First Responder Safety in the Event of a Dirty Bomb Detonation in Urban Environment

The malevolent dispersion of radioactive material, with the aim of contaminating people and the environment, is considered a credible terroristic threat. This article analyzes a hypothetical Dirty Bomb detonation in an urban area, estimating the radiological consequences to the involved population and to first responders. The dispersion of radioactive material is simulated using the HOTSPOT code, considering the explosion of devices containing (alternatively) 60Co, 137Cs, 192Ir, 238Pu or 241Am sources, frequently used in medical or industrial settings. Each source is evaluated separately. The resulting ground deposition is used to calculate the effective dose received by first responders in two different scenarios. Based on the dispersed radionuclide, the influence of the use of personal protective respirators is analyzed. Confirming previous published results, this article illustrates that the radioactive material is diluted by the detonation, resulting in relatively low doses to the general public. However, the emergency workers’ stay time in the most contaminated area must be carefully planned, in order to limit the received dose. Due to the general fear of radiation, extensive psychological effects are expected in the public, irrespective of the evaluated radiation dose

The HotSpot Code as a Tool to Improve Risk Analysis During Emergencies: Predicting I-131 and CS-137 Dispersion in the Fukushima Nuclear Accident

Conventional and non-conventional emergencies are among the most important safety and security concerns of the new millennium. Nuclear power and research plants, high-energy particle accelerators, radioactive substances for industrial and medical uses are all considered credible sources of threats both in warfare and in terror scenarios. Estimates of potential radiation releases of radioactive contamination related to these threats are therefore essential in order to prepare and respond to such scenarios. The goal of this paper is to demonstrate that computational modeling codes to simulate transport of radioactivity are extremely valuable to assess expected radiation levels and to improve risk analysis during emergencies helping the emergency planner and the first responders in the first hours of an occurring emergency

Phantom validation of quantitative Y-90 PET/CT based dosimetry in liver radioembolisation

Background PET/CT has recently been shown to be a viable alternative to traditional post-infusion imaging methods providing good quality images of 90Y-laden microspheres after selective internal radiation therapy (SIRT). In the present paper, first we assessed the quantitative accuracy of 90Y-PET using an anthropomorphic phantom provided with lungs, liver, spine, and a cylindrical homemade lesion located into the hepatic compartment. Then, we explored the accuracy of different computational approaches on dose calculation, including (I) direct Monte Carlo radiation transport using Raydose, (II) Kernel convolution using Philips Stratos, (III) local deposition algorithm, (IV) Monte Carlo technique (MCNP) considering a uniform activity distribution, and (V) MIRD (Medical Internal Radiation Dose) analytical approach. Finally, calculated absorbed doses were compared with those obtained performing measurements with LiF:Mg,Cu,P TLD chips in a liquid environment. Results Our results indicate that despite 90Y-PET being likely to provide high-resolution images, the 90Y low branch ratio, along with other image-degrading factors, may produce non-uniform activity maps, even in the presence of uniform activity. A systematic underestimation of the recovered activity, both for the tumor insert and for the liver background, was found. This is particularly true if no partial volume correction is applied through recovery coefficients. All dose algorithms performed well, the worst case scenario providing an agreement between absorbed dose evaluations within 20%. Average absorbed doses determined with the local deposition method are in excellent agreement with those obtained using the MIRD and the kernel-convolution dose calculation approach. Finally, absorbed dose assessed with MC codes are in good agreement with those obtained using TLD in liquid solution, thus confirming the soundness of both calculation approaches. This is especially true for Raydose, which provided an absorbed dose value within 3% of the measured dose, well within the stated uncertainties. Conclusions Patient-specific dosimetry is possible even in a scenario with low true coincidences and high random fraction, as in 90Y–PET imaging, granted that accurate absolute PET calibration is performed and acquisition times are sufficiently long. Despite Monte Carlo calculations seeming to outperform all dose estimation algorithms, our data provide a strong argument for encouraging the use of the local deposition algorithm for routine 90Y dosimetry based on PET/CT imaging, due to its simplicity of implementation

SARS-CoV-2 vaccination modelling for safe surgery to save lives: Data from an international prospective cohort study

Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population

Preliminary Assessment of Radiolysis for the Cooling Water System in the Rotating Target of {SORGENTINA}-{RF}

The SORGENTINA-RF project aims at developing a 14 MeV fusion neutron source featuring an emission rate in the order of 5-7 x 10(13) s(-1). The plant relies on a metallic water-cooled rotating target and a deuterium (50%) and tritium (50%) ion beam. Beyond the main focus of medical radioisotope production, the source may represent a multi-purpose neutron facility by implementing a series of neutron-based techniques. Among the different engineering and technological issues to be addressed, the production of incondensable gases and corrosion product into the rotating target deserves a dedicated investigation. In this study, a preliminary analysis is carried out, considering the general layout of the target and the present choice of the target material

Uncertainty Analysis in the Calibration of an Emission Tomography System for Quantitative Imaging

It is generally acknowledged that calibration of the imaging system (be it a SPECT or a PET scanner) is one of the critical components associated with in vivo activity quantification in nuclear medicine. The system calibration is generally performed through the acquisition of a source with a known amount of radioactivity. The decay-corrected calibration factor is the “output” quantity in a measurement model for the process. This quantity is a function of a number of “input” variables, including total counts in the volume of interest (VOI), radionuclide activity concentration, source volume, acquisition duration, radionuclide half-life, and calibration time of the radionuclide. Uncertainties in the input variables propagate through the calculation to the “combined” uncertainty in the output quantity. In the present study, using the general formula given in the GUM (Guide to the Expression of Uncertainty in Measurement) for aggregating uncertainty components, we derive a practical relation to assess the combined standard uncertainty for the calibration factor of an emission tomography system. At a time of increasing need for accuracy in quantification studies, the proposed approach has the potential to be easily implemented in clinical practice

Modelling mixing and transport of radioactive effluents in water reservoirs: an application to the operation of a fusion facility

The aim of the present study is to model mixing and transport of radioactive effluents in the course of time between two water reservoirs. To test the model, a hypothetical case study is presented of liquid effluents potentially released during normal operation of a fusion neutron source devoted to radioisotopes production. A suitable example is an accelerator-driven intense D-T 14 MeV neutron source relying on T and D ion beams, with the potential to provide a neutron yield in the range 5−7⋅1013 s-1. It is expected that during normal operation a number of radionuclides will be produced and managed. The present report discusses the mechanisms and parameters which affect and control the fate of radionuclides potentially released into two connected water reservoirs during normal operation of the plant. A mathematical mixing model is developed that describes groundwater flow and radioactive transport between the two basins. The aim of this study is to estimate the amount of radioactivity concentration in both water reservoirs at any time, an information that can be used for radiation protection purposes

Sopravvivenza delle megaprotesi nel trattamento delle metastasi osee

Introduzione: Il trattamento delle metastasi ossee è sovente palliativo, mirando al controllo del dolore e alla stabilizzazione o prevenzione di fratture patologiche; tuttavia, in casi selezionati può esser eseguita una resezione completa con finalità curative. Obiettivo del nostro lavoro è stato valutare la sopravvivenza delle megaprotesi utilizzate per ricostruzione dopo resezione di metastasi ossea Materiali e Metodi: Tra gennaio 2001 a marzo 2015 abbiamo impiantato 169 Megasystem-C® (Waldemar LINK® GmbH & Co. KG, Amburgo, Germania) dopo resezione di metastasi ossea. I pazienti, 95 femmine e 74 maschi, sono stati operati a un’età media di 61 (12-87) anni per resezione prossimale di femore in 135 (79.9%) casi, distale di femore in 24 (14.2%), prossimale di tibia in 6 (3.6%), totale di femore in 3 (1.8%) e intercalare di femore in 1 (0.6%). Sono state principalmente trattate metastasi da carcinoma mammario (30.8%), renale (17.8%) e polmonare (14.2%). Risultati: A un follow-up medio di 21 (1-150) mesi, abbiamo riscontrato un tasso di salvataggio dell’arto del 99.4%, e un tasso di sopravvivenza libera da fallimento dell’impianto del 96.1% a 1 anno, 92.8% a 2 anni, e 86.8% a 5 e 10 anni. Abbiamo denotato 9 (5.3%) casi di lussazione di megaprotesi di femore prossimale, 3 dei quali necessitanti di riduzione chirurgica; 2 (1.2%) casi di mobilizzazione asettica dello stelo protesico; 2 (1.2%) casi d’infezione periprotesica, uno dei quali necessitante una revisione in 2 tempi. Discussione: A oggi, pochi studi in letteratura hanno valutato la sopravvivenza di megaprotesi nel trattamento di metastasi ossee. I nostri dati evidenziano come in questo specifico contesto il tasso di complicanze è nettamente inferiore a quanto atteso in chirurgia ortopedica oncologica generale. In particolar modo, riteniamo che il basso tasso d’infezione denotato, quasi sovrapponibile a quello atteso in procedure primarie, sia da addebitarsi a puntuali gestioni dei tessuti molli (in particolar modo in ricostruzioni prossimali di tibia) e a una profilassi antibiotica prolungata. Conclusioni: L’utilizzo delle protesi modulari è una valida strategia ricostruttiva dopo resezione di metastasi ossee in pazienti selezionati. Il tasso di complicanze a breve termine è eccezionalmente basso; studi successivi dovranno confermare ciò a più lungo termine

A practical and improved synthesis of 1, 2, 3, 4, 4a, 10, 11, 11a-octahydro-3-(5H-dibenzo-[a,d]cyclohepten-5-ilyden)-N,N-dimethylpropylamine

The aim of our work was to develop a synthetic pathway in order to obtain 1,2,3,4,4a,10,11,11a-octahydro-3- (5H-dibenzo-[a,d]cyclohepten-5-ilyden)-N,N-dimethylpropylamine, an impurity arising from the Amitriptyline industrial production and reported in the most important Pharmacopoeias. To own a standard of the aforementioned impurity is useful for any company that wants to market Amitriptyline. We performed the synthesis of the target compound in 9 steps, with a good overall yield, exploiting as a keystep a MW-assisted Heck-reaction. Moreover MW heating was successful in the optimization of the entire synthetic scheme

A mathematical model for the diffusion of emergency warning messages during CBRNe emergencies

Understanding the diffusion of warning messages is essential to adequately respond to emergency events and situations. This is especially true in urgent scenarios, that is situations where external events are happening at the same rate or faster than the diffusion process itself. In this paper, an information diffusion model (Bass model) is proposed to study the spread of warning messages during emergencies involving urgent diffusion dynamics, for example a CBRNe event. In the present study, the Bass model is applied to two hazardous materials transportation accidents reported in the literature: the Pittsburgh phosphorus oxychloride release and the precautionary evacuation occurred in Confluence due to toxic chemicals released after a train derailment. Warning data collected from the two accidents and reported in published literature studies were used in this work and fitted with the Bass model. The diffusion of emergency warning messages is modelled as a two‐component system, where the spread of information is characterized by (a) a “broadcast process” that disseminates the emergency warning vertically (in the sense that many people are alerted simultaneously) and (b) a horizontal “contagion process” whereby people first hear of the event and then sequentially tell others (social media, word‐of‐mouth and peer‐to‐peer communication). The Bass model provided an excellent fit of the warning diffusion times related to both accidents suggesting that the very first phase of the warning process is sustained by a “broadcast” information diffusion process. However, after less than 1 hr from the beginning of the warning process the efficacy of its diffusion is dominated by the “contagion” component, that is the effectiveness of a robust social network between individuals. In conclusion, the Bass model proved to be a handy tool to assess epidemics spreading of information from the people who adopted the information. Our results suggest that the general Bass model applied to diffusion of emergency warning has the potential to provide key information in the management of emergencies. This approach can be applied right away by professional communicators, advisors and decision‐makers in case of a CBRNe event