzyme-linked immunospot (ELISPOT) assay with ovalbumin (OVA) as the surrogate tumor antigen and the contribution of regulatory T cells (Tregs) determined by the proportion of CD4{sup +}CD25{sup hi}Foxp3{sup +} T cells. Results: After single doses, tumor control increased with the size of radiation dose, as did the number of tumor-reactive T cells. This was offset at the highest dose by an increase in Treg representation. Fractionated treatment with medium-size radiation doses of 7.5 Gy/fraction gave the best tumor control and tumor immunity while maintaining low Treg numbers. Conclusions: Radiation can be an immune adjuvant, but the response varies with the size of dose per fraction. The ultimate challenge is to optimally integrate cancer immunotherapy into radiation therapy.« less

Evaluation of a commercial automatic treatment planning system for liver stereotactic body radiation therapy treatments.

PubMed

Gallio, Elena; Giglioli, Francesca Romana; Girardi, Andrea; Guarneri, Alessia; Ricardi, Umberto; Ropolo, Roberto; Ragona, Riccardo; Fiandra, Christian

2018-02-01

Automated treatment planning is a new frontier in radiotherapy. The Auto-Planning module of the Pinnacle 3 treatment planning system (TPS) was evaluated for liver stereotactic body radiation therapy treatments. Ten cases were included in the study. Six plans were generated for each case by four medical physics experts. The first two planned with Pinnacle TPS, both with manual module (MP) and Auto-Planning one (AP). The other two physicists generated two plans with Monaco TPS (VM). Treatment plan comparisons were then carried on the various dosimetric parameters of target and organs at risk, monitor units, number of segments, plan complexity metrics and human resource planning time. The user dependency of Auto-Planning was also tested and the plans were evaluated by a trained physician. Statistically significant differences (Anova test) were observed for spinal cord doses, plan average beam irregularity, number of segments, monitor units and human planning time. The Fisher-Hayter test applied to these parameters showed significant statistical differences between AP e MP for spinal cord doses and human planning time; between MP and VM for monitor units, number of segments and plan irregularity; for all those between AP and VM. The two plans created by different planners with AP were similar to each other. The plans created with Auto-Planning were comparable to the manually generated plans. The time saved in planning enables the planner to commit more resources to more complex cases. The independence of the planner enables to standardize plan quality. Copyright © 2018 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

RADIANCE: An automated, enterprise-wide solution for archiving and reporting CT radiation dose estimates.

PubMed

Cook, Tessa S; Zimmerman, Stefan L; Steingall, Scott R; Maidment, Andrew D A; Kim, Woojin; Boonn, William W

2011-01-01

There is growing interest in the ability to monitor, track, and report exposure to radiation from medical imaging. Historically, however, dose information has been stored on an image-based dose sheet, an arrangement that precludes widespread indexing. Although scanner manufacturers are beginning to include dose-related parameters in the Digital Imaging and Communications in Medicine (DICOM) headers of imaging studies, there remains a vast repository of retrospective computed tomographic (CT) data with image-based dose sheets. Consequently, it is difficult for imaging centers to monitor their dose estimates or participate in the American College of Radiology (ACR) Dose Index Registry. An automated extraction software pipeline known as Radiation Dose Intelligent Analytics for CT Examinations (RADIANCE) has been designed that quickly and accurately parses CT dose sheets to extract and archive dose-related parameters. Optical character recognition of information in the dose sheet leads to creation of a text file, which along with the DICOM study header is parsed to extract dose-related data. The data are then stored in a relational database that can be queried for dose monitoring and report creation. RADIANCE allows efficient dose analysis of CT examinations and more effective education of technologists, radiologists, and referring physicians regarding patient exposure to radiation at CT. RADIANCE also allows compliance with the ACR's dose reporting guidelines and greater awareness of patient radiation dose, ultimately resulting in improved patient care and treatment.

PRESERVATION OF FOOD BY LOW-DOSE IONIZING ENERGY

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1961-01-01

A review is presented of the current status of investigations on the radiation processing of foods. The technical feasibility of this preservation method is well established and the economic feasibility of the method appears promising, particularly in low-dose applications. The current status of development of radiation sources is discussed. Pork has responded best among the meats tested for radiation processing. Sausage, luncheon meats, and chicken demonstrate good potential. Beef appears acceptable at low radiation dose ranges but presents flavor problems at high dosages. The storage life of refrigerated and unrefrigerated marine products is increased by radiation processing, Vegetable s aremore » easily damaged by comparatively small doses of radiation. Shredded cabbage treated at 300,000 rad is an excellent product and asparagus, snap beans, lima beans, broccoli, carrots, and corn are promising vegetables for radiation processing. Radiation treatment inhibits sprouting of potatoes and onions. Radiation processing of strawberries, grapes, peaches, tomatoes, and citrus fruits at doses between 200,000 and 800,000 rad affects molds that cause rotting and increases the storage life of these fruits. Radiation processing of cereal grains, cereal products, and military ration components destroys adult insects, larvae, and eggs of insect pests that infest these foods. No radioactivity has been induced in food products by high radiation doses. Extensive studies have shown that radiation processing has no effect on the wholesomeness of foods. The economic feasibility and potentialities of the radiation processing of foods are discussed. (C.H.)« less

Uveal Melanoma Treated With Iodine-125 Episcleral Plaque: An Analysis of Dose on Disease Control and Visual Outcomes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perez, Bradford A.; Mettu, Pradeep; Vajzovic, Lejla

2014-05-01

Purpose: To investigate, in the treatment of uveal melanomas, how tumor control, radiation toxicity, and visual outcomes are affected by the radiation dose at the tumor apex. Methods and Materials: A retrospective review was performed to evaluate patients treated for uveal melanoma with {sup 125}I plaques between 1988 and 2010. Radiation dose is reported as dose to tumor apex and dose to 5 mm. Primary endpoints included time to local failure, distant failure, and death. Secondary endpoints included eye preservation, visual acuity, and radiation-related complications. Univariate and multivariate analyses were performed to determine associations between radiation dose and the endpointmore » variables. Results: One hundred ninety patients with sufficient data to evaluate the endpoints were included. The 5-year local control rate was 91%. The 5-year distant metastases rate was 10%. The 5-year overall survival rate was 84%. There were no differences in outcome (local control, distant metastases, overall survival) when dose was stratified by apex dose quartile (<69 Gy, 69-81 Gy, 81-89 Gy, >89 Gy). However, increasing apex dose and dose to 5-mm depth were correlated with greater visual acuity loss (P=.02, P=.0006), worse final visual acuity (P=.02, P<.0001), and radiation complications (P<.0001, P=.0009). In addition, enucleation rates were worse with increasing quartiles of dose to 5 mm (P=.0001). Conclusions: Doses at least as low as 69 Gy prescribed to the tumor apex achieve rates of local control, distant metastasis–free survival, and overall survival that are similar to radiation doses of 85 Gy to the tumor apex, but with improved visual outcomes.« less

CARCINOGENIC EFFECTS OF LOW DOSES OF IONIZING RADIATION

EPA Science Inventory

Carcinogenic Effects of Low Doses of Ionizing Radiation

R Julian Preston, Environmental Carcinogenesis Division, NHEERL, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

The form of the dose-response curve for radiation-induced cancers, particu...

Chernobyl Doses. Volume 1. Analysis of Forest Canopy Radiation Response from Multispectral Imagery and the Relationship to Doses

DTIC Science & Technology

1994-09-01

AD-A284 746 Defense Nuclear Agency Alexandria, VA 22310-3398 DNA-TR-92-37-V1 Chernobyl Doses Volume 1-Analysis of Forest Canopy Radiation Response...REPORT DATE 3. REPORT TYPE AND DATES COVERED 940901 Technical 870929- 930930 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS Chernobyl Doses Volume 1-Analysis of...volume of the report Chernobyl Doses presents details of a new, quantitative method for remotely sensing ionizing radiation dose to vegetation

Eye lens radiation exposure to interventional cardiologists: a retrospective assessment of cumulative doses.

PubMed

Jacob, Sophie; Donadille, Laurent; Maccia, Carlo; Bar, Olivier; Boveda, Serge; Laurier, Dominique; Bernier, Marie-Odile

2013-03-01

Radiation dose to the eye lens is a crucial issue for interventional cardiologists (ICs) who are exposed during the procedures they perform. This paper presents a retrospective assessment of the cumulative eye lens doses of ICs enrolled in the O'CLOC study for Occupational Cataracts and Lens Opacities in interventional Cardiology. Information on the workload in the catheterisation laboratory, radiation protection equipment, eye lens dose per procedure and dose reduction factors associated with eye-protective equipment were considered. For the 129 ICs at an average age of 51 who had worked for an average period of 22 years, the estimated cumulative eye lens dose ranged from 25 mSv to more than 1600 mSv; the mean ± SD was 423 ± 359 mSv. After several years of practice, without eye protection, ICs may exceed the new ICRP lifetime eye dose threshold of 500 mSv and be at high risk of developing early radiation-induced cataracts. Radiation protection equipment can reduce these doses and should be used routinely.

THE DEPRESSANT EFFECT OF CONTINUOUS COBALT-60 RADIATION ON THE SECONDARY TETANUS ANTITOXIN RESPONSE IN MICE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoner, R.D.; Hale, W.M.

1958-05-01

The radiosensitivity of the secondary tetanus antitoxin response in mice was demonstrated after rather low doses of continuous gamma -radiation given at a dose rate of 4 rep/hr. Accumulated doses of 48 to 288 rep depressed antitoxin formation. Comparable doses of acute gamma radiation did not depress antitoxin production. Acute doses of 350 to 650 rep sharply depressed the secondary antibody response, however. Extended periods of continuous gamma -radiation from 10 to 28 days to accumulated doses of 960 to 2688 rep markedly depressed the secondary antibody response. An accumulated dose of 2688 rep was needed to depress antitoxin formationmore » to the level observed after an acute dose of 650 rep. When the secondary stimulus of fluid tetanus toxoid was given prior to 10 days of continuous exposure to an accumulated dose of 860 rep, the secondary antibody respense was not depressed. Irradiated mice recovered the ability to produce a normal secondary antitoxin response during the second week after an accumulated dose of 1248 rep. The secondary antitoxin response was depressed in mice given long-continued gamma -radiation at a dose rate of 1 rep/hr. (auth)« less

Investigation of genotoxic effect of taxol plus radiation on mice bone marrow cells.

PubMed

Ozkan, Lütfi; Egeli, Unal; Tunca, Berrin; Aydemir, Nilüfer; Ceçener, Gülşah; Akpinar, Gürler; Ergül, Emel; Cimen, Ciğdem; Ozuysal, Sema; Kahraman-Cetintaş, Sibel; Engin, Kayihan; Ahmed, Mansoor M

2002-01-01

In this study, we investigated the genotoxic effect of taxol, radiation, or taxol plus radiation on highly proliferative normal tissue-bone marrow cells of Swiss albino mice. Swiss-albino mice, 3-4 months old, were used in this study. Taxol was administered bolus intravenously through the tail vein. Radiation was given by using a linear accelerator. There were four treatment categories, which had a total of 34 groups. Each group consisted of five animals. The first was the control category that had one group (n = 5). The second treatment category was taxol alone, which had three groups as per taxol dose alone (n = 15). The third treatment category was radiation alone, which had three groups as per the radiation dose (n = 15). The fourth treatment category was taxol plus radiation, which had 27 groups as per combined radiation dose plus taxol dose concentration and as per pre-treatment timing sequence of taxol before radiation (n = 135). Mice were sacrificed 24 h after taxol or radiation or combined administration using ether anesthesia. The cells were then dropped on two labeled slides, flamed, air dried, and stained in 7% Giemsa; 20-30 well-spread mitotic metaphases were analyzed for each animal; the cells with chromosome breaks, acentric fragments, and rearrangements were evaluated on x1,000 magnification with light microscope (Zeiss axioplan). The mitotic index was determined by counting the number of mitotic cells among 1,000 cells per animal. Differences between groups were evaluated with Student's t-test statistically. Taxol caused a dose-dependent increase in chromosomal aberrations (P = 0.027). Similarly, radiation caused a dose-dependent increase in chromosomal aberrations (P = 0.003) and decreased mitotic index (P = 0.002). In combination, there were a small enhancements at the 40 mg/kg taxol dose level and at 0.25 and 0.5 Gy radiation doses in the 48 h group. However, an increase in chromosomal aberrations was observed after 48 hours of taxol exposure when compared 12 or 24 h of taxol exposure (P = 0.001 and P = 0.019). These findings suggest that taxol at the high doses with low dose radiation caused radiosensitizing effect in bone marrow cells. Forty-eight-hour pretreatment of taxol exposure followed by radiation caused significant induction of chromosomal aberrations and a reduction of mitotic index when compared to other taxol timing sequence. Copyright 2002 Wiley-Liss, Inc.

Low dose radiation effects on the brain - from mechanisms and behavioral outcomes to mitigation strategies.

PubMed

Kovalchuk, Anna; Kolb, Bryan

2017-07-03

Based on the most recent estimates by the Canadian Cancer Society, 2 in 5 Canadians will develop cancer in their lifetimes. More than half of all cancer patients receive some type of radiation therapy, and all patients undergo radiation-based diagnostics. While radiation is one of the most important diagnostic and treatments modalities, high-dose cranial radiation therapy causes numerous central nervous system side-effects, including declines in cognitive function, memory, and attention. While the mechanisms of these effects have been studies, they still need to be further elucidated. On the other hand, the effects of low dose radiation as well as indirect radiation bystander effects on the brain remain elusive. We pioneered analysis of the molecular and cellular effects of low dose direct, bystander and scatter radiation on the brain. Using a rat model, we showed that low dose radiation exposures cause molecular and cellular changes in the brain and impacts animal behavior. Here we reflect upon our recent findings and current state of knowledge in the field, and suggest novel radiation effect biomarkers and means of prevention. We propose strategies and interventions to prevent and mitigate radiation effects on the brain.

Cancer risk above 1 Gy and the impact for space radiation protection

NASA Astrophysics Data System (ADS)

Schneider, Uwe; Walsh, Linda

2009-07-01

Analyses of the epidemiological data on the Japanese A-bomb survivors, who were exposed to γ-rays and neutrons, provide most current information on the dose-response of radiation-induced cancer. Since the dose span of main interest is usually between 0 and 1 Gy, for radiation protection purposes, the analysis of the A-bomb survivors is often focused on this range. However, estimates of cancer risk for doses larger than 1 Gy are becoming more important for long-term manned space missions. Therefore in this work, emphasis is placed on doses larger than 1 Gy with respect to radiation-induced solid cancer and leukemia mortality. The present analysis of the A-bomb survivors data was extended by including two extra high-dose categories and applying organ-averaged dose instead of the colon-weighted dose. In addition, since there are some recent indications for a high neutron dose contribution, the data were fitted separately for three different values for the relative biological effectiveness (RBE) of the neutrons (10, 35 and 100) and a variable RBE as a function of dose. The data were fitted using a linear and a linear-exponential dose-response relationship using a dose and dose-rate effectiveness factor (DDREF) of both one and two. The work presented here implies that the use of organ-averaged dose, a dose-dependent neutron RBE and the bending-over of the dose-response relationship for radiation-induced cancer could result in a reduction of radiation risk by around 50% above 1 Gy. This could impact radiation risk estimates for space crews on long-term mission above 500 days who might be exposed to doses above 1 Gy. The consequence of using a DDREF of one instead of two increases cancer risk by about 40% and would therefore balance the risk decrease described above.

Brain dose-sparing radiotherapy techniques for localized intracranial germinoma: Case report and literature review of modern irradiation.

PubMed

Leung, H W C; Chan, A L F; Chang, M B

2016-05-01

We examined the effects of intensity-modulated radiation therapy with dose-sparing and avoidance technique on a pediatric patient with localized intracranial germinoma. We also reviewed the literature regarding modern irradiation techniques in relation to late neurocognitive sequelae. A patient with a localized intracranial germinoma in the third ventricle anterior to the pineal gland received a dose-sparing intensity-modulated radiation therapy. The planning was compared to the radiation oncologist's guide of organs at risk and dose constraints for dosimetric analyses. The patient received radiation therapy alone. The total dose was 54Gy delivered in 2.0Gy fractions to the primary tumour and 37Gy in 1.4Gy fractions to whole ventricles using a dose-sculpting plan. Dosimetry analyses showed that dose-sparing intensity-modulated radiation therapy delivered reduced doses to the whole brain, temporal lobes, hippocampi, cochleae, and optic nerves. With a follow-up of 22 months, failure-free survival was 100% for the patient and no adverse events during radiation treatment process. Intensity-modulated radiation therapy with dose sparing and avoidance technique can spare the limbic circuit, central nervous system, and hippocampus for pineal germ cell tumours. This technique reduces the integral dose delivered to the uninvolved normal brain tissues and may reduce late neurocognitive sequelae caused by cranial radiotherapy. Copyright © 2016 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

Dose-dependent analysis of acute medical effects of mixed neutron-gamma radiation from selected severe 235U or 239Pu criticality accidents in USSR, United States, and Argentina.

PubMed

Barabanova, Tatyana; Wiley, Albert L; Bushmanov, Andrey

2012-04-01

Eight of the most severe cases of acute radiation disease (ARS) known to have occurred in humans (as the result of criticality accidents) had survival times less than 120 h (herein defined as "early death"). These accidents were analyzed and are discussed with respect to the specific accident scenarios and the resulting accident-specific, mixed neutron-gamma radiation clinical dose distributions. This analysis concludes that the cardiovascular system appears to be the most critical organ system failure for causing "early death" following approximate total body, mixed gamma-neutron radiation doses greater than 40-50 Gy. The clinical data also suggest that there was definite chest dose dependence in the resulting survival times for these eight workers, who unfortunately suffered profound radiation injury and unusual clinical effects from such high dose radiation exposures. In addition, "toxemic syndrome" is correlated with the irradiation of large volumes of soft tissues. Doses to the hands or legs greater than 80-100 Gy or radiation lung injury also play significant but secondary roles in causing "early death" in accidents delivering chest doses greater than 50 Gy.

Probability Distribution of Dose and Dose-Rate Effectiveness Factor for use in Estimating Risks of Solid Cancers From Exposure to Low-Let Radiation.

PubMed

Kocher, David C; Apostoaei, A Iulian; Hoffman, F Owen; Trabalka, John R

2018-06-01

This paper presents an analysis to develop a subjective state-of-knowledge probability distribution of a dose and dose-rate effectiveness factor for use in estimating risks of solid cancers from exposure to low linear energy transfer radiation (photons or electrons) whenever linear dose responses from acute and chronic exposure are assumed. A dose and dose-rate effectiveness factor represents an assumption that the risk of a solid cancer per Gy at low acute doses or low dose rates of low linear energy transfer radiation, RL, differs from the risk per Gy at higher acute doses, RH; RL is estimated as RH divided by a dose and dose-rate effectiveness factor, where RH is estimated from analyses of dose responses in Japanese atomic-bomb survivors. A probability distribution to represent uncertainty in a dose and dose-rate effectiveness factor for solid cancers was developed from analyses of epidemiologic data on risks of incidence or mortality from all solid cancers as a group or all cancers excluding leukemias, including (1) analyses of possible nonlinearities in dose responses in atomic-bomb survivors, which give estimates of a low-dose effectiveness factor, and (2) comparisons of risks in radiation workers or members of the public from chronic exposure to low linear energy transfer radiation at low dose rates with risks in atomic-bomb survivors, which give estimates of a dose-rate effectiveness factor. Probability distributions of uncertain low-dose effectiveness factors and dose-rate effectiveness factors for solid cancer incidence and mortality were combined using assumptions about the relative weight that should be assigned to each estimate to represent its relevance to estimation of a dose and dose-rate effectiveness factor. The probability distribution of a dose and dose-rate effectiveness factor for solid cancers developed in this study has a median (50th percentile) and 90% subjective confidence interval of 1.3 (0.47, 3.6). The harmonic mean is 1.1, which implies that the arithmetic mean of an uncertain estimate of the risk of a solid cancer per Gy at low acute doses or low dose rates of low linear energy transfer radiation is only about 10% less than the mean risk per Gy at higher acute doses. Data were also evaluated to define a low acute dose or low dose rate of low linear energy transfer radiation, i.e., a dose or dose rate below which a dose and dose-rate effectiveness factor should be applied in estimating risks of solid cancers.

Development of probabilistic internal dosimetry computer code

NASA Astrophysics Data System (ADS)

Noh, Siwan; Kwon, Tae-Eun; Lee, Jai-Ki

2017-02-01

Internal radiation dose assessment involves biokinetic models, the corresponding parameters, measured data, and many assumptions. Every component considered in the internal dose assessment has its own uncertainty, which is propagated in the intake activity and internal dose estimates. For research or scientific purposes, and for retrospective dose reconstruction for accident scenarios occurring in workplaces having a large quantity of unsealed radionuclides, such as nuclear power plants, nuclear fuel cycle facilities, and facilities in which nuclear medicine is practiced, a quantitative uncertainty assessment of the internal dose is often required. However, no calculation tools or computer codes that incorporate all the relevant processes and their corresponding uncertainties, i.e., from the measured data to the committed dose, are available. Thus, the objective of the present study is to develop an integrated probabilistic internal-dose-assessment computer code. First, the uncertainty components in internal dosimetry are identified, and quantitative uncertainty data are collected. Then, an uncertainty database is established for each component. In order to propagate these uncertainties in an internal dose assessment, a probabilistic internal-dose-assessment system that employs the Bayesian and Monte Carlo methods. Based on the developed system, we developed a probabilistic internal-dose-assessment code by using MATLAB so as to estimate the dose distributions from the measured data with uncertainty. Using the developed code, we calculated the internal dose distribution and statistical values ( e.g. the 2.5th, 5th, median, 95th, and 97.5th percentiles) for three sample scenarios. On the basis of the distributions, we performed a sensitivity analysis to determine the influence of each component on the resulting dose in order to identify the major component of the uncertainty in a bioassay. The results of this study can be applied to various situations. In cases of severe internal exposure, the causation probability of a deterministic health effect can be derived from the dose distribution, and a high statistical value ( e.g., the 95th percentile of the distribution) can be used to determine the appropriate intervention. The distribution-based sensitivity analysis can also be used to quantify the contribution of each factor to the dose uncertainty, which is essential information for reducing and optimizing the uncertainty in the internal dose assessment. Therefore, the present study can contribute to retrospective dose assessment for accidental internal exposure scenarios, as well as to internal dose monitoring optimization and uncertainty reduction.

Thyroid Radiation Dose and Other Risk Factors of Thyroid Carcinoma Following Childhood Cancer.

PubMed

de Vathaire, Florent; Haddy, Nadia; Allodji, Rodrigue S; Hawkins, Mike; Guibout, Catherine; El-Fayech, Chiraz; Teinturier, Cécile; Oberlin, Odile; Pacquement, Hélène; Diop, Fara; Kalhouche, Amar; Benadjaoud, Mohamedamine; Winter, David; Jackson, Angela; Bezin Mai-Quynh, Giao; Benabdennebi, Aymen; Llanas, Damien; Veres, Cristina; Munzer, Martine; Nguyen, Tan Dat; Bondiau, Pierre-Yves; Berchery, Delphine; Laprie, Anne; Deutsch, Eric; Lefkopoulos, Dimitri; Schlumberger, Martin; Diallo, Ibrahima; Rubino, Carole

2015-11-01

Thyroid carcinoma is a frequent complication of childhood cancer radiotherapy. The dose response to thyroid radiation dose is now well established, but the potential modifier effect of other factors requires additional investigation. This study aimed to investigate the role of potential modifiers of the dose response. We followed a cohort of 4338 5-year survivors of solid childhood cancer treated before 1986 over an average of 27 years. The dose received by the thyroid gland and some other anatomical sites during radiotherapy was estimated after reconstruction of the actual conditions in which irradiation was delivered. Fifty-five patients developed thyroid carcinoma. The risk of thyroid carcinoma increased with a radiation dose to the thyroid of up to two tenths of Gy, then leveled off for higher doses. When taking into account the thyroid radiation dose, a surgical or radiological splenectomy (>20 Gy to the spleen) increased thyroid cancer risk (relative risk [RR] = 2.3; 95% confidence interval [CI], 1.3-4.0), high radiation doses (>5 Gy) to pituitary gland lowered this risk (RR = 0.2; 95% CI, 0.1-0.6). Patients who received nitrosourea chemotherapy had a 6.6-fold (95% CI, 2.5-15.7) higher risk than those who did not. The excess RR per Gy of radiation to the thyroid was 4.7 (95% CI, 1.7-22.6). It was 7.6 (95% CI, 1.6-33.3) if body mass index at time of interview was equal or higher than 25 kg/m(2), and 4.1 (95% CI, 0.9-17.7) if not (P for interaction = .1). Predicting thyroid cancer risk following childhood cancer radiation therapy probably requires the assessment of more than just the radiation dose to the thyroid. Chemotherapy, splenectomy, radiation dose to pituitary gland, and obesity also play a role.

Risk of Radiation Retinopathy in Patients With Orbital and Ocular Lymphoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaushik, Megha; Pulido, Jose S.; Schild, Steven E.

2012-12-01

Purpose: Radiation retinopathy is a potential long-term complication of radiation therapy to the orbit. The risk of developing this adverse effect is dose dependent; however, the threshold is unclear. The aim of this study was to identify the risk of developing radiation retinopathy at increasing radiation doses. Methods and Materials: A 40-year retrospective review was performed of patients who received external beam radiation therapy for ocular/orbital non-Hodgkin lymphoma (NHL). Results: Sixty-seven patients who had at least one ophthalmic follow-up examination were included in this study. Most patients (52%) were diagnosed with NHL involving the orbit. Patients received external beam radiationmore » therapy at doses between 1886 and 5400 cGy (mean, 3033 {+-} 782 cGy). Radiation retinopathy developed in 12% of patients, and the median time to diagnosis was 27 months (range, 15-241months). The mean prescribed radiation dose in patients with retinopathy was 3309 {+-} 585 cGy, and the estimated retinal dose (derived by reviewing the dosimetry) was 3087 {+-} 1030 cGy. The incidence of retinopathy increased with dose. The average prescribed daily fractionated dose was higher in patients who developed retinopathy than in patients who did not (mean, 202 cGy vs 180 cGy, respectively; P = .04). More patients with radiation retinopathy had comorbid diabetes mellitus type 2 than patients without retinopathy (P = .015). In our study, the mean visual acuity of the eyes that received radiation was worse than that of the eyes that did not (P = .027). Other postradiotherapy ocular findings included keratitis (6%), dry eyes (39%), and cataract (33%). Conclusions: Radiation retinopathy, a known complication of radiotherapy for orbital tumors, relates to vascular comorbidities and dose. Higher total doses and larger daily fractions (>180 cGy) appear to be related to higher rates of retinopathy. Future larger studies are required to identify a statistically significant threshold for the development of retinopathy.« less

Group consensus peer review in radiation oncology: commitment to quality.

PubMed

Duggar, W Neil; Bhandari, Rahul; Yang, Chunli Claus; Vijayakumar, Srinivasan

2018-03-27

Peer review, especially prospective peer review, has been supported by professional organizations as an important element in optimal Radiation Oncology practice based on its demonstration of efficacy at detecting and preventing errors prior to patient treatment. Implementation of peer review is not without barriers, but solutions do exist to mitigate or eliminate some of those barriers. Peer review practice at our institution involves three key elements: new patient conference, treatment planning conference, and chart rounds. The treatment planning conference is an adaptation of the group consensus peer review model from radiology which utilizes a group of peers reviewing each treatment plan prior to implementation. The peer group in radiation oncology includes Radiation Oncologists, Physician Residents, Medical Physicists, Dosimetrists, and Therapists. Thus, technical and clinical aspects of each plan are evaluated simultaneously. Though peer review is held in high regard in Radiation Oncology, many barriers commonly exist preventing optimal implementation such as time intensiveness, repetition, and distraction from clinic time with patients. Through the use of automated review tools and commitment by individuals and administration in regards to staffing, scheduling, and responsibilities, these barriers have been mitigated to implement this Group Consensus Peer Review model into a Radiation Oncology Clinic. A Group Consensus Peer Review model has been implemented with strategies to address common barriers to effective and efficient peer review.

Ultraviolet Radiation Dose National Standard of México

NASA Astrophysics Data System (ADS)

Cardoso, R.; Rosas, E.

2006-09-01

We present the Ultraviolet (UV) Radiation Dose National Standard for México. The establishment of this measurement reference at Centro Nacional de Metrología (CENAM) eliminates the need of contacting foreign suppliers in the search for traceability towards the SI units when calibrating instruments at 365 nm. Further more, the UV Radiation Dose National Standard constitutes a highly accurate and reliable source for the UV radiation dose measurements performed in medical and cosmetic treatments as in the the food and pharmaceutics disinfection processes, among other.

TU-C-18A-01: Models of Risk From Low-Dose Radiation Exposures: What Does the Evidence Say?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bushberg, J; Boreham, D; Ulsh, B

2014-06-15

At dose levels of (approximately) 500 mSv or more, increased cancer incidence and mortality have been clearly demonstrated. However, at the low doses of radiation used in medical imaging, the relationship between dose and cancer risk is not well established. As such, assumptions about the shape of the dose-response curve are made. These assumptions, or risk models, are used to estimate potential long term effects. Common models include 1) the linear non-threshold (LNT) model, 2) threshold models with either a linear or curvilinear dose response above the threshold, and 3) a hormetic model, where the risk is initially decreased belowmore » background levels before increasing. The choice of model used when making radiation risk or protection calculations and decisions can have significant implications on public policy and health care decisions. However, the ongoing debate about which risk model best describes the dose-response relationship at low doses of radiation makes informed decision making difficult. This symposium will review the two fundamental approaches to determining the risk associated with low doses of ionizing radiation, namely radiation epidemiology and radiation biology. The strengths and limitations of each approach will be reviewed, the results of recent studies presented, and the appropriateness of different risk models for various real world scenarios discussed. Examples of well-designed and poorly-designed studies will be provided to assist medical physicists in 1) critically evaluating publications in the field and 2) communicating accurate information to medical professionals, patients, and members of the general public. Equipped with the best information that radiation epidemiology and radiation biology can currently provide, and an understanding of the limitations of such information, individuals and organizations will be able to make more informed decisions regarding questions such as 1) how much shielding to install at medical facilities, 2) at what dose level are risk vs. benefit discussions with patients appropriate, 3) at what dose level should we tell a pregnant woman that the baby’s health risk from a prenatal radiation exposure is “significant”, 4) is informed consent needed for patients undergoing medical imaging, and 5) at what dose level is evacuation appropriate after a radiological accident. Examples of the tremendous impact that choosing different risks models can have on the answers to these types of questions will be given.A moderated panel discussion will allow audience members to pose questions to the faculty members, each of whom is an established expert in his respective discipline. Learning Objectives: Understand the fundamental principles, strengths and limitations of radiation epidemiology and radiation biology for determining the risk from exposures to low doses of ionizing radiation Become familiar with common models of risk used to describe the dose-response relationship at low dose levels Learn to identify strengths and weaknesses in studies designed to measure the effect of low doses of ionizing radiation Understand the implications of different risk models on public policy and health care decisions.« less

TH-A-BRD-01: Radiation Biology for Radiation Therapy Physicists

DOE Office of Scientific and Technical Information (OSTI.GOV)

Orton, C; Borras, C; Carlson, D

Mechanisms by which radiation kills cells and ways cell damage can be repaired will be reviewed. The radiobiological parameters of dose, fractionation, delivery time, dose rate, and LET will be discussed. The linear-quadratic model for cell survival for high and low dose rate treatments and the effect of repopulation will be presented and discussed. The rationale for various radiotherapy techniques such as conventional fractionation, hyperfractionation, hypofractionation, and low and high dose rate brachytherapy, including permanent implants, will be presented. The radiobiological principles underlying radiation protection guidelines and the different radiation dosimetry terms used in radiation biology and in radiation protectionmore » will be reviewed. Human data on radiation induced cancer, including increases in the risk of second cancers following radiation therapy, as well as data on radiation induced tissue reactions, such as cardiovascular effects, for follow up times up to 20–40 years, published by ICRP, NCRP and BEIR Committees, will be examined. The latest risk estimates per unit dose will be presented. Their adoption in recent radiation protection standards and guidelines and their impact on patient and workers safety in radiotherapy will be discussed. Biologically-guided radiotherapy (BGRT) provides a systematic method to derive prescription doses that integrate patient-specific information about tumor and normal tissue biology. Treatment individualization based on patient-specific biology requires the identification of biological objective functions to facilitate the design and comparison of competing treatment modalities. Biological objectives provide a more direct approach to plan optimization instead of relying solely on dose-based surrogates and can incorporate factors that alter radiation response, such as DNA repair, tumor hypoxia, and relative biological effectiveness. We review concepts motivating biological objectives and provide examples of how they might be used to address clinically relevant problems. Underlying assumptions and limitations of existing models and their proper application will be discussed. This multidisciplinary educational session combines the fundamentals of radiobiology for radiation therapy and radiation protection with the practical application of biophysical models for treatment planning and evaluation. Learning Objectives: To understand fractionation in teletherapy and dose rate techniques in brachytherapy. To understand how the linear-quadratic models the effect of radiobiological parameters for radiotherapy. To understand the radiobiological basis of radiation protection standards applied to radiotherapy. To distinguish between stochastic effects and tissue reactions. To learn how to apply concepts of biological effective dose and RBE-weighted dose and to incorporate biological factors that alter radiation response. To discuss clinical strategies to increase therapeutic ratio, i.e., maximize local control while minimizing the risk of acute and late normal tissue effects.« less

Lung dose and the potential risk of death in postoperative radiation therapy for non-small cell lung cancer: A study using the method of stratified grouping.

PubMed

Heo, Jaesung; Noh, O Kyu; Kim, Hwan-Ik; Chun, Mison; Cho, Oyeon; Park, Rae Woong; Yoon, Dukyong; Oh, Young-Taek

2018-04-19

Postoperative radiation therapy may have a detrimental effect on survival in patients with non-small cell lung cancer. We investigated the association of the lung radiation dose with the risk of death in patients treated with postoperative radiation therapy. We analyzed 178 patients with non-small cell lung cancer who received postoperative radiation therapy. The mean lung dose was calculated from dose-volume data, and we categorized patients into the high and low lung dose groups using 2 different methods; (1) simple grouping using the median lung dose of all patients, and (2) stratified grouping using the median lung dose of each subgroup sharing the same confounders. We compared clinical variables, and survival between the high and low lung dose groups. In the simple grouping, there were no significant differences in survivals between the high and low lung dose groups. After stratification, the overall survival of low lung dose group was significantly longer than that of high lung dose group (5-year survival, 60.1% vs. 35.3%, p = 0.039). On multivariable analyses, the lung dose remained a significant prognostic factor for overall survival (hazard ratio, HR = 2.08, p = 0.019). The lung dose was associated with the risk of death in patients with non-small cell lung cancer having the same confounders. Further studies evaluating the risk of death according to the lung dose will be helpful to administer more precise and individualized postoperative radiation therapy. Copyright © 2018 Elsevier B.V. All rights reserved.

Membrane Signaling Induced by High Doses of Ionizing Radiation in the Endothelial Compartment. Relevance in Radiation Toxicity

PubMed Central

Corre, Isabelle; Guillonneau, Maëva; Paris, François

2013-01-01

Tumor areas can now be very precisely delimited thanks to technical progress in imaging and ballistics. This has also led to the development of novel radiotherapy protocols, delivering higher doses of ionizing radiation directly to cancer cells. Despite this, radiation toxicity in healthy tissue remains a major issue, particularly with dose-escalation in these new protocols. Acute and late tissue damage following irradiation have both been linked to the endothelium irrigating normal tissues. The molecular mechanisms involved in the endothelial response to high doses of radiation are associated with signaling from the plasma membrane, mainly via the acid sphingomyelinase/ceramide pathway. This review describes this signaling pathway and discusses the relevance of targeting endothelial signaling to protect healthy tissues from the deleterious effects of high doses of radiation. PMID:24252908

Sperm quality and DNA damage in men from Jilin Province, China, who are occupationally exposed to ionizing radiation.

PubMed

Zhou, D D; Hao, J L; Guo, K M; Lu, C W; Liu, X D

2016-03-22

Long-term radiation exposure affects human health. Ionizing radiation has long been known to raise the risk of cancer. In addition to high doses of radiation, low-dose ionizing radiation might increase the risk of cardiovascular disease, lens opacity, and some other non-cancerous diseases. Low- and high-dose exposures to ionizing radiation elicit different signaling events at the molecular level, and may involve different response mechanisms. The health risks arising from exposure to low doses of ionizing radiation should be re-evaluated. Health workers exposed to ionizing radiation experience low-dose radiation and have an increased risk of hematological malignancies. Reproductive function is sensitive to changes in the physical environment, including ionizing radiation. However, data is scarce regarding the association between occupational radiation exposure and risk to human fertility. Sperm DNA integrity is a functional parameter of male fertility evaluation. Hence, we aimed to report sperm quality and DNA damage in men from Jilin Province, China, who were occupationally exposed to ionizing radiation. Sperm motility and normal morphology were significantly lower in the exposed compared with the non-exposed men. There was no statistically significant difference in sperm concentration between exposed and non-exposed men. The sperm DNA fragmentation index was significantly higher in the exposed than the non-exposed men. Chronic long-term exposure to low doses of ionizing radiation could affect sperm motility, normal morphology, and the sperm DNA fragmentation index in the Chinese population. Sperm quality and DNA integrity are functional parameters that could be used to evaluate occupational exposure to ionizing radiation.

Radiation Exposure to Relatives of Patients Treated with Iodine-131 for Thyroid Cancer at Siriraj Hospital.

PubMed

Tonnonchiang, Siriporn; Sritongkul, Nopamon; Chaudakshetrin, Pachee; Tuntawiroon, Malulee

2016-02-01

Thyroid cancer patients treated with 1-131 are potential source of radiation exposure to relatives who are knowingly and willingly exposed to ionizing radiation as a result of providing comfort to patients undergoing I-131 therapy. This study aims to determine radiation dose received by relatives who care for non self-supporting 1-131 patients at Siriraj Hospital. Twenty caregivers of 20 patients underwent I-131 therapy for thyroid cancer with a standard protocol were given specific instructions with regard to radiation safety and provided with electronic digital dosimeter to continuously measure radiation dose received on daily basis, three days in the hospital. On the day patient is released, thyroid uptake estimates were performed to assess internal radiation dose received by caregivers. The 3-day accumulative doses to caregivers to patients receiving 150 mCi (n = 11) and 200 mCi (n = 9) of I-131 ranged from 37 to 333 uSv and 176 to 1,920 pSv respectively depending on the level of supports required. Thyroid uptake estimates in all caregivers were undetectable. Dosimeter indicated a maximum whole-body dose of1.92 mSv was more than the public dose limit of] mSv but within the dose constraint of 5 mSv for caregivers. Radiation dose to caregivers of a non self-supporting hospitalized patient undergoing 1-131 therapy were well below the limits recommended by the ICRP. The patients can be comforted with confidence that dose to caregivers will be less than the limit. This study provides guidance for medical practitioners to obtain practical radiation safety concerns associated with hospitalized patients receiving I-131 therapy especially when patient needs assistance.

Diagnostic radiation exposure in pediatric trauma patients.

PubMed

Brunetti, Marissa A; Mahesh, Mahadevappa; Nabaweesi, Rosemary; Locke, Paul; Ziegfeld, Susan; Brown, Robert

2011-02-01

The amount of imaging studies performed for disease diagnosis has been rapidly increasing. We examined the amount of radiation exposure that pediatric trauma patients receive because they are an at-risk population. Our hypothesis was that pediatric trauma patients are exposed to high levels of radiation during a single hospital visit. Retrospective review of children who presented to Johns Hopkins Pediatric Trauma Center from July 1, 2004, to June 30, 2005. Radiographic studies were recorded for each patient and doses were calculated to give a total effective dose of radiation. All radiographic studies that each child received during evaluation, including any associated hospital admission, were included. A total of 945 children were evaluated during the study year. A total of 719 children were included in the analysis. Mean age was 7.8 (±4.6) years. Four thousand six hundred three radiographic studies were performed; 1,457 were computed tomography (CT) studies (31.7%). Average radiation dose was 12.8 (±12) mSv. We found that while CT accounted for only 31.7% of the radiologic studies performed, it accounted for 91% of the total radiation dose. Mean dose for admitted children was 17.9 (±13.8) mSv. Mean dose for discharged children was 8.4 (±7.8) mSv (p<0.0001). Burn injuries had the lowest radiation dose [1.2 (±2.6) mSv], whereas motor vehicle collision victims had the highest dose [18.8 (±14.7) mSv]. When the use of radiologic imaging is considered essential, cumulative radiation exposure can be high. In young children with relatively long life spans, the benefit of each imaging study and the cumulative radiation dose should be weighed against the long-term risks of increased exposure.

Ischaemic heart disease incidence and mortality in an extended cohort of Mayak workers first employed in 1948–1982

PubMed Central

Grigoryeva, Evgeniya S; Haylock, Richard G E; Pikulina, Maria V; Moseeva, Maria B

2015-01-01

Objective: Incidence and mortality from ischaemic heart disease (IHD) was studied in an extended cohort of 22,377 workers first employed at the Mayak Production Association during 1948–82 and followed up to the end of 2008. Methods: Relative risks and excess relative risks per unit dose (ERR/Gy) were calculated based on the maximum likelihood using Epicure software (Hirosoft International Corporation, Seattle, WA). Dose estimates used in analyses were provided by an updated “Mayak Worker Dosimetry System—2008”. Results: A significant increasing linear trend in IHD incidence with total dose from external γ-rays was observed after having adjusted for non-radiation factors and dose from internal radiation {ERR/Gy = 0.10 [95% confidence interval (CI): 0.04 to 0.17]}. The pure quadratic model provided a better fit of the data than did the linear one. No significant association of IHD mortality with total dose from external γ-rays after having adjusted for non-radiation factors and dose from internal alpha radiation was observed in the study cohort [ERR/Gy = 0.06 (95% CI: <0 to 0.15)]. A significant increasing linear trend was observed in IHD mortality with total absorbed dose from internal alpha radiation to the liver after having adjusted for non-radiation factors and dose from external γ-rays in both the whole cohort [ERR/Gy = 0.21 (95% CI: 0.01 to 0.58)] and the subcohort of workers exposed at alpha dose <1.00 Gy [ERR/Gy = 1.08 (95% CI: 0.34 to 2.15)]. No association of IHD incidence with total dose from internal alpha radiation to the liver was found in the whole cohort after having adjusted for non-radiation factors and external gamma dose [ERR/Gy = 0.02 (95% CI: not available to 0.10)]. Statistically significant dose effect was revealed in the subcohort of workers exposed to internal alpha radiation at dose to the liver <1.00 Gy [ERR/Gy = 0.44 (95% CI: 0.09 to 0.85)]. Conclusion: This study provides strong evidence of IHD incidence and mortality association with external γ-ray exposure and some evidence of IHD incidence and mortality association with internal alpha-radiation exposure. Advances in knowledge: It is the first time the validity of internal radiation dose estimates has been shown to affect the risk of IHD incidence. PMID:26224431

Effects of Low-Dose Mindfulness-Based Stress Reduction (MBSR-ld) on Working Adults

ERIC Educational Resources Information Center

Klatt, Maryanna D.; Buckworth, Janet; Malarkey, William B.

2009-01-01

Mindfulness-based stress reduction (MBSR) has produced behavioral, psychological, and physiological benefits, but these programs typically require a substantial time commitment from the participants. This study assessed the effects of a shortened (low-dose [ld]) work-site MBSR intervention (MBSR-ld) on indicators of stress in healthy working…

Internal dose assessment of 238U contaminated soils based on in-vitro gastrointestinal protocol

NASA Astrophysics Data System (ADS)

Perama, Yasmin Mohd Idris; Rashid, Nur Shahidah Abdul; Majid, Amran Ab.; Siong, Khoo Kok

2017-01-01

Human exposure to natural radioactive uranium has been a great interest as more industrial rapidly growing contributes to radiation risks. The aim of this case study was to determine the internal dose in humans incorporated with ingestion of 238U contaminated soils. A gastrointestinal analogue test was employed to simulate the human digestive tract. In-vitro approach via German DIN 19738 model was developed in order to estimate the internal exposure of 238U due to ingestion of different types of soils. Synthetic gastrointestinal fluids assay via in-vitro method were produced to determine the concentration of 238U in various soils using ICP-MS. Based on the results, concentration of 238U in BRIS, laterite, peat and alluvium soils were in ranged between (0.0061 ± 0.0057 - 0.0488 ± 0.0148) ppm and (0.0005 ± 0.0004 - 0.0046 ± 0.0007) ppm in gastric and gastrointestinal phase respectively. Types of soil compositions and pH medium were some of the factors that influence mobilization and solubility of 238U contaminanted soil into the digestive juices that resembles human gastrointestinal tract. For the purpose of internal dose assessment, the committed efective dose from 238U intake in soils ranged between 1.237 × 10-11 - 9.8993 × 10-11 Sv y-1 for gastric phase and 1.0184 × 10-12 - 9.3294 × 10-12 Sv y-1 for gastric-intestinal phase. The internal dose measurements from this study were much lower from the recommended values. Hence, ingestion of 238U contaminated soils would not be expected to pose major health risk to humans.

NASA Space Radiation Program Integrative Risk Model Toolkit

NASA Technical Reports Server (NTRS)

Kim, Myung-Hee Y.; Hu, Shaowen; Plante, Ianik; Ponomarev, Artem L.; Sandridge, Chris

2015-01-01

NASA Space Radiation Program Element scientists have been actively involved in development of an integrative risk models toolkit that includes models for acute radiation risk and organ dose projection (ARRBOD), NASA space radiation cancer risk projection (NSCR), hemocyte dose estimation (HemoDose), GCR event-based risk model code (GERMcode), and relativistic ion tracks (RITRACKS), NASA radiation track image (NASARTI), and the On-Line Tool for the Assessment of Radiation in Space (OLTARIS). This session will introduce the components of the risk toolkit with opportunity for hands on demonstrations. The brief descriptions of each tools are: ARRBOD for Organ dose projection and acute radiation risk calculation from exposure to solar particle event; NSCR for Projection of cancer risk from exposure to space radiation; HemoDose for retrospective dose estimation by using multi-type blood cell counts; GERMcode for basic physical and biophysical properties for an ion beam, and biophysical and radiobiological properties for a beam transport to the target in the NASA Space Radiation Laboratory beam line; RITRACKS for simulation of heavy ion and delta-ray track structure, radiation chemistry, DNA structure and DNA damage at the molecular scale; NASARTI for modeling of the effects of space radiation on human cells and tissue by incorporating a physical model of tracks, cell nucleus, and DNA damage foci with image segmentation for the automated count; and OLTARIS, an integrated tool set utilizing HZETRN (High Charge and Energy Transport) intended to help scientists and engineers study the effects of space radiation on shielding materials, electronics, and biological systems.

Radiation exposure in X-ray-based imaging techniques used in osteoporosis

PubMed Central

Adams, Judith E.; Guglielmi, Giuseppe; Link, Thomas M.

2010-01-01

Recent advances in medical X-ray imaging have enabled the development of new techniques capable of assessing not only bone quantity but also structure. This article provides (a) a brief review of the current X-ray methods used for quantitative assessment of the skeleton, (b) data on the levels of radiation exposure associated with these methods and (c) information about radiation safety issues. Radiation doses associated with dual-energy X-ray absorptiometry are very low. However, as with any X-ray imaging technique, each particular examination must always be clinically justified. When an examination is justified, the emphasis must be on dose optimisation of imaging protocols. Dose optimisation is more important for paediatric examinations because children are more vulnerable to radiation than adults. Methods based on multi-detector CT (MDCT) are associated with higher radiation doses. New 3D volumetric hip and spine quantitative computed tomography (QCT) techniques and high-resolution MDCT for evaluation of bone structure deliver doses to patients from 1 to 3 mSv. Low-dose protocols are needed to reduce radiation exposure from these methods and minimise associated health risks. PMID:20559834

THE STATE OF IMMUNITY IN GUINEA-PIGS IMMUNIZED WITH LIVE BRUCELLOSIS VACCINE AND EXPOSED TO RADIATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shevtsova, Z.V.

1960-01-01

On immunization with 19-BA live brucellosis vaccine on the 3rd and 10th days after exposure to radiation in a dose of 200 r, guinea pigs died 4 and 2 times more frequently than unvaccinated guinea pigs. If immunization was carried out on the 30th day after irradiation the mortality among irradiated animals showed only a slight increase compared with the mortality among unvaccinated control animals. Immunization carried out before exposure to radiation had no influence upon the mortality of the animals caused by radiation sickness. Guinea pigs immunized after exposure to radiation were insusceptible when infected with the doses ofmore » virulent strains of Brucella usually employed to challenge immunity (2-4 infective doses). If, however, the animals were infected with a dose twice as high (8 infective doses) the degree of immunity proved to be lower in guinea pigs exposed to radiation, than in guinea pigs immunized and not exposed to radiation. Exposure of guinea pigs to radiation at a time when immunity had already developed had no influence upon the degree of immunity on infection with 4 infective doses of the virulent strain. (auth)« less

Leukemia and other cancers following radiation treatment of pelvic disease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, P.G.

1977-04-01

Follow-up studies of patients treated for cancer of the cervix with radiotherapy have shown such women to be at little or no increased risk of leukemia subsequent to the radiation exposure. However, women exposed to lower doses of radiation in the pelvic area, in the induction of an artificial menopause, appear to show increased risks of both leukemia and cancers of those sites directly in the radiation field. The studies of these two types of radiation exposure are reviewed. The findings may possibly be reconciled with each other on the basis of the distribution of radiation dose to the bonemore » marrow. Irradiation for cancer of the cervix delivers radiation doses to a small portion of the marrow which are probably lethal for most marrow cells. The mean dose to cells distant from the cervix may be too small to produce a detectable increase in leukemia incidence. The lower and more uniformly distributed radiation dose used to induce an artificial menopause will be less lethal for marrow cells and may consequently deliver a higher ''effective'' marrow dose to surviving cells, resulting in an increased leukemia risk.« less

Radiation sensitivity and EPR dosimetric potential of gallic acid and its esters

NASA Astrophysics Data System (ADS)

Tuner, Hasan; Oktay Bal, M.; Polat, Mustafa

2015-02-01

In the preset work the radiation sensitivities of Gallic Acid anhydrous and monohydrate, Octyl, Lauryl, and Ethyl Gallate (GA, GAm, OG, LG, and EG) were investigated in the intermediate (0.5-20 kGy) and low radiation (<10 Gy) dose range using Electron Paramagnetic Resonance (EPR) spectroscopy. While OG, LG, and EG are presented a singlet EPR spectra, their radiation sensitivity found to be very different in the intermediate dose range. At low radiation dose range (<10 Gy) only LG is found to be present a signal that easily distinguished from the noise signals. The intermediate and low dose range radiation sensitivities are compared using well known EPR dosimeter alanine. The radiation yields (G) of the interested material were found to be 1.34×10-2, 1.48×10-2, 4.14×10-2, and 6.03×10-2, 9.44×10-2 for EG, GA, GAm, OG, and LG, respectively at the intermediate dose range. It is found that the simple EPR spectra and the noticeable EPR signal of LG make it a promising dosimetric material to be used below 10 Gy of radiation dose.

Radiation dose to the global flying population.

PubMed

Alvarez, Luis E; Eastham, Sebastian D; Barrett, Steven R H

2016-03-01

Civil airliner passengers and crew are exposed to elevated levels of radiation relative to being at sea level. Previous studies have assessed the radiation dose received in particular cases or for cohort studies. Here we present the first estimate of the total radiation dose received by the worldwide civilian flying population. We simulated flights globally from 2000 to 2013 using schedule data, applying a radiation propagation code to estimate the dose associated with each flight. Passengers flying in Europe and North America exceed the International Commission on Radiological Protection annual dose limits at an annual average of 510 or 420 flight hours per year, respectively. However, this falls to 160 or 120 h on specific routes under maximum exposure conditions.

Carbon Heavy-ion Radiation Induced Biological effects on Oryza sativa L.

NASA Astrophysics Data System (ADS)

Zhang, Meng; Sun, Yeqing; Li, Xishan; Gong, Ning; Meng, Qingmei; Liu, Jiawei; Wang, Ting

2016-07-01

Large number of researches on rice after spaceflights indicated that rice was a favorable model organism to study biological effects induced by space radiation. The stimulative effect could often be found on rice seedlings after irradiation by low-dose energetic heavy-ion radiation. Spaceflight also could induce stimulative effect on kinds of seeds. To further understand the mechanism of low-dose radiation biological effects and the dose range, the germinated rice seeds which were irradiated by different doses of carbon heavy-ion (0, 0.02, 0.1, 0.2, 1, 2, 5, 10, 15 and 20Gy, LET=27.3keV/µm) were used as materials to study. By investigating the variation of rice phenotype under different doses, we found that 2Gy radiation dose was a dividing point of the phenotypic variation. Transmission electron microscopy was used to observe the variation of mitochondria, chloroplast, endoplasmic reticulum, ribosome and nucleus in mesophyll cell of rice apical meristem at 24 hours after radiation with different doses. The cells were not apparently physiologically damaged when the dose of radiation was less than 2Gy. The number of chloroplast did not change significantly, but the number of mitochondria was significantly increased, and gathered around in the chloroplast and endoplasmic reticulum; the obvious lesion of chloroplast and mitochondria were found at the mesophyll cells when radiation dose was higher than 2Gy. The mitochondria were swelling and appearing blurred crest. The chloroplast and mitochondrial mutation rate increased significantly (p<0.01). These phenomena showed that cell biological changes may be the reasons of the stimulation and inhibition effects with the boundary of 2Gy. Since mitochondrial was an important organelle involved in the antioxidative systems, its dysfunction could result in the increase of reactive oxygen species and lipid peroxidation. We found that the growth stimulation induced by low-dose radiation mainly occurred at three-leaf stage along with the increasing activity of antioxidase system and damages of lipid peroxidation. We also found that the relative expression of genes sdhb and aox1a which encode the key proteins in mitochondria changed differently after exposed to different doses of radiation, and the lower dose of the radiation could cause longer effect. The chlorophyll was an important organ of photosynthesis, its dysfunction could result in the phenotypic variation. We found that the chlorophyll fluorescence parameter Fv/Fm, the content of chlorophyll (including chlorophyll a, chlorophyll b and total chlorophyll) and both the relative expression of CP24 and its encoding gene lhcb6 changed significantly in different doses. The changes of the relative expression of CP24 and its encoding gene lhcb6 were completely opposite at the lower dose and agreed at the higher dose. The possible mechanisms of growth stimulation and inhibition effects induced by low and high dose radiations were discussed on multiple levels. Moreover, our findings were important to understand the spaceflight induced growth stimulation and inhibition effects of plant. Keywords: Heavy-ion radiation; Low dose; Stimulation effect; Inhibition effect; Rice.

HADOC: a computer code for calculation of external and inhalation doses from acute radionuclide releases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strenge, D.L.; Peloquin, R.A.

The computer code HADOC (Hanford Acute Dose Calculations) is described and instructions for its use are presented. The code calculates external dose from air submersion and inhalation doses following acute radionuclide releases. Atmospheric dispersion is calculated using the Hanford model with options to determine maximum conditions. Building wake effects and terrain variation may also be considered. Doses are calculated using dose conversion factor supplied in a data library. Doses are reported for one and fifty year dose commitment periods for the maximum individual and the regional population (within 50 miles). The fractional contribution to dose by radionuclide and exposure modemore » are also printed if requested.« less

Space weather effects measured in atmospheric radiation on aircraft

NASA Astrophysics Data System (ADS)

Tobiska, W. K.; Bouwer, D.; Bailey, J. J.; Didkovsky, L. V.; Judge, K.; Wieman, S. R.; Atwell, W.; Gersey, B.; Wilkins, R.; Rice, D.; Schunk, R. W.; Bell, L. D.; Mertens, C. J.; Xu, X.; Wiltberger, M. J.; Wiley, S.; Teets, E.; Shea, M. A.; Smart, D. F.; Jones, J. B. L.; Crowley, G.; Azeem, S. I.; Halford, A. J.

2016-12-01

Space weather's effects upon the near-Earth environment are due to dynamic changes in the energy transfer processes from the Sun's photons, particles, and fields. Of the domains that are affected by space weather, the coupling between the solar and galactic high-energy particles, the magnetosphere, and atmospheric regions can significantly affect humans and our technology as a result of radiation exposure. Since 2013 Space Environment Technologies (SET) has been conducting observations of the atmospheric radiation environment at aviation altitudes using a small fleet of six instruments. The objective of this work is to improve radiation risk management in air traffic operations. Under the auspices of the Automated Radiation Measurements for Aerospace Safety (ARMAS) and Upper-atmospheric Space and Earth Weather eXperiment (USEWX) projects our team is making dose rate measurements on multiple aircraft flying global routes. Over 174 ARMAS and USEWX flights have successfully demonstrated the operation of a micro dosimeter on commercial aviation altitude aircraft that captures the radiation environment resulting from Galactic Cosmic Rays (GCRs), Solar Energetic Protons (SEPs), and outer radiation belt energetic electrons. The real-time radiation exposure is measured as an absorbed dose rate in silicon and then computed as an ambient dose equivalent rate for reporting dose relevant to radiative-sensitive organs and tissue in units of microsieverts per hour. ARMAS total ionizing absorbed dose is captured on the aircraft, downlinked in real-time, processed on the ground into ambient dose equivalent rates, compared with NASA's Langley Research Center (LaRC) most recent Nowcast of Atmospheric Ionizing Radiation System (NAIRAS) global radiation climatology model runs, and then made available to end users. Dose rates from flight altitudes up to 56,700 ft. are shown for flights across the planet under a variety of space weather conditions. We discuss several space weather effects on the atmospheric radiation environment, including the levels of GCR background radiation, small SEP events, and possible EMIC wave driven energetic electrons from the outer radiation belt creating "radiation" clouds in the troposphere.

An assessment of radiation doses at an educational institution 57.8 km away from the Fukushima Daiichi nuclear power plant 1 month after the nuclear accident.

PubMed

Tsuji, Masayoshi; Kanda, Hideyuki; Kakamu, Takeyasu; Kobayashi, Daisuke; Miyake, Masao; Hayakawa, Takehito; Mori, Yayoi; Okochi, Toshiyasu; Hazama, Akihiro; Fukushima, Tetsuhito

2012-03-01

On 11 March 2011, the Great East Japan Earthquake occurred. Due to this earthquake and subsequent tsunami, malfunctions occurred at the Fukushima Daiichi nuclear power plant. Radioactive material even reached the investigated educational institution despite being 57.8 km away from the power station. With the goal of ensuring the safety of our students, we decided to carry out a risk assessment of the premises of this educational institution by measuring radiation doses at certain locations, making it possible to calculate estimated radiation accumulation. Systematic sampling was carried out at measurement points spaced at regular intervals for a total of 24 indoor and outdoor areas, with 137 measurements at heights of 1 cm and 100 cm above the ground surface. Radiation survey meters were used to measure environmental radiation doses. Radiation dose rates and count rates were higher outdoors than indoors, and higher 1 cm above the ground surface than at 100 cm. Radiation doses 1 cm above the ground surface were higher on grass and moss than on asphalt and soil. The estimated radiation exposure for a student spending an average of 11 h on site at this educational institution was 9.80 μSv. Environmental radiation doses at our educational institution 57.8 km away from the Fukushima Daiichi nuclear power plant 1 month after the accident were lower than the national regulation dose for schools (3.8 μSv/h) at most points. Differences in radiation doses depending on outdoor surface properties are important to note for risk reduction.

New patient-controlled abdominal compression method in radiography: radiation dose and image quality.

PubMed

Piippo-Huotari, Oili; Norrman, Eva; Anderzén-Carlsson, Agneta; Geijer, Håkan

2018-05-01

The radiation dose for patients can be reduced with many methods and one way is to use abdominal compression. In this study, the radiation dose and image quality for a new patient-controlled compression device were compared with conventional compression and compression in the prone position . To compare radiation dose and image quality of patient-controlled compression compared with conventional and prone compression in general radiography. An experimental design with quantitative approach. After obtaining the approval of the ethics committee, a consecutive sample of 48 patients was examined with the standard clinical urography protocol. The radiation doses were measured as dose-area product and analyzed with a paired t-test. The image quality was evaluated by visual grading analysis. Four radiologists evaluated each image individually by scoring nine criteria modified from the European quality criteria for diagnostic radiographic images. There was no significant difference in radiation dose or image quality between conventional and patient-controlled compression. Prone position resulted in both higher dose and inferior image quality. Patient-controlled compression gave similar dose levels as conventional compression and lower than prone compression. Image quality was similar with both patient-controlled and conventional compression and was judged to be better than in the prone position.

Effects of radiation exposure from cardiac imaging: how good are the data?

PubMed

Einstein, Andrew J

2012-02-07

Concerns about medical exposure to ionizing radiation have become heightened in recent years as a result of rapid growth in procedure volumes and the high radiation doses incurred from some procedures. This paper summarizes the evidence base undergirding concerns about radiation exposure in cardiac imaging. After classifying radiation effects, explaining terminology used to quantify the radiation received by patients, and describing typical doses from cardiac imaging procedures, this paper will address the major epidemiological studies having bearing on radiation effects at doses comparable to those received by patients undergoing cardiac imaging. These include studies of atomic bomb survivors, nuclear industry workers, and children exposed in utero to x-rays, all of which have evidenced increased cancer risks at low doses. Additional higher-dose epidemiological studies of cohorts exposed to radiation in the context of medical treatment are described and found to be generally compatible with these cardiac dose-level studies, albeit with exceptions. Using risk projection models developed by the U.S. National Academies that incorporate these data and reflect several evidence-based assumptions, cancer risk from cardiac imaging can be estimated and compared with the benefits from imaging. Several ongoing epidemiological studies will provide better understanding of radiation-associated cancer risks. Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Looking into future: challenges in radiation protection in medicine.

PubMed

Rehani, M M

2015-07-01

Radiation protection in medicine is becoming more and more important with increasing wider use of X-rays, documentation of effects besides the potential for long-term carcinogenic effects. With computed tomography (CT) likely to become sub-mSv in coming years, positron emission tomography (PET), single photon emission computed tomography (SPECT) and some of the nuclear medical examination will become focus of attraction as high-dose examinations, even though they are less-frequent ones. Clarity will be needed on radiation effects at levels of radiation doses encountered in a couple of CT scans and if effects are really cumulative. There is challenge to develop radiation metrics that can be used as easily as units of temperature and length and avoidance of multiple meaning of a single dose metric. Other challenges include development of biological indicators of radiation dose, transition from dose to a representative phantom to dose to individual patient, system for tracking of radiation exposure history of patient, avoidance of radiation-induced skin injury in patients and radiation cataract in staff, cutting down inappropriate referrals for radiological examinations, confidence building in patient and patient safety in radiotherapy. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Flight attendant radiation dose from solar particle events.

PubMed

Anderson, Jeri L; Mertens, Christopher J; Grajewski, Barbara; Luo, Lian; Tseng, Chih-Yu; Cassinelli, Rick T

2014-08-01

Research has suggested that work as a flight attendant may be related to increased risk for reproductive health effects. Air cabin exposures that may influence reproductive health include radiation dose from galactic cosmic radiation and solar particle events. This paper describes the assessment of radiation dose accrued during solar particle events as part of a reproductive health study of flight attendants. Solar storm data were obtained from the National Oceanic and Atmospheric Administration Space Weather Prediction Center list of solar proton events affecting the Earth environment to ascertain storms relevant to the two study periods (1992-1996 and 1999-2001). Radiation dose from exposure to solar energetic particles was estimated using the NAIRAS model in conjunction with galactic cosmic radiation dose calculated using the CARI-6P computer program. Seven solar particle events were determined to have potential for significant radiation exposure, two in the first study period and five in the second study period, and over-lapped with 24,807 flight segments. Absorbed (and effective) flight segment doses averaged 6.5 μGy (18 μSv) and 3.1 μGy (8.3 μSv) for the first and second study periods, respectively. Maximum doses were as high as 440 μGy (1.2 mSv) and 20 flight segments had doses greater than 190 μGy (0.5 mSv). During solar particle events, a pregnant flight attendant could potentially exceed the equivalent dose limit to the conceptus of 0.5 mSv in a month recommended by the National Council on Radiation Protection and Measurements.

Exposure of medical staff to radiation during osteosynthesis of proximal femoral fracture: descriptive analysis and comparison of different devices.

PubMed

Siedlecki, Cédric; Gauthé, Rémi; Gillibert, André; Bellenger, Kevin; Roussignol, Xavier; Ould-Slimane, Mourad

2017-10-01

The use of fluoroscopy is necessary during proximal femoral fracture (PFF) osteosynthesis. The frequency of these procedures justifies a description of radiation exposure and comparisons between different techniques and between the different surgical team members. This observational prospective and comparative study includes a series of 68 patients with PFF receiving osteosynthesis. Radiation exposure was assessed for all members of the operating team. The radiation dose measurements for the different members of the surgical team during PFF osteosynthesis were compared. The factors affecting the radiation dose were investigated. The mean active dosimeter readings for each operation were 7.39 µSv for the primary surgeon, 3.93 µSv for the assistant surgeon, 1.92 µSv for the instrument nurse, 1.25 µSv for the circulating nurse, and 0.64 µSv for the anaesthesiologist, respectively. Doses decreased significantly between these different members of the medical team (all p < 0.001). The dose also varied with patient age and BMI, as well as with fluoroscopy time and operating time, but not with type of fracture or type of osteosynthesis. Medical staff receives significantly different doses depending on their position in relation to the radiation source. Operating time and fluoroscopy time are the modifiable factors that affect the radiation dose. The radiation doses received by the different members of the medical teams involved in proximal femur osteosynthesis procedures all fall below the doses recommended by the International Commission on Radiation Units and Measurements.

Current status of radiological protection at nuclear power stations in Japan.

PubMed

Suzuki, Akira; Hori, Shunsuke

2011-07-01

The radiation dose to workers at nuclear power stations (NPSs) in Japan was drastically reduced between the late-1970s and the early-1990s by continuous dose-reduction programmes. The total collective dose of radiation workers in FY 2008 was 84.04 person Sv, while the average collective dose was 1.5 person Sv per reactor. The average annual individual dose was 1.1 mSv and the maximum annual individual dose was 19.5 mSv. These values are sufficiently lower than the regulatory dose limits. Radioactive effluent released from NPSs is already so trivial that additional protective measures will not be necessary. Experience in radiation protection at NPSs has been accumulated over 40 y and will be very useful in establishing a rational radiation control system in the future.

DICOM structured report to track patient's radiation dose to organs from abdominal CT exam

NASA Astrophysics Data System (ADS)

Morioka, Craig; Turner, Adam; McNitt-Gray, Michael; Zankl, Maria; Meng, Frank; El-Saden, Suzie

2011-03-01

The dramatic increase of diagnostic imaging capabilities over the past decade has contributed to increased radiation exposure to patient populations. Several factors have contributed to the increase in imaging procedures: wider availability of imaging modalities, increase in technical capabilities, rise in demand by patients and clinicians, favorable reimbursement, and lack of guidelines to control utilization. The primary focus of this research is to provide in depth information about radiation doses that patients receive as a result of CT exams, with the initial investigation involving abdominal CT exams. Current dose measurement methods (i.e. CTDIvol Computed Tomography Dose Index) do not provide direct information about a patient's organ dose. We have developed a method to determine CTDIvol normalized organ doses using a set of organ specific exponential regression equations. These exponential equations along with measured CTDIvol are used to calculate organ dose estimates from abdominal CT scans for eight different patient models. For each patient, organ dose and CTDIvol were estimated for an abdominal CT scan. We then modified the DICOM Radiation Dose Structured Report (RDSR) to store the pertinent patient information on radiation dose to their abdominal organs.

Radioprotective effect of Rapana thomasiana hemocyanin in gamma induced acute radiation syndrome.

PubMed

Kindekov, Ivan; Mileva, Milka; Krastev, Dimo; Vassilieva, Vladimira; Raynova, Yuliana; Doumanova, Lyuba; Aljakov, Mitko; Idakieva, Krassimira

2014-05-04

The radioprotective effect of Rapana thomasiana hemocyanin (RtH) against radiation-induced injuries (stomach ulcers, survival time and endogenous haemopoiesis) and post-radiation recovery was investigated in male albino mice (C3H strain). Radiation course was in a dose of 7.5 Gy (LD 100/30 - dose that kills 100% of the mice at 30 days) from 137 Cs with a dose of 2.05 Gy/min. Radiation injuries were manifested by inducing а hematopoietic form of acute radiation syndrome. RtH was administered intraperitoneally in a single dose of 50, 100, 150 and 200 mg/kg body weight (b. w.) once a day for five consecutive days before irradiation. The results obtained showed that radiation exposure led to (1) 100% mortality rate, (2) ulceration in the stomach mucosa and (3) decrease formation of spleen colonies as a marker of endogenous haemopoiesis. Administration of RtH at a dose of 200 mg/kg provided better protection against radiation-induced stomach ulceration, mitigated the lethal effects of radiation exposure and recovered endogenous haemopoiesis versus irradiated but not supplemented mice. It could be expected that RtH will find a use in mitigating radiation induced injury and enhanced radiorecovery.

Multiple Testing, Cumulative Radiation Dose, and Clinical Indications in Patients Undergoing Myocardial Perfusion Imaging

PubMed Central

Einstein, Andrew J.; Weiner, Shepard D.; Bernheim, Adam; Kulon, Michal; Bokhari, Sabahat; Johnson, Lynne L.; Moses, Jeffrey W.; Balter, Stephen

2013-01-01

Context Myocardial perfusion imaging (MPI) is the single medical test with the highest radiation burden to the US population. While many patients undergoing MPI receive repeat MPI testing, or additional procedures involving ionizing radiation, no data are available characterizing their total longitudinal radiation burden and relating radiation burden with reasons for testing. Objective To characterize procedure counts, cumulative estimated effective doses of radiation, and clinical indications, for patients undergoing MPI. Design, Setting, Patients Retrospective cohort study evaluating, for 1097 consecutive patients undergoing index MPI during the first 100 days of 2006 at Columbia University Medical Center, all preceding medical imaging procedures involving ionizing radiation undergone beginning October 1988, and all subsequent procedures through June 2008, at that center. Main Outcome Measures Cumulative estimated effective dose of radiation, number of procedures involving radiation, and indications for testing. Results Patients underwent a median (interquartile range, mean) of 15 (6–32, 23.9) procedures involving radiation exposure; 4 (2–8, 6.5) were high-dose (≥3 mSv, i.e. one year's background radiation), including 1 (1–2, 1.8) MPI studies per patient. 31% of patients received cumulative estimated effective dose from all medical sources >100mSv. Multiple MPIs were performed in 39% of patients, for whom cumulative estimated effective dose was 121 (81–189, 149) mSv. Men and whites had higher cumulative estimated effective doses, and there was a trend towards men being more likely to undergo multiple MPIs than women (40.8% vs. 36.6%, Odds ratio 1.29, 95% confidence interval 0.98–1.69). Over 80% of initial and 90% of repeat MPI exams were performed in patients with known cardiac disease or symptoms consistent with it. Conclusion In this institution, multiple testing with MPI was very common, and in many patients associated with very high cumulative estimated doses of radiation. PMID:21078807

Patient Dose In Diagnostic Radiology: When & How?

NASA Astrophysics Data System (ADS)

Lassen, Margit; Gorson, Robert O.

1980-08-01

Different situations are discussed in which it is of value to know radiation dose to the patient in diagnostic radiology. Radiation dose to specific organs is determined using the Handbook on Organ Doses published by the Bureau of Radiological Health of the Food and Drug Administration; the method is applied to a specific case. In this example dose to an embryo is calculated in examinations involving both fluoroscopy and radiography. In another example dose is determined to a fetus in late pregnancy using tissue air ratios. Patient inquiries about radiation dose are discussed, and some answers are suggested. The reliability of dose calculations is examined.

Risk of Subsequent Leukemia After a Solid Tumor in Childhood: Impact of Bone Marrow Radiation Therapy and Chemotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allodji, Rodrigue S., E-mail: rodrigue.allodji@gustaveroussy.fr; Gustave Roussy, Villejuif; Paris Sud University, Orsay

Purpose: To investigate the roles of radiation therapy and chemotherapy in the occurrence of subsequent leukemia after childhood cancer. Methods and Materials: We analyzed data from a case-control study with 35 cases and 140 controls. The active bone marrow (ABM) was segmented into 19 compartments, and the radiation dose was estimated in each. The chemotherapy drug doses were also estimated to enable adjustments. Models capable of accounting for radiation dose heterogeneity were implemented for analysis. Results: Univariate analysis showed a significant trend in the increase of secondary leukemia risk with radiation dose, after accounting for dose heterogeneity (P=.046). This trendmore » became nonsignificant after adjustment for doses of epipodophyllotoxins, alkylating agents, and platinum compounds and the first cancer on multivariate analysis (P=.388). The role of the radiation dose appeared to be dwarfed, mostly by the alkylating agents (odds ratio 6.9, 95% confidence interval 1.9-25.0). Among the patients who have received >16 Gy to the ABM, the radiogenic risk of secondary leukemia was about 4 times greater in the subgroup with no alkylating agents than in the subgroup receiving ≥10 g/m{sup 2}. Conclusions: Notwithstanding the limitations resulting from the size of our study population and the quite systematic co-treatment with chemotherapy, the use of detailed information on the radiation dose distribution to ABM enabled consideration of the role of radiation therapy in secondary leukemia induction after childhood cancer.« less

Radiation dose to workers due to the inhalation of dust during granite fabrication.

PubMed

Zwack, L M; McCarthy, W B; Stewart, J H; McCarthy, J F; Allen, J G

2014-03-01

There has been very little research conducted to determine internal radiation doses resulting from worker exposure to ionising radiation in granite fabrication shops. To address this issue, we estimated the effective radiation dose of granite workers in US fabrication shops who were exposed to the maximum respirable dust and silica concentrations allowed under current US regulations, and also to concentrations reported in the literature. Radiation doses were calculated using standard methods developed by the International Commission on Radiological Protection. The calculated internal doses were very low, and below both US occupational standards (50 mSv yr(-1)) and limits applicable to the general public (1 mSv yr(-1)). Workers exposed to respirable granite dust concentrations at the US Occupational Safety and Health Administration (OSHA) respirable dust permissible exposure limit (PEL) of 5 mg m(-3) over a full year had an estimated radiation dose of 0.062 mSv yr(-1). Workers exposed to respirable granite dust concentrations at the OSHA silica PEL and at the American Conference of Governmental Industrial Hygienists Threshold Limit Value for a full year had expected radiation doses of 0.007 mSv yr(-1) and 0.002 mSv yr(-1), respectively. Using data from studies of respirable granite dust and silica concentrations measured in granite fabrication shops, we calculated median expected radiation doses that ranged from <0.001 to 0.101 mSv yr(-1).

Investigation on γ-irradiated PP/ethylene acrylic elastomer TPVs by rheological and thermal approaches

NASA Astrophysics Data System (ADS)

Dutta, Anindya; Ghosh, Anup K.

2018-03-01

Polypropylene (PP) was melt blended with varying concentration of ethylene acrylic elastomer (AEM) in a twin screw extruder and then γ-irradiated at several radiation doses to achieve a series of thermoplastic vulcanizates (TPV). The effect of AEM concentration and γ-irradiation on flow characteristics, crystallization and thermal degradation of blends were explained using melt dynamic rheology, differential scanning calorimetry and thermogravimetric analysis. Gel content values and dynamic rheological data of PP and AEM at different radiation doses confirmed the incessant scissioning of PP chains with radiation doses except for highest radiation dose, where crosslinking of PP chains took place and the incessant crosslinking of AEM chains irrespective of radiation doses. Oxidative degradation of PP was confirmed by FTIR spectroscopy, which also exhibited absence of any chemical interaction between two constituent polymers. Normalized crystallinity and melting point of compositions, obtained from DSC, decreased with the radiation doses. Furthermore, with the radiation doses clear shifts of maxima of the melting peak towards the lower temperature were observed for neat PP and blends. Thermal stability of PP and blends, as observed by TGA, reduced significantly with irradiation; whereas for AEM, no discernable change was observed. Enhanced chain scissioning of PP in presence of AEM reduced the thermal stability of blends, especially at lower irradiation. This reduction of thermal stability was established by "rule of mixture", applied to the activation energy of thermal degradation. Thus, optimization of radiation doses to prepare TPVs was established.

A study of the effects of therapeutic doses of ionizing radiation in vitro on Lactobacillus isolates originating from the vagina - a pilot study.

PubMed

Gosiewski, Tomasz; Mróz, Tomasz; Ochońska, Dorota; Pabian, Wojciech; Bulanda, Malgorzata; Brzychczy-Wloch, Monika

2016-05-31

Ionizing radiation is used as a therapeutic option in the treatment of certain neoplastic lesions located, among others, in the pelvic region. The therapeutic doses of radiation employed often result in adverse effects manifesting themselves primarily in the form of genital tract infections in patients or diarrhea. The data available in the literature indicate disorders in the microbial ecosystem caused by ionizing radiation, which leads to the problems mentioned above. In the present study, we examined the influence of ionizing radiation on 52 selected strains of bacteria: Lactobacillus crispatus, L. fermentum, L. plantarum, L. reuteri, L. acidophilus L. amylovorus, L. casei, L. helveticus, L. paracasei, L. rhamnosus, L. salivarius and L. gasseri. This collection of Lactobacillus bacteria isolates of various species, obtained from the genital tract and gastrointestinal tract of healthy women, was tested for resistance to therapeutic doses of ionizing radiation. The species studied, were isolated from the genital tract (n = 30) and from the anus (n = 22) of healthy pregnant women. Three doses of 3 Gy (fractionated dose) and 50 Gy (total dose of the whole radiotherapy cycle) were applied. The greatest differences in survival of the tested strains in comparison to the control group (not subjected to radiation) were observed at the dose of 50 Gy. However, the results were not statistically significant. Survival decrease to zero was not demonstrated for any of the tested strains. Therapeutic doses of radiation do not affect the Lactobacillus bacteria significantly.

Patient doses and occupational exposure in a hybrid operating room.

PubMed

Andrés, C; Pérez-García, H; Agulla, M; Torres, R; Miguel, D; Del Castillo, A; Flota, C M; Alonso, D; de Frutos, J; Vaquero, C

2017-05-01

This study aimed to characterize the radiation exposure to patients and workers in a new vascular hybrid operating room during X-ray-guided procedures. During one year, data from 260 interventions performed in a hybrid operating room equipped with a Siemens Artis Zeego angiography system were monitored. The patient doses were analysed using the following parameters: radiation time, kerma-area product, patient entrance reference point dose and peak skin dose. Staff radiation exposure and ambient dose equivalent were also measured using direct reading dosimeters and thermoluminescent dosimeters. The radiation time, kerma-area product, patient entrance reference point dose and peak skin dose were, on average, 19:15min, 67Gy·cm 2 , 0.41Gy and 0.23Gy, respectively. Although the contribution of the acquisition mode was smaller than 5% in terms of the radiation time, this mode accounted for more than 60% of the effective dose per patient. All of the worker dose measurements remained below the limits established by law. The working conditions in the hybrid operating room HOR are safe in terms of patient and staff radiation protection. Nevertheless, doses are highly dependent on the workload; thus, further research is necessary to evaluate any possible radiological deviation of the daily working conditions in the HOR. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Low radiation dose in computed tomography: the role of iodine

PubMed Central

Aschoff, Andrik J; Catalano, Carlo; Krix, Martin; Albrecht, Thomas

2017-01-01

Recent approaches to reducing radiation exposure during CT examinations typically utilize automated dose modulation strategies on the basis of lower tube voltage combined with iterative reconstruction and other dose-saving techniques. Less clearly appreciated is the potentially substantial role that iodinated contrast media (CM) can play in low-radiation-dose CT examinations. Herein we discuss the role of iodinated CM in low-radiation-dose examinations and describe approaches for the optimization of CM administration protocols to further reduce radiation dose and/or CM dose while maintaining image quality for accurate diagnosis. Similar to the higher iodine attenuation obtained at low-tube-voltage settings, high-iodine-signal protocols may permit radiation dose reduction by permitting a lowering of mAs while maintaining the signal-to-noise ratio. This is particularly feasible in first pass examinations where high iodine signal can be achieved by injecting iodine more rapidly. The combination of low kV and IR can also be used to reduce the iodine dose. Here, in optimum contrast injection protocols, the volume of CM administered rather than the iodine concentration should be reduced, since with high-iodine-concentration CM further reductions of iodine dose are achievable for modern first pass examinations. Moreover, higher concentrations of CM more readily allow reductions of both flow rate and volume, thereby improving the tolerability of contrast administration. PMID:28471242

Comparison of eye lens dose on neuroimaging protocols between 16- and 64-section multidetector CT: achieving the lowest possible dose.

PubMed

Tan, J S P; Tan, K-L; Lee, J C L; Wan, C-M; Leong, J-L; Chan, L-L

2009-02-01

To our knowledge, there has been no study that compares the radiation dose delivered to the eye lens by 16- and 64-section multidetector CT (MDCT) for standard clinical neuroimaging protocols. Our aim was to assess radiation-dose differences between 16- and 64-section MDCT from the same manufacturer, by using near-identical neuroimaging protocols. Three cadaveric heads were scanned on 16- and 64-section MDCT by using standard neuroimaging CT protocols. Eye lens dose was measured by using thermoluminescent dosimeters (TLD), and each scanning was repeated to reduce random error. The dose-length product, volume CT dose index (CTDI(vol)), and TLD readings for each imaging protocol were averaged and compared between scanners and protocols, by using the paired Student t test. Statistical significance was defined at P < .05. The radiation dose delivered and eye lens doses were lower by 28.1%-45.7% (P < .000) on the 64-section MDCT for near-identical imaging protocols. On the 16-section MDCT, lens dose reduction was greatest (81.1%) on a tilted axial mode, compared with a nontilted helical mode for CT brain scans. Among the protocols studied, CT of the temporal bone delivered the greatest radiation dose to the eye lens. Eye lens radiation doses delivered by the 64-section MDCT are significantly lower, partly due to improvements in automatic tube current modulation technology. However, where applicable, protection of the eyes from the radiation beam by either repositioning the head or tilting the gantry remains the best way to reduce eye lens dose.

Retrospective cohort study of bronchial doses and radiation-induced atelectasis after stereotactic body radiation therapy of lung tumors located close to the bronchial tree.

PubMed

Karlsson, Kristin; Nyman, Jan; Baumann, Pia; Wersäll, Peter; Drugge, Ninni; Gagliardi, Giovanna; Johansson, Karl-Axel; Persson, Jan-Olov; Rutkowska, Eva; Tullgren, Owe; Lax, Ingmar

2013-11-01

To evaluate the dose-response relationship between radiation-induced atelectasis after stereotactic body radiation therapy (SBRT) and bronchial dose. Seventy-four patients treated with SBRT for tumors close to main, lobar, or segmental bronchi were selected. The association between incidence of atelectasis and bronchial dose parameters (maximum point-dose and minimum dose to the high-dose bronchial volume [ranging from 0.1 cm(3) up to 2.0 cm(3)]) was statistically evaluated with survival analysis models. Prescribed doses varied between 4 and 20 Gy per fraction in 2-5 fractions. Eighteen patients (24.3%) developed atelectasis considered to be radiation-induced. Statistical analysis showed a significant correlation between the incidence of radiation-induced atelectasis and minimum dose to the high-dose bronchial volumes, of which 0.1 cm(3) (D(0.1cm3)) was used for further analysis. The median value of D(0.1cm3) (α/β = 3 Gy) was EQD(2,LQ) = 147 Gy3 (range, 20-293 Gy3). For patients who developed atelectasis the median value was EQD(2,LQ) = 210 Gy3, and for patients who did not develop atelectasis, EQD(2,LQ) = 105 Gy3. Median time from treatment to development of atelectasis was 8.0 months (range, 1.1-30.1 months). In this retrospective study a significant dose-response relationship between the incidence of atelectasis and the dose to the high-dose volume of the bronchi is shown. Copyright © 2013 Elsevier Inc. All rights reserved.

Mimicking the effects of spaceflight on bone: Combined effects of disuse and chronic low-dose rate radiation exposure on bone mass in mice

NASA Astrophysics Data System (ADS)

Yu, Kanglun; Doherty, Alison H.; Genik, Paula C.; Gookin, Sara E.; Roteliuk, Danielle M.; Wojda, Samantha J.; Jiang, Zhi-Sheng; McGee-Lawrence, Meghan E.; Weil, Michael M.; Donahue, Seth W.

2017-11-01

During spaceflight, crewmembers are subjected to biomechanical and biological challenges including microgravity and radiation. In the skeleton, spaceflight leads to bone loss, increasing the risk of fracture. Studies utilizing hindlimb suspension (HLS) as a ground-based model of spaceflight often neglect the concomitant effects of radiation exposure, and even when radiation is accounted for, it is often delivered at a high-dose rate over a very short period of time, which does not faithfully mimic spaceflight conditions. This study was designed to investigate the skeletal effects of low-dose rate gamma irradiation (8.5 cGy gamma radiation per day for 20 days, amounting to a total dose of 1.7 Gy) when administered simultaneously to disuse from HLS. The goal was to determine whether continuous, low-dose rate radiation administered during disuse would exacerbate bone loss in a murine HLS model. Four groups of 16 week old female C57BL/6 mice were studied: weight bearing + no radiation (WB+NR), HLS + NR, WB + radiation exposure (WB+RAD), and HLS+RAD. Surprisingly, although HLS led to cortical and trabecular bone loss, concurrent radiation exposure did not exacerbate these effects. Our results raise the possibility that mechanical unloading has larger effects on the bone loss that occurs during spaceflight than low-dose rate radiation.

Thermoluminescence glow-curve characteristics of LiF phosphors at high doses of gamma radiation

NASA Astrophysics Data System (ADS)

Benny, P. G.; Khader, S. A.; Sarma, K. S. S.

2013-05-01

High doses of ionising radiation are becoming increasingly common for radiation-processing applications of various medical, agricultural and polymer products using gamma and electron beams. The objective of this work was to study thermoluminescence (TL) glow-curve characteristics of commonly used commercial LiF TL phosphors at high doses of radiation with a view to use them in dosimetry of radiation-processing applications. The TL properties of TLD 100 and 700 phosphors, procured from the Thermo-Scientific (previously Harshaw) company, have been studied in the dose range of 1-60 kGy. The shift in glow peaks was observed in this dose range. Integral TL responses of TLD 100 and TLD 700 were found to decrease as a linear function of dose in the range of 5-50 kGy. The paper describes initial results related to the glow-curve characteristics of these phosphors.

Occupational radiation doses during interventional procedures

NASA Astrophysics Data System (ADS)

Nuraeni, N.; Hiswara, E.; Kartikasari, D.; Waris, A.; Haryanto, F.

2016-03-01

Digital subtraction angiography (DSA) is a type of fluoroscopy technique used in interventional radiology to clearly visualize blood vessels in a bony or dense soft tissue environment. The use of DSA procedures has been increased quite significantly in the Radiology departments in various cities in Indonesia. Various reports showed that both patients and medical staff received a noticeable radiation dose during the course of this procedure. A study had been carried out to measure these doses among interventionalist, nurse and radiographer. The results show that the interventionalist and the nurse, who stood quite close to the X-ray beams compared with the radiographer, received radiation higher than the others. The results also showed that the radiation dose received by medical staff were var depending upon the duration and their position against the X-ray beams. Compared tothe dose limits, however, the radiation dose received by all these three medical staff were still lower than the limits.

Low-dose radiation: a cause of breast cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Land, C.E.

1980-08-15

It is likely that the breast is the organ most sensitive to radiation carcinogenesis in postpubertal women. Studies of different exposed populations have yielded remarkably consistent results, in spite of wide differences in underlying breast cancer rates and conditions of exposure. Excess risk is approximately proportional to dose, and is relatively independent of ionization density and fractionization of dose. This implies that the risk associated with low-dose exposures to ionizing radiation can be estimated with some confidence from higher-dose data. Excess risk is heavily dependent on age at exposure but relatively independent of population differences in normal risk. The temporalmore » patterns after exposure of both radiation-induced and naturally occurring breast cancer are similar, suggesting a strong influence of factors other than radiation on radiation-induced breast cancer. Uncertainties remain about risks from exposures before puberty and after menopause.« less

[Methodology for an assessment of derived radiation levels for agrocenoses].

PubMed

Udalova, A A; Ul'ianenko, L N; Aleksakhin, R M; Geras'kin, S A; Filipas, A S

2010-01-01

Radiation protection of agrarian ecosystems should be considered as an integral part of a system for radiation protection of environment, with a special concern to agroecosystems' features. A methodology is proposed for an assessment of maximum permissible doses of radiation impact for agrocenoses based on an unified analysis of available data about effects of radiation in cultivated plants. It is considered as a component of radiation protection system for agricultural ecosystems. Critical doses and dose rates are estimated for crops under different exposure situations. It is shown that doses that could result in decreasing indexes of productivity and survival for main crops below 50% are unlikely up to 170-200 Gy and 15-17 Gy at an acute exposure of dormant seeds and vegetative plants, correspondingly. At chronic exposure, above 10% loss of productivity in crops is not expected at dose rates below 3-10 mGy/h.

Monitoring the eye lens: which dose quantity is adequate?

NASA Astrophysics Data System (ADS)

Behrens, R.; Dietze, G.

2010-07-01

Recent epidemiological studies suggest a rather low dose threshold (below 0.5 Gy) for the induction of a cataract of the eye lens. Some other studies even assume that there is no threshold at all. Therefore, protection measures have to be optimized and current dose limits for the eye lens may be reduced in the future. The question of which personal dose equivalent quantity is appropriate for monitoring the dose to the eye lens arises from this situation. While in many countries dosemeters calibrated in terms of the dose equivalent quantity Hp(0.07) have been seen as being adequate for monitoring the dose to the eye lens, this might be questionable in the case of reduced dose limits and, thus, it may become necessary to use the dose equivalent quantity Hp(3) for this purpose. To discuss this question, the dose conversion coefficients for the equivalent dose of the eye lens (in the following eye lens dose) were determined for realistic photon and beta radiation fields and compared with the values of the corresponding conversion coefficients for the different operational quantities. The values obtained lead to the following conclusions: in radiation fields where most of the dose comes from photons, especially x-rays, it is appropriate to use dosemeters calibrated in terms of Hp(0.07) on a slab phantom, while in other radiation fields (dominated by beta radiation or unknown contributions of photon and beta radiation) dosemeters calibrated in terms of Hp(3) on a slab phantom should be used. As an alternative, dosemeters calibrated in terms of Hp(0.07) on a slab phantom could also be used; however, in radiation fields containing beta radiation with the end point energy near 1 MeV, an overestimation of the eye lens dose by up to a factor of 550 is possible.

Monitoring the eye lens: which dose quantity is adequate?

PubMed

Behrens, R; Dietze, G

2010-07-21

Recent epidemiological studies suggest a rather low dose threshold (below 0.5 Gy) for the induction of a cataract of the eye lens. Some other studies even assume that there is no threshold at all. Therefore, protection measures have to be optimized and current dose limits for the eye lens may be reduced in the future. The question of which personal dose equivalent quantity is appropriate for monitoring the dose to the eye lens arises from this situation. While in many countries dosemeters calibrated in terms of the dose equivalent quantity H(p)(0.07) have been seen as being adequate for monitoring the dose to the eye lens, this might be questionable in the case of reduced dose limits and, thus, it may become necessary to use the dose equivalent quantity H(p)(3) for this purpose. To discuss this question, the dose conversion coefficients for the equivalent dose of the eye lens (in the following eye lens dose) were determined for realistic photon and beta radiation fields and compared with the values of the corresponding conversion coefficients for the different operational quantities. The values obtained lead to the following conclusions: in radiation fields where most of the dose comes from photons, especially x-rays, it is appropriate to use dosemeters calibrated in terms of H(p)(0.07) on a slab phantom, while in other radiation fields (dominated by beta radiation or unknown contributions of photon and beta radiation) dosemeters calibrated in terms of H(p)(3) on a slab phantom should be used. As an alternative, dosemeters calibrated in terms of H(p)(0.07) on a slab phantom could also be used; however, in radiation fields containing beta radiation with the end point energy near 1 MeV, an overestimation of the eye lens dose by up to a factor of 550 is possible.

Time- and dose-dependent changes in neuronal activity produced by X radiation in brain slices.

PubMed

Pellmar, T C; Schauer, D A; Zeman, G H

1990-05-01

A new method of exposing tissues to X rays in a lead Faraday cage has made it possible to examine directly radiation damage to isolated neuronal tissue. Thin slices of hippocampus from brains of euthanized guinea pigs were exposed to 17.4 ke V X radiation. Electrophysiological recordings were made before, during, and after exposure to doses between 5 and 65 Gy at a dose rate of 1.54 Gy/min. Following exposure to doses of 40 Gy and greater, the synaptic potential was enhanced, reaching a steady level soon after exposure. The ability of the synaptic potential to generate a spike was reduced and damage progressed after termination of the radiation exposure. Recovery was not observed following termination of exposure. These results demonstrate that an isolated neuronal network can show complex changes in electrophysiological properties following moderate doses of ionizing radiation. An investigation of radiation damage directly to neurons in vitro will contribute to the understanding of the underlying mechanisms of radiation-induced nervous system dysfunction.

Two years comparative studies on biological effects of environmental UV radiation

NASA Astrophysics Data System (ADS)

Grof, P.; Ronto, Gyorgyi; Gaspar, S.; Berces, A.; Szabo, Laszlo D.

1994-07-01

A method has been developed for determination of the biologically effective UV dose based on T7 phage as biosensor. In field experiments clockwork driven telescope has been used for determining doses from direct and global (direct plus diffuse) solar radiation. On fine summer days at mid-latitude this arrangement allowed the following comparisons: measured doses from direct and global radiation obtained at the same time and measuring site reflecting the biological importance of diffuse radiation; direct and global radiation obtained at the same time and measuring site reflecting the biological importance of diffuse radiation; direct and global doses obtained at the same time on different measuring sites (downtown, suburb, outside the town) reflecting the differences caused by air quality; direct and global doses obtained on the same measuring place, in summertime of two different years reflecting the importance of the long-term measurements for estimating the biological risk caused by increased UV-B radiation; measured data and model calculations.

Effects of Solar Particle Event Proton Radiation on Parameters Related to Ferret Emesis

PubMed Central

Sanzari, J. K.; Wan, X. S.; Krigsfeld, G. S.; King, G. L.; Miller, A.; Mick, R.; Gridley, D. S.; Wroe, A. J.; Rightnar, S.; Dolney, D.; Kennedy, A. R.

2013-01-01

The effectiveness of simulated solar particle event (SPE) proton radiation to induce retching and vomiting was evaluated in the ferret experimental animal model. The endpoints measured in the study included: (1) the fraction of animals that retched or vomited, (2) the number of retches or vomits observed, (3) the latency period before the first retch or vomit and (4) the duration between the first and last retching or vomiting events. The results demonstrated that γ ray and proton irradiation delivered at a high dose rate of 0.5 Gy/min induced dose-dependent changes in the endpoints related to retching and vomiting. The minimum radiation doses required to induce statistically significant changes in retching- and vomiting-related endpoints were 0.75 and 1.0 Gy, respectively, and the relative biological effectiveness (RBE) of proton radiation at the high dose rate did not significantly differ from 1. Similar but less consistent and smaller changes in the retching- and vomiting-related endpoints were observed for groups irradiated with γ rays and protons delivered at a low dose rate of 0.5 Gy/h. Since this low dose rate is similar to a radiation dose rate expected during a SPE, these results suggest that the risk of SPE radiation-induced vomiting is low and may reach statistical significance only when the radiation dose reaches 1 Gy or higher. PMID:23883319

Spectral analysis of paramagnetic centers induced in human tooth enamel by x-rays and gamma radiation

NASA Astrophysics Data System (ADS)

Kirillov, V. A.; Kuchuro, I. I.

2010-03-01

Based on study of spectral and relaxation characteristics, we have established that paramagnetic centers induced in tooth enamel by x-rays and gamma radiation are identical in nature. We show that for the same exposure dose, the intensity of the electron paramagnetic resonance (EPR) signal induced by x-radiation with effective energy 34 keV is about an order of magnitude higher than the amplitude of the signal induced by gamma radiation. We have identified a three-fold attenuation of the EPR signal along the path of the x-radiation from the buccal to the lingual side of a tooth, which is evidence that the individual had undergone diagnostic x-ray examination of the dentition or skull. We have shown that the x-ray exposure doses reconstructed from the EPR spectra are an order of magnitude higher than the applied doses, while the dose loads due to gamma radiation are equal to the applied doses. The data obtained indicate that for adequate reconstruction of individual absorbed doses from EPR spectra of tooth enamel in the population subjected to the combined effect of x-radiation and accidental external gamma radiation as a result of the disaster at the Chernobyl nuclear power plant, we need to take into account the contribution to the dose load from diagnostic x-rays in examination of the teeth, jaw, or skull.

TH-E-209-01: Fluoroscopic Dose Monitoring and Patient Follow-Up Program at Massachusetts General Hospital

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, B.

2016-06-15

Radiation dose monitoring solutions have opened up new opportunities for medical physicists to be more involved in modern clinical radiology practices. In particular, with the help of comprehensive radiation dose data, data-driven protocol management and informed case follow up are now feasible. Significant challenges remain however and the problems faced by medical physicists are highly heterogeneous. Imaging systems from multiple vendors and a wide range of vintages co-exist in the same department and employ data communication protocols that are not fully standardized or implemented making harmonization complex. Many different solutions for radiation dose monitoring have been implemented by imaging facilitiesmore » over the past few years. Such systems are based on commercial software, home-grown IT solutions, manual PACS data dumping, etc., and diverse pathways can be used to bring the data to impact clinical practice. The speakers will share their experiences with creating or tailoring radiation dose monitoring/management systems and procedures over the past few years, which vary significantly in design and scope. Topics to cover: (1) fluoroscopic dose monitoring and high radiation event handling from a large academic hospital; (2) dose monitoring and protocol optimization in pediatric radiology; and (3) development of a home-grown IT solution and dose data analysis framework. Learning Objectives: Describe the scope and range of radiation dose monitoring and protocol management in a modern radiology practice Review examples of data available from a variety of systems and how it managed and conveyed. Reflect on the role of the physicist in radiation dose awareness.« less

TH-E-209-02: Dose Monitoring and Protocol Optimization: The Pediatric Perspective

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacDougall, R.

Radiation dose monitoring solutions have opened up new opportunities for medical physicists to be more involved in modern clinical radiology practices. In particular, with the help of comprehensive radiation dose data, data-driven protocol management and informed case follow up are now feasible. Significant challenges remain however and the problems faced by medical physicists are highly heterogeneous. Imaging systems from multiple vendors and a wide range of vintages co-exist in the same department and employ data communication protocols that are not fully standardized or implemented making harmonization complex. Many different solutions for radiation dose monitoring have been implemented by imaging facilitiesmore » over the past few years. Such systems are based on commercial software, home-grown IT solutions, manual PACS data dumping, etc., and diverse pathways can be used to bring the data to impact clinical practice. The speakers will share their experiences with creating or tailoring radiation dose monitoring/management systems and procedures over the past few years, which vary significantly in design and scope. Topics to cover: (1) fluoroscopic dose monitoring and high radiation event handling from a large academic hospital; (2) dose monitoring and protocol optimization in pediatric radiology; and (3) development of a home-grown IT solution and dose data analysis framework. Learning Objectives: Describe the scope and range of radiation dose monitoring and protocol management in a modern radiology practice Review examples of data available from a variety of systems and how it managed and conveyed. Reflect on the role of the physicist in radiation dose awareness.« less

Reduction of radiation dose during facet joint injection using the new image guidance system SabreSource™: a prospective study in 60 patients

PubMed Central

Proschek, Dirk; Kafchitsas, K.; Rauschmann, M. A.; Kurth, A. A.; Vogl, T. J.

2008-01-01

Interventional procedures are associated with high radiation doses for both patients and surgeons. To reduce the risk from ionizing radiation, it is essential to minimize radiation dose. This prospective study was performed to evaluate the effectiveness in reducing radiation dose during facet joint injection in the lumbar spine and to evaluate the feasibility and possibilities of the new real time image guidance system SabreSource™. A total of 60 patients, treated with a standardized injection therapy of the facet joints L4–L5 or L5–S1, were included in this study. A total of 30 patients were treated by fluoroscopy guidance alone, the following 30 patients were treated using the new SabreSource™ system. Thus a total of 120 injections to the facet joints were performed. Pain, according to the visual analogue scale (VAS), was documented before and 6 h after the intervention. Radiation dose, time of radiation and the number of exposures needed to place the needle were recorded. No significant differences concerning age (mean age 60.5 years, range 51–69), body mass index (mean BMI 26.2, range 22.2–29.9) and preoperative pain (VAS 7.9, range 6–10) were found between the two groups. There was no difference in pain reduction between the two groups (60 vs. 61.5%; P = 0.001) but the radiation dose was significantly smaller with the new SabreSource™ system (reduction of radiation dose 32.7%, P = 0.01; reduction of mean entrance surface dose 32.3%, P = 0.01). The SabreSource™ System significantly reduced the radiation dose received during the injection therapy of the lumbar facet joints. With minimal effort for the setup at the beginning of a session, the system is easy to handle and can be helpful for other injection therapies (e.g. nerve root block therapies). PMID:19082641

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

The DOE Occupational Radiation Exposure Report, 1992-1994 reports occupational radiation exposures incurred by individuals at US Department of Energy (DOE) facilities from 1992 through 1994. This report includes occupational radiation exposure information for all DOE employees, contractors, subcontractors, and visitors. This information is analyzed and trended over time to provide a measure of the DOE`s performance in protecting its workers from radiation. Occupational radiation exposure at DOE has been decreasing over the past 5 years. In particular, doses in the higher dose ranges are decreasing, including the number of doses in excess of the DOE limits and doses in excessmore » of the 2 rem Administrative Control Level (ACL). This is an indication of greater attention being given to protecting these individuals from radiation in the workplace.« less

Method for microbeam radiation therapy

DOEpatents

Slatkin, Daniel N.; Dilmanian, F. Avraham; Spanne, Per O.

1994-01-01

A method of performing radiation therapy on a patient, involving exposing a target, usually a tumor, to a therapeutic dose of high energy electromagnetic radiation, preferably X-ray radiation, in the form of at least two non-overlapping microbeams of radiation, each microbeam having a width of less than about 1 millimeter. Target tissue exposed to the microbeams receives a radiation dose during the exposure that exceeds the maximum dose that such tissue can survive. Non-target tissue between the microbeams receives a dose of radiation below the threshold amount of radiation that can be survived by the tissue, and thereby permits the non-target tissue to regenerate. The microbeams may be directed at the target from one direction, or from more than one direction in which case the microbeams overlap within the target tissue enhancing the lethal effect of the irradiation while sparing the surrounding healthy tissue.

Estimating the effective radiation dose imparted to patients by intraoperative cone-beam computed tomography in thoracolumbar spinal surgery.

PubMed

Lange, Jeffrey; Karellas, Andrew; Street, John; Eck, Jason C; Lapinsky, Anthony; Connolly, Patrick J; Dipaola, Christian P

2013-03-01

Observational. To estimate the radiation dose imparted to patients during typical thoracolumbar spinal surgical scenarios. Minimally invasive techniques continue to become more common in spine surgery. Computer-assisted navigation systems coupled with intraoperative cone-beam computed tomography (CT) represent one such method used to aid in instrumented spinal procedures. Some studies indicate that cone-beam CT technology delivers a relatively low dose of radiation to patients compared with other x-ray-based imaging modalities. The goal of this study was to estimate the radiation exposure to the patient imparted during typical posterior thoracolumbar instrumented spinal procedures, using intraoperative cone-beam CT and to place these values in the context of standard CT doses. Cone-beam CT scans were obtained using Medtronic O-arm (Medtronic, Minneapolis, MN). Thermoluminescence dosimeters were placed in a linear array on a foam-plastic thoracolumbar spine model centered above the radiation source for O-arm presets of lumbar scans for small or large patients. In-air dosimeter measurements were converted to skin surface measurements, using published conversion factors. Dose-length product was calculated from these values. Effective dose was estimated using published effective dose to dose-length product conversion factors. Calculated dosages for many full-length procedures using the small-patient setting fell within the range of published effective doses of abdominal CT scans (1-31 mSv). Calculated dosages for many full-length procedures using the large-patient setting fell within the range of published effective doses of abdominal CT scans when the number of scans did not exceed 3. We have demonstrated that single cone-beam CT scans and most full-length posterior instrumented spinal procedures using O-arm in standard mode would likely impart a radiation dose within the range of those imparted by a single standard CT scan of the abdomen. Radiation dose increases with patient size, and the radiation dose received by larger patients as a result of more than 3 O-arm scans in standard mode may exceed the dose received during standard CT of the abdomen. Understanding radiation imparted to patients by cone-beam CT is important for assessing risks and benefits of this technology, especially when spinal surgical procedures require multiple intraoperative scans.

Low and high dose rate heavy ion radiation-induced intestinal and colonic tumorigenesis in APC1638N/+ mice

NASA Astrophysics Data System (ADS)

Suman, Shubhankar; Kumar, Santosh; Moon, Bo-Hyun; Fornace, Albert J.; Datta, Kamal

2017-05-01

Ionizing radiation (IR) is a recognized risk factor for colorectal cancer (CRC) and astronauts undertaking long duration space missions are expected to receive IR doses in excess of permissible limits with implications for colorectal carcinogenesis. Exposure to IR in outer space occurs at low doses and dose rates, and energetic heavy ions due to their high linear energy transfer (high-LET) characteristics remain a major concern for CRC risk in astronauts. Previously, we have demonstrated that intestinal tumorigenesis in a mouse model (APC1638N/+) of human colorectal cancer was significantly higher after exposure to high dose rate energetic heavy ions relative to low-LET γ radiation. The purpose of the current study was to compare intestinal tumorigenesis in APC1638N/+ mice after exposure to energetic heavy ions at high (50 cGy/min) and relatively low (0.33 cGy/min) dose rate. Male and female mice (6-8 weeks old) were exposed to either 10 or 50 cGy of 28Si (energy: 300 MeV/n; LET: 70 keV/μm) or 56Fe (energy: 1000 MeV/n; LET: 148 keV/μm) ions at NASA Space Radiation Laboratory in Brookhaven National Laboratory. Mice (n = 20 mice/group) were euthanized and intestinal and colon tumor frequency and size were counted 150 days after radiation exposure. Intestinal tumorigenesis in male mice exposed to 56Fe was similar for high and low dose rate exposures. Although male mice showed a decreasing trend at low dose rate relative to high dose rate exposures, the differences in tumor frequency between the two types of exposures were not statistically significant after 28Si radiation. In female mice, intestinal tumor frequency was similar for both radiation type and dose rates tested. In both male and female mice intestinal tumor size was not different after high and low dose rate radiation exposures. Colon tumor frequency in male and female mice after high and low dose rate energetic heavy ions was also not significantly different. In conclusion, intestinal and colonic tumor frequency and size was similar irrespective of energetic heavy ion radiation dose rate suggesting that carcinogenic potential of energetic heavy ions is independent of dose rate.

Analysis of dose to patient, spouse/caretaker, and staff, from an implanted trackable radioactive fiducial for use in the radiation treatment of prostate cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neustadter, David; Barnea, Gideon; Stokar, Saul

Purpose: A fiducial tracking system based on a novel radioactive tracking technology is being developed for real-time target tracking in radiation therapy. In this study, the authors calculate the radiation dose to the patient, the spouse/caretaker, and the medical staff that would result from a 100 {mu}Ci Ir192 radioactive fiducial marker permanently implanted in the prostate of a radiation therapy patient. Methods: Local tissue dose was calculated by Monte Carlo simulation. The patient's whole body effective dose equivalent was calculated by summing the doses to the sensitive organs. Exposure of the spouse/caretaker was calculated from the NRC guidelines. Exposure ofmore » the medical staff was based on estimates of proximity to and time spent with the patient. Results: The local dose is below 40 Gy at 5 mm from the marker and below 10 Gy at 10 mm from the marker. The whole body effective dose equivalent to the patient is 64 mSv. The dose to the spouse/caretaker is 0.25 mSv. The annual exposures of the medical staff are 0.2 mSv for a doctor performing implantations and 0.34 mSv for a radiation therapist positioning patients for therapy. Conclusions: The local dose is not expected to have any clinically significant effect on the surrounding tissue which is irradiated during therapy. The dose to the patient is small in comparison to the whole body dose received from the therapy itself. The exposure of all other people is well below the recommended limits. The authors conclude that there is no radiation exposure related contraindication for use of this technology in the radiation treatment of prostate cancer.« less

The development of remote wireless radiation dose monitoring system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Jin-woo; Chonbuk National University, Jeonjoo-Si; Jeong, Kyu-hwan

Internet of things (IoT) technology has recently shown a large flow of IT trends in human life. In particular, our lives are now becoming integrated with a lot of items around the 'smart-phone' with IoT, including Bluetooth, Near Field Communication (NFC), Beacons, WiFi, and Global Positioning System (GPS). Our project focuses on the interconnection of radiation dosimetry and IoT technology. The radiation workers at a nuclear facility should hold personal dosimeters such as a Thermo-Luminescence Dosimeter (TLD), an Optically Stimulated Luminescence Dosimeter (OSL), pocket ionization chamber dosimeters, an Electronic Personal Dosimeter (EPD), or an alarm dosimeter on their body. Somemore » of them have functions that generate audible or visible alarms to radiation workers in a real working area. However, such devices used in radiation fields these days have no functions for communicating with other areas or the responsible personnel in real time. In particular, when conducting a particular task in a high dose area, or a number of repair works within a radiation field, radiation dose monitoring is important for the health of the workers and the work efficiency. Our project aims at the development of a remote wireless radiation dose monitoring system (RWRD) that can be used to monitor the radiation dose in a nuclear facility for radiation workers and a radiation protection program In this project, a radiation dosimeter is the detection device for personal radiation dose, a smart phone is the mobile wireless communication tool, and, Beacon is the wireless starter for the detection, communication, and position of the worker using BLE (Bluetooth Low Energy). In this report, we report the design of the RWRD and a demonstration case in a real radiation field. (authors)« less

Chernobyl doses. Volume 1. Analysis of forest canopy radiation response from multispectral imagery and the relationship to doses. Technical report, 29 July 1987-30 September 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

McClennan, G.E.; Anno, G.H.; Whicker, F.W.

1994-09-01

This volume of the report Chernobyl Doses presents details of a new, quantitative method for remotely sensing ionizing radiation dose to vegetation. Analysis of Landsat imagery of the area within a few kilometers of the Chernobyl nuclear reactor station provides maps of radiation dose to pine forest canopy resulting from the accident of April 26, 1986. Detection of the first date of significant, persistent deviation from normal of the spectral reflectance signature of pine foliage produces contours of radiation dose in the 20 to 80 Gy range extending up to 4 km from the site of the reactor explosion. Themore » effective duration of exposure for the pine foliage is about 3 weeks. For this exposure time, the LD50 of Pinus sylvestris (Scotch pine) is about 23 Gy. The practical lower dose limit for the remote detection of radiation dose to pine foliage with the Landsat Thematic Mapper is about 5 Gy or 1/4 of the LD50.« less

Occupational Exposure of the Eye Lens in Interventional Procedures: How to Assess and Manage Radiation Dose.

PubMed

Ciraj-Bjelac, Olivera; Carinou, Eleftheria; Ferrari, Paolo; Gingaume, Merce; Merce, Marta Sans; O'Connor, Una

2016-11-01

Occupational exposure from interventional x-ray procedures is one of the areas in which increased eye lens exposure may occur. Accurate dosimetry is an important element to investigate the correlation of observed radiation effects with radiation dose, to verify the compliance with regulatory dose limits, and to optimize radiation protection practice. The objective of this work is to review eye lens dose levels in clinical practice that may occur from the use of ionizing radiation. The use of a dedicated eye lens dosimeter is the recommended methodology; however, in practice it cannot always be easily implemented. Alternatively, the eye lens dose could be assessed from measurements of other dosimetric quantities or other indirect parameters, such as patient dose. The practical implementation of monitoring eye lens doses and the use of adequate protective equipment still remains a challenge. The use of lead glasses with a good fit to the face, appropriate lateral coverage, and/or ceiling-suspended screens is recommended in workplaces with potential high eye lens doses. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.

10 CFR 20.1302 - Compliance with dose limits for individual members of the public.

Code of Federal Regulations, 2013 CFR

2013-01-01

... public. 20.1302 Section 20.1302 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Radiation Dose Limits for Individual Members of the Public § 20.1302 Compliance with dose limits..., surveys of radiation levels in unrestricted and controlled areas and radioactive materials in effluents...

10 CFR 20.1302 - Compliance with dose limits for individual members of the public.

Code of Federal Regulations, 2014 CFR

2014-01-01

... public. 20.1302 Section 20.1302 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Radiation Dose Limits for Individual Members of the Public § 20.1302 Compliance with dose limits..., surveys of radiation levels in unrestricted and controlled areas and radioactive materials in effluents...

10 CFR 20.1302 - Compliance with dose limits for individual members of the public.

Code of Federal Regulations, 2012 CFR

2012-01-01

... public. 20.1302 Section 20.1302 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Radiation Dose Limits for Individual Members of the Public § 20.1302 Compliance with dose limits..., surveys of radiation levels in unrestricted and controlled areas and radioactive materials in effluents...

10 CFR 20.1302 - Compliance with dose limits for individual members of the public.

Code of Federal Regulations, 2011 CFR

2011-01-01

... public. 20.1302 Section 20.1302 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Radiation Dose Limits for Individual Members of the Public § 20.1302 Compliance with dose limits..., surveys of radiation levels in unrestricted and controlled areas and radioactive materials in effluents...

10 CFR 20.1302 - Compliance with dose limits for individual members of the public.

Code of Federal Regulations, 2010 CFR

2010-01-01

... public. 20.1302 Section 20.1302 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Radiation Dose Limits for Individual Members of the Public § 20.1302 Compliance with dose limits..., surveys of radiation levels in unrestricted and controlled areas and radioactive materials in effluents...

Low-dose radiation attenuates chemical mutagenesis in vivo.

PubMed

Kakinuma, Shizuko; Yamauchi, Kazumi; Amasaki, Yoshiko; Nishimura, Mayumi; Shimada, Yoshiya

2009-09-01

The biological effects of low-dose radiation are not only of social concern but also of scientific interest. The radioadaptive response, which is defined as an increased radioresistance by prior exposure to low-dose radiation, has been extensively studied both in vitro and in vivo. Here we briefly review the radioadaptive response with respect to mutagenesis, survival rate, and carcinogenesis in vivo, and introduce our recent findings of cross adaptation in mouse thymic cells, that is, the suppressive effect of repeated low-dose radiation on mutation induction by the alkylating agent N-ethyl-N-nitrosourea.

Circulating Cytokine/Chemokine Concentrations Respond to Ionizing Radiation Doses but not Radiation Dose Rates: Granulocyte-Colony Stimulating Factor and Interleukin-18.

PubMed

Kiang, Juliann G; Smith, Joan T; Hegge, Sara R; Ossetrova, Natalia I

2018-06-01

Exposure to ionizing radiation is a crucial life-threatening factor in nuclear and radiological incidents. It is known that ionizing radiation affects cytokine/chemokine concentrations in the blood of B6D2F1 mice. It is not clear whether radiation dose rates would vary the physiological response. Therefore, in this study we utilized data from two experiments using B6D2F1 female mice exposed to six different dose rates ranging from low to high rates. In one experiment, mice received a total dose of 8 Gy (LD 0/30 ) of 60 Co gamma radiation at four dose rates: 0.04, 0.15, 0.30 and 0.47 Gy/min. Blood samples from mice were collected at 24 and 48 h postirradiation for cytokine/chemokine measurements, including interleukin (IL)-1β, IL-6, IL-10, keratinocyte cytokine (KC), IL-12p70, IL-15, IL-17A, IL-18, granulocyte-colony stimulating factor (G-CSF), granulocyte macrophage (GM)-CSF, macrophage (M)-CSF, monokine induced by gamma interferon (MIG), tumor necrosis factor (TNF)-α, fibroblast growth factor (FGF)-basic, vascular endothelial growth factor (VEGF) and platelet-derived growth factor basic (PDGF-bb). At 24 h after ionizing irradiation at dose rate of 0.04 Gy/min, significant increases were observed only in G-CSF and M-CSF ( P < 0.05). At 0.15 Gy/min, IL-10, IL-17A, G-CSF and GM-CSF concentrations were increased. At 0.3 Gy/min, IL-15, IL-18, G-CSF, GM-CSF, M-CSF, MCP-1, MIP-2, MIG, FGF-basic, VEGF and PDGF-bb were significantly elevated ( P < 0.05). At 0.47 Gy/min, IL-6, KC, IL-10, MCP-1, G-CSF, GM-CSF and M-CSF were significantly increased. At 48 h postirradiation, all cytokines/chemokines except MCP-1 returned to or were below their baselines, suggesting these increases are transient at LD 0/30 irradiation. Of note, there is a limitation on day 2 because cytokines/chemokines are either at or below their baselines. Other parameters such as fms-like tyrosine kinase receptor-3 ligand (Flt-3 ligand) concentrations and lymphocyte counts, which have proven to be unaffected by radiation dose rates, can be used instead for assessing the radiation dose. However, in a separate radiation dose and time-course experiment, increases in IL-18 and G-CSF depended on the radiation doses but showed no significant differences between 0.58 and 1.94 Gy/min ( P > 0.05) at 3 and 6 Gy but not 12 Gy. G-CSF continued to increase up to day 7, whereas IL-18 increased on day 4 and remained above baseline level on day 7. Therefore, time after irradiation at different doses should be taken into consideration. To our knowledge, these results are the first to suggest that ionizing radiation, even at a very low-dose-rate (0.04 Gy/min), induces circulating G-CSF increases but not others for selected time points; radiation-induced increases in IL-18 at radiation dose rates between 0.15 and 1.94 Gy/min are also not in a radiation dose-rate-dependent manner. C-CSF, lymphocyte counts and circulating Flt-3 ligand should be explored further as possible biomarkers of radiation exposure at early time points. IL-18 is also worthy of further study as a potential biomarker at later time points.

Automatic radiation dose monitoring for CT of trauma patients with different protocols: feasibility and accuracy.

PubMed

Higashigaito, K; Becker, A S; Sprengel, K; Simmen, H-P; Wanner, G; Alkadhi, H

2016-09-01

To demonstrate the feasibility and accuracy of automatic radiation dose monitoring software for computed tomography (CT) of trauma patients in a clinical setting over time, and to evaluate the potential of radiation dose reduction using iterative reconstruction (IR). In a time period of 18 months, data from 378 consecutive thoraco-abdominal CT examinations of trauma patients were extracted using automatic radiation dose monitoring software, and patients were split into three cohorts: cohort 1, 64-section CT with filtered back projection, 200 mAs tube current-time product; cohort 2, 128-section CT with IR and identical imaging protocol; cohort 3, 128-section CT with IR, 150 mAs tube current-time product. Radiation dose parameters from the software were compared with the individual patient protocols. Image noise was measured and image quality was semi-quantitatively determined. Automatic extraction of radiation dose metrics was feasible and accurate in all (100%) patients. All CT examinations were of diagnostic quality. There were no differences between cohorts 1 and 2 regarding volume CT dose index (CTDIvol; p=0.62), dose-length product (DLP), and effective dose (ED, both p=0.95), while noise was significantly lower (chest and abdomen, both -38%, p<0.017). Compared to cohort 1, CTDIvol, DLP, and ED in cohort 3 were significantly lower (all -25%, p<0.017), similar to the noise in the chest (-32%) and abdomen (-27%, both p<0.017). Compared to cohort 2, CTDIvol (-28%), DLP, and ED (both -26%) in cohort 3 was significantly lower (all, p<0.017), while noise in the chest (+9%) and abdomen (+18%) was significantly higher (all, p<0.017). Automatic radiation dose monitoring software is feasible and accurate, and can be implemented in a clinical setting for evaluating the effects of lowering radiation doses of CT protocols over time. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

WE-FG-BRA-05: Potential Clinical Benefit of LINAC Flattening-Filter-Free (FFF) Mode - Improvement of Treatment Therapeutic Ratio

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, S; Department of Biomedical Engineering, University of North Carolina- Chapel Hill/ North Carolina State University, Chapel Hill, North Carolina; Lineberger Clinical Cancer Center, University of North Carolina, Chapel Hill, NC

Purpose: Ultrahigh dose-rate radiation at >40Gy/s has demonstrated astonishing normal-tissue sparing and tumor control in recent preclinical naive and tumor-bearing rodent studies when compared to the same radiation dose at a conventional dose-rate. The working mechanism of this fascinating dose-rate effect is currently under investigation. The aims of this work include investigating 1) whether LINAC FFF mode radiation at approximately 1Gy/s also has an improved therapeutic ratio compared to the same radiation dose at the conventional dose-rate of 0.05Gy/s, and 2) the dose-rate effect’s potential working mechanism by studying the expression of the P53 gene, linked to tumor suppression andmore » cell regulation after radiation damage. Methods: We used mouse model C57BL/6J, the same as that used in the ultrahigh dose-rate studies, and exposed them to total body irradiation (TBI) using the Elekta Versa accelerator 10MV photons. Mice (N=20) were given a total dose of 12Gy in both the high dose-rate group (n=10) using the FFF-mode and the conventional dose-rate group (n=10) using the conventional does rate mode. The FFF-mode treatment setup consisted of a 15cm×15cm field size setting at 53.2cm SSD while the conventional-mode set-up consisted of a 10cm×10cm field size at 100SSD. Post-radiation, animals were monitored daily for survival analysis and signs of moribundity requiring euthanasia. In addition, mouse spleens were harvested for P53 analysis at different time points. Results: For 12Gy TBI, the 1.3Gy/s FFF-mode high dose-rate produced a statistically significant (p=0.02) improvement in mouse survival compared to the 0.05Gy/s conventional dose-rate. An initial P53 study at the time of death time-point indicates that high dose-rate radiation induced a stronger expression of P53 than conventional dose-rate radiation. Conclusion: Our pilot study indicates that the FFF-mode high dose-rate radiation, which has been used largely to improve clinical throughput, may provide the added clinical benefit of improving treatment therapeutic ratio. Animal Studies were performed within the LCCC Animal Studies Core Facility at the University of North Carolina at Chapel Hill. The LCCC Animal Studies Core is supported in part by an NCI Center Core Support Grant (CA16086) to the UNC Lineberger Comprehensive Cancer Center.« less

Radiation Parameters of High Dose Rate Iridium -192 Sources

NASA Astrophysics Data System (ADS)

Podgorsak, Matthew B.

A lack of physical data for high dose rate (HDR) Ir-192 sources has necessitated the use of basic radiation parameters measured with low dose rate (LDR) Ir-192 seeds and ribbons in HDR dosimetry calculations. A rigorous examination of the radiation parameters of several HDR Ir-192 sources has shown that this extension of physical data from LDR to HDR Ir-192 may be inaccurate. Uncertainty in any of the basic radiation parameters used in dosimetry calculations compromises the accuracy of the calculated dose distribution and the subsequent dose delivery. Dose errors of up to 0.3%, 6%, and 2% can result from the use of currently accepted values for the half-life, exposure rate constant, and dose buildup effect, respectively. Since an accuracy of 5% in the delivered dose is essential to prevent severe complications or tumor regrowth, the use of basic physical constants with uncertainties approaching 6% is unacceptable. A systematic evaluation of the pertinent radiation parameters contributes to a reduction in the overall uncertainty in HDR Ir-192 dose delivery. Moreover, the results of the studies described in this thesis contribute significantly to the establishment of standardized numerical values to be used in HDR Ir-192 dosimetry calculations.

A nested case-control study of leukemia mortality and ionizing radiation at the Portsmouth Naval Shipyard.

PubMed

Kubale, Travis L; Daniels, Robert D; Yiin, James H; Couch, James; Schubauer-Berigan, Mary K; Kinnes, Gregory M; Silver, Sharon R; Nowlin, Susan J; Chen, Pi-Hsueh

2005-12-01

A nested case-control study using conditional logistic regression was conducted to evaluate the exposure-response relationship between external ionizing radiation exposure and leukemia mortality among civilian workers at the Portsmouth Naval Shipyard (PNS), Kittery, Maine. The PNS civilian workers received occupational radiation exposure while performing construction, overhaul, repair and refueling activities on nuclear-powered submarines. The study age-matched 115 leukemia deaths with 460 controls selected from a cohort of 37,853 civilian workers employed at PNS between 1952 and 1992. In addition to radiation doses received in the workplace, a secondary analysis incorporating doses from work-related medical X rays and other occupational radiation exposures was conducted. A significant positive association was found between leukemia mortality and external radiation exposure, adjusting for gender, radiation worker status, and solvent exposure duration (OR = 1.08 at 10 mSv of exposure; 95% CI = 1.01, 1.16). Solvent exposure (including benzene and carbon tetrachloride) was also significantly associated with leukemia mortality adjusting for radiation dose, radiation worker status, and gender. Incorporating doses from work-related medical X rays did not change the estimated leukemia risk per unit of dose.

Is the Linear No-Threshold Dose-Response Paradigm Still Necessary for the Assessment of Health Effects of Low Dose Radiation?

PubMed Central

2016-01-01

Inevitable human exposure to ionizing radiation from man-made sources has been increased with the proceeding of human civilization and consequently public concerns focus on the possible risk to human health. Moreover, Fukushima nuclear power plant accidents after the 2011 East-Japan earthquake and tsunami has brought the great fear and anxiety for the exposure of radiation at low levels, even much lower levels similar to natural background. Health effects of low dose radiation less than 100 mSv have been debated whether they are beneficial or detrimental because sample sizes were not large enough to allow epidemiological detection of excess effects and there was lack of consistency among the available experimental data. We have reviewed an extensive literature on the low dose radiation effects in both radiation biology and epidemiology, and highlighted some of the controversies therein. This article could provide a reasonable view of utilizing radiation for human life and responding to the public questions about radiation risk. In addition, it suggests the necessity of integrated studies of radiobiology and epidemiology at the national level in order to collect more systematic and profound information about health effects of low dose radiation. PMID:26908982

Cancer risk estimation caused by radiation exposure during endovascular procedure

NASA Astrophysics Data System (ADS)

Kang, Y. H.; Cho, J. H.; Yun, W. S.; Park, K. H.; Kim, H. G.; Kwon, S. M.

2014-05-01

The objective of this study was to identify the radiation exposure dose of patients, as well as staff caused by fluoroscopy for C-arm-assisted vascular surgical operation and to estimate carcinogenic risk due to such exposure dose. The study was conducted in 71 patients (53 men and 18 women) who had undergone vascular surgical intervention at the division of vascular surgery in the University Hospital from November of 2011 to April of 2012. It had used a mobile C-arm device and calculated the radiation exposure dose of patient (dose-area product, DAP). Effective dose was measured by attaching optically stimulated luminescence on the radiation protectors of staff who participates in the surgery to measure the radiation exposure dose of staff during the vascular surgical operation. From the study results, DAP value of patients was 308.7 Gy cm2 in average, and the maximum value was 3085 Gy cm2. When converted to the effective dose, the resulted mean was 6.2 m Gy and the maximum effective dose was 61.7 milliSievert (mSv). The effective dose of staff was 3.85 mSv; while the radiation technician was 1.04 mSv, the nurse was 1.31 mSv. All cancer incidences of operator are corresponding to 2355 persons per 100,000 persons, which deemed 1 of 42 persons is likely to have all cancer incidences. In conclusion, the vascular surgeons should keep the radiation protection for patient, staff, and all participants in the intervention in mind as supervisor of fluoroscopy while trying to understand the effects by radiation by themselves to prevent invisible danger during the intervention and to minimize the harm.

Total-dose radiation effects data for semiconductor devices, volume 2

NASA Technical Reports Server (NTRS)

Price, W. E.; Martin, K. E.; Nichols, D. K.; Gauthier, M. K.; Brown, S. F.

1981-01-01

Total ionizing dose radiation test data on integrated circuits are analyzed. Tests were performed with the electron accelerator (Dynamitron) that provides a steady state 2.5 MeV electron beam. Some radiation exposures were made with a Cobalt-60 gamma ray source. The results obtained with the Cobalt-60 source are considered an approximate measure of the radiation damage that would be incurred by an equivalent dose of electrons.

Retrospective Reconstruction of Radiation Doses of Chernobyl Liquidators by Electron Paramagnetic Resonance

DTIC Science & Technology

1997-12-01

Armed Forces Rad I Research Institute Retrospective Reconstruction of Radiation Doses of Chernobyl Liquidators by Electron Paramagnetic Resonance A...of Radiation Doses of Chernobyl Liquidators by Electron Paramagnetic Resonance Authored by Scientific Center of Radiation Medicine Academy of Medical...libraries associated with the U.S. Government’s Depository Library System. Preface On April 26, 1986, Reactor #4 at the Chernobyl Nuclear Power Plant near

Cancer risk at low doses of ionizing radiation: artificial neural networks inference from atomic bomb survivors.

PubMed

Sasaki, Masao S; Tachibana, Akira; Takeda, Shunichi

2014-05-01

Cancer risk at low doses of ionizing radiation remains poorly defined because of ambiguity in the quantitative link to doses below 0.2 Sv in atomic bomb survivors in Hiroshima and Nagasaki arising from limitations in the statistical power and information available on overall radiation dose. To deal with these difficulties, a novel nonparametric statistics based on the 'integrate-and-fire' algorithm of artificial neural networks was developed and tested in cancer databases established by the Radiation Effects Research Foundation. The analysis revealed unique features at low doses that could not be accounted for by nominal exposure dose, including (i) the presence of a threshold that varied with organ, gender and age at exposure, and (ii) a small but significant bumping increase in cancer risk at low doses in Nagasaki that probably reflects internal exposure to (239)Pu. The threshold was distinct from the canonical definition of zero effect in that it was manifested as negative excess relative risk, or suppression of background cancer rates. Such a unique tissue response at low doses of radiation exposure has been implicated in the context of the molecular basis of radiation-environment interplay in favor of recently emerging experimental evidence on DNA double-strand break repair pathway choice and its epigenetic memory by histone marking.

Evaluation of radiation dose to anthropomorphic paediatric models from positron-emitting labelled tracers

NASA Astrophysics Data System (ADS)

Xie, Tianwu; Zaidi, Habib

2014-03-01

PET uses specific molecules labelled with positron-emitting radionuclides to provide valuable biochemical and physiological information. However, the administration of radiotracers to patients exposes them to low-dose ionizing radiation, which is a concern in the paediatric population since children are at a higher cancer risk from radiation exposure than adults. Therefore, radiation dosimety calculations for commonly used positron-emitting radiotracers in the paediatric population are highly desired. We evaluate the absorbed dose and effective dose for 19 positron-emitting labelled radiotracers in anthropomorphic paediatric models including the newborn, 1-, 5-, 10- and 15-year-old male and female. This is achieved using pre-calculated S-values of positron-emitting radionuclides of UF-NCI paediatric phantoms and published biokinetic data for various radiotracers. The influence of the type of anthropomorphic model, tissue weight factors and direct human- versus mouse-derived biokinetic data on the effective dose for paediatric phantoms was also evaluated. In the case of 18F-FDG, dosimetry calculations of reference paediatric patients from various dose regimens were also calculated. Among the considered radiotracers, 18F-FBPA and 15O-water resulted in the highest and lowest effective dose in the paediatric phantoms, respectively. The ICRP 103 updated tissue-weighting factors decrease the effective dose in most cases. Substantial differences of radiation dose were observed between direct human- versus mouse-derived biokinetic data. Moreover, the effect of using voxel- versus MIRD-type models on the calculation of the effective dose was also studied. The generated database of absorbed organ dose and effective dose for various positron-emitting labelled radiotracers using new generation computational models and the new ICRP tissue-weighting factors can be used for the assessment of radiation risks to paediatric patients in clinical practice. This work also contributes to a better understanding of the factors influencing patient-specific radiation dose calculation.

The threshold vs LNT showdown: Dose rate findings exposed flaws in the LNT model part 1. The Russell-Muller debate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calabrese, Edward J., E-mail: edwardc@schoolph.uma

This paper assesses the discovery of the dose-rate effect in radiation genetics and how it challenged fundamental tenets of the linear non-threshold (LNT) dose response model, including the assumptions that all mutational damage is cumulative and irreversible and that the dose-response is linear at low doses. Newly uncovered historical information also describes how a key 1964 report by the International Commission for Radiological Protection (ICRP) addressed the effects of dose rate in the assessment of genetic risk. This unique story involves assessments by two leading radiation geneticists, Hermann J. Muller and William L. Russell, who independently argued that the report'smore » Genetic Summary Section on dose rate was incorrect while simultaneously offering vastly different views as to what the report's summary should have contained. This paper reveals occurrences of scientific disagreements, how conflicts were resolved, which view(s) prevailed and why. During this process the Nobel Laureate, Muller, provided incorrect information to the ICRP in what appears to have been an attempt to manipulate the decision-making process and to prevent the dose-rate concept from being adopted into risk assessment practices. - Highlights: • The discovery of radiation dose rate challenged the scientific basis of LNT. • Radiation dose rate occurred in males and females. • The dose rate concept supported a threshold dose-response for radiation.« less

The PEREGRINETM program: using physics and computer simulation to improve radiation therapy for cancer

NASA Astrophysics Data System (ADS)

Hartmann Siantar, Christine L.; Moses, Edward I.

1998-11-01

When using radiation to treat cancer, doctors rely on physics and computer technology to predict where the radiation dose will be deposited in the patient. The accuracy of computerized treatment planning plays a critical role in the ultimate success or failure of the radiation treatment. Inaccurate dose calculations can result in either insufficient radiation for cure, or excessive radiation to nearby healthy tissue, which can reduce the patient's quality of life. This paper describes how advanced physics, computer, and engineering techniques originally developed for nuclear weapons and high-energy physics research are being used to predict radiation dose in cancer patients. Results for radiation therapy planning, achieved in the Lawrence Livermore National Laboratory (LLNL) 0143-0807/19/6/005/img2 program show that these tools can give doctors new insights into their patients' treatments by providing substantially more accurate dose distributions than have been available in the past. It is believed that greater accuracy in radiation therapy treatment planning will save lives by improving doctors' ability to target radiation to the tumour and reduce suffering by reducing the incidence of radiation-induced complications.

Knowledge-based iterative model reconstruction: comparative image quality and radiation dose with a pediatric computed tomography phantom.

PubMed

Ryu, Young Jin; Choi, Young Hun; Cheon, Jung-Eun; Ha, Seongmin; Kim, Woo Sun; Kim, In-One

2016-03-01

CT of pediatric phantoms can provide useful guidance to the optimization of knowledge-based iterative reconstruction CT. To compare radiation dose and image quality of CT images obtained at different radiation doses reconstructed with knowledge-based iterative reconstruction, hybrid iterative reconstruction and filtered back-projection. We scanned a 5-year anthropomorphic phantom at seven levels of radiation. We then reconstructed CT data with knowledge-based iterative reconstruction (iterative model reconstruction [IMR] levels 1, 2 and 3; Philips Healthcare, Andover, MA), hybrid iterative reconstruction (iDose(4), levels 3 and 7; Philips Healthcare, Andover, MA) and filtered back-projection. The noise, signal-to-noise ratio and contrast-to-noise ratio were calculated. We evaluated low-contrast resolutions and detectability by low-contrast targets and subjective and objective spatial resolutions by the line pairs and wire. With radiation at 100 peak kVp and 100 mAs (3.64 mSv), the relative doses ranged from 5% (0.19 mSv) to 150% (5.46 mSv). Lower noise and higher signal-to-noise, contrast-to-noise and objective spatial resolution were generally achieved in ascending order of filtered back-projection, iDose(4) levels 3 and 7, and IMR levels 1, 2 and 3, at all radiation dose levels. Compared with filtered back-projection at 100% dose, similar noise levels were obtained on IMR level 2 images at 24% dose and iDose(4) level 3 images at 50% dose, respectively. Regarding low-contrast resolution, low-contrast detectability and objective spatial resolution, IMR level 2 images at 24% dose showed comparable image quality with filtered back-projection at 100% dose. Subjective spatial resolution was not greatly affected by reconstruction algorithm. Reduced-dose IMR obtained at 0.92 mSv (24%) showed similar image quality to routine-dose filtered back-projection obtained at 3.64 mSv (100%), and half-dose iDose(4) obtained at 1.81 mSv.

Recommended de minimis radiation dose rates for Canada. Report No. INFO-0355

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1990-01-01

A de minimis dose or dose rate as used in this report represents a level of risk which is generally accepted as being of no significance to an individual, or in the case of a population, of no significance to society. The report describes the risk of biological effects from radiation; radiation from natural and man-made sources; normal incidences of cancer and genetic defects; initiatives by other agencies in the U.S., the U.K. and internationally; the importance of collective dose and dose rate; assigning values to the de minimis dose rates; and application of the de minimis dose rates.

A comparative study of space radiation organ doses and associated cancer risks using PHITS and HZETRN.

PubMed

Bahadori, Amir A; Sato, Tatsuhiko; Slaba, Tony C; Shavers, Mark R; Semones, Edward J; Van Baalen, Mary; Bolch, Wesley E

2013-10-21

NASA currently uses one-dimensional deterministic transport to generate values of the organ dose equivalent needed to calculate stochastic radiation risk following crew space exposures. In this study, organ absorbed doses and dose equivalents are calculated for 50th percentile male and female astronaut phantoms using both the NASA High Charge and Energy Transport Code to perform one-dimensional deterministic transport and the Particle and Heavy Ion Transport Code System to perform three-dimensional Monte Carlo transport. Two measures of radiation risk, effective dose and risk of exposure-induced death (REID) are calculated using the organ dose equivalents resulting from the two methods of radiation transport. For the space radiation environments and simplified shielding configurations considered, small differences (<8%) in the effective dose and REID are found. However, for the galactic cosmic ray (GCR) boundary condition, compensating errors are observed, indicating that comparisons between the integral measurements of complex radiation environments and code calculations can be misleading. Code-to-code benchmarks allow for the comparison of differential quantities, such as secondary particle differential fluence, to provide insight into differences observed in integral quantities for particular components of the GCR spectrum.

A comparative study of space radiation organ doses and associated cancer risks using PHITS and HZETRN

NASA Astrophysics Data System (ADS)

Bahadori, Amir A.; Sato, Tatsuhiko; Slaba, Tony C.; Shavers, Mark R.; Semones, Edward J.; Van Baalen, Mary; Bolch, Wesley E.

2013-10-01

NASA currently uses one-dimensional deterministic transport to generate values of the organ dose equivalent needed to calculate stochastic radiation risk following crew space exposures. In this study, organ absorbed doses and dose equivalents are calculated for 50th percentile male and female astronaut phantoms using both the NASA High Charge and Energy Transport Code to perform one-dimensional deterministic transport and the Particle and Heavy Ion Transport Code System to perform three-dimensional Monte Carlo transport. Two measures of radiation risk, effective dose and risk of exposure-induced death (REID) are calculated using the organ dose equivalents resulting from the two methods of radiation transport. For the space radiation environments and simplified shielding configurations considered, small differences (<8%) in the effective dose and REID are found. However, for the galactic cosmic ray (GCR) boundary condition, compensating errors are observed, indicating that comparisons between the integral measurements of complex radiation environments and code calculations can be misleading. Code-to-code benchmarks allow for the comparison of differential quantities, such as secondary particle differential fluence, to provide insight into differences observed in integral quantities for particular components of the GCR spectrum.

General equations for optimal selection of diagnostic image acquisition parameters in clinical X-ray imaging.

PubMed

Zheng, Xiaoming

2017-12-01

The purpose of this work was to examine the effects of relationship functions between diagnostic image quality and radiation dose on the governing equations for image acquisition parameter variations in X-ray imaging. Various equations were derived for the optimal selection of peak kilovoltage (kVp) and exposure parameter (milliAmpere second, mAs) in computed tomography (CT), computed radiography (CR), and direct digital radiography. Logistic, logarithmic, and linear functions were employed to establish the relationship between radiation dose and diagnostic image quality. The radiation dose to the patient, as a function of image acquisition parameters (kVp, mAs) and patient size (d), was used in radiation dose and image quality optimization. Both logistic and logarithmic functions resulted in the same governing equation for optimal selection of image acquisition parameters using a dose efficiency index. For image quality as a linear function of radiation dose, the same governing equation was derived from the linear relationship. The general equations should be used in guiding clinical X-ray imaging through optimal selection of image acquisition parameters. The radiation dose to the patient could be reduced from current levels in medical X-ray imaging.

Anti-radiation vaccine: Immunologically-based Prophylaxis of Acute Toxic Radiation Syndromes Associated with Long-term Space Flight

NASA Technical Reports Server (NTRS)

Popov, Dmitri; Maliev, Vecheslav; Jones, Jeffrey; Casey, Rachael C.

2007-01-01

Protecting crew from ionizing radiation is a key life sciences problem for long-duration space missions. The three major sources/types of radiation are found in space: galactic cosmic rays, trapped Van Allen belt radiation, and solar particle events. All present varying degrees of hazard to crews; however, exposure to high doses of any of these types of radiation ultimately induce both acute and long-term biological effects. High doses of space radiation can lead to the development of toxicity associated with the acute radiation syndrome (ARS) which could have significant mission impact, and even render the crew incapable of performing flight duties. The creation of efficient radiation protection technologies is considered an important target in space radiobiology, immunology, biochemistry and pharmacology. Two major mechanisms of cellular, organelle, and molecular destruction as a result of radiation exposure have been identified: 1) damage induced directly by incident radiation on the macromolecules they encounter and 2) radiolysis of water and generation of secondary free radicals and reactive oxygen species (ROS), which induce chemical bond breakage, molecular substitutions, and damage to biological molecules and membranes. Free-radical scavengers and antioxidants, which neutralize the damaging activities of ROS, are effective in reducing the impact of small to moderate doses of radiation. In the case of high doses of radiation, antioxidants alone may be inadequate as a radioprotective therapy. However, it remains a valuable component of a more holistic strategy of prophylaxis and therapy. High doses of radiation directly damage biological molecules and modify chemical bond, resulting in the main pathological processes that drive the development of acute radiation syndromes (ARS). Which of two types of radiation-induced cellular lethality that ultimately develops, apoptosis or necrosis, depends on the spectrum of incident radiation, dose, dose rate, and functional conditions of impacted cells/organisms. The administration of an experimental anti-radiation vaccine may provide an immunologically based, adjunct method of prevention or prophylaxis against clinical ARS. The administration of experimental anti-radiation serum (ARS) and the use of the blood dialysis methods, such as immune plasma-sorption, may assist in the clearance of radiation-specific toxins and may enhance established strategies for the mitigation of the biological effects leading to ARS, and should be evaluated for use on exploration-class space missions.

Addressing as low as reasonably achievable (ALARA) issues: investigation of worker collective external and extremity dose data

DOE PAGES

Cournoyer, Michael Edward; Costigan, Stephen Andrew; Schreiber, Stephen Bruce

2017-03-17

Plutonium emits both neutrons and photons and when it is stored or handled inside a glovebox, both photons and neutrons are significant external radiation hazards. Doses to the extremities are usually dominated by gamma radiation in typical plutonium glovebox operations. Excess external dose can generates stochastic effects consisting of cancer and benign tumors in some organs. Direct doses from radiation sources external to the body are measured by thermoluminescent dosimeters (TLDs) placed on the glovebox worker between the neck and waist. Wrist dosimeters are used to assess externally penetrating radiation including neutrons and provide an estimate of neutron radiation exposuremore » to the extremities. Both TLDs and wrist dosimeters are processed monthly for most glovebox workers. Here, worker collective extremity and external dose data have been analyzed to prevent and mitigate external radiation events through the use of Lean Manufacturing and Six Sigma business practices (LSS). Employing LSS, statistically significant variations (trends) are identified in worker collective extremity and external dose data. Finally, the research results presented in this paper are pivotal to the ultimate focus of this program, which is to minimize external radiation events.« less

Nuclear energy and health: and the benefits of low-dose radiation hormesis.

PubMed

Cuttler, Jerry M; Pollycove, Myron

2009-01-01

Energy needs worldwide are expected to increase for the foreseeable future, but fuel supplies are limited. Nuclear reactors could supply much of the energy demand in a safe, sustainable manner were it not for fear of potential releases of radioactivity. Such releases would likely deliver a low dose or dose rate of radiation, within the range of naturally occurring radiation, to which life is already accustomed. The key areas of concern are discussed. Studies of actual health effects, especially thyroid cancers, following exposures are assessed. Radiation hormesis is explained, pointing out that beneficial effects are expected following a low dose or dose rate because protective responses against stresses are stimulated. The notions that no amount of radiation is small enough to be harmless and that a nuclear accident could kill hundreds of thousands are challenged in light of experience: more than a century with radiation and six decades with reactors. If nuclear energy is to play a significant role in meeting future needs, regulatory authorities must examine the scientific evidence and communicate the real health effects of nuclear radiation. Negative images and implications of health risks derived by unscientific extrapolations of harmful effects of high doses must be dispelled.

Nuclear Energy and Health: And the Benefits of Low-Dose Radiation Hormesis

PubMed Central

Cuttler, Jerry M.; Pollycove, Myron

2009-01-01

Energy needs worldwide are expected to increase for the foreseeable future, but fuel supplies are limited. Nuclear reactors could supply much of the energy demand in a safe, sustainable manner were it not for fear of potential releases of radioactivity. Such releases would likely deliver a low dose or dose rate of radiation, within the range of naturally occurring radiation, to which life is already accustomed. The key areas of concern are discussed. Studies of actual health effects, especially thyroid cancers, following exposures are assessed. Radiation hormesis is explained, pointing out that beneficial effects are expected following a low dose or dose rate because protective responses against stresses are stimulated. The notions that no amount of radiation is small enough to be harmless and that a nuclear accident could kill hundreds of thousands are challenged in light of experience: more than a century with radiation and six decades with reactors. If nuclear energy is to play a significant role in meeting future needs, regulatory authorities must examine the scientific evidence and communicate the real health effects of nuclear radiation. Negative images and implications of health risks derived by unscientific extrapolations of harmful effects of high doses must be dispelled. PMID:19343116

Addressing as low as reasonably achievable (ALARA) issues: investigation of worker collective external and extremity dose data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cournoyer, Michael Edward; Costigan, Stephen Andrew; Schreiber, Stephen Bruce

Plutonium emits both neutrons and photons and when it is stored or handled inside a glovebox, both photons and neutrons are significant external radiation hazards. Doses to the extremities are usually dominated by gamma radiation in typical plutonium glovebox operations. Excess external dose can generates stochastic effects consisting of cancer and benign tumors in some organs. Direct doses from radiation sources external to the body are measured by thermoluminescent dosimeters (TLDs) placed on the glovebox worker between the neck and waist. Wrist dosimeters are used to assess externally penetrating radiation including neutrons and provide an estimate of neutron radiation exposuremore » to the extremities. Both TLDs and wrist dosimeters are processed monthly for most glovebox workers. Here, worker collective extremity and external dose data have been analyzed to prevent and mitigate external radiation events through the use of Lean Manufacturing and Six Sigma business practices (LSS). Employing LSS, statistically significant variations (trends) are identified in worker collective extremity and external dose data. Finally, the research results presented in this paper are pivotal to the ultimate focus of this program, which is to minimize external radiation events.« less

Continuous Exposure to Low-Dose-Rate Gamma Irradiation Reduces Airway Inflammation in Ovalbumin-Induced Asthma.

PubMed

Kim, Joong Sun; Son, Yeonghoon; Bae, Min Ji; Lee, Seung Sook; Park, Sun Hoo; Lee, Hae June; Lee, Soong In; Lee, Chang Geun; Kim, Sung Dae; Jo, Wol Soon; Kim, Sung Ho; Shin, In Sik

2015-01-01

Although safe doses of radiation have been determined, concerns about the harmful effects of low-dose radiation persist. In particular, to date, few studies have investigated the correlation between low-dose radiation and disease development. Asthma is a common chronic inflammatory airway disease that is recognized as a major public health problem. In this study, we evaluated the effects of low-dose-rate chronic irradiation on allergic asthma in a murine model. Mice were sensitized and airway-challenged with ovalbumin (OVA) and were exposed to continuous low-dose-rate irradiation (0.554 or 1.818 mGy/h) for 24 days after initial sensitization. The effects of chronic radiation on proinflammatory cytokines and the activity of matrix metalloproteinase-9 (MMP-9) were investigated. Exposure to low-dose-rate chronic irradiation significantly decreased the number of inflammatory cells, methylcholine responsiveness (PenH value), and the levels of OVA-specific immunoglobulin E, interleukin (IL)-4, and IL-5. Furthermore, airway inflammation and the mucus production in lung tissue were attenuated and elevated MMP-9 expression and activity induced by OVA challenge were significantly suppressed. These results indicate that low-dose-rate chronic irradiation suppresses allergic asthma induced by OVA challenge and does not exert any adverse effects on asthma development. Our findings can potentially provide toxicological guidance for the safe use of radiation and relieve the general anxiety about exposure to low-dose radiation.

Principals Of Radiation Toxicology: Important Aspects.

NASA Astrophysics Data System (ADS)

Popov, Dmitri; Maliev, Slava; Jones, Jeffrey

“All things are poison, and nothing is without poison; only the dose permits something not to be poisonous.” Paracelsus Key Words: Radiation Toxins (RT), Radiation Toxicants (RTc), Radiation Poisons (RP), Radiation Exposure (RE), Radiation Toxicology is the science about radiation poisons. [D.Popov et al. 2012,J.Zhou et al. 2007,] Radiation Toxins is a specific proteins with high enzymatic activity produced by living irradiated mammals. [D.Popov et al. 2012,] Radiation Toxicants is a substances that produce radiomimetics effects, adverse biological effects which specific for radiation. [D.Popov et al. 2012,] Radiation Toxic agent is specific proteins that can produce pathological biological effects specific for physical form of radiation.[D.Popov et al. 1990,2012,V. Maliev 2007] Different Toxic Substances isolated from cells or from blood or lymph circulation. [Kudriashov I. et al. 1970, D.Popov et al. 1990,2012,V. Maliev et al. 2007,] Radiation Toxins may affects many organs or specific organ, tissue, specific group of cells. [Kudriashov I. et al. 1970, D.Popov et al. 1990,2012,V. Maliev et al. 2007] For example: Radiation Toxins could induce collective toxic clinical states to include: systemic inflammatory response syndrome (SIRS),toxic multiple organ injury (TMOI), toxic multiple organ dysfunction syndromes (TMODS),and finally, toxic multiple organ failure (TMOF). [T. Azizova et al. 2005, Konchalovsky et al., 2005, D. Popov et al 2012] However, Radiation Toxins could induce specific injury of organs or tissue and induce Acute Radiation Syndromes such as Acute Radiation Cerebrovascular Syndrome, Acute Radiation Cardiovascular Syndrome, Acute Radiation Hematopoietic Syndrome, Acute Radiation GastroIntestinal Syndrome. [ D.Popov et al. 1990, 2012, V. Maliev et al. 2007] Radiation Toxins correlates with Radiation Exposure and the dose-response relationship is a fundamental and essential concept in classic Toxicology and Radiation Toxicology.[ D.Popov et al. 1990, 2012] Moderate and high doses of radiation induces necrosis of radiosensitive cells with the subsequent formation of radiation toxins and their induced acute inflammatory processes. Radiation necrosis is the most substantial and most severe form of radiation induced injury, and when widespread, has grave therapeutic implications. [D. Popov et al. 1990, 2012,Claudio A. et al. 2002, Robertson J. et al. 2002, ] Relatively small doses of Radiation Toxins induce apoptosis and high doses of Radiation Toxins induce necrosis. [Rastogi P. et al. 2009, D. Popov et al. 1990, 2012,] Threshold of Toxic Effects occurs and can be defined. [D. Popov et al. 2012, ] Radiation Toxins affects Somatic cells and Germ Cells. Radiation Toxins can induce teratogenic processes. Specific Toxicity of Radiation Toxins can affects developing fetus. Material and Methods, Results: http://www.intechopen.com/books/current-topics-in-ionizing-radiation-research/radiation-toxins-molecular-mechanisms-of-toxicity-and-radiomimetic-properties- Conclusion: Radiation is a physical agent - induce activation of some secretory proteins with high enzymatic activity. This proteins called as Radiation Toxins can produce specific for radiation biological and toxic effects after administration to radiation naive mammals. [V. Maliev et al. 2007, D. Popov et al. 1990, 2012] Radiation Toxins are teratogenic and oncogenic. Radiation Toxins effects depend on Administered Dose and Radiation effects depend on Exposure Dose and Absorbed Dose. The levels of Radiation Toxins correlates with Radiation Exposure.

Awareness of radiation protection and dose levels of imaging procedures among medical students, radiography students, and radiology residents at an academic hospital: Results of a comprehensive survey.

PubMed

Faggioni, Lorenzo; Paolicchi, Fabio; Bastiani, Luca; Guido, Davide; Caramella, Davide

2017-01-01

To evaluate the awareness of radiation protection issues and the knowledge of dose levels of imaging procedures among medical students, radiology residents, and radiography students at an academic hospital. A total of 159 young doctors and students (including 60 radiology residents, 56 medical students, and 43 radiography students) were issued a questionnaire consisting of 16 multiple choice questions divided into three separated sections (i.e., demographic data, awareness about radiation protection issues, and knowledge about radiation dose levels of common radiological examinations). Medical students claimed to have at least a good knowledge of radiation protection issues more frequently than radiology residents and radiography students (94.4% vs 55% and 35.7%, respectively; P<0.05), with no cases of perceived excellent knowledge among radiography students. However, the actual knowledge of essential radiation protection topics such as regulations, patient and tissue susceptibility to radiation damage, professional radiation risk and dose optimisation, as well as of radiation doses delivered by common radiological procedures was significantly worse among medical students than radiology residents and radiography students (P<0.05). Those latter significantly outperformed radiology residents as to knowledge of radiation protection issues (P<0.01). Overall, less than 50% of survey respondents correctly answered all questions of the survey. Radiology residents, radiography students and medical students have a limited awareness about radiation protection, with a specific gap of knowledge concerning real radiation doses of daily radiological examinations. Both undergraduate and postgraduate teaching needs to be effectively implemented with radiation safety courses. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

IMRT delivers lower radiation doses to dental structures than 3DRT in head and neck cancer patients.

PubMed

Fregnani, Eduardo Rodrigues; Parahyba, Cláudia Joffily; Morais-Faria, Karina; Fonseca, Felipe Paiva; Ramos, Pedro Augusto Mendes; de Moraes, Fábio Yone; da Conceição Vasconcelos, Karina Gondim Moutinho; Menegussi, Gisela; Santos-Silva, Alan Roger; Brandão, Thais B

2016-09-07

Radiotherapy (RT) is frequently used in the treatment of head and neck cancer, but different side-effects are frequently reported, including a higher frequency of radiation-related caries, what may be consequence of direct radiation to dental tissue. The intensity-modulated radiotherapy (IMRT) was developed to improve tumor control and decrease patient's morbidity by delivering radiation beams only to tumor shapes and sparing normal tissue. However, teeth are usually not included in IMRT plannings and the real efficacy of IMRT in the dental context has not been addressed. Therefore, the aim of this study is to assess whether IMRT delivers lower radiation doses to dental structures than conformal 3D radiotherapy (3DRT). Radiation dose delivery to dental structures of 80 patients treated for head and neck cancers (oral cavity, tongue, nasopharynx and oropharynx) with IMRT (40 patients) and 3DRT (40 patients) were assessed by individually contouring tooth crowns on patients' treatment plans. Clinicopathological data were retrieved from patients' medical files. The average dose of radiation to teeth delivered by IMRT was significantly lower than with 3DRT (p = 0.007); however, only patients affected by nasopharynx and oral cavity cancers demonstrated significantly lower doses with IMRT (p = 0.012 and p = 0.011, respectively). Molars received more radiation with both 3DRT and IMRT, but the latter delivered significantly lower radiation in this group of teeth (p < 0.001), whereas no significant difference was found for the other dental groups. Maxillary teeth received lower doses than mandibular teeth, but only IMRT delivered significantly lower doses (p = 0.011 and p = 0.003). Ipsilateral teeth received higher doses than contralateral teeth with both techniques and IMRT delivered significantly lower radiation than 3DRT for contralateral dental structures (p < 0.001). IMRT delivered lower radiation doses to teeth than 3DRT, but only for some groups of patients and teeth, suggesting that this decrease was more likely due to the protection of other high risk organs, and was not enough to remove teeth from the zone of high risk for radiogenic disturbance (>30Gy).

An organ-based approach to dose calculation in the assessment of dose-dependent biological effects of ionising radiation in Arabidopsis thaliana.

PubMed

Biermans, Geert; Horemans, Nele; Vanhoudt, Nathalie; Vandenhove, Hildegarde; Saenen, Eline; Van Hees, May; Wannijn, Jean; Vives i Batlle, Jordi; Cuypers, Ann

2014-07-01

There is a need for a better understanding of biological effects of radiation exposure in non-human biota. Correct description of these effects requires a more detailed model of dosimetry than that available in current risk assessment tools, particularly for plants. In this paper, we propose a simple model for dose calculations in roots and shoots of Arabidopsis thaliana seedlings exposed to radionuclides in a hydroponic exposure setup. This model is used to compare absorbed doses for three radionuclides, (241)Am (α-radiation), (90)Sr (β-radiation) and (133)Ba (γ radiation). Using established dosimetric calculation methods, dose conversion coefficient values were determined for each organ separately based on uptake data from the different plant organs. These calculations were then compared to the DCC values obtained with the ERICA tool under equivalent geometry assumptions. When comparing with our new method, the ERICA tool appears to overestimate internal doses and underestimate external doses in the roots for all three radionuclides, though each to a different extent. These observations might help to refine dose-response relationships. The DCC values for (90)Sr in roots are shown to deviate the most. A dose-effect curve for (90)Sr β-radiation has been established on biomass and photosynthesis endpoints, but no significant dose-dependent effects are observed. This indicates the need for use of endpoints at the molecular and physiological scale. Copyright © 2013 Elsevier Ltd. All rights reserved.

A CONCEPTUAL FRAMEWORK FOR MANAGING RADIATION DOSE TO PATIENTS IN DIAGNOSTIC RADIOLOGY USING REFERENCE DOSE LEVELS.

PubMed

Almén, Anja; Båth, Magnus

2016-06-01

The overall aim of the present work was to develop a conceptual framework for managing radiation dose in diagnostic radiology with the intention to support optimisation. An optimisation process was first derived. The framework for managing radiation dose, based on the derived optimisation process, was then outlined. The outset of the optimisation process is four stages: providing equipment, establishing methodology, performing examinations and ensuring quality. The optimisation process comprises a series of activities and actions at these stages. The current system of diagnostic reference levels is an activity in the last stage, ensuring quality. The system becomes a reactive activity only to a certain extent engaging the core activity in the radiology department, performing examinations. Three reference dose levels-possible, expected and established-were assigned to the three stages in the optimisation process, excluding ensuring quality. A reasonably achievable dose range is also derived, indicating an acceptable deviation from the established dose level. A reasonable radiation dose for a single patient is within this range. The suggested framework for managing radiation dose should be regarded as one part of the optimisation process. The optimisation process constitutes a variety of complementary activities, where managing radiation dose is only one part. This emphasises the need to take a holistic approach integrating the optimisation process in different clinical activities. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Mimicking the effects of spaceflight on bone: Combined effects of disuse and chronic low-dose rate radiation exposure on bone mass in mice.

PubMed

Yu, Kanglun; Doherty, Alison H; Genik, Paula C; Gookin, Sara E; Roteliuk, Danielle M; Wojda, Samantha J; Jiang, Zhi-Sheng; McGee-Lawrence, Meghan E; Weil, Michael M; Donahue, Seth W

2017-11-01

During spaceflight, crewmembers are subjected to biomechanical and biological challenges including microgravity and radiation. In the skeleton, spaceflight leads to bone loss, increasing the risk of fracture. Studies utilizing hindlimb suspension (HLS) as a ground-based model of spaceflight often neglect the concomitant effects of radiation exposure, and even when radiation is accounted for, it is often delivered at a high-dose rate over a very short period of time, which does not faithfully mimic spaceflight conditions. This study was designed to investigate the skeletal effects of low-dose rate gamma irradiation (8.5 cGy gamma radiation per day for 20 days, amounting to a total dose of 1.7 Gy) when administered simultaneously to disuse from HLS. The goal was to determine whether continuous, low-dose rate radiation administered during disuse would exacerbate bone loss in a murine HLS model. Four groups of 16 week old female C57BL/6 mice were studied: weight bearing + no radiation (WB+NR), HLS + NR, WB + radiation exposure (WB+RAD), and HLS+RAD. Surprisingly, although HLS led to cortical and trabecular bone loss, concurrent radiation exposure did not exacerbate these effects. Our results raise the possibility that mechanical unloading has larger effects on the bone loss that occurs during spaceflight than low-dose rate radiation. Copyright © 2017 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.

Analysis of Radiation Impact on White Mice through Radiation Dose Mapping in Medical Physics Laboratory

NASA Astrophysics Data System (ADS)

Sutikno, Madnasri; Susilo; Arya Wijayanti, Riza

2016-08-01

A study about X-ray radiation impact on the white mice through radiation dose mapping in Medical Physic Laboratory is already done. The purpose of this research is to determine the minimum distance of radiologist to X-ray instrument through treatment on the white mice. The radiation exposure doses are measured on the some points in the distance from radiation source between 30 cm up to 80 with interval of 30 cm. The impact of radiation exposure on the white mice and the effects of radiation measurement in different directions are investigated. It is founded that minimum distance of radiation worker to radiation source is 180 cm and X-ray has decreased leukocyte number and haemoglobin and has increased thrombocyte number in the blood of white mice.

Radioprotective effect of Rapana thomasiana hemocyanin in gamma induced acute radiation syndrome

PubMed Central

Kindekov, Ivan; Mileva, Milka; Krastev, Dimo; Vassilieva, Vladimira; Raynova, Yuliana; Doumanova, Lyuba; Aljakov, Mitko; Idakieva, Krassimira

2014-01-01

The radioprotective effect of Rapana thomasiana hemocyanin (RtH) against radiation-induced injuries (stomach ulcers, survival time and endogenous haemopoiesis) and post-radiation recovery was investigated in male albino mice (C3H strain). Radiation course was in a dose of 7.5 Gy (LD 100/30 – dose that kills 100% of the mice at 30 days) from 137Cs with a dose of 2.05 Gy/min. Radiation injuries were manifested by inducing а hematopoietic form of acute radiation syndrome. RtH was administered intraperitoneally in a single dose of 50, 100, 150 and 200 mg/kg body weight (b. w.) once a day for five consecutive days before irradiation. The results obtained showed that radiation exposure led to (1) 100% mortality rate, (2) ulceration in the stomach mucosa and (3) decrease formation of spleen colonies as a marker of endogenous haemopoiesis. Administration of RtH at a dose of 200 mg/kg provided better protection against radiation-induced stomach ulceration, mitigated the lethal effects of radiation exposure and recovered endogenous haemopoiesis versus irradiated but not supplemented mice. It could be expected that RtH will find a use in mitigating radiation induced injury and enhanced radiorecovery. PMID:26019540

Estimation of internal radiation dose from both immediate releases and continued exposures to contaminated materials.

PubMed

Napier, Bruce

2012-03-01

A brief description is provided of the basic concepts related to 'internal dose' and how it differs from doses that result from radioactive materials and direct radiation outside of the body. The principles of radiation dose reconstruction, as applied to both internal and external doses, are discussed on the basis of a recent publication prepared by the US National Council on Radiation Protection and Measurements. Finally, ideas are introduced related to residual radioactive contamination in the environment that has resulted from the releases from damaged reactors and also to the management of wastes that may be generated in both regional cleanup and decommissioning of the Fukushima nuclear power plant.

Total-dose radiation effects data for semiconductor devices: 1985 supplement, volume 1

NASA Technical Reports Server (NTRS)

Martin, K. E.; Gauthier, M. K.; Coss, J. R.; Dantas, A. R. V.; Price, W. E.

1985-01-01

Steady-state, total-dose radiation test data are provided, in graphic format, for use by electronic designers and other personnel using semiconductor devices in a radiation environment. The data were generated by JPL for various NASA space programs. The document is in two volumes: Volume 1 provides data on diodes, bipolar transistors, field effect transistors, and miscellaneous semiconductor types, and Volume 2 provides total-dose radiation test data on integrated circuits. Volume 1 of this 1985 Supplement contains new total-dose radiation test data generated since the August 1, 1981 release date of the original Volume 1. Publication of Volume 2 of the 1985 Supplement will follow that of Volume 1 by approximately three months.

Characterization of Radiation Hardened Bipolar Linear Devices for High Total Dose Missions

NASA Technical Reports Server (NTRS)

McClure, Steven S.; Harris, Richard D.; Rax, Bernard G.; Thorbourn, Dennis O.

2012-01-01

Radiation hardened linear devices are characterized for performance in combined total dose and displacement damage environments for a mission scenario with a high radiation level. Performance at low and high dose rate for both biased and unbiased conditions is compared and the impact to hardness assurance methodology is discussed.

The reduction methods of operator's radiation dose for portable dental X-ray machines.

PubMed

Cho, Jeong-Yeon; Han, Won-Jeong

2012-08-01

This study was aimed to investigate the methods to reduce operator's radiation dose when taking intraoral radiographs with portable dental X-ray machines. Two kinds of portable dental X-ray machines (DX3000, Dexcowin and Rextar, Posdion) were used. Operator's radiation dose was measured with an 1,800 cc ionization chamber (RadCal Corp.) at the hand level of X-ray tubehead and at the operator's chest and waist levels with and without the backscatter shield. The operator's radiation dose at the hand level was measured with and without lead gloves and with long and short cones. The backscatter shield reduced operator's radiation dose at the hand level of X-ray tubehead to 23 - 32%, the lead gloves to 26 - 31%, and long cone to 48 - 52%. And the backscatter shield reduced operator's radiation dose at the operator's chest and waist levels to 0.1 - 37%. When portable dental X-ray systems are used, it is recommended to select X-ray machine attached with a backscatter shield and a long cone and to wear the lead gloves.

Radiation dose reduction in digital breast tomosynthesis (DBT) by means of deep-learning-based supervised image processing

NASA Astrophysics Data System (ADS)

Liu, Junchi; Zarshenas, Amin; Qadir, Ammar; Wei, Zheng; Yang, Limin; Fajardo, Laurie; Suzuki, Kenji

2018-03-01

To reduce cumulative radiation exposure and lifetime risks for radiation-induced cancer from breast cancer screening, we developed a deep-learning-based supervised image-processing technique called neural network convolution (NNC) for radiation dose reduction in DBT. NNC employed patched-based neural network regression in a convolutional manner to convert lower-dose (LD) to higher-dose (HD) tomosynthesis images. We trained our NNC with quarter-dose (25% of the standard dose: 12 mAs at 32 kVp) raw projection images and corresponding "teaching" higher-dose (HD) images (200% of the standard dose: 99 mAs at 32 kVp) of a breast cadaver phantom acquired with a DBT system (Selenia Dimensions, Hologic, CA). Once trained, NNC no longer requires HD images. It converts new LD images to images that look like HD images; thus the term "virtual" HD (VHD) images. We reconstructed tomosynthesis slices on a research DBT system. To determine a dose reduction rate, we acquired 4 studies of another test phantom at 4 different radiation doses (1.35, 2.7, 4.04, and 5.39 mGy entrance dose). Structural SIMilarity (SSIM) index was used to evaluate the image quality. For testing, we collected half-dose (50% of the standard dose: 32+/-14 mAs at 33+/-5 kVp) and full-dose (standard dose: 68+/-23 mAs at 33+/-5 kvp) images of 10 clinical cases with the DBT system at University of Iowa Hospitals and Clinics. NNC converted half-dose DBT images of 10 clinical cases to VHD DBT images that were equivalent to full dose DBT images. Our cadaver phantom experiment demonstrated 79% dose reduction.

Stray radiation dose and second cancer risk for a pediatric patient receiving craniospinal irradiation with proton beams

PubMed Central

Taddei, Phillip J; Mirkovic, Dragan; Fontenot, Jonas D; Giebeler, Annelise; Zheng, Yuanshui; Kornguth, David; Mohan, Radhe; Newhauser, Wayne D

2014-01-01

Proton beam radiotherapy unavoidably exposes healthy tissue to stray radiation emanating from the treatment unit and secondary radiation produced within the patient. These exposures provide no known benefit and may increase a patient's risk of developing a radiogenic cancer. The aims of this study were to calculate doses to major organs and tissues and to estimate second cancer risk from stray radiation following craniospinal irradiation (CSI) with proton therapy. This was accomplished using detailed Monte Carlo simulations of a passive-scattering proton treatment unit and a voxelized phantom to represent the patient. Equivalent doses, effective dose and corresponding risk for developing a fatal second cancer were calculated for a 10-year-old boy who received proton therapy. The proton treatment comprised CSI at 30.6 Gy plus a boost of 23.4 Gy to the clinical target volume. The predicted effective dose from stray radiation was 418 mSv, of which 344 mSv was from neutrons originating outside the patient; the remaining 74 mSv was caused by neutrons originating within the patient. This effective dose corresponds to an attributable lifetime risk of a fatal second cancer of 3.4%. The equivalent doses that predominated the effective dose from stray radiation were in the lungs, stomach and colon. These results establish a baseline estimate of the stray radiation dose and corresponding risk for a pediatric patient undergoing proton CSI and support the suitability of passively-scattered proton beams for the treatment of central nervous system tumors in pediatric patients. PMID:19305045

A comparison of two dose calculation algorithms-anisotropic analytical algorithm and Acuros XB-for radiation therapy planning of canine intranasal tumors.

PubMed

Nagata, Koichi; Pethel, Timothy D

2017-07-01

Although anisotropic analytical algorithm (AAA) and Acuros XB (AXB) are both radiation dose calculation algorithms that take into account the heterogeneity within the radiation field, Acuros XB is inherently more accurate. The purpose of this retrospective method comparison study was to compare them and evaluate the dose discrepancy within the planning target volume (PTV). Radiation therapy (RT) plans of 11 dogs with intranasal tumors treated by radiation therapy at the University of Georgia were evaluated. All dogs were planned for intensity-modulated radiation therapy using nine coplanar X-ray beams that were equally spaced, then dose calculated with anisotropic analytical algorithm. The same plan with the same monitor units was then recalculated using Acuros XB for comparisons. Each dog's planning target volume was separated into air, bone, and tissue and evaluated. The mean dose to the planning target volume estimated by Acuros XB was 1.3% lower. It was 1.4% higher for air, 3.7% lower for bone, and 0.9% lower for tissue. The volume of planning target volume covered by the prescribed dose decreased by 21% when Acuros XB was used due to increased dose heterogeneity within the planning target volume. Anisotropic analytical algorithm relatively underestimates the dose heterogeneity and relatively overestimates the dose to the bone and tissue within the planning target volume for the radiation therapy planning of canine intranasal tumors. This can be clinically significant especially if the tumor cells are present within the bone, because it may result in relative underdosing of the tumor. © 2017 American College of Veterinary Radiology.

A Systems Genetic Approach to Identify Low Dose Radiation-Induced Lymphoma Susceptibility/DOE2013FinalReport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balmain, Allan; Song, Ihn Young

2013-05-15

The ultimate goal of this project is to identify the combinations of genetic variants that confer an individual's susceptibility to the effects of low dose (0.1 Gy) gamma-radiation, in particular with regard to tumor development. In contrast to the known effects of high dose radiation in cancer induction, the responses to low dose radiation (defined as 0.1 Gy or less) are much less well understood, and have been proposed to involve a protective anti-tumor effect in some in vivo scientific models. These conflicting results confound attempts to develop predictive models of the risk of exposure to low dose radiation, particularlymore » when combined with the strong effects of inherited genetic variants on both radiation effects and cancer susceptibility. We have used a Systems Genetics approach in mice that combines genetic background analysis with responses to low and high dose radiation, in order to develop insights that will allow us to reconcile these disparate observations. Using this comprehensive approach we have analyzed normal tissue gene expression (in this case the skin and thymus), together with the changes that take place in this gene expression architecture a) in response to low or high- dose radiation and b) during tumor development. Additionally, we have demonstrated that using our expression analysis approach in our genetically heterogeneous/defined radiation-induced tumor mouse models can uniquely identify genes and pathways relevant to human T-ALL, and uncover interactions between common genetic variants of genes which may lead to tumor susceptibility.« less

Evaluation of optimum room entry times for radiation therapists after high energy whole pelvic photon treatments.

PubMed

Ho, Lavine; White, Peter; Chan, Edward; Chan, Kim; Ng, Janet; Tam, Timothy

2012-01-01

Linear accelerators operating at or above 10 MV produce neutrons by photonuclear reactions and induce activation in machine components, which are a source of potential exposure for radiation therapists. This study estimated gamma dose contributions to radiation therapists during high energy, whole pelvic, photon beam treatments and determined the optimum room entry times, in terms of safety of radiation therapists. Two types of technique (anterior-posterior opposing and 3-field technique) were studied. An Elekta Precise treatment system, operating up to 18 MV, was investigated. Measurements with an area monitoring device (a Mini 900R radiation monitor) were performed, to calculate gamma dose rates around the radiotherapy facility. Measurements inside the treatment room were performed when the linear accelerator was in use. The doses received by radiation therapists were estimated, and optimum room entry times were determined. The highest gamma dose rates were approximately 7 μSv/h inside the treatment room, while the doses in the control room were close to background (~0 μSv/h) for all techniques. The highest personal dose received by radiation therapists was estimated at 5 mSv/yr. To optimize protection, radiation therapists should wait for up to11 min after beam-off prior to room entry. The potential risks to radiation therapists with standard safety procedures were well below internationally recommended values, but risks could be further decreased by delaying room entry times. Dependent on the technique used, optimum entry times ranged between 7 to 11 min. A balance between moderate treatment times versus reduction in measured equivalent doses should be considered.

Automated size-specific CT dose monitoring program: assessing variability in CT dose.

PubMed

Christianson, Olav; Li, Xiang; Frush, Donald; Samei, Ehsan

2012-11-01

The potential health risks associated with low levels of ionizing radiation have created a movement in the radiology community to optimize computed tomography (CT) imaging protocols to use the lowest radiation dose possible without compromising the diagnostic usefulness of the images. Despite efforts to use appropriate and consistent radiation doses, studies suggest that a great deal of variability in radiation dose exists both within and between institutions for CT imaging. In this context, the authors have developed an automated size-specific radiation dose monitoring program for CT and used this program to assess variability in size-adjusted effective dose from CT imaging. The authors radiation dose monitoring program operates on an independent health insurance portability and accountability act compliant dosimetry server. Digital imaging and communication in medicine routing software is used to isolate dose report screen captures and scout images for all incoming CT studies. Effective dose conversion factors (k-factors) are determined based on the protocol and optical character recognition is used to extract the CT dose index and dose-length product. The patient's thickness is obtained by applying an adaptive thresholding algorithm to the scout images and is used to calculate the size-adjusted effective dose (ED(adj)). The radiation dose monitoring program was used to collect data on 6351 CT studies from three scanner models (GE Lightspeed Pro 16, GE Lightspeed VCT, and GE Definition CT750 HD) and two institutions over a one-month period and to analyze the variability in ED(adj) between scanner models and across institutions. No significant difference was found between computer measurements of patient thickness and observer measurements (p = 0.17), and the average difference between the two methods was less than 4%. Applying the size correction resulted in ED(adj) that differed by up to 44% from effective dose estimates that were not adjusted by patient size. Additionally, considerable differences were noted in ED(adj) distributions between scanners, with scanners employing iterative reconstruction exhibiting significantly lower ED(adj) (range: 9%-64%). Finally, a significant difference (up to 59%) in ED(adj) distributions was observed between institutions, indicating the potential for dose reduction. The authors developed a robust automated size-specific radiation dose monitoring program for CT. Using this program, significant differences in ED(adj) were observed between scanner models and across institutions. This new dose monitoring program offers a unique tool for improving quality assurance and standardization both within and across institutions.

Automated size-specific CT dose monitoring program: Assessing variability in CT dose

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christianson, Olav; Li Xiang; Frush, Donald

2012-11-15

Purpose: The potential health risks associated with low levels of ionizing radiation have created a movement in the radiology community to optimize computed tomography (CT) imaging protocols to use the lowest radiation dose possible without compromising the diagnostic usefulness of the images. Despite efforts to use appropriate and consistent radiation doses, studies suggest that a great deal of variability in radiation dose exists both within and between institutions for CT imaging. In this context, the authors have developed an automated size-specific radiation dose monitoring program for CT and used this program to assess variability in size-adjusted effective dose from CTmore » imaging. Methods: The authors radiation dose monitoring program operates on an independent health insurance portability and accountability act compliant dosimetry server. Digital imaging and communication in medicine routing software is used to isolate dose report screen captures and scout images for all incoming CT studies. Effective dose conversion factors (k-factors) are determined based on the protocol and optical character recognition is used to extract the CT dose index and dose-length product. The patient's thickness is obtained by applying an adaptive thresholding algorithm to the scout images and is used to calculate the size-adjusted effective dose (ED{sub adj}). The radiation dose monitoring program was used to collect data on 6351 CT studies from three scanner models (GE Lightspeed Pro 16, GE Lightspeed VCT, and GE Definition CT750 HD) and two institutions over a one-month period and to analyze the variability in ED{sub adj} between scanner models and across institutions. Results: No significant difference was found between computer measurements of patient thickness and observer measurements (p= 0.17), and the average difference between the two methods was less than 4%. Applying the size correction resulted in ED{sub adj} that differed by up to 44% from effective dose estimates that were not adjusted by patient size. Additionally, considerable differences were noted in ED{sub adj} distributions between scanners, with scanners employing iterative reconstruction exhibiting significantly lower ED{sub adj} (range: 9%-64%). Finally, a significant difference (up to 59%) in ED{sub adj} distributions was observed between institutions, indicating the potential for dose reduction. Conclusions: The authors developed a robust automated size-specific radiation dose monitoring program for CT. Using this program, significant differences in ED{sub adj} were observed between scanner models and across institutions. This new dose monitoring program offers a unique tool for improving quality assurance and standardization both within and across institutions.« less

TH-E-209-03: Development of An In-House CT Dose Monitoring and Management System Based On Open-Source Software Resources -- Pearls and Pitfalls

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, D.

Radiation dose monitoring solutions have opened up new opportunities for medical physicists to be more involved in modern clinical radiology practices. In particular, with the help of comprehensive radiation dose data, data-driven protocol management and informed case follow up are now feasible. Significant challenges remain however and the problems faced by medical physicists are highly heterogeneous. Imaging systems from multiple vendors and a wide range of vintages co-exist in the same department and employ data communication protocols that are not fully standardized or implemented making harmonization complex. Many different solutions for radiation dose monitoring have been implemented by imaging facilitiesmore » over the past few years. Such systems are based on commercial software, home-grown IT solutions, manual PACS data dumping, etc., and diverse pathways can be used to bring the data to impact clinical practice. The speakers will share their experiences with creating or tailoring radiation dose monitoring/management systems and procedures over the past few years, which vary significantly in design and scope. Topics to cover: (1) fluoroscopic dose monitoring and high radiation event handling from a large academic hospital; (2) dose monitoring and protocol optimization in pediatric radiology; and (3) development of a home-grown IT solution and dose data analysis framework. Learning Objectives: Describe the scope and range of radiation dose monitoring and protocol management in a modern radiology practice Review examples of data available from a variety of systems and how it managed and conveyed. Reflect on the role of the physicist in radiation dose awareness.« less

Relative Biological Effectiveness of Energetic Heavy Ions for Intestinal Tumorigenesis Shows Male Preponderance and Radiation Type and Energy Dependence in APC(1638N/+) Mice.

PubMed

Suman, Shubhankar; Kumar, Santosh; Moon, Bo-Hyun; Strawn, Steve J; Thakor, Hemang; Fan, Ziling; Shay, Jerry W; Fornace, Albert J; Datta, Kamal

2016-05-01

There are uncertainties associated with the prediction of colorectal cancer (CRC) risk from highly energetic heavy ion (HZE) radiation. We undertook a comprehensive assessment of intestinal and colonic tumorigenesis induced after exposure to high linear energy transfer (high-LET) HZE radiation spanning a range of doses and LET in a CRC mouse model and compared the results with the effects of low-LET γ radiation. Male and female APC(1638N/+) mice (n=20 mice per group) were whole-body exposed to sham-radiation, γ rays, (12)C, (28)Si, or (56)Fe radiation. For the >1 Gy HZE dose, we used γ-ray equitoxic doses calculated using relative biological effectiveness (RBE) determined previously. The mice were euthanized 150 days after irradiation, and intestinal and colon tumor frequency was scored. The highest number of tumors was observed after (28)Si, followed by (56)Fe and (12)C radiation, and tumorigenesis showed a male preponderance, especially after (28)Si. Analysis showed greater tumorigenesis per unit of radiation (per cGy) at lower doses, suggesting either radiation-induced elimination of target cells or tumorigenesis reaching a saturation point at higher doses. Calculation of RBE for intestinal and colon tumorigenesis showed the highest value with (28)Si, and lower doses showed greater RBE relative to higher doses. We have demonstrated that the RBE of heavy ion radiation-induced intestinal and colon tumorigenesis is related to ion energy, LET, gender, and peak RBE is observed at an LET of 69 keV/μm. Our study has implications for understanding risk to astronauts undertaking long duration space missions. Copyright © 2016 Elsevier Inc. All rights reserved.

Dose responses for adaption to low doses of (60)Co gamma rays and (3)H beta particles in normal human fibroblasts.

PubMed

Broome, E J; Brown, D L; Mitchel, R E J

2002-08-01

The dose response for adaption to radiation at low doses was compared in normal human fibroblasts (AG1522) exposed to either (60)Co gamma rays or (3)H beta particles. Cells were grown in culture to confluence and exposed at either 37 degrees C or 0 degrees C to (3)H beta-particle or (60)Co gamma-ray adapting doses ranging from 0.1 mGy to 500 mGy. These cells, and unexposed control cells, were allowed to adapt during a fixed 3-h, 37 degrees C incubation prior to a 4-Gy challenge dose of (60)Co gamma rays. Adaption was assessed by measuring micronucleus frequency in cytokinesis-blocked, binucleate cells. No adaption was detected in cells exposed to (60)Co gamma radiation at 37 degrees C after a dose of 0.1 mGy given at a low dose rate or to 500 mGy given at a high dose rate. However, low-dose-rate exposure (1-3 mGy/min) to any dose between 1 and 500 mGy from either radiation, delivered at either temperature, caused cells to adapt and reduced the micronucleus frequency that resulted from the subsequent 4-Gy exposure. Within this dose range, the magnitude of the reduction was the same, regardless of the dose or radiation type. These results demonstrate that doses as low as (on average) about one track per cell (1 mGy) produce the same maximum adaptive response as do doses that deposit many tracks per cell, and that the two radiations were not different in this regard. Exposure at a temperature where metabolic processes, including DNA repair, were inactive (0 degrees C) did not alter the result, indicating that the adaptive response is not sensitive to changes in the accumulation of DNA damage within this range. The results also show that the RBE for low doses of tritium beta-particle radiation is 1, using adaption as the end point.

Factors modifying the response of large animals to low-intensity radiation exposure

NASA Technical Reports Server (NTRS)

Page, N. P.; Still, E. T.

1972-01-01

In assessing the biological response to space radiation, two of the most important modifying factors are dose protraction and dose distribution to the body. Studies are reported in which sheep and swine were used to compare the hematology and lethality response resulting from radiation exposure encountered in a variety of forms, including acute (high dose-rate), chronic (low dose-rate), combinations of acute and chronic, and whether received as a continuous or as fractionated exposure. While sheep and swine are basically similar in response to acute radiation, their sensitivity to chronic irradiation is markedly different. Sheep remain relatively sensitive as the radiation exposure is protracted while swine are more resistant and capable of surviving extremely large doses of chronic irradiation. This response to chronic irradiation correlated well with changes in radiosensitivity and recovery following an acute, sublethal exposure.

A radiotherapy technique to limit dose to neural progenitor cell niches without compromising tumor coverage

PubMed Central

Redmond, Kristin J.; Achanta, Pragathi; Grossman, Stuart A.; Armour, Michael; Reyes, Juvenal; Kleinberg, Lawrence; Tryggestad, Erik; Quinones-Hinojosa, Alfredo

2015-01-01

Radiation therapy (RT) for brain tumors is associated with neurocognitive toxicity which may be a result of damage to neural progenitor cells (NPCs). We present a novel technique to limit the radiation dose to NPC without compromising tumor coverage. A study was performed in mice to examine the rationale and another was conducted in humans to determine its feasibility. C57BL/6 mice received localized radiation using a dedicated animal irradiation system with on-board CT imaging with either: (1) Radiation which spared NPC containing regions; (2) Radiation which did not spare these niches; or (3) Sham irradiation. Mice were sacrificed 24 h later and the brains were processed for immunohistochemical Ki-67 staining. For the human component of the study, 33 patients with primary brain tumors were evaluated. Two intensity modulated radiotherapy (IMRT) plans were retrospectively compared: a standard clinical plan and a plan which spares NPC regions while maintaining the same dose coverage of the tumor. The change in radiation dose to the contralateral NPC-containing regions was recorded. In the mouse model, non-NPC-sparing radiation treatment resulted in a significant decrease in the number of Ki67+ cells in dentate gyrus (DG) (P = 0.008) and subventricular zone (SVZ) (P = 0.005) compared to NPC-sparing radiation treatment. In NPC-sparing clinical plans, NPC regions received significantly lower radiation dose with no clinically relevant changes in tumor coverage. This novel radiation technique should significantly reduce radiation doses to NPC containing regions of the brain which may reduce neurocognitive deficits following RT for brain tumors. PMID:21327710

Abdominal Pediatric Cancer Surveillance using Serial CT: Evaluation of Organ Absorbed Dose and Effective Dose

PubMed Central

Lam, Diana; Wootton-Gorges, Sandra L.; McGahan, John P.; Stern, Robin; Boone, John M.

2012-01-01

Computed tomography (CT) is used extensively in cancer diagnosis, staging, evaluation of response to treatment, and in active surveillance for cancer reoccurrence. A review of CT technology is provided, at a level of detail appropriate for a busy clinician to review. The basis of x-ray CT dosimetry is also discussed, and concepts of absorbed dose and effective dose are distinguished. Absorbed dose is a physical quantity (measured in milliGray) equal to the x-ray energy deposited in a mass of tissue, whereas effective dose utilizes an organ-specific weighting method which converts organ doses to effective dose measured in milliSieverts. The organ weighting values carry with them a measure of radiation risk, and so effective dose (in mSv) is not a physical dose metric but rather is one that conveys radiation risk. The use of CT in a cancer surveillance protocol was used as an example of a pediatric patient who had kidney cancer, with surgery and radiation therapy. The active use of CT for cancer surveillance along with diagnostic CT scans led to a total of 50 CT scans performed on this child in a 7 year period. It was estimated that the patient received an average organ dose of 431 mGy from these CT scans. By comparison, the radiation therapy was performed and delivered 50.4 Gy to the patient’s abdomen. Thus, the total dose from CT represented only 0.8% of the patients radiation dose. PMID:21362521

Estimated radiation exposure of German commercial airline cabin crew in the years 1960-2003 modeled using dose registry data for 2004-2015.

PubMed

Wollschläger, Daniel; Hammer, Gaël Paul; Schafft, Thomas; Dreger, Steffen; Blettner, Maria; Zeeb, Hajo

2018-05-01

Exposure to ionizing radiation of cosmic origin is an occupational risk factor in commercial aircrew. In a historic cohort of 26,774 German aircrew, radiation exposure was previously estimated only for cockpit crew using a job-exposure matrix (JEM). Here, a new method for retrospectively estimating cabin crew dose is developed. The German Federal Radiation Registry (SSR) documents individual monthly effective doses for all aircrew. SSR-provided doses on 12,941 aircrew from 2004 to 2015 were used to model cabin crew dose as a function of age, sex, job category, solar activity, and male pilots' dose; the mean annual effective dose was 2.25 mSv (range 0.01-6.39 mSv). In addition to an inverse association with solar activity, exposure followed age- and sex-dependent patterns related to individual career development and life phases. JEM-derived annual cockpit crew doses agreed with SSR-provided doses for 2004 (correlation 0.90, 0.40 mSv root mean squared error), while the estimated average annual effective dose for cabin crew had a prediction error of 0.16 mSv, equaling 7.2% of average annual dose. Past average annual cabin crew dose can be modeled by exploiting systematic external influences as well as individual behavioral determinants of radiation exposure, thereby enabling future dose-response analyses of the full aircrew cohort including measurement error information.

[SUBSTANTIATION OF DOSE LIMITS FOR A NEW NORMATIVE DOCUMENT ON RADIATION SAFETY OF LONG-DURATION SPACE MISSIONS AT ORBIT ALTITUDES OF UP TO 500 KM].

PubMed

Ushakov, I B; Grigoriev, Yu G; Shafirkin, A V; Shurshakov, V A

2016-01-01

Review of the data of experimental radiobiology and epidemiological follow-up of large groups of people subjected to radiation exposures on Earth has been undertaken to substantiate dose limits for critical organs of cosmonauts in order to ensure good performance and vitality while on long-duration orbital missions. The career dose limits for cosmonauts and astronauts established earlier in the USSR and USA amounted to nothing more but banning the risk of cancer death increase to 3%. To apply more rigorous criteria of delayed radiation risks, the Russian limits for cosmonauts were revised to substantiate a 4-fold reduction of the average tissue equivalent dose maximum to 1 Sv. The total of cancer and non-cancer radiation risks over lifetime and probable reduction of mean life expectancy (MLE) were calculated using the model of radiation-induced mortality for mammals and taken as the main damage to health. The established dose limit is equal to the career dose for nuclear industry personnel set forth by Russian standard document NRB 99/2009. For better agreement of admissible threshold doses to critical human organs (bone marrow, lens and skin) in the revised radiation limits for long-duration space missions and radiation safety limits on Earth, reduction of dose limits for the critical organs were substantiated additionally; these limits comply with those for planned over-exposure on Earth in document NRB 99/2009.

Reducing ionizing radiation doses during cardiac interventions in pregnant women.

PubMed

Orchard, Elizabeth; Dix, Sarah; Wilson, Neil; Mackillop, Lucy; Ormerod, Oliver

2012-09-01

There is concern over ionizing radiation exposure in women who are pregnant or of child-bearing age. Due to the increasing prevalence of congenital and acquired heart disease, the number of women who require cardiac interventions during pregnancy has increased. We have developed protocols for cardiac interventions in pregnant women and women of child-bearing age, aimed at substantially reducing both fluoroscopy duration and radiation doses. Over five years, we performed cardiac interventions on 15 pregnant women, nine postpartum women and four as part of prepregnancy assessment. Fluoroscopy times were minimized by simultaneous use of intracardiac echocardiography, and by using very low frame rates (2/second) during fluoroscopy. The procedures most commonly undertaken were closure of atrial septal defect (ASD) or patent foramen ovale (PFO) in 16 women, coronary angiograms in seven, right and left heart catheters in three and two stent placements. The mean screening time for all patients was 2.38 minutes (range 0.48-13.7), the median radiation dose was 66 (8.9-1501) Gy/cm(2). The median radiation dose to uterus was 1.92 (0.59-5.47) μGy, and the patient estimated dose was 0.24 (0.095-0.80) mSv. Ionizing radiation can be used safely in the management of severe cardiac structural disease in pregnancy, with very low ionizing radiation dose to the mother and extremely low exposure to the fetus. With experience, ionizing radiation doses at our institution have been reduced.

Guidance on radiation dose limits for the lens of the eye: overview of the recommendations in NCRP Commentary No. 26.

PubMed

Dauer, Lawrence T; Ainsbury, Elizabeth A; Dynlacht, Joseph; Hoel, David; Klein, Barbara E K; Mayer, Donald; Prescott, Christina R; Thornton, Raymond H; Vano, Eliseo; Woloschak, Gayle E; Flannery, Cynthia M; Goldstein, Lee E; Hamada, Nobuyuki; Tran, Phung K; Grissom, Michael P; Blakely, Eleanor A

2017-10-01

This review summarizes the conclusions and recommendations of the new National Council on Radiation Protection and Measurements (NCRP) Commentary No. 26 guidance on radiation dose limits for the lens of the eye. The NCRP addressed radiation protection principles in respect to the lens of the eye, discussed the current understanding of eye biology and lens effects, reviewed and evaluated epidemiology, and assessed exposed populations with the potential for significant radiation exposures to the lens while suggesting monitoring and protection practices. Radiation-induced damage to the lens of the eye can include the loss of clarity resulting in opacification or clouding several years after exposure. The impact is highly dependent on the type of radiation, how the exposure of the lens was delivered, the genetic susceptibilities of the individual exposed, and the location of the opacity relative to the visual axis of the individual. The preponderance of epidemiological evidence suggests that lens damage could occur at lower doses than previously considered and the NCRP has determined that it is prudent to reduce the recommended annual lens of the eye occupational dose limit from an equivalent dose of 150 mSv to an absorbed dose of 50 mGy. Significant additional research is still needed in the following areas: comprehensive evaluation of the overall effects of ionizing radiation on the eye, dosimetry methodology and dose-sparing optimization techniques, additional high quality epidemiology studies, and a basic understanding of the mechanisms of cataract development.

The effect of low dose ionizing radiation on homeostasis and functional integrity in an organotypic human skin model

DOE Office of Scientific and Technical Information (OSTI.GOV)

von Neubeck, Claere; Geniza, Matthew; Kauer, Paula M.

Outside the protection of earth’s atmosphere, astronauts are exposed to low doses of high linear energy transfer (LET) radiation. Future NASA plans for deep space missions or a permanent settlement on the moon are limited by the health risks associated with space radiation exposures. There is a paucity of direct epidemiological data for low dose exposures to space radiation-relevant high LET ions. Health risk models are used to estimate the risk for such exposures, though these models are based on high dose experiments. There is increasing evidence, however, that low and high dose exposures result in different signaling events atmore » the molecular level, and may involve different response mechanisms. Further, despite their low abundance, high LET particles have been identified as the major contributor to health risk during manned space flight. The human skin is exposed in every external radiation scenario, making it an ideal epithelial tissue model in which to study radiation induced effects. Here, we exposed an in vitro three dimensional (3-D) human organotypic skin tissue model to low doses of high LET oxygen (O), silicon (Si) and iron (Fe) ions. We measured proliferation and differentiation profiles in the skin tissue and examined the integrity of the skin’s barrier function. We discuss the role of secondary particles in changing the proportion of cells receiving a radiation dose, emphasizing the possible impact on radiation-induced health issues in astronauts.« less

Pulmonary Venous Anatomy Imaging with Low-Dose, Prospectively ECG-Triggered, High-Pitch 128-Slice Dual Source Computed Tomography

PubMed Central

Thai, Wai-ee; Wai, Bryan; Lin, Kaity; Cheng, Teresa; Heist, E. Kevin; Hoffmann, Udo; Singh, Jagmeet; Truong, Quynh A.

2012-01-01

Background Efforts to reduce radiation from cardiac computed tomography (CT) are essential. Using a prospectively triggered, high-pitch dual source CT (DSCT) protocol, we aim to determine the radiation dose and image quality (IQ) in patients undergoing pulmonary vein (PV) imaging. Methods and Results In 94 patients (61±9 years, 71% male) who underwent 128-slice DSCT (pitch 3.4), radiation dose and IQ were assessed and compared between 69 patients in sinus rhythm (SR) and 25 in atrial fibrillation (AF). Radiation dose was compared in a subset of 19 patients with prior retrospective or prospectively triggered CT PV scans without high-pitch. In a subset of 18 patients with prior magnetic resonance imaging (MRI) for PV assessment, PV anatomy and scan duration were compared to high-pitch CT. Using the high-pitch protocol, total effective radiation dose was 1.4 [1.3, 1.9] mSv, with no difference between SR and AF (1.4 vs 1.5 mSv, p=0.22). No high-pitch CT scans were non-diagnostic or had poor IQ. Radiation dose was reduced with high-pitch (1.6 mSv) compared to standard protocols (19.3 mSv, p<0.0001). This radiation dose reduction was seen with SR (1.5 vs 16.7 mSv, p<0.0001) but was more profound with AF (1.9 vs 27.7 mSv, p=0.039). There was excellent agreement of PV anatomy (kappa 0.84, p<0.0001), and a shorter CT scan duration (6 minutes) compared to MRI (41 minutes, p<0.0001). Conclusions Using a high-pitch DSCT protocol, PV imaging can be performed with minimal radiation dose, short scan acquisition, and excellent IQ in patients with SR or AF. This protocol highlights the success of new cardiac CT technology to minimize radiation exposure, giving clinicians a new low-dose imaging alternative to assess PV anatomy. PMID:22586259

The Hematopoietic Syndrome of the Acute Radiation Syndrome in Rhesus Macaques: A Systematic Review of the Lethal Dose Response Relationship.

PubMed

MacVittie, Thomas J; Farese, Ann M; Jackson, William

2015-11-01

Well characterized animal models that mimic the human response to potentially lethal doses of radiation are required to assess the efficacy of medical countermeasures under the criteria of the U.S. Food and Drug Administration "animal rule." Development of a model requires the determination of the radiation dose response relationship and time course of mortality and morbidity across the hematopoietic acute radiation syndrome. The nonhuman primate, rhesus macaque, is a relevant animal model that may be used to determine the efficacy of medical countermeasures to mitigate major signs of morbidity and mortality at selected lethal doses of total body irradiation. A systematic review of relevant studies that determined the dose response relationship for the hematopoietic acute radiation syndrome in the rhesus macaque relative to radiation quality, dose rate, and exposure uniformity has never been performed. The selection of data cohorts was made from the following sources: Ovid Medline (1957-present), PubMed (1954-present), AGRICOLA (1976-present), Web of Science (1954-present), and U.S. HHS REPORT (2002 to present). The following terms were used: Rhesus, total body-irradiation, total body x irradiation, TBI, irradiation, gamma radiation, hematopoiesis, LD50/60, Macaca mulatta, whole-body irradiation, nonhuman primate, NHP, monkey, primates, hematopoietic radiation syndrome, mortality, and nuclear radiation. The reference lists of all studies, published and unpublished, were reviewed for additional studies. The total number of hits across all search sites was 3,001. There were a number of referenced, unpublished, non-peer reviewed government reports that were unavailable for review. Fifteen studies, 11 primary (n = 863) and four secondary (n = 153) studies [n = 1,016 total nonhuman primates (NHP), rhesus Macaca mulatta] were evaluated to provide an informative and consistent review. The dose response relationships (DRRs) were determined for uniform or non-uniform total body irradiation (TBI) with 250 kVp or 2 MeV x radiation, Co gamma radiation and reactor- and nuclear weapon-derived mixed gamma: neutron-radiation, delivered at various dose rates from a total body, bilateral, rotational, or unilateral exposure aspect. The DRRs established by a probit analysis vs. linear dose relationship were characterized by two main parameters or dependent variables: a slope and LD50/30. Respective LD50/30 values for studies that used 250 kVp x radiation (five primary studies combined, n = 338), 2 MeV x radiation, Co gamma radiation, and steady-state reactor-derived mixed gamma:neutron radiation for total body uniform exposures were 521 rad [498, 542], 671 rad [632, 715], 644 rad [613, 678], and 385 rad [357, 413]. The respective slopes were steep and ranged from 0.738 to 1.316. The DRR, LD50/30 values and slopes were also determined for total body, non-uniform, unilateral, pulse-rate exposures of mixed gamma:neutron radiation derived at reactor and nuclear weapon detonations. The LD50/30 values were, respectively, 395 rad [337, 432] and 412 rad [359, 460]. Secondary data sets of limited studies that did not describe a DRR were used to support the mid-to-high lethal dose range for the H-ARS and the threshold dose range for the concurrent acute GI ARS. The available evidence provided a reliable and extensive database that characterized the DRR for the H-ARS in young rhesus macaques exposed to 250 kVp uniform total body x radiation without the benefit of medical management. A less substantial but consistent database demonstrated the DRR for total body exposure of differing radiation quality, dose rate and non-uniform exposure. The DRR for the H-ARS is characterized by steep slopes and relative LD50/30 values that reflect the radiation quality, exposure aspect, and dose rate over a range in time from 1954-2012.

Low-energy electron effects on tensile modulus and infrared transmission properties of a polypyromellitimide film

NASA Technical Reports Server (NTRS)

Ferl, J. E.; Long, E. R., Jr.

1981-01-01

Infrared (IR) spectroscopy and tensile modulus testing were used to evaluate the importance of experimental procedure on changes in properties of pyromellitic dianhydride-p,p prime-oxydianiline film exposed to electron radiation. The radiation exposures were accelerated, approximate equivalents to the total dose expected for a 30 year mission in geosynchronous Earth orbit. The change in the tensile modulus depends more on the dose rate and the time interval between exposure and testing than on total dose. The IR data vary with both total dose and dose rate. A threshold dose rate exists below which reversible radiation effects on the IR spectra occur. Above the threshold dose rate, irreversible effects occur with the appearance of a new band. Post-irradiation and in situ IR absorption bands are significantly different. It is suggested that the electron radiation induced metastable, excites molecular states.

Inconstant sun: how solar evolution has affected cosmic and ultraviolet radiation exposure over the history of life on Earth.

PubMed

Karam, P Andrew

2003-03-01

Four billion years ago, sea-level UV exposure was more than 400 times as intense as today, the dose from solar cosmic rays was five times present levels, and galactic cosmic rays accounted for only about 10% their current contribution to sea-level radiation doses. Exposure to cosmic radiation accounts for about 10% of natural background radiation exposure today and includes dose from galactic cosmic rays and solar charged particles. There is little exposure to ionizing wavelengths of UV due to absorption by ozone. The sun has evolved significantly over its life; in the past there were higher levels of particulate radiation and lower UV emissions from the sun, and a stronger solar wind reduced radiation dose in the inner solar system from galactic cosmic rays. Finally, since the early atmosphere contained little to no oxygen, surface levels of UV radiation were far higher in the past.

Dose relations between goal setting, theory-based correlates of goal setting and increases in physical activity during a workplace trial.

PubMed

Dishman, Rod K; Vandenberg, Robert J; Motl, Robert W; Wilson, Mark G; DeJoy, David M

2010-08-01

The effectiveness of an intervention depends on its dose and on moderators of dose, which usually are not studied. The purpose of the study is to determine whether goal setting and theory-based moderators of goal setting had dose relations with increases in goal-related physical activity during a successful workplace intervention. A group-randomized 12-week intervention that included personal goal setting was implemented in fall 2005, with a multiracial/ethnic sample of employees at 16 geographically diverse worksites. Here, we examined dose-related variables in the cohort of participants (N = 664) from the 8 worksites randomized to the intervention. Participants in the intervention exceeded 9000 daily pedometer steps and 300 weekly minutes of moderate-to-vigorous physical activity (MVPA) during the last 6 weeks of the study, which approximated or exceeded current public health guidelines. Linear growth modeling indicated that participants who set higher goals and sustained higher levels of self-efficacy, commitment and intention about attaining their goals had greater increases in pedometer steps and MVPA. The relation between change in participants' satisfaction with current physical activity and increases in physical activity was mediated by increases in self-set goals. The results show a dose relation of increased physical activity with changes in goal setting, satisfaction, self-efficacy, commitment and intention, consistent with goal-setting theory.

Gross alpha and beta activity and annual committed effective dose due to natural radionuclides in some water spinach (ipomoea aquatica Forssk) samples in Ho Chi Minh City, Vietnam.

PubMed

Le, Hao Cong; Nguyen, Thang Van; Huynh, Thu Nguyen Phong; Huynh, Phuong Truc

2017-07-01

The results of gross alpha and beta radioactivity measurement in water spinach samples from some districts in Ho Chi Minh City, Vietnam are presented in this paper. The measurements were performed using a low-background proportional counters LB4200 manufactured by Canberra Company, Inc. Mean concentrations of gross alpha and beta activity were found to be 1.50 ± 0.38 Bq kg -1 to 84.25 ± 8.67 Bq kg -1 . In order to keep the recommended dose level, a recommended maximum intake of water spinach was proposed to be 6 kg fresh per year. The total annual committed effective dose due to natural radionuclides in water spinach samples was then found in range from 0.07 mSv y -1 to 0.82 mSv y -1 . The dose from 26.32% of samples exceeds the exemption mean dose criterion of 0.3 mSv y -1 but complies with the upper dose principle of 1 mSv y -1 provided in UNSCEAR 2008 report. The estimated soil-to-plant transfer factors for gross alpha and beta for water spinach samples were also presented. Copyright © 2016 Elsevier Ltd. All rights reserved.

Radiation-Induced Leukemia at Doses Relevant to Radiation Therapy: Modeling Mechanisms and Estimating Risks

NASA Technical Reports Server (NTRS)

Shuryak, Igor; Sachs, Rainer K.; Hlatky, Lynn; Mark P. Little; Hahnfeldt, Philip; Brenner, David J.

2006-01-01

Because many cancer patients are diagnosed earlier and live longer than in the past, second cancers induced by radiation therapy have become a clinically significant issue. An earlier biologically based model that was designed to estimate risks of high-dose radiation induced solid cancers included initiation of stem cells to a premalignant state, inactivation of stem cells at high radiation doses, and proliferation of stem cells during cellular repopulation after inactivation. This earlier model predicted the risks of solid tumors induced by radiation therapy but overestimated the corresponding leukemia risks. Methods: To extend the model to radiation-induced leukemias, we analyzed in addition to cellular initiation, inactivation, and proliferation a repopulation mechanism specific to the hematopoietic system: long-range migration through the blood stream of hematopoietic stem cells (HSCs) from distant locations. Parameters for the model were derived from HSC biologic data in the literature and from leukemia risks among atomic bomb survivors v^ ho were subjected to much lower radiation doses. Results: Proliferating HSCs that migrate from sites distant from the high-dose region include few preleukemic HSCs, thus decreasing the high-dose leukemia risk. The extended model for leukemia provides risk estimates that are consistent with epidemiologic data for leukemia risk associated with radiation therapy over a wide dose range. For example, when applied to an earlier case-control study of 110000 women undergoing radiotherapy for uterine cancer, the model predicted an excess relative risk (ERR) of 1.9 for leukemia among women who received a large inhomogeneous fractionated external beam dose to the bone marrow (mean = 14.9 Gy), consistent with the measured ERR (2.0, 95% confidence interval [CI] = 0.2 to 6.4; from 3.6 cases expected and 11 cases observed). As a corresponding example for brachytherapy, the predicted ERR of 0.80 among women who received an inhomogeneous low-dose-rate dose to the bone marrow (mean = 2.5 Gy) was consistent with the measured ERR (0.62, 95% Cl =-0.2 to 1.9). Conclusions: An extended, biologically based model for leukemia that includes HSC initiation, inactivation, proliferation, and, uniquely for leukemia, long-range HSC migration predicts, %Kith reasonable accuracy, risks for radiationinduced leukemia associated with exposure to therapeutic doses of radiation.

High-performing simulations of the space radiation environment for the International Space Station and Apollo Missions

NASA Astrophysics Data System (ADS)

Lund, Matthew Lawrence

The space radiation environment is a significant challenge to future manned and unmanned space travels. Future missions will rely more on accurate simulations of radiation transport in space through spacecraft to predict astronaut dose and energy deposition within spacecraft electronics. The International Space Station provides long-term measurements of the radiation environment in Low Earth Orbit (LEO); however, only the Apollo missions provided dosimetry data beyond LEO. Thus dosimetry analysis for deep space missions is poorly supported with currently available data, and there is a need to develop dosimetry-predicting models for extended deep space missions. GEANT4, a Monte Carlo Method, provides a powerful toolkit in C++ for simulation of radiation transport in arbitrary media, thus including the spacecraft and space travels. The newest version of GEANT4 supports multithreading and MPI, resulting in faster distributive processing of simulations in high-performance computing clusters. This thesis introduces a new application based on GEANT4 that greatly reduces computational time using Kingspeak and Ember computational clusters at the Center for High Performance Computing (CHPC) to simulate radiation transport through full spacecraft geometry, reducing simulation time to hours instead of weeks without post simulation processing. Additionally, this thesis introduces a new set of detectors besides the historically used International Commission of Radiation Units (ICRU) spheres for calculating dose distribution, including a Thermoluminescent Detector (TLD), Tissue Equivalent Proportional Counter (TEPC), and human phantom combined with a series of new primitive scorers in GEANT4 to calculate dose equivalence based on the International Commission of Radiation Protection (ICRP) standards. The developed models in this thesis predict dose depositions in the International Space Station and during the Apollo missions showing good agreement with experimental measurements. From these models the greatest contributor to radiation dose for the Apollo missions was from Galactic Cosmic Rays due to the short time within the radiation belts. The Apollo 14 dose measurements were an order of magnitude higher compared to other Apollo missions. The GEANT4 model of the Apollo Command Module shows consistent doses due to Galactic Cosmic Rays and Radiation Belts for all missions, with a small variation in dose distribution across the capsule. The model also predicts well the dose depositions and equivalent dose values in various human organs for the International Space Station or Apollo Command Module.

Radiation Dose-Response Model for Locally Advanced Rectal Cancer After Preoperative Chemoradiation Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Appelt, Ane L., E-mail: ane.lindegaard.appelt@slb.regionsyddanmark.dk; University of Southern Denmark, Odense; Ploen, John

2013-01-01

Purpose: Preoperative chemoradiation therapy (CRT) is part of the standard treatment of locally advanced rectal cancers. Tumor regression at the time of operation is desirable, but not much is known about the relationship between radiation dose and tumor regression. In the present study we estimated radiation dose-response curves for various grades of tumor regression after preoperative CRT. Methods and Materials: A total of 222 patients, treated with consistent chemotherapy and radiation therapy techniques, were considered for the analysis. Radiation therapy consisted of a combination of external-beam radiation therapy and brachytherapy. Response at the time of operation was evaluated from themore » histopathologic specimen and graded on a 5-point scale (TRG1-5). The probability of achieving complete, major, and partial response was analyzed by ordinal logistic regression, and the effect of including clinical parameters in the model was examined. The radiation dose-response relationship for a specific grade of histopathologic tumor regression was parameterized in terms of the dose required for 50% response, D{sub 50,i}, and the normalized dose-response gradient, {gamma}{sub 50,i}. Results: A highly significant dose-response relationship was found (P=.002). For complete response (TRG1), the dose-response parameters were D{sub 50,TRG1} = 92.0 Gy (95% confidence interval [CI] 79.3-144.9 Gy), {gamma}{sub 50,TRG1} = 0.982 (CI 0.533-1.429), and for major response (TRG1-2) D{sub 50,TRG1} and {sub 2} = 72.1 Gy (CI 65.3-94.0 Gy), {gamma}{sub 50,TRG1} and {sub 2} = 0.770 (CI 0.338-1.201). Tumor size and N category both had a significant effect on the dose-response relationships. Conclusions: This study demonstrated a significant dose-response relationship for tumor regression after preoperative CRT for locally advanced rectal cancer for tumor dose levels in the range of 50.4-70 Gy, which is higher than the dose range usually considered.« less

OCCUPATIONAL RADIATION DOSES TO OPERATORS PERFORMING FLUOROSCOPICALLY-GUIDED PROCEDURES

PubMed Central

Kim, Kwang Pyo; Miller, Donald L.; de Gonzalez, Amy Berrington; Balter, Stephen; Kleinerman, Ruth A.; Ostroumova, Evgenia; Simon, Steven L.; Linet, Martha S.

2012-01-01

In the past 30 years, the numbers and types of fluoroscopically-guided (FG) procedures have increased dramatically. The objective of the present study is to provide estimated radiation doses to physician specialists, other than cardiologists, who perform FG procedures. We searched Medline to identify English-language journal articles reporting radiation exposures to these physicians. We then identified several primarily therapeutic FG procedures that met specific criteria: well-defined procedures for which there were at least five published reports of estimated radiation doses to the operator, procedures performed frequently in current medical practice, and inclusion of physicians from multiple medical specialties. These procedures were percutaneous nephrolithotomy (PCNL), vertebroplasty, orthopedic extremity nailing for treatment of fractures, biliary tract procedures, transjugular intrahepatic portosystemic shunt creation (TIPS), head/neck endovascular therapeutic procedures, and endoscopic retrograde cholangiopancreatography (ERCP). We abstracted radiation doses and other associated data, and estimated effective dose to operators. Operators received estimated doses per patient procedure equivalent to doses received by interventional cardiologists. The estimated effective dose per case ranged from 1.7 – 56μSv for PCNL, 0.1 – 101 μSv for vertebroplasty, 2.5 – 88μSv for orthopedic extremity nailing, 2.0 – 46μSv for biliary tract procedures, 2.5 – 74μSv for TIPS, 1.8 – 53μSv for head/neck endovascular therapeutic procedures, and 0.2 – 49μSv for ERCP. Overall, mean operator radiation dose per case measured over personal protective devices at different anatomic sites on the head and body ranged from 19 – 800 (median = 113) μSv at eye level, 6 – 1180 (median = 75)μSv at the neck, and 2 – 1600 (median = 302) μSv at the trunk. Operators’ hands often received greater doses than the eyes, neck or trunk. Large variations in operator doses suggest that optimizing procedure protocols and proper use of protective devices and shields might reduce occupational radiation dose substantially. PMID:22647920

Hybrid dose calculation: a dose calculation algorithm for microbeam radiation therapy

NASA Astrophysics Data System (ADS)

Donzelli, Mattia; Bräuer-Krisch, Elke; Oelfke, Uwe; Wilkens, Jan J.; Bartzsch, Stefan

2018-02-01

Microbeam radiation therapy (MRT) is still a preclinical approach in radiation oncology that uses planar micrometre wide beamlets with extremely high peak doses, separated by a few hundred micrometre wide low dose regions. Abundant preclinical evidence demonstrates that MRT spares normal tissue more effectively than conventional radiation therapy, at equivalent tumour control. In order to launch first clinical trials, accurate and efficient dose calculation methods are an inevitable prerequisite. In this work a hybrid dose calculation approach is presented that is based on a combination of Monte Carlo and kernel based dose calculation. In various examples the performance of the algorithm is compared to purely Monte Carlo and purely kernel based dose calculations. The accuracy of the developed algorithm is comparable to conventional pure Monte Carlo calculations. In particular for inhomogeneous materials the hybrid dose calculation algorithm out-performs purely convolution based dose calculation approaches. It is demonstrated that the hybrid algorithm can efficiently calculate even complicated pencil beam and cross firing beam geometries. The required calculation times are substantially lower than for pure Monte Carlo calculations.

21 CFR 352.72 - General testing procedures.

Code of Federal Regulations, 2010 CFR

2010-04-01

... administered the doses of UV radiation. After UV radiation exposure from the solar simulator is completed, all... specified dosage of UV radiation, in a series of UV radiation exposures, in which the test site area is... subsites should be exposed to the varying doses of UV radiation in a randomized manner. (f) Waiting period...

Crosstalk between Fas and JNK determines lymphocyte apoptosis after ionizing radiation.

PubMed

Praveen, Koganti; Saxena, Nandita

2013-06-01

Radiation simultaneously activate Fas and JNK pathway in lymphocytes but their precise interaction is not clearly understood. Activation of Fas pathway is required for radiation induced apoptosis, however induction of JNK pathway may or may not contribute in apoptosis. Here we report that Fas, Fas associated death domain and total JNK are activated in a dose- and time-dependent radiation exposure. A biphasic pattern of phospho-JNK was found at lower doses (1 and 2 Gy), however at higher doses of radiation phospho-JNK was continuously activated. Interestingly, Fas ligand expression remained biphasic at all the doses of radiation. Our results suggest that the Fas pathway is the major player in radiation-induced apoptosis, with JNK playing a contributory role. We also observed that Fas ligand expression by radiation is dependent on JNK activation. We also propose that radiation activates JNK pathway, but sustained activation is required for maximal induction of apoptosis at later times. Our findings define a mechanism for crosstalk between JNK and Fas pathway in radiation-induced apoptosis, which may lead to the development of new therapeutic strategies.

Environmental standards for ionizing radiation: theoretical basis for dose-response curves.

PubMed Central

Upton, A C

1983-01-01

The types of injury attributable to ionizing radiation are subdivided, for purposes of risk assessment and radiological protection, into two broad categories: stochastic effects and nonstochastic effects. Stochastic effects are viewed as probablistic phenomena, varying in frequency but not severity as a function of the dose, without any threshold; nonstochastic effects are viewed as deterministic phenomena, varying in both frequency and severity as a function of the dose, with clinical thresholds. Included among stochastic effects are heritable effects (mutations and chromosome aberrations) and carcinogenic effects. Both types of effects are envisioned as unicellular phenomena which can result from nonlethal injury of individual cells, without the necessity of damage to other cells. For the induction of mutations and chromosome aberrations in the low-to-intermediate dose range, the dose-response curve with high-linear energy transfer (LET) radiation generally conforms to a linear nonthreshold relationship and varies relatively little with the dose rate. In contrast, the curve with low-LET radiation generally conforms to a linear-quadratic relationship, rising less steeply than the curve with high-LET radiation and increasing in slope with increasing dose and dose rate. The dose-response curve for carcinogenic effects varies widely from one type of neoplasm to another in the intermediate-to-high dose range, in part because of differences in the way large doses of radiation can affect the promotion and progression of different neoplasms. Information about dose-response relations for low-level irradiation is fragmentary but consistent, in general, with the hypothesis that the neoplastic transformation may result from mutation, chromosome aberration or genetic recombination in a single susceptible cell. PMID:6653536

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berrington de Gonzalez, Amy, E-mail: berringtona@mail.nih.gov; Gilbert, Ethel; Curtis, Rochelle

Rapid innovations in radiation therapy techniques have resulted in an urgent need for risk projection models for second cancer risks from high-dose radiation exposure, because direct observation of the late effects of newer treatments will require patient follow-up for a decade or more. However, the patterns of cancer risk after fractionated high-dose radiation are much less well understood than those after lower-dose exposures (0.1-5 Gy). In particular, there is uncertainty about the shape of the dose-response curve at high doses and about the magnitude of the second cancer risk per unit dose. We reviewed the available evidence from epidemiologic studiesmore » of second solid cancers in organs that received high-dose exposure (>5 Gy) from radiation therapy where dose-response curves were estimated from individual organ-specific doses. We included 28 eligible studies with 3434 second cancer patients across 11 second solid cancers. Overall, there was little evidence that the dose-response curve was nonlinear in the direction of a downturn in risk, even at organ doses of ≥60 Gy. Thyroid cancer was the only exception, with evidence of a downturn after 20 Gy. Generally the excess relative risk per Gray, taking account of age and sex, was 5 to 10 times lower than the risk from acute exposures of <2 Gy among the Japanese atomic bomb survivors. However, the magnitude of the reduction in risk varied according to the second cancer. The results of our review provide insights into radiation carcinogenesis from fractionated high-dose exposures and are generally consistent with current theoretical models. The results can be used to refine the development of second solid cancer risk projection models for novel radiation therapy techniques.« less

Enhanced Low Dose Rate Effects in Bipolar Circuits: A New Hardness Assurance Problem for NASA

NASA Technical Reports Server (NTRS)

Johnston, A.; Barnes, C.

1995-01-01

Many bipolar integrated circuits are much more susceptible to ionizing radiation at low dose rates than they are at high dose rates typically used for radiation parts testing. Since the low dose rate is equivalent to that seen in space, the standard lab test no longer can be considered conservative and has caused the Air Force to issue an alert. Although a reliable radiation hardness assurance test has not yet been designed, possible mechanisms for low dose rate enhancement and hardness assurance tests are discussed.

An Overview of NASA's Risk of Cardiovascular Disease from Radiation Exposure

NASA Technical Reports Server (NTRS)

Patel, Zarana S.; Huff, Janice L.; Simonsen, Lisa C.

2015-01-01

The association between high doses of radiation exposure and cardiovascular damage is well established. Patients that have undergone radiotherapy for primary cancers of the head and neck and mediastinal regions have shown increased risk of heart and vascular damage and long-term development of radiation-induced heart disease [1]. In addition, recent meta-analyses of epidemiological data from atomic bomb survivors and nuclear industry workers has also shown that acute and chronic radiation exposures is strongly correlated with an increased risk of circulatory disease at doses above 0.5 Sv [2]. However, these analyses are confounded for lower doses by lifestyle factors, such as drinking, smoking, and obesity. The types of radiation found in the space environment are significantly more damaging than those found on Earth and include galactic cosmic radiation (GCR), solar particle events (SPEs), and trapped protons and electrons. In addition to the low-LET data, only a few studies have examined the effects of heavy ion radiation on atherosclerosis, and at lower, space-relevant doses, the association between exposure and cardiovascular pathology is more varied and unclear. Understanding the qualitative differences in biological responses produced by GCR compared to Earth-based radiation is a major focus of space radiation research and is imperative for accurate risk assessment for long duration space missions. Other knowledge gaps for the risk of radiation-induced cardiovascular disease include the existence of a dose threshold, low dose rate effects, and potential synergies with other spaceflight stressors. The Space Radiation Program Element within NASA's Human Research Program (HRP) is managing the research and risk mitigation strategies for these knowledge gaps. In this presentation, we will review the evidence and present an overview of the HRP Risk of Cardiovascular Disease and Other Degenerative Tissue Effects from Radiation Exposure.

Space-type radiation induces multimodal responses in the mouse gut microbiome and metabolome.

PubMed

Casero, David; Gill, Kirandeep; Sridharan, Vijayalakshmi; Koturbash, Igor; Nelson, Gregory; Hauer-Jensen, Martin; Boerma, Marjan; Braun, Jonathan; Cheema, Amrita K

2017-08-18

Space travel is associated with continuous low dose rate exposure to high linear energy transfer (LET) radiation. Pathophysiological manifestations after low dose radiation exposure are strongly influenced by non-cytocidal radiation effects, including changes in the microbiome and host gene expression. Although the importance of the gut microbiome in the maintenance of human health is well established, little is known about the role of radiation in altering the microbiome during deep-space travel. Using a mouse model for exposure to high LET radiation, we observed substantial changes in the composition and functional potential of the gut microbiome. These were accompanied by changes in the abundance of multiple metabolites, which were related to the enzymatic activity of the predicted metagenome by means of metabolic network modeling. There was a complex dynamic in microbial and metabolic composition at different radiation doses, suggestive of transient, dose-dependent interactions between microbial ecology and signals from the host's cellular damage repair processes. The observed radiation-induced changes in microbiota diversity and composition were analyzed at the functional level. A constitutive change in activity was found for several pathways dominated by microbiome-specific enzymatic reactions like carbohydrate digestion and absorption and lipopolysaccharide biosynthesis, while the activity in other radiation-responsive pathways like phosphatidylinositol signaling could be linked to dose-dependent changes in the abundance of specific taxa. The implication of microbiome-mediated pathophysiology after low dose ionizing radiation may be an unappreciated biologic hazard of space travel and deserves experimental validation. This study provides a conceptual and analytical basis of further investigations to increase our understanding of the chronic effects of space radiation on human health, and points to potential new targets for intervention in adverse radiation effects.

Dosimetric and Clinical Analysis of Spatial Distribution of the Radiation Dose in Gamma Knife Radiosurgery for Vestibular Schwannoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Massager, Nicolas, E-mail: nmassage@ulb.ac.be; Neurosurgery-Department, Hospital Erasme, Brussels; Lonneville, Sarah

2011-11-15

Objectives: We investigated variations in the distribution of radiation dose inside (dose inhomogeneity) and outside (dose falloff) the target volume during Gamma Knife (GK) irradiation of vestibular schwannoma (VS). We analyzed the relationship between some parameters of dose distribution and the clinical and radiological outcome of patients. Methods and Materials: Data from dose plans of 203 patients treated for a vestibular schwannoma by GK C using same prescription dose (12 Gy at the 50% isodose) were collected. Four different dosimetric indexes were defined and calculated retrospectively in all plannings on the basis of dose-volume histograms: Paddick conformity index (PI), gradientmore » index (GI), homogeneity index (HI), and unit isocenter (UI). The different measures related to distribution of the radiation dose were compared with hearing and tumor outcome of 203 patients with clinical and radiological follow-up of minimum 2 years. Results: Mean, median, SD, and ranges of the four indexes of dose distribution analyzed were calculated; large variations were found between dose plans. We found a high correlation between the target volume and PI, GI, and UI. No significant association was found between the indexes of dose distribution calculated in this study and tumor control, tumor volume shrinkage, hearing worsening, loss of functional hearing, or complete hearing loss at last follow-up. Conclusions: Parameters of distribution of the radiation dose during GK radiosurgery for VS can be highly variable between dose plans. The tumor and hearing outcome of patients treated is not significantly related to these global indexes of dose distribution inside and around target volume. In GK radiosurgery for VS, the outcome seems more to be influenced by local radiation dose delivered to specific structures or volumes than by global dose gradients.« less

Imaging and characterization of primary and secondary radiation in ion beam therapy

NASA Astrophysics Data System (ADS)

Granja, Carlos; Martisikova, Maria; Jakubek, Jan; Opalka, Lukas; Gwosch, Klaus

2016-07-01

Imaging in ion beam therapy is an essential and increasingly significant tool for treatment planning and radiation and dose deposition verification. Efforts aim at providing precise radiation field characterization and online monitoring of radiation dose distribution. A review is given of the research and methodology of quantum-imaging, composition, spectral and directional characterization of the mixed-radiation fields in proton and light ion beam therapy developed by the IEAP CTU Prague and HIT Heidelberg group. Results include non-invasive imaging of dose deposition and primary beam online monitoring.

Hypothyroidism after Radiation Therapy for Childhood Cancer: A Report from the Childhood Cancer Survivor Study.

PubMed

Inskip, Peter D; Veiga, Lene H S; Brenner, Alina V; Sigurdson, Alice J; Ostroumova, Evgenia; Chow, Eric J; Stovall, Marilyn; Smith, Susan A; Weathers, Rita E; Leisenring, Wendy; Robison, Leslie L; Armstrong, Gregory T; Sklar, Charles A; Lubin, Jay H

2018-05-15

While thyroid cancer risks from exposure to ionizing radiation early in life are well characterized quantitatively, the association of radiation with nonmalignant, functional thyroid disorders has been less studied. Here, we report on a risk analysis study of hypothyroidism with radiation dose to the thyroid gland and the hypothalamic-pituitary axis among survivors of childhood cancer. Utilizing data from the Childhood Cancer Survivor Study, a cohort of 14,364 five-year survivors of childhood cancer diagnosed at 26 hospitals in the U.S. and Canada between 1970 and 1986 and followed through 2009, the occurrence of hypothyroidism was ascertained among 12,015 survivors through serial questionnaires. Radiation doses to the thyroid gland and pituitary gland were estimated from radiotherapy records. Binary outcome regression was used to estimate prevalence odds ratios for hypothyroidism at five years from diagnosis of childhood cancer and Poisson regression to model incidence rate ratios (RR) after the first five years. A total of 1,193 cases of hypothyroidism were observed, 777 (65%) of which occurred five or more years after cancer diagnosis. The cumulative proportion affected with hypothyroidism (prevalence at five years after cancer diagnosis plus incidence through 30 years after cancer diagnosis) was highest among five-year survivors of Hodgkin lymphoma (32.3%; 95% CI: 29.5-34.9) and cancers of the central nervous system (17.7%; 95% CI: 15.2-20.4). The incidence rate was significantly associated with radiation dose to the thyroid and pituitary. The joint association of hypothyroidism with thyroid and pituitary dose was sub-additive for pituitary doses greater than 16 Gy. In particular, a very strong thyroid radiation dose dependence at low-to-moderate pituitary/hypothalamic doses was diminished at high pituitary doses. Radiation-related risks were higher in males than females and inversely associated with age at exposure and time since exposure but remained elevated more than 25 years after exposure. Our findings indicated that hypothyroidism was significantly associated with treatment with bleomycin (RR = 3.4; 95% CI: 1.6-7.3) and the alkylating agents cyclohexyl-chloroethyl-nitrosourea (CCNU) (RR = 3.0; 95% CI: 1.5-5.3) and cyclophosphamide (RR = 1.3; 95% CI: 1.0-1.8), with a significant dose response for CCNU ( P < 0.01). The risk of hypothyroidism among childhood cancer survivors treated with radiation depends both on direct, dose-dependent radiation-induced damage to the thyroid gland and on dose-dependent indirect effects secondary to irradiation of the hypothalamic-pituitary axis. The dose-response relationship for each site depends on dose to the other. Radiation-related risk persists for more than 25 years after treatment. Treatment with certain chemotherapy agents may increase the risk of hypothyroidism.

A dose-response curve for biodosimetry from a 6 MV electron linear accelerator

PubMed Central

Lemos-Pinto, M.M.P.; Cadena, M.; Santos, N.; Fernandes, T.S.; Borges, E.; Amaral, A.

2015-01-01

Biological dosimetry (biodosimetry) is based on the investigation of radiation-induced biological effects (biomarkers), mainly dicentric chromosomes, in order to correlate them with radiation dose. To interpret the dicentric score in terms of absorbed dose, a calibration curve is needed. Each curve should be constructed with respect to basic physical parameters, such as the type of ionizing radiation characterized by low or high linear energy transfer (LET) and dose rate. This study was designed to obtain dose calibration curves by scoring of dicentric chromosomes in peripheral blood lymphocytes irradiated in vitro with a 6 MV electron linear accelerator (Mevatron M, Siemens, USA). Two software programs, CABAS (Chromosomal Aberration Calculation Software) and Dose Estimate, were used to generate the curve. The two software programs are discussed; the results obtained were compared with each other and with other published low LET radiation curves. Both software programs resulted in identical linear and quadratic terms for the curve presented here, which was in good agreement with published curves for similar radiation quality and dose rates. PMID:26445334

Scattered radiation from dental metallic crowns in head and neck radiotherapy.

PubMed

Shimozato, T; Igarashi, Y; Itoh, Y; Yamamoto, N; Okudaira, K; Tabushi, K; Obata, Y; Komori, M; Naganawa, S; Ueda, M

2011-09-07

We aimed to estimate the scattered radiation from dental metallic crowns during head and neck radiotherapy by irradiating a jaw phantom with external photon beams. The phantom was composed of a dental metallic plate and hydroxyapatite embedded in polymethyl methacrylate. We used radiochromic film measurement and Monte Carlo simulation to calculate the radiation dose and dose distribution inside the phantom. To estimate dose variations in scattered radiation under different clinical situations, we altered the incident energy, field size, plate thickness, plate depth and plate material. The simulation results indicated that the dose at the incident side of the metallic dental plate was approximately 140% of that without the plate. The differences between dose distributions calculated with the radiation treatment-planning system (TPS) algorithms and the data simulation, except around the dental metallic plate, were 3% for a 4 MV photon beam. Therefore, we should carefully consider the dose distribution around dental metallic crowns determined by a TPS.

Relationship between Eustachian tube dysfunction and otitis media with effusion in radiotherapy patients.

PubMed

Akazawa, K; Doi, H; Ohta, S; Terada, T; Fujiwara, M; Uwa, N; Tanooka, M; Sakagami, M

2018-02-01

This study evaluated the relationship between radiation and Eustachian tube dysfunction, and examined the radiation dose required to induce otitis media with effusion. The function of 36 Eustachian tubes in 18 patients with head and neck cancer were examined sonotubometrically before, during, and 1, 2 and 3 months after, intensity-modulated radiotherapy. Patients with an increase of 5 dB or less in sound pressure level (dB) during swallowing were categorised as being in the dysfunction group. Additionally, radiation dose distributions were assessed in all Eustachian tubes using three dose-volume histogram parameters. Twenty-two of 25 normally functioning Eustachian tubes before radiotherapy (88.0 per cent) shifted to the dysfunction group after therapy. All ears that developed otitis media with effusion belonged to the dysfunction group. The radiation dose threshold evaluation revealed that ears with otitis media with effusion received significantly higher doses to the Eustachian tubes. The results indicate a relationship between radiation dose and Eustachian tube dysfunction and otitis media with effusion.

Scattered radiation from dental metallic crowns in head and neck radiotherapy

NASA Astrophysics Data System (ADS)

Shimozato, T.; Igarashi, Y.; Itoh, Y.; Yamamoto, N.; Okudaira, K.; Tabushi, K.; Obata, Y.; Komori, M.; Naganawa, S.; Ueda, M.

2011-09-01

We aimed to estimate the scattered radiation from dental metallic crowns during head and neck radiotherapy by irradiating a jaw phantom with external photon beams. The phantom was composed of a dental metallic plate and hydroxyapatite embedded in polymethyl methacrylate. We used radiochromic film measurement and Monte Carlo simulation to calculate the radiation dose and dose distribution inside the phantom. To estimate dose variations in scattered radiation under different clinical situations, we altered the incident energy, field size, plate thickness, plate depth and plate material. The simulation results indicated that the dose at the incident side of the metallic dental plate was approximately 140% of that without the plate. The differences between dose distributions calculated with the radiation treatment-planning system (TPS) algorithms and the data simulation, except around the dental metallic plate, were 3% for a 4 MV photon beam. Therefore, we should carefully consider the dose distribution around dental metallic crowns determined by a TPS.

Epidemiological studies on radiation carcinogenesis in human populations following acute exposure: nuclear explosions and medical radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fabrikant, J.I.

1982-08-01

The present review provides an understanding of our current knowledge of the carcinogenic effect of low-dose radiation in man, and surveys the epidemiological studies of human populations exposed to nuclear explosions and medical radiation. Discussion centers on the contributions of quantitative epidemiology to present knowledge, the reliability of the dose-incidence data, and those relevant epidemiological studies that provide the most useful information for risk estimation of cancer-induction in man. Reference is made to dose-incidence relationships from laboratory animal experiments where they may obtain for problems and difficulties in extrapolation from data obtained at high doses to low doses, and frommore » animal data to the human situation. The paper describes the methods of application of such epidemiological data for estimation of excess risk of radiation-induced cancer in exposed human populations, and discusses the strengths and limitations of epidemiology in guiding radiation protection philosophy and public health policy.« less

Epidemiological studies on radiation carcinogenesis in human populations following acute exposure: nuclear explosions and medical radiation.

PubMed Central

Fabrikant, J. I.

1981-01-01

The present review provides an understanding of our current knowledge of the carcinogenic effect of low-dose radiation in man, and surveys the epidemiological studies of human populations exposed to nuclear explosions and medical radiation. Discussion centers on the contributions of quantitative epidemiology to present knowledge, the reliability of the dose-incidence data, and those relevant epidemiological studies that provide the most useful information for risk estimation of cancer induction in man. Reference is made to dose-incidence relationships from laboratory animal experiments where they may obtain, for problems and difficulties in extrapolation from data obtained at high doses to low doses, and from animal data to the human situation. The paper describes the methods of application of such epidemiological data for estimation of excess risk of radiation-induced cancer in exposed human populations and discusses the strengths and limitations of epidemiology in guiding radiation protection philosophy and public health policy. PMID:7043913

Dosimeter for measuring skin dose and more deeply penetrating radiation

DOEpatents

Jones, Donald E.; Parker, DeRay; Boren, Paul R.

1981-01-01

A personnel dosimeter includes a plurality of compartments containing thermoluminescent dosimeter phosphors for registering radiation dose absorbed in the wearer's sensitive skin layer and for registering more deeply penetrating radiation. Two of the phosphor compartments communicate with thin windows of different thicknesses to obtain a ratio of shallowly penetrating radiation, e.g. beta. A third phosphor is disposed within a compartment communicating with a window of substantially greater thickness than the windows of the first two compartments for estimating the more deeply penetrating radiation dose. By selecting certain phosphors that are insensitive to neutrons and by loading the holder material with netruon-absorbing elements, energetic neutron dose can be estimated separately from other radiation dose. This invention also involves a method of injection molding of dosimeter holders with thin windows of consistent thickness at the corresponding compartments of different holders. This is achieved through use of a die insert having the thin window of precision thickness in place prior to the injection molding step.

Tumor Induction in Mice After Localized Single- or Fractionated-Dose Irradiation: Differences in Tumor Histotype and Genetic Susceptibility Based on Dose Scheduling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edmondson, Elijah F., E-mail: elijah.edmondson@colostate.edu; Hunter, Nancy R.; Weil, Michael M.

2015-07-15

Purpose: To investigate differences in tumor histotype, incidence, latency, and strain susceptibility in mice exposed to single-dose or clinically relevant, fractioned-dose γ-ray radiation. Methods and Materials: C3Hf/Kam and C57BL/6J mice were locally irradiated to the right hindlimb with either single large doses between 10 and 70 Gy or fractionated doses totaling 40 to 80 Gy delivered at 2-Gy/d fractions, 5 d/wk, for 4 to 8 weeks. The mice were closely evaluated for tumor development in the irradiated field for 800 days after irradiation, and all tumors were characterized histologically. Results: A total of 210 tumors were induced within the radiation field in 788 mice. Anmore » overall decrease in tumor incidence was observed after fractionated irradiation (16.4%) in comparison with single-dose irradiation (36.1%). Sarcomas were the predominant postirradiation tumor observed (n=201), with carcinomas occurring less frequently (n=9). The proportion of mice developing tumors increased significantly with total dose for both single-dose and fractionated schedules, and latencies were significantly decreased in mice exposed to larger total doses. C3Hf/Kam mice were more susceptible to tumor induction than C57BL/6J mice after single-dose irradiation; however, significant differences in tumor susceptibilities after fractionated radiation were not observed. For both strains of mice, osteosarcomas and hemangiosarcomas were significantly more common after fractionated irradiation, whereas fibrosarcomas and malignant fibrous histiocytomas were significantly more common after single-dose irradiation. Conclusions: This study investigated the tumorigenic effect of acute large doses in comparison with fractionated radiation in which both the dose and delivery schedule were similar to those used in clinical radiation therapy. Differences in tumor histotype after single-dose or fractionated radiation exposures provide novel in vivo evidence for differences in tumor susceptibility among stromal cell populations.« less

Space Radiation Organ Doses for Astronauts on Past and Future Missions

NASA Technical Reports Server (NTRS)

Cucinotta, Francis A.

2007-01-01

We review methods and data used for determining astronaut organ dose equivalents on past space missions including Apollo, Skylab, Space Shuttle, NASA-Mir, and International Space Station (ISS). Expectations for future lunar missions are also described. Physical measurements of space radiation include the absorbed dose, dose equivalent, and linear energy transfer (LET) spectra, or a related quantity, the lineal energy (y) spectra that is measured by a tissue equivalent proportional counter (TEPC). These data are used in conjunction with space radiation transport models to project organ specific doses used in cancer and other risk projection models. Biodosimetry data from Mir, STS, and ISS missions provide an alternative estimate of organ dose equivalents based on chromosome aberrations. The physical environments inside spacecraft are currently well understood with errors in organ dose projections estimated as less than plus or minus 15%, however understanding the biological risks from space radiation remains a difficult problem because of the many radiation types including protons, heavy ions, and secondary neutrons for which there are no human data to estimate risks. The accuracy of projections of organ dose equivalents described here must be supplemented with research on the health risks of space exposure to properly assess crew safety for exploration missions.

Mutagenesis and repair by low doses of α radiation in mammalian cells

PubMed Central

Puck, Theodore T.; Johnson, Robert; Webb, Patricia; Cui, Helen; Valdez, Joseph G.; Crissman, Harry

2002-01-01

Low doses of α radiation in basements have been causally implicated in lung cancer. Previous studies have concentrated on high dose effects, for which no significant repair was found. In the present study, the methodology for measuring mutation by quantitating mitotic breaks and gaps was found to be applicable to G2-phase Chinese hamster ovary cells irradiated with 10–50 cGy of α radiation. The mutation yield in such cells closely resembles that of γ irradiation. Caffeine, which inhibits repair, produces the same straight line increase of α and γ mutation yields plotted against the dose. In the absence of caffeine, the repair of α radiation lesions is almost twice as great as for γ radiation. Mitotic index changes substantiate these interpretations. It is proposed that the higher ion density associated with α radiation may result in fewer lesions being missed by the repair processes. The quantitation of chromosomal lesions for G2 cells exposed to low doses of α radiation, γ radiation, or chemical mutagens in the presence and absence of caffeine is a rapid and reproducible methodology. Protection from mutational disease in a fashion similar to the use of sanitation for infectious disease appears practical. PMID:12198179

Intriguing radiation signatures at aviation altitudes

NASA Astrophysics Data System (ADS)

Tobiska, W. K.

2017-12-01

The Automated Radiation Measurements for Aerospace Safety (ARMAS) project captures absorbed dose in Si with a fleet of 6 instruments on research aircraft. These dose rates are then converted to an effective dose rate. Over 325 flights since 2013 have captured global radiation at nearly all altitudes and latitudes. The radiation is predominantly caused by atmospheric neutrons and protons from galactic cosmic rays (GCRs). We have not yet obtained dose from solar energetic particle (SEP) events, which are rather rare. On 13 flights we have also measured dose rates that are up to twice the GCR background for approximately a half an hour per event while flying at higher magnetic latitudes near 60 degrees. The timing of the radiation appears to be coincident with periods of mild geomagnetic disturbances while flying above 10 km at L-shells of 3 to 6. The radiation source is best modeled as secondary gamma-ray photons caused by precipitating ultra-relativistic electrons from the outer Van Allen radiation belt originating as loss cone electrons scattered by electromagnetic ion cyclotron (EMIC) waves. We describe the observations and the lines of evidence for this intriguing new radiation source relevant to aviation crew and frequent flyers.

Radiation-induced genomic instability: radiation quality and dose response

NASA Technical Reports Server (NTRS)

Smith, Leslie E.; Nagar, Shruti; Kim, Grace J.; Morgan, William F.

2003-01-01

Genomic instability is a term used to describe a phenomenon that results in the accumulation of multiple changes required to convert a stable genome of a normal cell to an unstable genome characteristic of a tumor. There has been considerable recent debate concerning the importance of genomic instability in human cancer and its temporal occurrence in the carcinogenic process. Radiation is capable of inducing genomic instability in mammalian cells and instability is thought to be the driving force responsible for radiation carcinogenesis. Genomic instability is characterized by a large collection of diverse endpoints that include large-scale chromosomal rearrangements and aberrations, amplification of genetic material, aneuploidy, micronucleus formation, microsatellite instability, and gene mutation. The capacity of radiation to induce genomic instability depends to a large extent on radiation quality or linear energy transfer (LET) and dose. There appears to be a low dose threshold effect with low LET, beyond which no additional genomic instability is induced. Low doses of both high and low LET radiation are capable of inducing this phenomenon. This report reviews data concerning dose rate effects of high and low LET radiation and their capacity to induce genomic instability assayed by chromosomal aberrations, delayed lethal mutations, micronuclei and apoptosis.

Medical and Dental Patient Issues

MedlinePlus

... procedures. Because the Health Physics Society recommends against quantitative estimates of health risks for radiation doses below ... Society for Radiation Oncology Cancer Mechanisms - Radiation Effects Research Foundation Dose and Risk Calculator for Standard Medical ...

Current methods of monitoring radiation exposure from CT.

PubMed

Talati, Ronak K; Dunkin, Jared; Parikh, Shrujal; Moore, William H

2013-09-01

Increased public and regulatory scrutiny of imaging-related radiation exposure requires familiarity with current dose-monitoring techniques and best practices. CT-related ionizing radiation exposure has been cited as the largest and fastest growing source of population-wide iatrogenic ionizing radiation exposure. Upcoming federal regulations require imaging centers to familiarize themselves with available dose-monitoring techniques and implement comprehensive strategies to track patient dose, with particular emphasis on CT. Because of institution-specific and vendor-specific technologies, there are significant barriers to adoption and implementation. In this article, the authors outline the core components of a universal dose-monitoring strategy and detail a few of the many available commercial platforms. In addition, the authors introduce a cloud-based hybrid model dose-tracking system with the goal of rapid implementation, multicenter scalability, real-time dose feedback for technologists, cumulative dose monitoring, and optional dose communication to patients and into the record; doing so results in improved patient loyalty, referring physician satisfaction, and opportunity for repeat business. Copyright © 2013 American College of Radiology. All rights reserved.

Estimation of occupational cosmic radiation exposure among airline personnel: Agreement between a job-exposure matrix, aggregate, and individual dose estimates.

PubMed

Talibov, Madar; Salmelin, Raili; Lehtinen-Jacks, Susanna; Auvinen, Anssi

2017-04-01

Job-exposure matrices (JEM) are used for exposure assessment in occupational studies, but they can involve errors. We assessed agreement between the Nordic Occupational Cancer Studies JEM (NOCCA-JEM) and aggregate and individual dose estimates for cosmic radiation exposure among Finnish airline personnel. Cumulative cosmic radiation exposure for 5,022 airline crew members was compared between a JEM and aggregate and individual dose estimates. The NOCCA-JEM underestimated individual doses. Intraclass correlation coefficient was 0.37, proportion of agreement 64%, kappa 0.46 compared with individual doses. Higher agreement was achieved with aggregate dose estimates, that is annual medians of individual doses and estimates adjusted for heliocentric potentials. The substantial disagreement between NOCCA-JEM and individual dose estimates of cosmic radiation may lead to exposure misclassification and biased risk estimates in epidemiological studies. Using aggregate data may provide improved estimates. Am. J. Ind. Med. 60:386-393, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Associated factors of radiation pneumonitis induced by precise radiotherapy in 186 elderly patients with esophageal cancer.

PubMed

Cui, Zhen; Tian, Ye; He, Bin; Li, Hongwei; Li, Duojie; Liu, Jingjing; Cai, Hanfei; Lou, Jianjun; Jiang, Hao; Shen, Xueming; Peng, Kaigui

2015-01-01

Radiation pneumonitis is one of the most severe complications of esophageal cancer. To explore the factors correlated to radiation pneumonitis induced by precise radiotherapy for elderly patients with esophageal cancer. The retrospective analysis was used to collect clinical data from 186 elderly patients with esophageal cancer. The incidence of radiation pneumonitis was observed, followed by statistical analysis through ANVON or multiple regression analysis. 27 in 186 cases of esophageal cancer suffered from radiation pneumonitis, with incidence of 14.52%. The single factor analysis showed that, Karnofsky performance status (KPS) score, chronic obstructive pulmonary disease, concurrent chemoradiotherapy, gross tumor volume (GTV) dose, lung V20, mean lung dose (MLD) and planning target volume (PTV) were associated with radiation pneumonitis. The logistic regression analysis indicated that, concurrent chemoradiotherapy, GTV dose, lung V20 and PTV were the independent factors of radiation pneumonitis. The concurrent chemoradiotherapy, GTV dose, lung V20, MLD and PTV are the major risk factors of radiation pneumonitis for elderly patients with esophageal cancer.

Pilot Study: Unique Response of Bone Tissue During an Investigation of Radio-Adaptive Effects in Mice

NASA Technical Reports Server (NTRS)

Sibonga, J. D.; Iwaniec, U.; Wu, H.

2011-01-01

PURPOSE: We obtained bone tissue to evaluate the collateral effects of experiments designed to investigate molecular mechanisms of radio-adaptation in a mouse model. Radio-adaptation describes a process by which the prior exposure to low dose radiation can protect against the toxic effect of a subsequent high dose exposure. In the radio-adaptation experiments, C57Bl/6 mice were exposed to either a Sham or a priming Low Dose (5 cGy) of Cs-137 gamma rays before being exposed to either a Sham or High Dose (6 Gy) 24 hours later. ANALYSIS: Bone tissue were obtained from two experiments where mice were sacrificed at 3 days (n=3/group, 12 total) and at 14 days (n=6/group, 24 total) following high dose exposure. Tissues were analyzed to 1) evaluate a radio-adaptive response in bone tissue and 2) describe cellular and microstructural effects for two skeletal sites with different rates of bone turnover. One tibia and one lumbar vertebrae (LV2), collected at the 3-day time-point, were analyzed by bone histomorphometry and micro-CT to evaluate the cellular response and any evidence of microarchitectural impact. Likewise, tibia and LV2, collected at the 14-day time-point, were analyzed by micro-CT alone to evaluate resulting changes to bone structure and microarchitecture. The data were analyzed by 2-way ANOVA to evaluate the effects of the priming low dose radiation, of the high dose radiation, and of any interaction between the priming low and high doses of radiation. Bone histomorphometry was performed in the cancellous bone (aka trabecular bone) compartments of the proximal tibial metaphysis and of LV2. RESULTS: Cellular Response @ 3 Days The priming Low Dose radiation decreased osteoblast-covered bone perimeter in the proximal tibia and the total cell density in the bone marrow in the LV2. High Dose radiation, regardless of prior exposure to priming dose, dramatically reduced total cell density in bone marrow of both the long bone and vertebra. However, in the proximal tibia, High Dose radiation increased the osteoclast-covered bone perimeters, the density of adipocytes in bone marrow, and the area of bone marrow occupied by fat cells -- while in the LV2, adipocytes were rare and not stimulated by High Dose radiation. In an unexpected response, High Dose radiation dramatically increased (10-fold) osteoblast-covered bone perimeter in the LV2.

The susceptibility of TaO x-based memristors to high dose rate ionizing radiation and total ionizing dose

DOE PAGES

McLain, Michael Lee; Sheridan, Timothy J.; Hjalmarson, Harold Paul; ...

2014-11-11

This paper investigates the effects of high dose rate ionizing radiation and total ionizing dose (TID) on tantalum oxide (TaO x) memristors. Transient data were obtained during the pulsed exposures for dose rates ranging from approximately 5.0 ×10 7 rad(Si)/s to 4.7 ×10 8 rad(Si)/s and for pulse widths ranging from 50 ns to 50 μs. The cumulative dose in these tests did not appear to impact the observed dose rate response. Static dose rate upset tests were also performed at a dose rate of ~3.0 ×10 8 rad(Si)/s. This is the first dose rate study on any type ofmore » memristive memory technology. In addition to assessing the tolerance of TaO x memristors to high dose rate ionizing radiation, we also evaluated their susceptibility to TID. The data indicate that it is possible for the devices to switch from a high resistance off-state to a low resistance on-state in both dose rate and TID environments. The observed radiation-induced switching is dependent on the irradiation conditions and bias configuration. Furthermore, the dose rate or ionizing dose level at which a device switches resistance states varies from device to device; the enhanced susceptibility observed in some devices is still under investigation. As a result, numerical simulations are used to qualitatively capture the observed transient radiation response and provide insight into the physics of the induced current/voltages.« less

Radiation arteriopathy in the transgenic arteriovenous fistula model.

PubMed

Lawton, Michael T; Arnold, Christine M; Kim, Yung J; Bogarin, Ernesto A; Stewart, Campbell L; Wulfstat, Amanda A; Derugin, Nikita; Deen, Dennis; Young, William L

2008-05-01

The transgenic arteriovenous fistula model, surgically constructed with transgenic mouse aorta interposed in common carotid artery-to-external jugular vein fistulae in nude rats, has a 4-month experimental window because patency and transgenic phenotype are lost over time. We adapted this model to investigate occlusive arteriopathy in brain arteriovenous malformations after radiosurgery by radiating grafted aorta before insertion in the fistula. We hypothesized that high-dose radiation would reproduce the arteriopathy observed clinically within the experimental time window and that deletions of endoglin (ENG) and endothelial nitric oxide synthase (eNOS) genes would modify the radiation response. Radiation arteriopathy in the common carotid arteries of 171 wild-type mice was examined with doses of 25, 80, 120, or 200 Gy (Experiment 1). Radiation arteriopathy in 68 wild-type arteriovenous fistulae was examined histologically and morphometrically with preoperative radiation doses of 0, 25, or 200 Gy (Experiment 2). Radiation arteriopathy in 51 transgenic arteriovenous fistulae (36 ENG and 15 eNOS knock-out fistulae) was examined using preoperative radiation doses of 0, 25, or 200 Gy (Experiment 3). High-dose radiation (200 Gy) of mouse common carotid arteries induced only mild arteriopathy (mean score, 0.66) without intimal hyperplasia and with high mortality (68%). Radiation arteriopathy in wild-type arteriovenous fistulae was severe (mean score, 3.5 at 200 Gy), with intimal hyperplasia and medial disruption at 3 months, decreasing luminal areas with increasing dose, and no mortality. Arteriopathy was robust in transgenic arteriovenous fistulae with ENG +/- and with eNOS +/-, with thick intimal hyperplasia in the former and distinct smooth muscle cell proliferation in the latter. The transgenic arteriovenous fistula model can be adapted to rapidly reproduce radiation arteriopathy observed in resected brain arteriovenous malformations after radiosurgery. High radiation doses accelerate the progression of arteriopathy to fit the 4-month time limitation of the model, allowing transgenic tissues to retain their phenotypes throughout the experimental window. Modified radiation responses in ENG and eNOS knock-out fistulae indicate that arteriopathy after arteriovenous malformation radiosurgery might potentially be enhanced by altered gene expression.

[Effects of radiation exposure on human body].

PubMed

Kamiya, Kenji; Sasatani, Megumi

2012-03-01

There are two types of radiation health effect; acute disorder and late on-set disorder. Acute disorder is a deterministic effect that the symptoms appear by exposure above a threshold. Tissues and cells that compose the human body have different radiation sensitivity respectively, and the symptoms appear in order, from highly radiosensitive tissues. The clinical symptoms of acute disorder begin with a decrease in lymphocytes, and then the symptoms appear such as alopecia, skin erythema, hematopoietic damage, gastrointestinal damage, central nervous system damage with increasing radiation dose. Regarding the late on-set disorder, a predominant health effect is the cancer among the symptoms of such as cancer, non-cancer disease and genetic effect. Cancer and genetic effect are recognized as stochastic effects without the threshold. When radiation dose is equal to or more than 100 mSv, it is observed that the cancer risk by radiation exposure increases linearly with an increase in dose. On the other hand, the risk of developing cancer through low-dose radiation exposure, less 100 mSv, has not yet been clarified scientifically. Although uncertainty still remains regarding low level risk estimation, ICRP propound LNT model and conduct radiation protection in accordance with LNT model in the low-dose and low-dose rate radiation from a position of radiation protection. Meanwhile, the mechanism of radiation damage has been gradually clarified. The initial event of radiation-induced diseases is thought to be the damage to genome such as radiation-induced DNA double-strand breaks. Recently, it is clarified that our cells could recognize genome damage and induce the diverse cell response to maintain genome integrity. This phenomenon is called DNA damage response which induces the cell cycle arrest, DNA repair, apoptosis, cell senescence and so on. These responses act in the direction to maintain genome integrity against genome damage, however, the death of large number of cells results in acute disorder, and then DNA mis-repair and mutation is speculated to cause cancer. The extent to which this kind of cellular response could reduce the low-dose radiation risk is a major challenge for future research.

Inactivation of avirulent Yersinia pestis in Butterfield's phosphate buffer and frankfurters by UVC (254 nm) and gamma radiation.

PubMed

Sommers, Christopher H; Cooke, Peter H

2009-04-01

Yersinia pestis is the causative agent of plague. Although rare, pharyngeal plague in humans has been associated with consumption or handling of meat prepared from infected animals. The risks of contracting plague from consumption of deliberately contaminated food are currently unknown. Gamma radiation is a penetrating form of electromagnetic radiation, and UVC radiation is used for decontamination of liquids or food surfaces. Gamma radiation D10-values (the radiation dose needed to inactivate 1 log unit pathogen) were 0.23 (+/-0.01) and 0.31 (+/-0.03) kGy for avirulent Y. pestis inoculated into Butterfield's phosphate buffer and onto frankfurter surfaces, respectively, at 0 degree C. A UVC radiation dose of 0.25 J/cm2 inactivated avirulent Y. pestis suspended in Butterfield's phosphate buffer. UVC radiation doses of 0.5 to 4.0 J/cm2 inactivated 0.97 to 1.20 log units of the Y. pestis surface inoculated onto frankfurters. A low gamma radiation dose of 1.6 kGy could provide a 5-log reduction and a UVC radiation dose of 1 to 4 J/cm2 would provide a 1-log reduction of Y. pestis surface inoculated onto frankfurters. Y. pestis was capable of growth on frankfurters during refrigerated storage (10 degrees C). Gamma radiation of frankfurters inhibited the growth of Y. pestis during refrigerated storage, and UVC radiation delayed the growth of Y. pestis.

[Optimizing staff radiation protection in radiology by minimizing the effective dose].

PubMed

von Boetticher, H; Lachmund, J; Hoffmann, W; Luska, G

2006-03-01

In the present study the optimization of radiation protection devices is achieved by minimizing the effective dose of the staff members since the stochastic radiation effects correlate to the effective dose. Radiation exposure dosimetry was performed with TLD measurements using one Alderson Phantom in the patient position and a second phantom in the typical position of the personnel. Various types of protective clothing as well as fixed shields were considered in the calculations. It was shown that the doses of the unshielded organs (thyroid, parts of the active bone marrow) contribute significantly to the effective dose of the staff. Therefore, there is no linear relationship between the shielding factors for protective garments and the effective dose. An additional thyroid protection collar reduces the effective dose by a factor of 1.7 - 3.0. X-ray protective clothing with a 0.35 mm lead equivalent and an additional thyroid protection collar provides better protection against radiation than an apron with a 0.5 mm lead equivalent but no collar. The use of thyroid protection collars is an effective preventive measure against exceeding occupational organ dose limits, and a thyroid shield also considerably reduces the effective dose. Therefore, thyroid protection collars should be a required component of anti-X protection.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowe, Xiu R; Bhattacharya, Sanchita; Marchetti, Francesco

Understanding the cognitive and behavioral consequences of brain exposures to low-dose ionizing radiation has broad relevance for health risks from medical radiation diagnostic procedures, radiotherapy, environmental nuclear contamination, as well as earth orbit and space missions. Analyses of transcriptome profiles of murine brain tissue after whole-body radiation showed that low-dose exposures (10 cGy) induced genes not affected by high dose (2 Gy), and low-dose genes were associated with unique pathways and functions. The low-dose response had two major components: pathways that are consistently seen across tissues, and pathways that were brain tissue specific. Low-dose genes clustered into a saturated networkmore » (p < 10{sup -53}) containing mostly down-regulated genes involving ion channels, long-term potentiation and depression, vascular damage, etc. We identified 9 neural signaling pathways that showed a high degree of concordance in their transcriptional response in mouse brain tissue after low-dose radiation, in the aging human brain (unirradiated), and in brain tissue from patients with Alzheimer's disease. Mice exposed to high-dose radiation did not show these effects and associations. Our findings indicate that the molecular response of the mouse brain within a few hours after low-dose irradiation involves the down-regulation of neural pathways associated with cognitive dysfunctions that are also down regulated in normal human aging and Alzheimer's disease.« less

EFFECT OF RADIATION DOSE LEVEL ON ACCURACY AND PRECISION OF MANUAL SIZE MEASUREMENTS IN CHEST TOMOSYNTHESIS EVALUATED USING SIMULATED PULMONARY NODULES

PubMed Central

Söderman, Christina; Johnsson, Åse Allansdotter; Vikgren, Jenny; Norrlund, Rauni Rossi; Molnar, David; Svalkvist, Angelica; Månsson, Lars Gunnar; Båth, Magnus

2016-01-01

The aim of the present study was to investigate the dependency of the accuracy and precision of nodule diameter measurements on the radiation dose level in chest tomosynthesis. Artificial ellipsoid-shaped nodules with known dimensions were inserted in clinical chest tomosynthesis images. Noise was added to the images in order to simulate radiation dose levels corresponding to effective doses for a standard-sized patient of 0.06 and 0.04 mSv. These levels were compared with the original dose level, corresponding to an effective dose of 0.12 mSv for a standard-sized patient. Four thoracic radiologists measured the longest diameter of the nodules. The study was restricted to nodules located in high-dose areas of the tomosynthesis projection radiographs. A significant decrease of the measurement accuracy and intraobserver variability was seen for the lowest dose level for a subset of the observers. No significant effect of dose level on the interobserver variability was found. The number of non-measurable small nodules (≤5 mm) was higher for the two lowest dose levels compared with the original dose level. In conclusion, for pulmonary nodules at positions in the lung corresponding to locations in high-dose areas of the projection radiographs, using a radiation dose level resulting in an effective dose of 0.06 mSv to a standard-sized patient may be possible in chest tomosynthesis without affecting the accuracy and precision of nodule diameter measurements to any large extent. However, an increasing number of non-measurable small nodules (≤5 mm) with decreasing radiation dose may raise some concerns regarding an applied general dose reduction for chest tomosynthesis examinations in the clinical praxis. PMID:26994093

EFFECT OF RADIATION DOSE LEVEL ON ACCURACY AND PRECISION OF MANUAL SIZE MEASUREMENTS IN CHEST TOMOSYNTHESIS EVALUATED USING SIMULATED PULMONARY NODULES.

PubMed

Söderman, Christina; Johnsson, Åse Allansdotter; Vikgren, Jenny; Norrlund, Rauni Rossi; Molnar, David; Svalkvist, Angelica; Månsson, Lars Gunnar; Båth, Magnus

2016-06-01

The aim of the present study was to investigate the dependency of the accuracy and precision of nodule diameter measurements on the radiation dose level in chest tomosynthesis. Artificial ellipsoid-shaped nodules with known dimensions were inserted in clinical chest tomosynthesis images. Noise was added to the images in order to simulate radiation dose levels corresponding to effective doses for a standard-sized patient of 0.06 and 0.04 mSv. These levels were compared with the original dose level, corresponding to an effective dose of 0.12 mSv for a standard-sized patient. Four thoracic radiologists measured the longest diameter of the nodules. The study was restricted to nodules located in high-dose areas of the tomosynthesis projection radiographs. A significant decrease of the measurement accuracy and intraobserver variability was seen for the lowest dose level for a subset of the observers. No significant effect of dose level on the interobserver variability was found. The number of non-measurable small nodules (≤5 mm) was higher for the two lowest dose levels compared with the original dose level. In conclusion, for pulmonary nodules at positions in the lung corresponding to locations in high-dose areas of the projection radiographs, using a radiation dose level resulting in an effective dose of 0.06 mSv to a standard-sized patient may be possible in chest tomosynthesis without affecting the accuracy and precision of nodule diameter measurements to any large extent. However, an increasing number of non-measurable small nodules (≤5 mm) with decreasing radiation dose may raise some concerns regarding an applied general dose reduction for chest tomosynthesis examinations in the clinical praxis. © The Author 2016. Published by Oxford University Press.

Personalized Feedback on Staff Dose in Fluoroscopy-Guided Interventions: A New Era in Radiation Dose Monitoring.

PubMed

Sailer, Anna M; Vergoossen, Laura; Paulis, Leonie; van Zwam, Willem H; Das, Marco; Wildberger, Joachim E; Jeukens, Cécile R L P N

2017-11-01

Radiation safety and protection are a key component of fluoroscopy-guided interventions. We hypothesize that providing weekly personal dose feedback will increase radiation awareness and ultimately will lead to optimized behavior. Therefore, we designed and implemented a personalized feedback of procedure and personal doses for medical staff involved in fluoroscopy-guided interventions. Medical staff (physicians and technicians, n = 27) involved in fluoroscopy-guided interventions were equipped with electronic personal dose meters (PDMs). Procedure dose data including the dose area product and effective doses from PDMs were prospectively monitored for each consecutive procedure over an 8-month period (n = 1082). A personalized feedback form was designed displaying for each staff individually the personal dose per procedure, as well as relative and cumulative doses. This study consisted of two phases: (1) 1-5th months: Staff did not receive feedback (n = 701) and (2) 6-8th months: Staff received weekly individual dose feedback (n = 381). An anonymous evaluation was performed on the feedback and occupational dose. Personalized feedback was scored valuable by 76% of the staff and increased radiation dose awareness for 71%. 57 and 52% reported an increased feeling of occupational safety and changing their behavior because of personalized feedback, respectively. For technicians, the normalized dose was significantly lower in the feedback phase compared to the prefeedback phase: [median (IQR) normalized dose (phase 1) 0.12 (0.04-0.50) µSv/Gy cm 2 versus (phase 2) 0.08 (0.02-0.24) µSv/Gy cm 2 , p = 0.002]. Personalized dose feedback increases radiation awareness and safety and can be provided to staff involved in fluoroscopy-guided interventions.

The effects of phototherapy and melanocytes on keratinocytes

PubMed Central

Tang, Luyan; Wu, Wenyu; Fu, Wenwen; Hu, Yao

2018-01-01

Phototherapy is widely used in the treatment of vitiligo. Previous studies have focused on the effects of ultraviolet (UV) radiation on melanocytes; however, the biological effects of phototherapy and melanocytes on keratinocytes remain to be elucidated. To investigate and assess the effects of clinically doses of broad band (BB)-UVA, narrow band (NB)-UVB and melanocytes on human keratinocytes in vitro, clinical doses of BB-UVA or NB-UVB radiation and human melanoma cell A375 co-culture were performed as stress divisors to HaCaT cells. Cell proliferation, expression of protease-activated receptor-2 (PAR-2) and nuclear factor E2-related factor 2 mRNA, lipid peroxidation and intracellular antioxidant level of keratinocytes were analyzed. It was demonstrated that UV radiation inhibited the proliferation of cells apart from following exposure to low dose (1 J/cm2) UVA. Medium dose (5 J/cm2) UVA radiation had no adverse effects on lipid peroxidation and increased antioxidant levels in HaCaT cells. Medium (200 mJ/cm2) and high (400 mJ/cm2) doses of UVB radiation induced cellular damage due to increased lipid peroxidation as indicated by levels of malondialdehyde. Furthermore, A375 co-culture treatment induced a similar effect on the lipid peroxidation of HaCaT as with low dose UVB radiation. Therefore, the results of the present study determined that clinical doses of BB-UVA and NB-UVB radiation had varying effects on proliferation and related protein levels in HaCaT cells. Co-culture with A375 had similar effects as those of low dose UVA and UVB radiation, in which the PAR-2 expression was significantly upregulated. PMID:29545869

MONTE CARLO SIMULATION OF OUT-OF-FIELD ORGAN DOSES AND CANCER RISK IN TANZANIA FOR RADIATION THERAPY OF UNILATERAL RETINOBLASTOMA USING A 60Co UNIT.

PubMed

Suleiman, Suleiman Ameir; Qi, Yaping; Pi, Yifei; George Xu, X

2018-05-01

The use of 60Co teletherapy unit for the treatment of unilateral retinoblastoma (Rb) patients is a very common procedure in many developing countries including Tanzania. The aim of this study was to estimate organ-specific absorbed doses from an external beam radiation therapy 60Co unit for unilateral Rb and to assess the risks of the patients developing a secondary primary cancer. The absorbed dose estimations were based on a Monte Carlo method and a set of age-dependent computational male phantoms. The estimated doses were used to calculate the secondary cancer risks in out-of-field organs using the Biological Effects of Ionising Radiation VII risk models. The survival information and baseline cancer risks were based on relevant statistics for the Tanzanian population. The resulting out-of-field organ doses data showed that organs which are close to the target volume, such as the brain, salivary glands and thyroid glands, received the highest absorbed dose from scattered photons during the treatment of Rb. It was also found that the resulting photons dose to specific organs depends on the patient's age. Younger patients are more sensitive to radiation and also received higher dose contributions from the treatment head due to a larger part of the body exposed to the photon radiation. In all sites considered, the overall risks associated with radiation-induced secondary cancer were relatively lower than the baseline risks. Thus, the results in this article can help to provide good estimations of radiation-induced secondary cancer after radiation treatment of unilateral Rb using 60Co teletherapy unit in Tanzania and other developing countries.

Monte Carlo simulations of the secondary neutron ambient and effective dose equivalent rates from surface to suborbital altitudes and low Earth orbit

NASA Astrophysics Data System (ADS)

El-Jaby, Samy; Richardson, Richard B.

2015-07-01

Occupational exposures from ionizing radiation are currently regulated for airline travel (<20 km) and for missions to low-Earth orbit (∼300-400 km). Aircrew typically receive between 1 and 6 mSv of occupational dose annually, while aboard the International Space Station, the area radiation dose equivalent measured over just 168 days was 106 mSv at solar minimum conditions. It is anticipated that space tourism vehicles will reach suborbital altitudes of approximately 100 km and, therefore, the annual occupational dose to flight crew during repeated transits is expected to fall somewhere between those observed for aircrew and astronauts. Unfortunately, measurements of the radiation environment at the high altitudes reached by suborbital vehicles are sparse, and modelling efforts have been similarly limited. In this paper, preliminary MCNPX radiation transport code simulations are developed of the secondary neutron flux profile in air from surface altitudes up to low Earth orbit at solar minimum conditions and excluding the effects of spacecraft shielding. These secondary neutrons are produced by galactic cosmic radiation interacting with Earth's atmosphere and are among the sources of radiation that can pose a health risk. Associated estimates of the operational neutron ambient dose equivalent, used for radiation protection purposes, and the neutron effective dose equivalent that is typically used for estimates of stochastic health risks, are provided in air. Simulations show that the neutron radiation dose rates received at suborbital altitudes are comparable to those experienced by aircrew flying at 7 to 14 km. We also show that the total neutron dose rate tails off beyond the Pfotzer maximum on ascension from surface up to low Earth orbit.

Monte Carlo simulations of the secondary neutron ambient and effective dose equivalent rates from surface to suborbital altitudes and low Earth orbit.

PubMed

El-Jaby, Samy; Richardson, Richard B

2015-07-01

Occupational exposures from ionizing radiation are currently regulated for airline travel (<20 km) and for missions to low-Earth orbit (∼300-400 km). Aircrew typically receive between 1 and 6 mSv of occupational dose annually, while aboard the International Space Station, the area radiation dose equivalent measured over just 168 days was 106 mSv at solar minimum conditions. It is anticipated that space tourism vehicles will reach suborbital altitudes of approximately 100 km and, therefore, the annual occupational dose to flight crew during repeated transits is expected to fall somewhere between those observed for aircrew and astronauts. Unfortunately, measurements of the radiation environment at the high altitudes reached by suborbital vehicles are sparse, and modelling efforts have been similarly limited. In this paper, preliminary MCNPX radiation transport code simulations are developed of the secondary neutron flux profile in air from surface altitudes up to low Earth orbit at solar minimum conditions and excluding the effects of spacecraft shielding. These secondary neutrons are produced by galactic cosmic radiation interacting with Earth's atmosphere and are among the sources of radiation that can pose a health risk. Associated estimates of the operational neutron ambient dose equivalent, used for radiation protection purposes, and the neutron effective dose equivalent that is typically used for estimates of stochastic health risks, are provided in air. Simulations show that the neutron radiation dose rates received at suborbital altitudes are comparable to those experienced by aircrew flying at 7 to 14 km. We also show that the total neutron dose rate tails off beyond the Pfotzer maximum on ascension from surface up to low Earth orbit. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

GDF-15 gene expression alterations in human lymphoblastoid cells and peripheral blood lymphocytes following exposure to ionizing radiation

PubMed Central

Li, Shuang; Zhang, Qing-Zhao; Zhang, De-Qin; Feng, Jiang-Bin; Luo, Qun; Lu, Xue; Wang, Xin-Ru; Li, Kun-Peng; Chen, De-Qing; Mu, Xiao-Feng; Gao, Ling; Liu, Qing-Jie

2017-01-01

The identification of rapid, sensitive and high-throughput biomarkers is imperative in order to identify individuals harmed by radiation accidents, and accurately evaluate the absorbed doses of radiation. DNA microarrays have previously been used to evaluate the alterations in growth/differentiation factor 15 (GDF15) gene expression in AHH-1 human lymphoblastoid cells, following exposure to γ-rays. The present study aimed to characterize the relationship between the dose of ionizing radiation and the produced effects in GDF-15 gene expression in AHH-1 cells and human peripheral blood lymphocytes (HPBLs). GDF-15 mRNA and protein expression levels following exposure to γ-rays and neutron radiation were assessed by reverse transcription-quantitative polymerase chain reaction and western blot analysis in AHH-1 cells. In addition, alterations in GDF-15 gene expression in HPBLs following ex vivo irradiation were evaluated. The present results demonstrated that GDF-15 mRNA and protein expression levels in AHH-1 cells were significantly upregulated following exposure to γ-ray doses ranging between 1 and 10 Gy, regardless of the dose rate. A total of 48 h following exposure to neutron radiation, a dose-response relationship was identified in AHH-1 cells at γ-ray doses between 0.4 and 1.6 Gy. GDF-15 mRNA levels in HPBLs were significantly upregulated following exposure to γ-ray doses between 1 and 8 Gy, within 4–48 h following irradiation. These results suggested that significant time- and dose-dependent alterations in GDF-15 mRNA and protein expression occur in AHH-1 cells and HPBLs in the early phases following exposure to ionizing radiation. In conclusion, alterations in GDF-15 gene expression may have potential as a biomarker to evaluate radiation exposure. PMID:28440431

OFFICE RADIOBIOLOGY AND THE TEST OF DIVIDED-DOSE IRRADIATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scanlon, P.W.

1963-08-01

A simple and quantitatively accurate radiobiologic test system for office use by the clinical radiotherapist is described. Radiation inhibition of Lemna minor, or duckweed grown in an aquarium, forms the basis of the test system. Results are reported from radiation-inhibition studies using this system with time-dose variables appropriate to the radiation dose. The system proved adequate for testing the relative biologic effectiveness of the various quantities of radiation employed in clinical radiotherapy. (C.H.)

Atmospheric radiation modeling of galactic cosmic rays using LRO/CRaTER and the EMMREM model with comparisons to balloon and airline based measurements

NASA Astrophysics Data System (ADS)

Joyce, C. J.; Schwadron, N. A.; Townsend, L. W.; deWet, W. C.; Wilson, J. K.; Spence, H. E.; Tobiska, W. K.; Shelton-Mur, K.; Yarborough, A.; Harvey, J.; Herbst, A.; Koske-Phillips, A.; Molina, F.; Omondi, S.; Reid, C.; Reid, D.; Shultz, J.; Stephenson, B.; McDevitt, M.; Phillips, T.

2016-09-01

We provide an analysis of the galactic cosmic ray radiation environment of Earth's atmosphere using measurements from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) aboard the Lunar Reconnaissance Orbiter (LRO) together with the Badhwar-O'Neil model and dose lookup tables generated by the Earth-Moon-Mars Radiation Environment Module (EMMREM). This study demonstrates an updated atmospheric radiation model that uses new dose tables to improve the accuracy of the modeled dose rates. Additionally, a method for computing geomagnetic cutoffs is incorporated into the model in order to account for location-dependent effects of the magnetosphere. Newly available measurements of atmospheric dose rates from instruments aboard commercial aircraft and high-altitude balloons enable us to evaluate the accuracy of the model in computing atmospheric dose rates. When compared to the available observations, the model seems to be reasonably accurate in modeling atmospheric radiation levels, overestimating airline dose rates by an average of 20%, which falls within the uncertainty limit recommended by the International Commission on Radiation Units and Measurements (ICRU). Additionally, measurements made aboard high-altitude balloons during simultaneous launches from New Hampshire and California provide an additional comparison to the model. We also find that the newly incorporated geomagnetic cutoff method enables the model to represent radiation variability as a function of location with sufficient accuracy.

External effective radiation dose to workers in the restricted area of the Fukushima Daiichi Nuclear Power Plant during the third year after the Great East Japan Earthquake.

PubMed

Sakumi, Akira; Miyagawa, Ryu; Tamari, Yuki; Nawa, Kanabu; Sakura, Osamu; Nakagawa, Keiichi

2016-03-01

Since the Great East Japan Earthquake on 11 March 2011, Iitate Village has continued to be classified as a deliberate evacuation area, in which residents are estimated to receive an annual additional effective radiation dose of >20 mSv. Some companies still operate in Iitate Village, with a special permit from the Cabinet Office Team in Charge of Assisting the Lives of Disaster Victims. In this study, we measured the annual effective radiation dose to workers in Iitate Village from 15 January to 13 December 2013. The workers stayed in Iitate for 10 h and left the village for the remaining 14 h each working day. They worked for 5 days each week in Iitate Village, but stayed outside of the village for the remaining 2 days each week. We found that the effective radiation dose of 70% of the workers was <2 mSv, including natural radiation; the maximum dose was 3.6 mSv. We estimated the potential annual additional effective radiation dose if people returned full-time to Iitate. Our analysis supports the plan for people to return to their home village at the end of 2017. © The Author 2015. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

Commentary: Ethical Issues of Current Health-Protection Policies on Low-Dose Ionizing Radiation

PubMed Central

Socol, Yehoshua; Dobrzyński, Ludwik; Doss, Mohan; Feinendegen, Ludwig E.; Janiak, Marek K.; Miller, Mark L.; Sanders, Charles L.; Scott, Bobby R.; Ulsh, Brant; Vaiserman, Alexander

2014-01-01

The linear no-threshold (LNT) model of ionizing-radiation-induced cancer is based on the assumption that every radiation dose increment constitutes increased cancer risk for humans. The risk is hypothesized to increase linearly as the total dose increases. While this model is the basis for radiation safety regulations, its scientific validity has been questioned and debated for many decades. The recent memorandum of the International Commission on Radiological Protection admits that the LNT-model predictions at low doses are “speculative, unproven, undetectable and ‘phantom’.” Moreover, numerous experimental, ecological, and epidemiological studies show that low doses of sparsely-ionizing or sparsely-ionizing plus highly-ionizing radiation may be beneficial to human health (hormesis/adaptive response). The present LNT-model-based regulations impose excessive costs on the society. For example, the median-cost medical program is 5000 times more cost-efficient in saving lives than controlling radiation emissions. There are also lives lost: e.g., following Fukushima accident, more than 1000 disaster-related yet non-radiogenic premature deaths were officially registered among the population evacuated due to radiation concerns. Additional negative impacts of LNT-model-inspired radiophobia include: refusal of some patients to undergo potentially life-saving medical imaging; discouragement of the study of low-dose radiation therapies; motivation for radiological terrorism and promotion of nuclear proliferation. PMID:24910586

Evaluation of background radiation dose contributions in the United Arab Emirates.

PubMed

Goddard, Braden; Bosc, Emmanuel; Al Hasani, Sarra; Lloyd, Cody

2018-09-01

The natural background radiation consists of three main components; cosmic, terrestrial, and skyshine. Although there are currently methods available to measure the total dose rate from background radiation, no established methods exist that allow for the measurement of each component the background radiation. This analysis consists of a unique methodology in which the dose rate contribution from each component of the natural background radiation is measured and calculated. This project evaluates the natural background dose rate in the Abu Dhabi City region from all three of these components using the developed methodology. Evaluating and understanding the different components of background radiation provides a baseline allowing for the detection, and possibly attribution, of elevated radiation levels. Measurements using a high-pressure ion chamber with different shielding configurations and two offshore measurements provided dose rate information that were attributed to the different components of the background radiation. Additional spectral information was obtained using an HPGe detector to verify and quantify the presence of terrestrial radionuclides. By evaluating the dose rates of the different shielding configurations the comic, terrestrial, and skyshine contribution in the Abu Dhabi City region were determined to be 33.0 ± 1.7, 15.7 ± 2.5, and 2.4 ± 2.1 nSv/h, respectively. Copyright © 2018. Published by Elsevier Ltd.

Rapid Acute Dose Assessment Using MCNP6

NASA Astrophysics Data System (ADS)

Owens, Andrew Steven

Acute radiation doses due to physical contact with a high-activity radioactive source have proven to be an occupational hazard. Multiple radiation injuries have been reported due to manipulating a radioactive source with bare hands or by placing a radioactive source inside a shirt or pants pocket. An effort to reconstruct the radiation dose must be performed to properly assess and medically manage the potential biological effects from such doses. Using the reference computational phantoms defined by the International Commission on Radiological Protection (ICRP) and the Monte Carlo N-Particle transport code (MCNP6), dose rate coefficients are calculated to assess doses for common acute doses due to beta and photon radiation sources. The research investigates doses due to having a radioactive source in either a breast pocket or pants back pocket. The dose rate coefficients are calculated for discrete energies and can be used to interpolate for any given energy of photon or beta emission. The dose rate coefficients allow for quick calculation of whole-body dose, organ dose, and/or skin dose if the source, activity, and time of exposure are known. Doses are calculated with the dose rate coefficients and compared to results from the International Atomic Energy Agency (IAEA) reports from accidents that occurred in Gilan, Iran and Yanango, Peru. Skin and organ doses calculated with the dose rate coefficients appear to agree, but there is a large discrepancy when comparing whole-body doses assessed using biodosimetry and whole-body doses assessed using the dose rate coefficients.

Determination of the gamma-ray skyshine dose contribution in a Loss Of Shielding accident

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dennis, M.L.; Weiner, R.F.; Osborn, D.M.

2007-07-01

The goal of this research is to determine the gamma-ray dose contribution from skyshine. In a transportation accident involving the loss of lead gamma shielding, first responders to the accident will be exposed to both direct gamma radiation streaming from the exposed spent nuclear fuel and atmospherically reflected gamma radiation. The reflected radiation is referred to as skyshine and should contribute minimally to the overall dose; however, when there is minimal shielding above the exposed source, skyshine at large distances from the source must be considered. The program SKYDOSE developed by Shultis and Faw evaluates the gamma-ray skyshine dose frommore » a point, isotropic, polyenergetic, gamma-photon source. Assuming an infinite black wall shielding all direct radiation, the model assumes a first responder is located at varying distances from the wall. Skyshine doses are calculated both through SKYDOSE's integral line-beam method and an approximate approach prescribed by the National Council of Radiation Protection and Measurements. Initial results from SKYDOSE indicate nearly equivalent dose rates from either direct or skyshine radiation at nine meters from the wall, which seemed unusual and not readily explained. NCRP methodology, however, yields skyshine dose rates which are drastically smaller than direct dose rates at the same distance. Further investigation using the program MicroSkyshine{sup R}, which allows a variety of source configurations, suggests skyshine contributes minimally to dose in a loss-of-shielding accident. (authors)« less

Inhibition of gamma-radiation induced DNA damage in plasmid pBR322 by TMG, a water-soluble derivative of vitamin E.

PubMed

Rajagopalan, Rema; Wani, Khalida; Huilgol, Nagaraj G; Kagiya, Tsutomu V; Nair, Cherupally K Krishnan

2002-06-01

Alpha-tocopherol monoglucoside (TMG), a water-soluble derivative of alpha-tocopherol, has been examined for its ability to protect DNA against radiation-induced strand breaks. Gamma radiation, up to a dose of 6 Gy (dose rate, 0.7 Gy/minute), induced a dose-dependent increase in single strand breaks (SSBs) in plasmid pBR322 DNA. TMG inhibited the formation of gamma-radiation induced DNA single strand breaks (SSBs) in a concentration-dependent manner; 500 microM of TMG protected the single strand breaks completely. It also protected thymine glycol formation induced by gamma-radiation in a dose-dependent manner, based on an estimation of thymine glycol by HPLC.

Hormetic Response to Low-Dose Radiation: Focus on the Immune System and Its Clinical Implications

PubMed Central

Cui, Jiuwei; Yang, Guozi; Pan, Zhenyu; Zhao, Yuguang; Liang, Xinyue; Li, Wei; Cai, Lu

2017-01-01

The interrelationship between ionizing radiation and the immune system is complex, multifactorial, and dependent on radiation dose/quality and immune cell type. High-dose radiation usually results in immune suppression. On the contrary, low-dose radiation (LDR) modulates a variety of immune responses that have exhibited the properties of immune hormesis. Although the underlying molecular mechanism is not fully understood yet, LDR has been used clinically for the treatment of autoimmune diseases and malignant tumors. These advancements in preclinical and clinical studies suggest that LDR-mediated immune modulation is a well-orchestrated phenomenon with clinical potential. We summarize recent developments in the understanding of LDR-mediated immune modulation, with an emphasis on its potential clinical applications. PMID:28134809

A Biodosimeter for Multiparametric Determination of Radiation Dose, Radiation Quality, and Radiation Risk

NASA Technical Reports Server (NTRS)

Richmond, Robert; Cruz, Angela; Jansen, Heather; Bors, Karen

2003-01-01

Predicting risk of human cancer following exposure of an individual or a population to ionizing radiation is challenging. To an approximation, this is because uncertainties of uniform absorption of dose and the uniform processing of dose-related damage at the cellular level within a complex set of biological variables degrade the confidence of predicting the delayed expression of cancer as a relatively rare event. Cellular biodosimeters that simultaneously report: 1) the quantity of absorbed dose after exposure to ionizing radiation, 2) the quality of radiation delivering that dose, and 3) the risk of developing cancer by the cells absorbing that dose would therefore be useful. An approach to such a multiparametric biodosimeter will be reported. This is the demonstration of a dose responsive field effect of enhanced expression of keratin 18 (K18) in cultures of human mammary epithelial cells irradiated with cesium-1 37 gamma-rays. Dose response of enhanced K18 expression was experimentally extended over a range of 30 to 90 cGy for cells evaluated at mid-log phase. K18 has been reported to be a marker for tumor staging and for apoptosis, and thereby serves as an example of a potential marker for cancer risk, where the reality of such predictive value would require additional experimental development. Since observed radiogenic increase in expression of K18 is a field effect, ie., chronically present in all cells of the irradiated population, it may be hypothesized that K18 expression in specific cells absorbing particulate irradiation, such as the high-LET-producing atomic nuclei of space radiation, will report on both the single-cell distributions of those particles amongst cells within the exposed population, and that the relatively high dose per cell delivered by densely ionizing tracks of those intersecting particles will lead to cell-specific high-expression levels of K18, thereby providing analytical end points that may be used to resolve both the quantity and the quality of the radiation dose absorbed by individual cells. The principal value of this reported potential multiparametric cellular biodosimeter is suggested to be that it justifies a search for similar but more robust radiogenic assays. That is, K18 is only one radiation dose-sensitive expressed protein, whereas analytical techniques of genomics and proteomics can be used to simultaneously analyze multiple gene and protein expressions resulting from radiation-dose absorption. The potential usefulness of multiparametric cellular biodosimeters will be best realized from quantitatively profiling these multiple markers using these modern techniques.

Association of radiation dose with prevalence of thyroid nodules among atomic bomb survivors exposed in childhood (2007-2011).

PubMed

Imaizumi, Misa; Ohishi, Waka; Nakashima, Eiji; Sera, Nobuko; Neriishi, Kazuo; Yamada, Michiko; Tatsukawa, Yoshimi; Takahashi, Ikuno; Fujiwara, Saeko; Sugino, Keizo; Ando, Takao; Usa, Toshiro; Kawakami, Atsushi; Akahoshi, Masazumi; Hida, Ayumi

2015-02-01

Few studies have evaluated the association of radiation dose with thyroid nodules among adults exposed to radiation in childhood. To evaluate radiation dose responses on the prevalence of thyroid nodules in atomic bomb survivors exposed in childhood. This survey study investigated 3087 Hiroshima and Nagasaki atomic bomb survivors who were younger than 10 years at exposure and participated in the thyroid study of the Adult Health Study at the Radiation Effects Research Foundation. Thyroid examinations including thyroid ultrasonography were conducted between October 2007 and October 2011, and solid nodules underwent fine-needle aspiration biopsy. Data from 2668 participants (86.4% of the total participants; mean age, 68.2 years; 1213 men; and 1455 women) with known atomic bomb thyroid radiation doses (mean dose, 0.182 Gy; median dose, 0.018 Gy; dose range, 0-4.040 Gy) were analyzed. The prevalence of all thyroid nodules having a diameter of 10 mm or more (consisting of solid nodules [malignant and benign] and cysts), prevalence of small thyroid nodules that were less than 10 mm in diameter detected by ultrasonography, and atomic bomb radiation dose-responses. Thyroid nodules with a diameter of 10 mm or more were identified in 470 participants (17.6%): solid nodules (427 cases [16.0%]), malignant tumors (47 cases [1.8%]), benign nodules (186 cases [7.0%]), and cysts (49 cases [1.8%]), and all were significantly associated with thyroid radiation dose. Excess odds ratios per gray unit were 1.65 (95% CI, 0.89-2.64) for all nodules, 1.72 (95% CI, 0.93-2.75) for solid nodules, 4.40 (95% CI, 1.75-9.97) for malignant tumors, 2.07 (95% CI, 1.16-3.39) for benign nodules, and 1.11 (95% CI, 0.15-3.12) for cysts. The interaction between age at exposure and the dose was significant for the prevalence of all nodules (P = .003) and solid nodules (P < .001), indicating that dose effects were significantly higher with earlier childhood exposure. No interactions were seen for sex, family history of thyroid disease, antithyroid antibodies, or seaweed intake. No dose-response relationships were observed for small (<10-mm diameter) thyroid nodules. Radiation effects on thyroid nodules exist in atomic bomb survivors 62 to 66 years after their exposure in childhood. However, radiation exposure is not associated with small thyroid nodules.

The Effect of High-Dose Ionizing Radiation on the Astrobiological Model Lichen Circinaria gyrosa

NASA Astrophysics Data System (ADS)

de la Torre, Rosa; Zélia Miller, Ana; Cubero, Beatriz; Martín-Cerezo, M. Luisa; Raguse, Marina; Meeßen, Joachim

2017-02-01

The lichen Circinaria gyrosa is an astrobiological model defined by its high capacity of resistance to space conditions and to a simulated martian environment. Therefore, it became part of the currently operated BIOMEX experiment on board the International Space Station and the recent STARLIFE campaign to study the effects of four types of space-relevant ionizing radiation. The samples were irradiated with helium and iron ions at doses up to 2 kGy, with X-rays at doses up to 5 kGy and with γ rays at doses from 6 to 113 kGy. Results on C. gyrosa's resistance to simulated space ionizing radiation and its post-irradiation viability were obtained by (i) chlorophyll a fluorescence of photosystem II (PSII), (ii) epifluorescence microscopy, (iii) confocal laser scanning microscopy (CLSM), and (iv) field emission scanning electron microscopy (FESEM). Results of photosynthetic activity and epifluorescence show no significant changes up to a dose of 1 kGy (helium ions), 2 kGy (iron ions), 5 kGy (X-rays) - the maximum doses applied for those radiation qualities - as well as a dose of 6 kGy of γ irradiation, which was the lowest dose applied for this low linear energy transfer (LET) radiation. Significant damage in a dose-related manner was observed only at much higher doses of γ irradiation (up to 113 kGy). These data corroborate the findings of the parallel STARLIFE studies on the effects of ionizing radiation on the lichen Circinaria gyrosa, its isolated photobiont, and the lichen Xanthoria elegans.

Multicentre dose audit for clinical trials of radiation therapy in Asia.

PubMed

Mizuno, Hideyuki; Fukuda, Shigekazu; Fukumura, Akifumi; Nakamura, Yuzuru-Kutsutani; Jianping, Cao; Cho, Chul-Koo; Supriana, Nana; Dung, To Anh; Calaguas, Miriam Joy; Devi, C R Beena; Chansilpa, Yaowalak; Banu, Parvin Akhter; Riaz, Masooma; Esentayeva, Surya; Kato, Shingo; Karasawa, Kumiko; Tsujii, Hirohiko

2017-05-01

A dose audit of 16 facilities in 11 countries has been performed within the framework of the Forum for Nuclear Cooperation in Asia (FNCA) quality assurance program. The quality of radiation dosimetry varies because of the large variation in radiation therapy among the participating countries. One of the most important aspects of international multicentre clinical trials is uniformity of absolute dose between centres. The National Institute of Radiological Sciences (NIRS) in Japan has conducted a dose audit of participating countries since 2006 by using radiophotoluminescent glass dosimeters (RGDs). RGDs have been successfully applied to a domestic postal dose audit in Japan. The authors used the same audit system to perform a dose audit of the FNCA countries. The average and standard deviation of the relative deviation between the measured and intended dose among 46 beams was 0.4% and 1.5% (k = 1), respectively. This is an excellent level of uniformity for the multicountry data. However, of the 46 beams measured, a single beam exceeded the permitted tolerance level of ±5%. We investigated the cause for this and solved the problem. This event highlights the importance of external audits in radiation therapy. © The Author 2016. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

It's All Relative: A Validation of Radiation Quality Comparison Metrics

NASA Technical Reports Server (NTRS)

Chappell, Lori J.; Milder, Caitlin M.; Elgart, S. Robin; Semones, Edward J.

2017-01-01

The difference between high-LET and low-LET radiation is quantified by a measure called relative biological effectiveness (RBE). RBE is defined as the ratio of the dose of a reference radiation to that of a test radiation to achieve the same effect level, and thus, is described either as an iso-effector dose-to-dose ratio. A single dose point is not sufficient to calculate an RBE value; therefore, studies with only one dose point usually calculate an effect-to-effect ratio. While not formally used in radiation protection, these iso-dose values may still be informative. Shuryak, et al 2017 investigated the use of an iso-dose metric termed "radiation effects ratio" (RER) and used both RBE and RER to estimate high-LET risks. To apply RBE or RER to risk prediction, the selected metric must be uniquely defined. That is, the calculated value must be consistent within a model given a constant set of constraints and assumptions, regardless of how effects are defined using statistical transformations from raw endpoint data. We first test the RBE and the RER to determine whether they are uniquely defined using transformations applied to raw data. Then, we test whether both metrics can predict heavy ion response data after simulated effect size scaling between human populations or when converting animal to human endpoints.

Space radiation risk limits and Earth-Moon-Mars environmental models

NASA Astrophysics Data System (ADS)

Cucinotta, Francis A.; Hu, Shaowen; Schwadron, Nathan A.; Kozarev, K.; Townsend, Lawrence W.; Kim, Myung-Hee Y.

2010-12-01

We review NASA's short-term and career radiation limits for astronauts and methods for their application to future exploration missions outside of low Earth orbit. Career limits are intended to restrict late occurring health effects and include a 3% risk of exposure-induced death from cancer and new limits for central nervous system and heart disease risks. Short-term dose limits are used to prevent in-flight radiation sickness or death through restriction of the doses to the blood forming organs and to prevent clinically significant cataracts or skin damage through lens and skin dose limits, respectively. Large uncertainties exist in estimating the health risks of space radiation, chiefly the understanding of the radiobiology of heavy ions and dose rate and dose protraction effects, and the limitations in human epidemiology data. To protect against these uncertainties NASA estimates the 95% confidence in the cancer risk projection intervals as part of astronaut flight readiness assessments and mission design. Accurate organ dose and particle spectra models are needed to ensure astronauts stay below radiation limits and to support the goal of narrowing the uncertainties in risk projections. Methodologies for evaluation of space environments, radiation quality, and organ doses to evaluate limits are discussed, and current projections for lunar and Mars missions are described.

A method to reduce patient's eye lens dose in neuro-interventional radiology procedures

NASA Astrophysics Data System (ADS)

Safari, M. J.; Wong, J. H. D.; Kadir, K. A. A.; Sani, F. M.; Ng, K. H.

2016-08-01

Complex and prolonged neuro-interventional radiology procedures using the biplane angiography system increase the patient's risk of radiation-induced cataract. Physical collimation is the most effective way of reducing the radiation dose to the patient's eye lens, but in instances where collimation is not possible, an attenuator may be useful in protecting the eyes. In this study, an eye lens protector was designed and fabricated to reduce the radiation dose to the patients' eye lens during neuro-interventional procedures. The eye protector was characterised before being tested on its effectiveness in a simulated aneurysm procedure on an anthropomorphic phantom. Effects on the automatic dose rate control (ADRC) and image quality are also evaluated. The eye protector reduced the radiation dose by up to 62.1% at the eye lens. The eye protector is faintly visible in the fluoroscopy images and increased the tube current by a maximum of 3.7%. It is completely invisible in the acquisition mode and does not interfere with the clinical procedure. The eye protector placed within the radiation field of view was able to reduce the radiation dose to the eye lens by direct radiation beam of the lateral x-ray tube with minimal effect on the ADRC system.

Radionuclides and radiation doses in heavy mineral sands and other mining operations in Mozambique.

PubMed

Carvalho, Fernando P; Matine, Obete F; Taímo, Suzete; Oliveira, João M; Silva, Lídia; Malta, Margarida

2014-01-01

Sites at the littoral of Mozambique with heavy mineral sands exploited for ilmenite, rutile and zircon and inland mineral deposits exploited for tantalite, uranium and bauxite were surveyed for ambient radiation doses, and samples were collected for the determination of radionuclide concentrations. In heavy mineral sands, (238)U and (232)Th concentrations were 70±2 and 308±9 Bq kg(-1) dry weight (dw), respectively, whereas after separation of minerals, the concentrations in the ilmenite fraction were 2240±64 and 6125±485 Bq kg(-1) (dw), respectively. Tantalite displayed the highest concentrations with 44 738±2474 Bq kg(-1) of (238)U. Radiation exposure of workers in mining facilities is likely to occur at levels above the dose limit for members of the public (1 mSv y(-1)) and therefore radiation doses should be assessed as occupational exposures. Local populations living in these regions in general are not exposed to segregated minerals with high radionuclide concentrations. However, there is intensive artisanal mining and a large number of artisanal miners and their families may be exposed to radiation doses exceeding the dose limit. A radiation protection programme is therefore needed to ensure radiation protection of the public and workers of developing mining projects.

Editor's choice--Use of disposable radiation-absorbing surgical drapes results in significant dose reduction during EVAR procedures.

PubMed

Kloeze, C; Klompenhouwer, E G; Brands, P J M; van Sambeek, M R H M; Cuypers, P W M; Teijink, J A W

2014-03-01

Because of the increasing number of interventional endovascular procedures with fluoroscopy and the corresponding high annual dose for interventionalists, additional dose-protecting measures are desirable. The purpose of this study was to evaluate the effect of disposable radiation-absorbing surgical drapes in reducing scatter radiation exposure for interventionalists and supporting staff during an endovascular aneurysm repair (EVAR) procedure. This was a randomized control trial in which 36 EVAR procedures were randomized between execution with and without disposable radiation-absorbing surgical drapes (Radpad: Worldwide Innovations & Technologies, Inc., Kansas City, US, type 5511A). Dosimetric measurements were performed on the interventionalist (hand and chest) and theatre nurse (chest) with and without the use of the drapes to obtain the dose reduction and effect on the annual dose caused by the drapes. Use of disposable radiation-absorbing surgical drapes resulted in dose reductions of 49%, 55%, and 48%, respectively, measured on the hand and chest of the interventionalist and the chest of the theatre nurse. The use of disposable radiation-absorbing surgical drapes significantly reduces scatter radiation exposure for both the interventionalist and the supporting staff during EVAR procedures. Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

A Model for Precise and Uniform Pelvic- and Limb-Sparing Abdominal Irradiation to Study the Radiation-Induced Gastrointestinal Syndrome in Mice Using Small Animal Irradiation Systems.

PubMed

Brodin, N Patrik; Velcich, Anna; Guha, Chandan; Tomé, Wolfgang A

2017-01-01

Currently, no readily available mitigators exist for acute abdominal radiation injury. Here, we present an animal model for precise and homogenous limb-sparing abdominal irradiation (LSAIR) to study the radiation-induced gastrointestinal syndrome (RIGS). The LSAIR technique was developed using the small animal radiation research platform (SARRP) with image guidance capabilities. We delivered LSAIR at doses between 14 and 18 Gy on 8- to 10-week-old male C57BL/6 mice. Histological analysis was performed to confirm that the observed mortality was due to acute abdominal radiation injury. A steep dose-response relationship was found for survival, with no deaths seen at doses below 16 Gy and 100% mortality at above 17 Gy. All deaths occurred between 6 and 10 days after irradiation, consistent with the onset of RIGS. This was further confirmed by histological analysis showing clear differences in the number of regenerative intestinal crypts between animals receiving sublethal (14 Gy) and 100% lethal (18 Gy) radiation. The developed LSAIR technique provides uniform dose delivery with a clear dose response, consistent with acute abdominal radiation injury on histological examination. This model can provide a useful tool for researchers investigating the development of mitigators for accidental or clinical high-dose abdominal irradiation.

SYNCHROTRON RADIATION, FREE ELECTRON LASER, APPLICATION OF NUCLEAR TECHNOLOGY, ETC.: Measurement of radiation dose at the north interaction point of BEPC II

NASA Astrophysics Data System (ADS)

Mo, Xiao-Hu; Zhang, Jian-Yong; Zhang, Tian-Bao; Zhang, Qing-Jiang; Achasov, Mikhail; Fu, Cheng-Dong; Muchnoi, Nikolay; Qin, Qing; Qu, Hua-Min; Wang, Yi-Fang; Wu, Jing-Min; Xu, Jin-Qiang; Yu, Bo-Xiang

2009-10-01

The technique details for measuring radiation dose are expounded. The results of gamma and neutron radiation levels are presented and the corresponding radiation shielding is discussed based on the simplified estimation. In addition, the photon radiation level move as background for future experiments is measured by a NaI(Tl) detector.

Ultra-Low-Dose Fetal CT With Model-Based Iterative Reconstruction: A Prospective Pilot Study.

PubMed

Imai, Rumi; Miyazaki, Osamu; Horiuchi, Tetsuya; Asano, Keisuke; Nishimura, Gen; Sago, Haruhiko; Nosaka, Shunsuke

2017-06-01

Prenatal diagnosis of skeletal dysplasia by means of 3D skeletal CT examination is highly accurate. However, it carries a risk of fetal exposure to radiation. Model-based iterative reconstruction (MBIR) technology can reduce radiation exposure; however, to our knowledge, the lower limit of an optimal dose is currently unknown. The objectives of this study are to establish ultra-low-dose fetal CT as a method for prenatal diagnosis of skeletal dysplasia and to evaluate the appropriate radiation dose for ultra-low-dose fetal CT. Relationships between tube current and image noise in adaptive statistical iterative reconstruction and MBIR were examined using a 32-cm CT dose index (CTDI) phantom. On the basis of the results of this examination and the recommended methods for the MBIR option and the known relationship between noise and tube current for filtered back projection, as represented by the expression SD = (milliamperes) -0.5 , the lower limit of the optimal dose in ultra-low-dose fetal CT with MBIR was set. The diagnostic power of the CT images obtained using the aforementioned scanning conditions was evaluated, and the radiation exposure associated with ultra-low-dose fetal CT was compared with that noted in previous reports. Noise increased in nearly inverse proportion to the square root of the dose in adaptive statistical iterative reconstruction and in inverse proportion to the fourth root of the dose in MBIR. Ultra-low-dose fetal CT was found to have a volume CTDI of 0.5 mGy. Prenatal diagnosis was accurately performed on the basis of ultra-low-dose fetal CT images that were obtained using this protocol. The level of fetal exposure to radiation was 0.7 mSv. The use of ultra-low-dose fetal CT with MBIR led to a substantial reduction in radiation exposure, compared with the CT imaging method currently used at our institution, but it still enabled diagnosis of skeletal dysplasia without reducing diagnostic power.

Study of runaway electrons using dosimetry of hard x-ray radiations in Damavand tokamak

NASA Astrophysics Data System (ADS)

Rasouli, C.; Pourshahab, B.; Hosseini Pooya, S. M.; Orouji, T.; Rasouli, H.

2014-05-01

In this work several studies have been conducted on hard x-ray emissions of Damavand tokamak based on radiation dosimetry using the Thermoluminescence method. The goal was to understand interactions of runaway electrons with plasma particles, vessel wall, and plasma facing components. Total of 354 GR-200 (LiF:Mg,Cu,P) thermoluminescence dosimeter (TLD) crystals have been placed on 118 points - three TLDs per point - to map hard x-ray radiation doses on the exterior of the vacuum vessel. Results show two distinctive levels of x-ray radiations doses on the exterior of the vessel. The low-dose area on which measured dose is about 0.5 mSv/shot. In the low-dose area there is no particular component inside the vessel. On the contrary, on high-dose area of the vessel, x-ray radiations dose exceeds 30 mSv/shot. The high-dose area coincides with the position of limiters, magnetic probe ducts, and vacuum vessel intersections. Among the high-dose areas, the highest level of dose is measured in the position of the limiter, which could be due to its direct contact with the plasma column and with runaway electrons. Direct collisions of runaway electrons with the vessel wall and plasma facing components make a major contribution for production of hard x-ray photons in Damavand tokamak.

Study of runaway electrons using dosimetry of hard x-ray radiations in Damavand tokamak.

PubMed

Rasouli, C; Pourshahab, B; Hosseini Pooya, S M; Orouji, T; Rasouli, H

2014-05-01

In this work several studies have been conducted on hard x-ray emissions of Damavand tokamak based on radiation dosimetry using the Thermoluminescence method. The goal was to understand interactions of runaway electrons with plasma particles, vessel wall, and plasma facing components. Total of 354 GR-200 (LiF:Mg,Cu,P) thermoluminescence dosimeter (TLD) crystals have been placed on 118 points--three TLDs per point--to map hard x-ray radiation doses on the exterior of the vacuum vessel. Results show two distinctive levels of x-ray radiations doses on the exterior of the vessel. The low-dose area on which measured dose is about 0.5 mSv/shot. In the low-dose area there is no particular component inside the vessel. On the contrary, on high-dose area of the vessel, x-ray radiations dose exceeds 30 mSv/shot. The high-dose area coincides with the position of limiters, magnetic probe ducts, and vacuum vessel intersections. Among the high-dose areas, the highest level of dose is measured in the position of the limiter, which could be due to its direct contact with the plasma column and with runaway electrons. Direct collisions of runaway electrons with the vessel wall and plasma facing components make a major contribution for production of hard x-ray photons in Damavand tokamak.

Image quality and radiation dose of brain computed tomography in children: effects of decreasing tube voltage from 120 kVp to 80 kVp.

PubMed

Park, Ji Eun; Choi, Young Hun; Cheon, Jung-Eun; Kim, Woo Sun; Kim, In-One; Cho, Hyun Suk; Ryu, Young Jin; Kim, Yu Jin

2017-05-01

Computed tomography (CT) has generated public concern associated with radiation exposure, especially for children. Lowering the tube voltage is one strategy to reduce radiation dose. To assess the image quality and radiation dose of non-enhanced brain CT scans acquired at 80 kilo-voltage peak (kVp) compared to those at 120 kVp in children. Thirty children who had undergone both 80- and 120-kVp non-enhanced brain CT were enrolled. For quantitative analysis, the mean attenuation of white and gray matter, attenuation difference, noise, signal-to-noise ratio, contrast-to-noise ratio and posterior fossa artifact index were measured. For qualitative analysis, noise, gray-white matter differentiation, artifact and overall image quality were scored. Radiation doses were evaluated by CT dose index, dose-length product and effective dose. The mean attenuations of gray and white matter and contrast-to-noise ratio were significantly increased at 80 kVp, while parameters related to image noise, i.e. noise, signal-to-noise ratio and posterior fossa artifact index were higher at 80 kVp than at 120 kVp. In qualitative analysis, 80-kVp images showed improved gray-white differentiation but more artifacts compared to 120-kVp images. Subjective image noise and overall image quality scores were similar between the two scans. Radiation dose parameters were significantly lower at 80 kVp than at 120 kVp. In pediatric non-enhanced brain CT scans, a decrease in tube voltage from 120 kVp to 80 kVp resulted in improved gray-white matter contrast, comparable image quality and decreased radiation dose.

Radiation Doses to Structures Within and Adjacent to the Larynx are Correlated With Long-Term Diet- and Speech-Related Quality of Life

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dornfeld, Ken; Simmons, Joel R.; Karnell, Lucy

Purpose: To test the hypothesis that radiation dose to key sites in the upper aerodigestive tract is associated with long-term functional outcome after (chemo)radiotherapy for head-and-neck cancers. Methods and Materials: This study examined the outcome for 27 patients treated with intensity-modulated radiotherapy for definitive management of their head-and-neck cancer who were disease free for at least 1 year after treatment. Head-and-neck cancer-specific quality of life (QoL) was assessed before treatment and at 1 year after treatment. Type of diet tolerated, presence of a feeding tube, and degree of weight loss 1 year after treatment were also used as outcome measures.more » Radiation doses delivered to various points along the upper aerodigestive tract, including base of tongue, lateral pharyngeal walls, and laryngeal structures, were determined from each treatment plan. Radiation doses for each of these points were tested for correlation with outcome measures. Results: Higher doses delivered to the aryepiglottic folds, false vocal cords, and lateral pharyngeal walls near the false cords correlated with a more restrictive diet, and higher doses to the aryepiglottic folds correlated with greater weight loss (p < 0.05) 1 year after therapy. Better posttreatment speech QoL scores were associated with lower doses delivered to structures within and surrounding the larynx. Conclusion: Our data show an inverse relationship between radiation dose delivered to laryngeal structures and speech and diet and QoL outcomes after definitive (chemo)radiation treatment. These findings suggest that efforts to deliver lower doses to laryngeal structures may improve outcomes after definitive (chemo)radiation therapy.« less

Dynamics of Cellular Responses to Radiation

PubMed Central

Wodarz, Dominik; Sorace, Ron; Komarova, Natalia L.

2014-01-01

Understanding the consequences of exposure to low dose ionizing radiation is an important public health concern. While the risk of low dose radiation has been estimated by extrapolation from data at higher doses according to the linear non-threshold model, it has become clear that cellular responses can be very different at low compared to high radiation doses. Important phenomena in this respect include radioadaptive responses as well as low-dose hyper-radiosensitivity (HRS) and increased radioresistance (IRR). With radioadaptive responses, low dose exposure can protect against subsequent challenges, and two mechanisms have been suggested: an intracellular mechanism, inducing cellular changes as a result of the priming radiation, and induction of a protected state by inter-cellular communication. We use mathematical models to examine the effect of these mechanisms on cellular responses to low dose radiation. We find that the intracellular mechanism can account for the occurrence of radioadaptive responses. Interestingly, the same mechanism can also explain the existence of the HRS and IRR phenomena, and successfully describe experimentally observed dose-response relationships for a variety of cell types. This indicates that different, seemingly unrelated, low dose phenomena might be connected and driven by common core processes. With respect to the inter-cellular communication mechanism, we find that it can also account for the occurrence of radioadaptive responses, indicating redundancy in this respect. The model, however, also suggests that the communication mechanism can be vital for the long term survival of cell populations that are continuously exposed to relatively low levels of radiation, which cannot be achieved with the intracellular mechanism in our model. Experimental tests to address our model predictions are proposed. PMID:24722167

The importance of protection glasses during neuroangiographies: A study on radiation exposure at the lens of the primary operator.

PubMed

Tavares, J B; Sacadura-Leite, E; Matoso, T; Neto, L L; Biscoito, L; Campos, J; Sousa-Uva, A

2016-06-01

In interventional neuroradiology, few operators routinely use radiation protection glasses. Moreover, in most centers, radiation dose data only accounts for whole body dose without specific information on lens dose. In 2012, the International Commission on Radiological Protection advised that the threshold limit value for the lens should be 20 mSv/year instead of the previous 150 mSv/year limit. The purpose of this study was to compare the radiation dose in the operator's lens during real diagnostic and interventional neuroangiographies, either using or without lead protection glasses. Using the Educational Direct Dosimeter (EDD30 dosimeter), accumulated radiation dose in the lens was measured in 13 neuroangiographies: seven diagnostic and six interventional. Operators with and without radiation protection glasses were included and the sensor was placed near their left eye, closest to the radiation beam. Without glasses, the corrected mean dose of radiation in the lens was 8.02 µSv for diagnostic procedures and 168.57 µSv for interventional procedures. Using glasses, these values were reduced to 1.74 µSv and 33.24 µSv, respectively. Considering 20 mSv as the suggested annual limit of equivalent dose in the lens, neuroradiologists may perform up to 2,494 diagnostic procedures per year without protecting glasses, a number that increases to 11,494 when glasses are used consistently. Regarding intervention, a maximum of 119 procedures per year is advised if glasses are not used, whereas up to 602 procedures/year may be performed using this protection. Therefore, neuroradiologists should always wear radiation protection glasses. © The Author(s) 2016.