Indoor radon exposure and lung cancer risk: a meta-analysis of case-control studies

The aim of this study was to assess a potential relationship between indoor radon exposure and the incidence of lung cancer worldwide. A systematic literature search was carried out in PubMed, Web of Science, and Google Scholar to identify relevant studies published in English conducted in the last 15 years until January 2016. Summary relative risks (RR) and the corresponding 95% confidence intervals (CIs) were calculated using a random-effects model and the influence of moderators using a mixed-effects model. Heterogeneity was assessed using the Q, I2 and H2 tests, and the source of heterogeneity was detected by meta-regression analysis. Publication bias was evaluated with Egger’s regression symmetry test and the contour-enhanced funnel plot. Leave-one-out sensitivity analysis was performed. Twenty-five lung cancer studies (case-control studies) with 13,569 cases and 22,701 controls were included. Indoor Radon exposure was significantly associated with increased risk for lung cancer (RR, 1.19; 95% CI, 1.02–1.39). Study location analysis showed that radon exposure was associated with increased risk for lung cancer from forty degrees absolute latitude (RR, 1.09; 95% CI, 0.92–1.31), to fifty degrees (RR 1.26; 95% CI, 1.08–1.48), to sixty degrees (RR, 1.46; 95% CI, 1.12–1.91). Indoor radon exposure may be associated with increased risk for lung cancer

Preliminary test of Bragg application for proton therapy using the Geant4 toolkit

In the treatment of tumors, the advantage of proton therapy is the sparing of dose to healthy tissue surrounding the target one, saving it from unnecessary damage. For protons, the dose increases with increasing penetration depth up to the Bragg peak that occurs near the end of the particle’s range. This work shows the first results obtained with a specific application, Bragg, which has been developed with the use of the Geant4 package. This application aims to contribute to develop and test innovative treatment planning models for particle therapy. The results from the numerical simulation have been compared with the experimental data in the literature. The validation of models against experimental data is a prerequisite for the use of any application and, therefore, highly demanded

Validation of the Electromagnetic Physical Processes with Software SPENVIS

The Space Radiation represents a serious risk for astronauts during space missions. The risk related to the space radiation exposure could involve acute and/or late effects. The Solar Cosmic Radiation that consists of protons (≈98%) with a very wide spectrum in energy (up to several GeV), is the major source of exposure for the crew. In this paper we present the results of the validation of the electromagnetic physical processes with the aim to contribute to the study of radiation protection for astronauts, in particular against the radiation due to the Solar Particle Events (SPE). The simulation was performed using MULASSIS, a module to the software SPENVIS, with protons as source, in the energy range from 800 MeV to 1.2 GeV, on a slab of aluminum of mass thickness of 20 g/cm2. The results obtained by the simulation were compared with PSTAR database of the NIST. Finally, a comparison between SPENVIS and Geant4-9.6p2 was performed

Nomex with boron as a neutron shielding in space: Preliminary study

In this work we present a study devoted to the evaluation of the efficiency of a radiation shield, made out of the Nomex material doped with boron, in reducing the absorbed dose after bombardment with a 1GeV proton beam. This study is relevant to the definition of optimal conditions for the shielding of astronauts from Solar Particle Events and Galactic Cosmic Radiation in space. Nomex shield is treated with boron at different concentrations. The production and transport of radiation produced after proton interaction is treated with a simulation tool based on Geant4. The added boron acts as an effective neutron mitigating material. The main preliminary result is that the average dose changes effectively despite the additional production of alpha particles from the reaction 10B(n,α)

Study of Surface Emissions of 220Rn (Thoron) at Two Sites in the Campi Flegrei Caldera (Italy) during Volcanic Unrest in the Period 2011–2017

The study concerns the analysis of 220Rn (thoron) recorded in the surface soil in two sites of the Campi Flegrei caldera (Naples, Southern Italy) characterized by phases of volcanic unrest in the seven-year period 1 July 2011–31 December 2017. Thoron comes only from the most surface layer, so the characteristics of its time series are strictly connected to the shallow phenomena, which can also act at a distance from the measuring point in these particular areas. Since we measured 220Rn in parallel with 222Rn (radon), we found that by using the same analysis applied to radon, we obtained interesting information. While knowing the limits of this radioisotope well, we highlight only the particular characteristics of the emissions of thoron in the surface soil. Here, we show that it also shows some clear features found in the radon signal, such as anomalies and signal trends. Consequently, we provide good evidence that, in spite of the very short life of 220Rn compared to 222Rn, both are related to the carrier effect of CO2, which has significantly increased in the last few years within the caldera. The hydrothermal alterations, induced by the increase in temperature and pressure of the caldera system, occur in the surface soils and significantly influence thoron's power of exhalation from the surface layer. The effects on the surface thoron are reflected in both sites, but with less intensity, the same behavior of 222Rn following the increasing movements and fluctuations of the geophysical and geochemical parameters (CO2 flux, fumarolic tremor, background seismicity, soil deformation). An overall linear correlation was found between the 222−220Rn signals, indicating the effect of the CO2 vector. The overall results represent a significant step forward in the use and interpretation of the thoron signal

X-rays affect cytoskeleton assembly and nanoparticle uptake: Preliminary results

Alterations of the cytoskeleton are commonly associated with tumor genesis and cancer progression. For this reason, the characterization of cytoskeletonassociated functions and properties is important to optimize the outcomes to classical and more recent therapeutic approaches, such as chemotherapy, radiotherapy and cancer nanomedicine. In such context, this work investigated the synergy between cancer nanomedicine and radiotherapy. In particular, the effects over time (24 and 48h) of two different doses of X-rays (2 and 10Gy) on spreading area, morphological parameters and the internalization mechanism of carboxylated nanoparticles in mammary epithelial cells and mammary adenocarcinoma cells were investigated

Radiation therapy affects YAP expression and intracellular localization by modulating lamin A/C levels in breast cancer

The microenvironment of breast cancer actively participates in tumorigenesis and cancer progression. The changes observed in the architecture of the extracellular matrix initiate an oncogene-mediated cell reprogramming, that leads to a massive triggering of YAP nuclear entry, and, therefore, to cancer cell proliferation, invasion and probably to increased radiation-resistance. However, it is not yet fully understood how radiotherapy regulates the expression and subcellular localization of YAP in breast cancer cells experiencing different microenvironmental stiffnesses. To elucidate the role of extracellular matrix stiffness and ionizing radiations on YAP regulation, we explored the behaviour of two different mammary cell lines, a normal epithelial cell line (MCF10A) and a highly aggressive and invasive adenocarcinoma cell line (MDA-MB-231) interacting with polyacrylamide substrates mimicking the mechanics of both normal and tumour tissues (~1 and ~13 kPa). We report that X-ray radiation affected in a significant way the levels of YAP expression, density, and localization in both cell lines. After 24 h, MCF10A and MDA-MB231 increased the expression level of YAP in both nucleus and cytoplasm in a dose dependent manner and particularly on the stiffer substrates. After 72 h, MCF10A reduced mostly the YAP expression in the cytoplasm, whereas it remained high in the nucleus of cells on stiffer substrates. Tumour cells continued to exhibit higher levels of YAP expression, especially in the cytoplasmic compartment, as indicated by the reduction of nuclear/ cytoplasmic ratio of total YAP. Then, we investigated the existence of a correlation between YAP localization and the expression of the nuclear envelope protein lamin A/C, considering its key role in modulating nuclear deformability and changes in YAP shuttling phenomena. As supposed, we found that the effects of radiation on YAP nucleus/cytoplasmic expression ratio, increasing in healthy cells and decreasing in tumour ones, were accompanied by lower and higher lamin A/C levels in MCF10A and MDAMB-231 cells, respectively. These findings point to obtain a deeper knowledge of the role of the extracellular matrix and the effects of X-rays on YAP and lamin A/C expression that can be used in the design of doses and timing of radiation therapy

Investigation of Biophysical Migration Parameters for Normal Tissue and Metastatic Cancer Cells After Radiotherapy Treatment

A large body of literature has demonstrated that the mechanical properties of microenvironment have a key role in regulating cancer cell adhesion, motility, and invasion. In this work, we have introduced two additional parameters, named cell trajectory extension and area traveled by cell, to describe the tendency of normal tissue and metastatic cancer cells to move in a directional way when they interact with physio-pathological substrates, characterized by stiffnesses of 1–13 kPa, before and after treatment with 2 doses of X-rays (2 and 10 Gy). We interpreted these data by evaluating also the impact of substrate stiffness on 2 morphological parameters which indicate not only the state of cell adhesion, but also cell polarization, prerequisite to directional movement, and the formation of protrusions over cell perimeters. We believe that a so wide analysis can give an efficient and easily readable overview of effects of radiation therapy on cell-ECM crosstalk when used as therapeutic agent

Radiological Protection in Industries Involving NORM: A (Graded) Methodological Approach to Characterize the Exposure Situations

The interest in radiation protection in industrial sectors involving Naturally Occurring Radioactive Materials (NORM) is increasingly growing. This is due also to the recent implementation of the European Council Directive 59/2013/Euratom which in Italy and in the other European Union Member States extends the field of application to industrial sectors never involved before. This paper reports main results of a research project on radiation protection in industries involving NORM carried out in Italy aimed to provide useful tools for stakeholders to comply new legal obligations. The project activities were mainly focused on different aspects relevant to the NORM involving industries, accounting for the positive list reported in the Italian law. Firstly, the inventory of the industries currently operating in Italy in order to identify the industrial sectors with an important radiological impact on population and workers was updated. Based on this information, a general methodology was elaborated taking into account a graded approach. The first phase consists in the identification and characterization of the most critical exposure scenarios and of the radiological content of NORMs involved in the different phases of the industrial processes. In the second phase calculation methods were developed for dose estimation for workers and members of public. These tools require the use of existing and well tested calculation codes, and the development of a dedicated user-friendly software