Radiation protection infrastructure-challenges in developing countries.

A special session was held in the International Radiation Protection Association (IRPA15) Congress to address the particular challenges facing developing countries regarding radiation protection infrastructure. The objective was to identify and share the key challenges facing developing countries regarding the ability to introduce and establish effective radiation protection programmes. The experiences of key international organisations (International Atomic Energy Agency, Pan American Health Organisation and World Health Organisation) that have support programmes were discussed, along with a perspective from several countries with developing programmes. The key common challenges include: governmental commitment at senior levels, with provision of the necessary resources: establishment of an independent regulatory body and related infrastructure: appropriate numbers of qualified staff in all necessary fields, including their education and training: supporting physical infrastructure, such as dosimetry and measurement equipment including calibration laboratories. In addressing these challenges the importance of support from the key international organisations was emphasised. More emphasis should be given to the application of the graded approach. The establishment of support networks at a national or regional level that allow for the sharing of experiences and resources, and that support the wellbeing of isolated professionals, is also crucial. In this aspect the support from wider professional bodies such as IRPA and established national radiation protection societies can also play a key role.

Stakeholder participation in nuclear and radiological emergency preparedness and recovery in Spain: benefits and challenges of working together.

Emergency preparedness and response (EP&R) to radiological or nuclear accidents depends on many different stakeholder groups: nuclear and radiological regulators and authorities; institutions and ministries concerned by health, environment and consumption; first-line responders including the police, military, firefighters and health workers; as well as local authorities and nuclear industries. Stakeholders also include the general public, such as people living near NPPs8 or affected by previous nuclear or radiological accidents and incidents. Teachers and journalists, bloggers and other social media figures would play a key role in effective dissemination of knowledge and information. NGOs9 or civil associations/societies can also be involved in radiation monitoring and protection. The present study describes the role of different research institutions (such as CIEMAT10, UPM11 and ISGlobal12) and of the Spanish Society of Radiological Protection (SEPR) in bringing together the above-listed stakeholders in Spain to discuss EP&R and identify benefits and challenges of working together. Stakeholder opinions on EP&R, collected mainly in the framework of several European-funded projects, are provided. Remaining barriers and examples of good practices in radiation protection are discussed, as well as recommendations for improving nuclear and radiological emergency preparedness in Spain. The conclusions may be useful for other countries.

Main problems and suggested solutions for improving radiation protection in medicine in Ibero-American countries. Summary of an International Conference held in Madrid, 2016.

During the International Conference on Radiation Protection in Medicine held in Bonn in 2012, several areas for improvement were identified, including specific actions related with justification, optimization, role of manufacturers, radiation protection education and training, strategic research, data collection on medical and occupational exposures, prevention of incidents and accidents, radiation safety culture, risk-benefit dialogue and implementation of the radiation safety standards. The outcomes of the Bonn Conference were summarized in the so-called 'Bonn Call for Action', identifying 10 priority actions to enhance RP in medicine. Trying to analyse the progress in the implementation of this 'Call for Action' in the Ibero-American region, several international organizations organized the 'Ibero-American Conference on Radiation Protection in Medicine' (Conferencia Iberoamericana sobre Protección Radiológica en Medicina, CIPRaM) held in Madrid, in October 2016. CIPRaM was structured in eight thematic sessions dealing with: diagnostic and dental radiology, image guided interventional radiology, nuclear medicine, radiation therapy, health authorities and radiation protection regulators, professional associations of technologists and nurses, professional associations of medical physicists and radiation protection experts, and universities and researchers in radiation protection in medicine. This paper summarizes the main results of that Conference based on the consensus achieved about main problems, solutions, and indicators to evaluate the implementation of the proposed solutions.

Effect of pentoxifylline on renal function and urinary albumin excretion in patients with diabetic kidney disease: the PREDIAN trial.

Diabetic kidney disease (DKD) is the leading cause of ESRD. We conducted an open-label, prospective, randomized trial to determine whether pentoxifylline (PTF), which reduces albuminuria, in addition to renin-angiotensin system (RAS) blockade, can slow progression of renal disease in patients with type 2 diabetes and stages 3-4 CKD. Participants were assigned to receive PTF (1200 mg/d) (n=82) or to a control group (n=87) for 2 years. All patients received similar doses of RAS inhibitors. At study end, eGFR had decreased by a mean±SEM of 2.1±0.4 ml/min per 1.73 m(2) in the PTF group compared with 6.5±0.4 ml/min per 1.73 m(2) in the control group, with a between-group difference of 4.3 ml/min per 1.73 m(2) (95% confidence interval [95% CI], 3.1 to 5.5 ml/min per 1.73 m(2); P<0.001) in favor of PTF. The proportion of patients with a rate of eGFR decline greater than the median rate of decline (0.16 ml/min per 1.73 m(2) per month) was lower in the PTF group than in the control group (33.3% versus 68.2%; P<0.001). Percentage change in urinary albumin excretion was 5.7% (95% CI, -0.3% to 11.1%) in the control group and -14.9% (95% CI, -20.4% to -9.4%) in the PTF group (P=0.001). Urine TNF-α decreased from a median 16 ng/g (interquartile range, 11-20.1 ng/g) to 14.3 ng/g (interquartile range, 9.2-18.4 ng/g) in the PTF group (P<0.01), with no changes in the control group. In this population, addition of PTF to RAS inhibitors resulted in a smaller decrease in eGFR and a greater reduction of residual albuminuria.

The limits of public communication coordination in a nuclear emergency: lessons from media reporting on the Fukushima case.

Coordination of public communication has become a key issue in management of complex emergencies, and is a matter of debate between nuclear emergency management professionals. A particular problem is when inconsistent information is sent to the media and public by official sources from different levels, which has led to calls for a more coordinated approach. The IAEA created guidelines recommending a one-voice communication approach that provides clear, consistent and coordinated information by relevant stakeholders. The reviewed theory on the emergency communication coordination and the empirical results in this paper demonstrate some challenges regarding the feasibility of the above stated goal. This paper explores the communication process in the two-month period of the Fukushima nuclear emergency by using a quantitative comparative content and discourse analysis of 1340 printed media articles on the Fukushima nuclear disaster from two major newspapers in Spain ('El País' and 'El Mundo'), Italy ('Corriere della Sera' and 'La Repubblica'), Norway ('Aftenposten' and 'Dagsavisen'), Slovenia ('Delo' and 'Vecer'), Belgium ('Le Soir' and 'De Standaard') and Russia ('Komsomolskaya Pravda' and 'Izvestiya'). The results show that it will be difficult to achieve a truly coordinated approach and one-voice communication in severe nuclear and radiological emergency due to the communication difficulties created by the dispersion of information sources, a broad and dispersed focus of the reported information, partially subjective and conflicting media reporting. The paper suggests ways to improve public communication coordination in nuclear and radiological disasters.

How did media present the radiation risks after the Fukushima accident: a content analysis of newspapers in Europe.

Any activity that might result in exposure of a population to contaminants requires communication of the associated risks. This communication is complicated by several factors including public perceptions, distrust, uncertainties in risk assessment and news media. These factors are especially prominent in communication of risks from ionizing radiation. A number of guidelines about the communication of risks related to radiation exposures have been made by national and international authorities and other stakeholders. The present paper investigates whether those guidelines were followed and evaluates how the radiation risk related information was presented in European newspapers and Russia in the aftermath of the Fukushima accident. It examines the use of measurement units and risk comparisons, the quality of the statements on radiation risk related issues and the use of visual materials in 1340 newspaper articles from Belgium, Italy, Norway, Russia, Slovenia and Spain. Our results indicated several misinterpretations and misrepresentations of radiological risks in the newspaper articles. We also show an inconsistency in the information that was reported with advice provided to risk communicators (e.g. authorities and experts) in the guidelines. The results suggest that risk communicators should improve their communication practices regarding radiological risks, in order to improve emergency management response.

Comparison of H*(10) estimations, due to neutrons and γ-rays, around FANT with two 241Am/9Be sources.

FANT (Fuente Ampliada de Neutrones Térmicos; in Spanish) is a thermal neutron irradiation facility with an extended and very uniform irradiation area, which has been developed by the Neutron Measurement Laboratory of the Energy Engineering Department at Universidad Politécnica de Madrid (LMN-UPM). In FANT, an isotopic neutron source (241Am/9Be) produces the primary neutrons. The design and facility optimization were carried out by extensive Monte Carlo calculations. In addition, Monte Carlo methods were used to evaluate the facility's performance to produce a constant and uniform thermal neutron field; these results were validated through experimental methods. FANT is designed to have two neutron sources; the objective of this work is to estimate the ambient dose equivalent due to neutrons and gamma-rays by Monte Carlo methods, and to compare these values with measured experimental doses. Thus, the performance of FANT with the two 241Am/9Be sources of LMN-UPM, with regard to the ambient dose equivalent H*(10) produced by both neutrons and photons around the facility, is analyzed in this work. The results are compared with those previously obtained in the framework of the results obtained with the LB6411 device around FANT.

Estimation with Monte Carlo of thermal neutrons in the FANT, using 252Cf and 241Am/9Be neutron source.

The thermal neutron irradiation device (FANT), developed at the Neutron Measurements Laboratory of the Energy Engineering Department at Universidad Politécnica de Madrid, is a high-density polyethylene regular parallelepiped, with a rather uniform neutron fluence inside its irradiation chamber. It uses a Am95241/Be49 neutron source aiming to provide thermal neutron fluence rates. Neutron spectra and neutron fluences were estimated with Monte Carlo methods in the FANT irradiation chamber when a Cf98252 neutron source is used and were compared with the results obtained with the Am95241/Be49 source. Regardless of the neutron source, the largest contribution is due to thermal neutrons, producing also epithermal and fast neutrons. Per neutron emitted by the source, the use of Cf98252 produces a larger amount of neutrons.

Colorectal cancer survival in Manizales, Colombia, 2008-2017: a population-based study.

OBJECTIVE: To determine 5-year survival in patients with colorectal cancer (CRC) according to patient and tumor characteristics. METHODS: Longitudinal study based on incident cases of invasive CRC between 2008 and 2017 captured by the Manizales Population-based Cancer Registry (n=850). Patients were followed up to August 24th, 2021. Cause-specific survival and net survival were calculated for sociodemographic and tumor characteristics, and Cox multivariate was fitted. RESULTS: Fifty-five percent of cases occurred in women. The most frequent histological type was adenocarcinoma (78.2%). The most frequent locations were rectum (32.0%), ascending colon (16.6%), and sigmoid (16.2%). Twenty-five percent of cases were diagnosed in stage IV. There were 567 deaths due to CRC. The 5-year specific survival was 45.8% (95%CI 42.4-49.3), with independent effects for age (HR=1.83; 95%CI 1.26-2.65 age >75 years vs. <50 years) and advanced clinical stage (HR=2.5 and HR 5.7 for stages III and IV vs. stage I, respectively). Lower survival was observed in patients of medium socioeconomic status compared with higher socioeconomic status (HR=1.52; 95%CI 1.08-2.14), but not in patients of low socioeconomic status. No independent effects were observed for the health insurance regime. CONCLUSIONS: In Manizales, approximately 5 out of 10 patients with invasive CRC die in the first five years after diagnosis, with a lower survival in patients older than 75 years, from medium socioeconomic level and diagnosed in advanced clinical stages.

Benchmarking of stray neutron fields produced by synchrocyclotrons and synchrotrons in compact protontherapy centers (CPTC) using MCNP6 Monte Carlo code.

Proton therapy is an external radiotherapy using proton beams with energies between 70 and 230 MeV to treat some type of tumours with outstanding benefits, due to its energy transfer plot. There is a growing demand of facilities taking up small spaces and Compact Proton Therapy Centers (CPTC), with one or two treatment rooms, supposing the technical response of manufacturers to this request. A large amount of stray radiation is yielded in the interaction of proton beam used in therapy, neutrons mainly, hence, optimal design of shielding and verifications must be carried out in commissioning phases. Currently, almost 50 proton centers are under construction and start up in several countries, including ten in Spain. In the present work the effectiveness of shielding in two CPTC was verified with the Monte Carlo code MCNP6 by calculating the ambient dose equivalent, H*(10) due to secondary neutrons, outside the enclosures and walls of the center. The facilities modelled were the two centers currently operating in Spain, the first, since December 2019, with a superconductor synchrocyclotron, and the second, since March 2020, with a compact synchrotron. The geometry and materials are based on dimensions proposed a priori by the vendors, therefore, the paper is focused on check the suitability of the materials and thickness of the walls of the centers. Several models of the radiation sources were simulated, starting from a conservative assumptions, followed by more realistic scenarios. In all cases, the results reached for the ambient dose equivalent, H*(10), were below 1 mSv/year, which is the legal limit considered for the public in international references. Finally, considering that the recent ICRU Report 95 proposes changes in the operational quantities, the dose outside shieldingt has been evaluated in terms of the new next area surveillance quantity, H*, known as ambient dose, in the process of implementation.

Application of an algebraic methodology for the combination of Berthold LB6411 and WENDI-II for neutron area monitoring in D-T neutron generators and fusion facilities.

Neutron area monitors do not often have a good adjustment of their dose response functions to the ICRP74 neutron fluence-to-H*(10) conversion function between 10 and 20 MeV. The objective of this work is to establish a methodology to combine the dose response functions of Berthold LB6411 and WENDI-II, adjusting this combined function to the ICRP74 conversion function: this combination shows an almost perfect adjustment between 0.5 and 20 MeV. Thus, this article presents an easy and cheap alternative to the recalibration in D-T generators.

Comparison of PHITS2.88 and MCNP6.1 for the characterization of a LUPIN-II neutron area monitor.

The use of different nuclear data libraries and physics models can be a source of discrepancies in neutron transport simulation. Different Monte Carlo simulation toolkits can be used to characterize neutron monitors, these codes usually employ by default different nuclear data libraries and physics models. This work presents, for the first time, a comparison of MCNP and PHITS for the characterization of a LUPIN-II neutron rem-meter. The most significant discrepancies between the codes have been found around 100 MeV.

A novel conceptualization in the analysis and design of passive neutron area monitors based on gold foil activation.

In the detection and measurement of neutron fields, with energies between 10 and 20 MeV, current passive neutron area monitors based on gold foil sensors usually do not have a perfect fitting of their dose response functions with the neutron fluence-to-ambient dose equivalent conversion function from ICRP74. However, apart from the radiative capture in 197Au, the common channel considered in these monitors, other nuclear reactions in 197Au can be considered to improve the fit between both functions. Therefore, this work aimed to develop a mathematical combination of response functions in passive monitors with gold foils, considering the (n, γ) and (n, 2n) channels in 197Au, to extend their response up to 20 MeV, improving their performance under neutron fields with high energies. The proposed methodology avoids introducing modifications in the original device, such as the insertion of sheets with high-Z materials, and simplifies the design and manufacturing of passive monitors, while reducing costs.

Comparison of FANT results using the ENDF/B-VII.1, JEFF-3.3 and TENDL2017 nuclear data libraries.

FANT (Fuente Ampliada de Neutrones Térmicos; in Spanish) is a thermal neutron irradiation facility with an extended and very uniform irradiation area, that has been developed by the Neutron Measurements Laboratory of the Energy Engineering Department at Universidad Politecnica de Madrid (LMN-UPM). This device is a parallelepiped box made of high-density polyethylene (HDPE), moderator material, that uses an A95241m/B49e neutron source of 111 GBq nominal activity for irradiating materials. The facility design was previously optimized, and the neutron spectra were estimated by extensive calculations with the MCNP6.1 code and carrying out experimental measurements (Bedogni et al., 2017). The facility takes advantage of the scattering reactions of neutrons with the HDPE surfaces of the chamber, where the moderation process is effective, achieving relevant thermal neutron fluence rates. The main goal of this work has been to simulate and analyse the FANT system by Monte Carlo methods using the MCNP6.1 code, employing 3 different nuclear data libraries: ENDF/B-VII.1, JEFF-3.3 and TENDL 2017. The transport of thermal neutrons in HDPE, E < 1eV, has been calculated in all the cases taking into account the thermal S (α,ß) treatment. The results achieved in this work have been compared with those previously obtained in the former development of FANT, using the MCNP6.1 code with the ENDF/B-VII.1 nuclear data, and experimental measurements. These results have shown that the JEFF-3.3 nuclear data library is the nuclear data library that provides of the best matching between the MCNP computational results, and the experimental data collected at FANT. Hence, the JEFF-3.3 nuclear data library seems to be the most correct library to design and benchmark thermal neutron activation devices.

Determination of the uncertainties associated to the use of different nuclear data libraries in the analysis of extended-range rem-meters.

In proton therapy centers stray neutron radiation of up to 230-250 MeV is yielded by (p, Xn) nuclear reactions. To monitor ambient dose in such facilities, extended-range rem-meters are needed. The aim of this project was to characterize the response of two extended-range rem-meters, WENDI-II and LUPIN-II, by Monte Carlo methods, for energies ranging from 10-9 MeV up to 230 MeV. Different nuclear data libraries (ENDF/B-VII.1, TENDL2017, TENDL2019, JEFF-3.3) have been used, determining the uncertainties associated with the application of the libraries in the calculation of the response functions of both monitors. The differences found are very significant at energies around 150-200 MeV. This is an issue for predicting by Monte Carlo methods the response of these instruments at high energies. The results point to the necessity of testing experimentally the response of rem-meters at 150 MeV-200 MeV neutron beams.

Nuclear and Radiological Emergencies: Biological Effects, Countermeasures and Biodosimetry.

Atomic and radiological crises can be caused by accidents, military activities, terrorist assaults involving atomic installations, the explosion of nuclear devices, or the utilization of concealed radiation exposure devices. Direct damage is caused when radiation interacts directly with cellular components. Indirect effects are mainly caused by the generation of reactive oxygen species due to radiolysis of water molecules. Acute and persistent oxidative stress associates to radiation-induced biological damages. Biological impacts of atomic radiation exposure can be deterministic (in a period range a posteriori of the event and because of destructive tissue/organ harm) or stochastic (irregular, for example cell mutation related pathologies and heritable infections). Potential countermeasures according to a specific scenario require considering basic issues, e.g., the type of radiation, people directly affected and first responders, range of doses received and whether the exposure or contamination has affected the total body or is partial. This review focuses on available medical countermeasures (radioprotectors, radiomitigators, radionuclide scavengers), biodosimetry (biological and biophysical techniques that can be quantitatively correlated with the magnitude of the radiation dose received), and strategies to implement the response to an accidental radiation exposure. In the case of large-scale atomic or radiological events, the most ideal choice for triage, dose assessment and victim classification, is the utilization of global biodosimetry networks, in combination with the automation of strategies based on modular platforms.

Early glomerular filtration rate changes in living kidney donors and recipients: an example of renal plasticity.

Background: In living kidney transplantation there are two different individuals, a healthy donor and a renal transplant recipient. This is an excellent human model to study factors that influence kidney function in the context of reduced renal mass and the adaptation of two comparable kidneys to different metabolic demands. Methods: We analyzed the changes in measured glomerular filtration rate (GFR, iohexol) from pretransplantation to 12 months after transplantation in 30 donor-recipient pairs. Each donor was compared with his/her recipient. We defined a priori three different groups based on GFR differences at 12 months: donor > recipient (Group A; 78 ± 8 versus 57 ± 8 mL/min), donor < recipient (Group B; 65 ± 11 versus 79 ± 11 mL/min) and donor ≈ recipient (Group C; 66 ± 7 versus 67 ± 7 mL/min). Other factors like donor/recipient mismatches in body mass index (BMI), surface area and gender were evaluated. Results: In Group A donors were mostly male and recipients were female (75% each). Donors had a higher baseline weight than their recipients. During follow-up, weight remained stable in donors but increased 7% in recipients. In Group B donors were mostly female (60%) and recipients male. At baseline, donors had a lower weight than recipients. At 12 months, weight was stable in donors but increased in recipients. In Group C donors were mostly (75%) female and recipients male. At baseline, donors had a higher BMI than their recipients. At 12 months, BMI was stable in donors but increased 14% in recipients. In multivariable analysis, higher GFR at 12 months was associated with higher baseline weight and GFR in donors and with male gender and higher baseline weight in recipients. Conclusions: Kidneys from living donors are more 'plastic' than originally thought and respond to metabolic demands and weight changes of their new host. These changes should be taken into account when assessing GFR outcomes in this population.

Experimental characterization of FANT, a new thermal neutron source.

FANT is the acronym of Enhanced Thermal Neutron Source (Fuente Ampliada de Neutrones Térmicos, in Spanish). This is a parallelepiped box of high-density polyethylene moderator and an isotopic neutron source. The moderator has a cylindrical irradiation chamber where a rather uniform thermal neutron flux is obtained. The FANT design was previously optimized and the neutron spectra were estimated by Monte Carlo calculations with the MCNP6.1 code. To check the characteristics of the FANT thermal neutron field, measurements have been performed at the reference point inside the irradiation chamber with a Bonner sphere spectrometer holding a small 6LiI(Eu) thermal neutron detector. To unfold the neutron spectrum BUNKIUT with UTA4 response matrix and NSDann Ver 4.0 codes were used. Some issues have been found and recommendations are made about the use of large BSS inside narrow spaces, and about the capacity of NSDann code to unfold these kind of spectra. However, the results confirm that the moderation process in FANT is very effective and allows obtaining useful thermal neutron fluence rates.

Neutron dosimetry and shielding verification in commissioning of Compact Proton Therapy Centers (CPTC) using MCNP6.2 Monte Carlo code.

Proton therapy (PT) is an external radiotherapy using proton beams with energies between 70 and 230 MeV to treat some type of tumours with outstanding benefits, due to its energy transfer plot. There is a growing demand of facilities taking up small spaces and Compact Proton Therapy Centers (CPTC), with one or two treatment rooms, supposing the technical response of manufacturers to this request. A large amount of stray radiation is produced in the interaction of protons used in therapy, neutrons mainly, hence, optimal design of shielding and verifications must be carried out in commissioning stages. Currently, almost 50 CPTC are under construction and start up in many countries, including several in Spain. In the present work, the effectiveness of shielding in a CPTC was verified with the Monte Carlo code MCNP6 by calculating the ambient dose equivalent, H*(10) due to secondary neutrons, outside the enclosures and walls of the center. The facility modelled was similar to one planned to start operating in 2019 in Spain, a CPTC, made up of a superconducting synchrocyclotron and one treatment room, with a configuration standard, shielding and width of barriers based on dimensions proposed a priori by the vendor. Therefore, the paper is focused in check the suitability of the materials and thickness of the walls of the center and develop the assessment of enclosures. Several models of the radiation sources and type of concrete in walls were simulated, starting from a conservative assumptions, followed by more realistic models. In all cases, the results were below 1 mSv/year, which is the international legal limit considered for the general public. This work is part of the project Contributions to Shielding and Dosimetry of Neutrons in Compact Proton Therapy Centers (CPTC).

Analysis by Monte Carlo methods of the response of an extended-range Bonner Sphere Spectrometer.

High-energy neutrons up to 230 MeV are generated as a consequence of (p,n) nuclear reactions in proton therapy facilities. The aim of this work is to evaluate the potential extension of the UPM Bonner Sphere Spectrometer (BSS) through the use of spallation materials, for its future application to determine neutron fluence spectra in such facilities. Monte Carlo methods have been used to model the response of the actual and modified spheres with the introduction of a spallation material layer, lead or copper, analyzing their response functions. An analysis is also made of the neutron fluence spectra over the 6LiI(Eu) scintillator volume and the uncertainty that can be associated to the response functions at high energies as a consequence of the different physics models that can be applied for their analysis.