Consequence assessment of hypothetical urban radiological dispersal device incident in Korea.

Radiological Dispersal Devices (RDDs) are designed to disperse radioactive material over a wide area, leading to significant consequences to the environment and public health. This paper discusses the radiological effects of a potential RDD detonation containing 137Cs and 241Am in the commercial area of Busan, South Korea. The assessment, conducted with HotSpot Health Physics and RESRAD-RDD codes, found that summer had the most significant impact, with a maximum total effective dose equivalent (TEDE) of 280 mSv at 100 m and this decreased to 1 mSv at 4.5 km from the detonation point within the time interval of 35 min.

Medical professionals' resistance against the arms race and nuclear weapons.

The atomic bombing of Hiroshima and Nagasaki 78 years ago changed the concept of the impact of wars. The hope that the level of devastation would make the world think seriously about taking steps to give up the arms race and focus on human welfare did not materialise. The arms race continues unabated. From one nuclear weapons state in 1945, the number has increased to nine. Nearly 13000 nuclear weapons present on earth are enough to extinguish humankind. This has raised serious concern among medical professionals resolving to preserve life and promote health, who are now coming together for the complete abolition of nuclear weapons.

Prognostic assessment of the zone of occurrence of radiation combined injuries within a nuclear blast area.

BACKGROUND: A detonation of nuclear weapon (NW) is considered as one of the most devastating radiological scenarios in the list of modern global threats. An essential proportion of victims in a mass casualty radiation event may require an immediate medical care due to radiation combined injuries (RCI). Surprisingly, there is a lack of clear guidance for quantitative prognosis of the spatial distribution of expected RCI casesin a given nuclear explosion scenario. PURPOSE: This work is aimed at the presentation of a new, improved model, allowing more confident evaluation of the contributions from different NW destructive forces to RCI formation, thus leading to more accurate approximation of the zone around the epicenter for a guided search for RCI cases. MATERIALS AND METHODS: The model is made compatible with a classic approach and provides the estimates of radial distance from the epicenter, at which NW explosion can produce RCI. Mathematical formalism comprises a set of equations for the reciprocal assessment of a distance-effect for radiation dose (separately for neutrons and gamma-rays), thermal wave and blast shock wave depending on the NW type, detonation yield and altitude, environmental conditions (i.e. season) and shielding factors. The model's capabilities were demonstrated using an example of the RCI grade causing a profound operational performance decrement of military personnel in two marginal scenarios: Troops deployed in an open area or a tank crew. RESULTS: A remarkable difference in the expected radial zones of possible RCI occurrence was found between the actions of a 'historical' atomic bomb, thermonuclear weapons, and low-yield neutron munitions, also with a noticeable impact of the season factor (summer/winter). For a tank crew the clinically manageable RCI are possible only in very high yield explosion scenarios, while the damage caused by radiation alone possess much higher risk. CONCLUSIONS: Suggested formalism may provide guidance for a preliminary planning of countermeasures, targeting of radiation reconnaissance, and clarification of triage results in a broad range of radiological scenarios based on NW detonation. Further improvement of the model is possible by considering neutrons' and gamma-rays' relative biological efficacy, possible shielding factors, and a synergetic effect of NW's destructive forces.

Assessment of residual radionuclide levels at the Bokak and Bikar Atolls in the northern Marshall Islands.

The Bikar and Bokak Atolls, located in the northern Marshall Islands, are extremely isolated and consist of pristine marine and terrestrial ecosystems. Both atolls may have experienced significant radioactive deposition following the nuclear weapon testing conducted at Bikini and Enewetak proving grounds. Here we report activity concentrations of artificial radionuclides (239Pu, 240Pu, 241Pu, 241Am, 137Cs and 90Sr) in marine and terrestrial samples collected from Bikar and Bokak Atolls. Artificial radionuclides in soil from the Majuro Atoll are also reported and form a radiological baseline against which the levels at the other atolls can be compared. We observed low levels of artificial radionuclides in soil from Majuro and Bokak, but significantly higher levels in soil from Bikar. The residual radioactivity in the Bikar environment is comparable to the levels previously reported for other nearby atolls, including Taka and Utrik, but lower than for Rongerik, Rongelap, Bikini and Enewetak. An analysis of 240Pu/239Pu isotope ratios and estimations of the dates of contamination from 241Am/241Pu activity ratios both indicated that the Bikar Atoll was contaminated mainly by radioactive fallout from the Castle Bravo test in 1954. We compare the results of our measurements at Bikar and Bokak to data from other atolls in the Marshall Islands and to regions of the world affected by both global and regional fallout from atmospheric nuclear weapons testing and nuclear accidents.

Dose Coefficient Calculation for Use in Dosimetry Assessment of a Fission-Based Weapon.

In the event of a fission-based weapon or improvised nuclear device (IND) detonation, dose coefficients can be harnessed to provide dose assessments for defense, emergency preparedness, and consequence management, as well as to prospectively inform the assessment of radiation biomarkers and development of medical prophylaxis countermeasures for defense and homeland security stakeholders and decision-makers. Although dose coefficients have previously been calculated for this group, they would apply specifically to the studied population, the 1945 Japanese cohort, after which their anthropomorphic computational phantoms were modeled. For this reason, applications to other populations may be limited, and instead, an assessment of a more standardized population is desired. We employed a series of computational human phantoms representing international reference individuals: UF/NCI voxel phantom series containing newborn, 1-, 5-, 10-, 15-, and 35-year-old males and females. Irradiation of the phantoms was simulated using the Monte Carlo N-Particle transport code to determine organ dose coefficients under four idealized irradiation geometries at three distances from the detonation hypocenter at Hiroshima and Nagasaki using DS02 free-in-air prompt neutron and photon fluence spectra. Through these simulations, age-specific dose coefficients were determined for individual organs. Various articulated PIMAL stylized phantoms were simulated as well to estimate the effect of body posture on dose coefficients and determine the effect of posture on dosimetric estimation and reconstruction. Results additionally demonstrate that 137Cs and the Watt fission spectra are not ideal general surrogate sources for fission weapons, which may be considered for experimental testing of medical countermeasures. Supplementary data provided tabulates the compilation of organ dose-rate coefficients in this study.

The secondary sex ratio in Italy over the past eighty years (1940 to 2019) and potential impact of radiological contamination after atmospheric nuclear testing and after Chernobyl: Temporal change-point analysis using Markov Chain Monte Carlo.

In Europe, the male to female ratio at birth (secondary sex ratio: SSR; sex odds: SO) is 1.04-1.06, is influenced by many factors and is declining in industrialized countries. This study was carried out to identify possible impacts of fallout by atomic bomb tests or by the Chernobyl event on SSR in Italy. Italy is a country without commercial nuclear power generation for the last four decades and thus nearly free of radiological confounders. Counts of annual male and female live births in Italy are provided by the World Health Organization (WHO) and by the Italian Istituto Nazionale di Statistica (ISTAT). This study included 57.7 million live births (1940-2019) with overall SSR 1.05829. The Italian SSR trend was modelled with linear and non-linear logistic regression. Trend changes, i.e., periods with level shifts were estimated with Markov Chain Monte Carlo (MCMC). Two distinct idealized level shifts were identified superimposed on a uniform secular downward trend. The first one is seen towards the end of the 1960s with a jump sex odds ratio (SOR) 1.00681, p < 0.0001. The second one occurred in 1987 with SOR 1.00474, p < 0.0001. In each of the 3 periods separated by the two jumps, SSR uniformly decreased with trend SOR per 100 years of 0.98549, p < 0.0001. In conclusion, the secular trend in the Italian SSR showed two marked level shifts, at the end of the 1960s and from 1987 onward. These follow the release of radioactivity by atmospheric atomic bomb tests during the 1960s and by Chernobyl in 1986 and corroborate the hypothesis that ionizing radiation increases SSR.

Preparing for a "dirty bomb" attack: the optimum mix of medical countermeasure resources.

BACKGROUND: In radiological emergencies with radionuclide incorporation, decorporation treatment is particularly effective if started early. Treating all people potentially contaminated ("urgent treatment") may require large antidote stockpiles. An efficacious way to reduce antidote requirements is by using radioactivity screening equipment. We analyzed the suitability of such equipment for triage purposes and determined the most efficient mix of screening units and antidote daily doses. METHODS: The committed effective doses corresponding to activities within the detection limits of monitoring portals and mobile whole-body counters were used to assess their usefulness as triage tools. To determine the optimal resource mix, we departed from a large-scale scenario (60,000 victims) and based on purchase prices of antidotes and screening equipment in Germany, we calculated efficiencies of different combinations of medical countermeasure resources by data envelopment analysis. Cost-effectiveness was expressed as the costs per life year saved and compared to risk reduction opportunities in other sectors of society as well as the values of a statistical life. RESULTS: Monitoring portals are adequate instruments for a sensitive triage after cesium-137 exposure with a high screening throughput. For the detection of americium-241 whole-body counters with a lower daily screening capacity per unit are needed. Assuming that 1% of the potentially contaminated patients actually need decorporation treatment, an efficient resource mix includes 6 monitoring portals and 25 mobile whole-body counters. The optimum mix depends on price discounts and in particular the fraction of victims actually needing treatment. The cost-effectiveness of preparedness for a "dirty bomb" attack is less than for common health care, but costs for a life year saved are less than for many risk-reduction interventions in the environmental sector. CONCLUSION: To achieve economic efficiency a high daily screening capacity is of major importance to substantially decrease the required amount of antidote doses. Among the determinants of the number of equipment units needed, the fraction of the potentially contaminated victims that actually needs treatment is the most difficult to assess. Judging cost-effectiveness of the preparedness for "dirty bomb" attacks is an issue of principle that must be dealt with by political leaders.

Assessment of the potential impact of embedded radioactive fragments following the use of a crude radiological dispersal device ('dirty bomb').

This work was undertaken to understand what would happen if a high-activity radioactive fragment became embedded in an individual following the use of a crude radiological dispersal device ('dirty bomb'). Two areas were addressed: how would a high-activity fragment be viewed on modern digital x-ray imaging systems; and, what would be the impact on medical management for the patient? A set of experimental trials were undertaken using an iridium-192 source and a DRagon mobile x-ray set equipped with a Canon CXDI-50G portable flat panel digital detector plate. In addition, the potential doses to a surgical team were calculated and potential doses to a patient were assessed using a Monte Carlo code, in which a radioactive point source of nil volume was located within a limb of an anthropomorphic voxel phantom. Three distinct effects on the digital imaging systems were observed, referred to in this paper as a localised 'bloom' effect, a 'discontinuity' effect towards the middle of the image and 'fogging' across the entire image. The first two of these effects were unexpected, and possible reasons for their appearance are discussed. The Monte Carlo modelling showed that the patient exposure can potentially lead to very high localised absorbed doses, which may result in symptoms associated with acute radiation syndrome. While the dose clearly depends upon the activity of the fragment and the length of time that the fragment is present inside the patient, it is clear that radiation necrosis of bone, muscle and other tissues may threaten the medium term viability of the limb. The dose rates associated with high-activity fragments may also restrict the time a surgeon has to operate, leading to challenging ethical and surgical decisions. Low-activity fragments allow for conventional surgical management to be considered with appropriate control measures.

Dosimetric Impact of a New Computational Voxel Phantom Series for the Japanese Atomic Bomb Survivors: Pregnant Females.

An important cohort of the atomic bomb survivors are women who were pregnant when exposed to the photon and neutron fields at both Hiroshima and Nagasaki, as well as their children who were exposed in utero. Estimates of organ dose to the developing fetus allow for the development of dose-dependent and gestational age-dependent models of deterministic (e.g., organ malformation) and stochastic (e.g., leukemia) risk of in utero exposure. To date, both the 1986 and 2002 dosimetry systems at the Radiation Effects Research Foundation have utilized the uterine wall in the non-pregnant adult female as a dose surrogate for individual fetal organs and tissues. Here we present a new J45 (Japanese 1945) series of high-resolution phantoms of the adult pregnant female at 8-, 15-, 25- and 38-weeks post-conception. These models, which were derived from the University of Florida (UF) series of ICRP Publication 89 compliant reference phantoms, have been rescaled to approximate the pregnant mother using 1945 Japanese morphometry data. Fetal and maternal organ doses were estimated by computationally exposing the pregnant female phantom series to DS02 free-in-air photon and neutron fluences at three distances from the hypocenter at both Hiroshima and Nagasaki under frontal (AP) and isotropic (ISO) particle incidence. As for the fetal organ doses, our results indicate that the uterine wall of the non-pregnant female generally underestimates fetal organ dose within the pregnant female. The magnitude of these differences varies with both radiation type and irradiation geometry, with the smallest differences (5-7%) seen for ISO photon fields and the largest differences (20-30%) seen for AP neutron fields. Significant discrepancies were seen in fetal brain dose and its uterine wall surrogate, particularly for photon AP fields (ratio of uterine wall to brain dose varied from 0.9 to 1.3) and neutron AP fields (dose ratios from 0.75 to 2.0). As for the maternal organ doses, the use of organ doses in a non-pregnant female was shown, in general, to overestimate the corresponding organ doses in the pregnant female, with greater deviations seen at later stages of pregnancy (12-16% for AP photons and 44-53% for AP neutrons). The one exception was the uterine wall dose in pregnancy which was seen to be underestimated by that in the non-pregnant female phantom, particularly for ISO and AP neutron fields. These results demonstrate that the J45 pregnant female phantom series offers the opportunity for significant improvements in both fetal and maternal organ dose assessment within this unique cohort of the atomic bomb survivors.

STATE INSTITUTION «NATIONAL RESEARCH CENTER FOR RADIATION MEDICINE OF THE NATIONAL ACADEMY OF MEDICAL SCIENCES OF UKRAINE¼ - RESEARCH ACTIVITIES AND SCIENTIFIC ADVANCE IN 2017. / REFORMUVANNIa SYSTEMY OKhORONY ZDOROV'Ia: ROL' I MISTsE ZAKLADIV OKhORONY ZDOROV'Ia TRETYNNOGO RIVNIa PRY RADIATsIINYKh NADZVYChAINYKh SYTUATsIIaKh V UMOVAKh VOIeNNOGO STANU.

The role and place of health care facilities of the highly specialized (tertiary) level in radiation emergencies in the conditions of martial law are considered taking into account the experience of overcoming of the Chornobyl catas-trophe consequences. The classification of emergencies and the main scenarios of radiation emergencies (nuclear terrorism, radiation accidents and incidents, the use of nuclear weapons) are presented. The principles of medical preparedness and providing the highly specialized medical care in a radiological emergency are presented on the base of the Chornobyl catastrophe experience. It is determined that the tertiary health care facilities in a radiological emergency should provide as follow: development and implementation of plans and protocols of highly specialized medical care; organization, direct provision, coordination and quality control of the highly specialized medical care; aggregation and coordination of efforts of all three levels of health care facilities; integration into the radiation emergency management system, and analysis and generalization of the experience gained.

Radionuclide observables of underwater nuclear explosive tests.

There remain technical challenges for an On-site Inspection (OSI) in the high seas environment, which gathers evidence of a violation of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). For terrestrial nuclear explosions, the radionuclide observables are well defined and States Parties have chosen 17 particulate radionuclides that allow discrimination from other nuclear events. However, an underwater nuclear explosion generates induced radionuclides from the neutron activation of seawater, which has the potential to interfere with the measurement of the radionuclide observables using gamma-spectrometry techniques. To understand these effects the inventory of OSI relevant (6.0 × 1016 Bq) and activation (1.6 × 1019 Bq) radionuclides has been calculated for a 1 kT underwater nuclear explosion. The activation products consist predominantly of 38Cl and 24Na, which decay to 5.56% and 0.0007% of their initial activity within 1 and 14 days. Monte Carlo techniques have been used to assess spectral interferences within this timeframe. It is demonstrated that during this period they do not interfere with the measurement of the existing radionuclide observables. Additionally, 24Na has been identified as useful for inspection purposes.

NEW DEVELOPMENTS AND APPLICATIONS OF SUPERHEATED EMULSIONS: WARHEAD VERIFICATION AND SPECIAL NUCLEAR MATERIAL INTERDICTION.

In recent years, neutron detection with superheated emulsions has received renewed attention thanks to improved detector manufacturing and read-out techniques, and thanks to successful applications in warhead verification and special nuclear material (SNM) interdiction. Detectors are currently manufactured with methods allowing high uniformity of the drop sizes, which in turn allows the use of optical read-out techniques based on dynamic light scattering. Small detector cartridges arranged in 2D matrices are developed for the verification of a declared warhead without revealing its design. For this application, the enabling features of the emulsions are that bubbles formed at different times cannot be distinguished from each other, while the passive nature of the detectors avoids the susceptibility to electronic snooping and tampering. Large modules of emulsions are developed to detect the presence of shielded special nuclear materials hidden in cargo containers 'interrogated' with high energy X-rays. In this case, the enabling features of the emulsions are photon discrimination, a neutron detection threshold close to 3 MeV and a rate-insensitive read-out.