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The indoor radon concentration was measured in 471 dwellings in the Province of Naples. Radon concentration measurements were carried out using LR-115 passive alpha track detectors (SSNTDs) that were exposed for two consecutive semesters. The annual average radon concentration in the dwellings was found to vary from 21 to 722 Bq m−3 with an average value of 107 ± 75 Bq m−3. In about 93% of the dwellings the radon concentrations were found to be below 200 Bq m−3, which is the recommended level by Italian law for new buildings. Simultaneously with the radon concentration measurements, indoor gamma dose rates were measured in 388 dwellings. Indoor gamma dose rates were measured using Thermoluminescent Dosimeters (TLDs) exposed in each dwelling for six months. The arithmetic mean value was found to be 327 ± 102 nGy h−1, after the subtraction of the cosmic ray contribution. A weak correlation between the indoor radon concentration and gamma dose rate was found. The correlation between indoor radon measurements and gamma dose rates and the same building characteristics was also studied.

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 PhD work I present the results of the validation of the electromagnetic and hadronic 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 simulations were performed using Geant4 and MULASSIS, a module to the Spenvis software, with protons of energy characteristic of SPE, 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 and experimental data measured during the experiment conducted at the NASA, Space Radiation Laboratory (NSRL), Brookhaven National Laboratory, USA. Moreover after validation, other materials were tested, in particular were studied the trends of dose of these materials.

The increasing use of ionizing radiation in healthcare is causing growing alarm about radiation protection of patients and the doses they receive during procedures. Radiation dose assessment for patients in radiodiagnostic procedures is the subject of interest in view of the recent Italian D.Lgs 31 July 2020, n. 101 (Decreto Legislativo 31 luglio 2020, n. 101) and one of its most important focuses is the prescription to provide patient exposure information as an integral part of the examination report. Dose monitoring systems are therefore essential for the collection of the dosimetric data. In order to analyse potential and critical issues of these software, different systems, adopted at the Antonio Cardarelli Hospital in Naples, were employed. Data extracted from the DoseWatch software (GE Healthcare) and Gray Detector (EL.CO. S.r.l. Healthcare Solutions, Italy) and relating to several protocols adopted for computed tomography (CT), were retrospectively analysed for the purpose of identifying critical issues in the data acquisition and recording phase, comparing with Italian nationwide diagnostic reference levels (DRLs), as provided for in regulatory provisions for radiation safety. Multiphase examinations were also included in this study. Once the distributions of volumetric CT Dose Index (CTDIvol) and dose-length product (DLP) were determined for each acquisition phase and total DLP (DLPtot) for each examination, the 25th, 50th and 75th percentiles were calculated for each distribution and then compared with the relevant Italian nationwide DRLs. In addition, to improve protocol optimization and dose reduction the magnitude of the CT acquisition settings chosen in each procedure was evaluated. In conclusion, these systems allow accurate analysis of radiation dose according to equipment and protocol over time. For the application of optimization measures, a constant use of the dose tracking software is required, which can be translated into actions on scan parameters and prospective data analysis.

In this study, the indoor radon concentrations map, starting from a sparse measurements survey, was realized with the Gini index method. This method was applied on a real dataset coming from indoor radon measurements carried out in Kpong, Ghana. The Gini coefficient variogram is shown to be a good estimator of the inhomogeneity degree of radon concentration because it allows for better constraining of the critical distance below which the radon geological source can be considered as uniform. The indoor radon measurements were performed in 96 dwellings in Kpong, Ghana. The data showed that 84% of the residences monitored had radon levels below 100 Bqm−3, versus 16% having levels above the World Health Organization’s (WHO) suggested reference range (100 Bqm−3). The survey indicated that the average indoor radon concentration (IRC) was 55 ± 36 Bqm−3. The concentrations range from 4–176 Bqm−3. The mean value 55 Bqm−3 is 38% higher than the world’s average IRC of 40 Bqm−3 (UNSCEAR, 1993).

Individualized dosimetry in nuclear medicine is currently at least advisable in order to obtain the best risk–benefit balance in terms of the maximal dose to lesions and under-threshold doses to radiosensitive organs. This article aims to propose a procedure for fast dosimetric calculations based on planar whole-body scintigraphy (WBS) images and developed to be employed in everyday clinical practice. Methods: For simplicity and legacy reasons, the method is based on planar imaging dosimetry, complemented with some assumptions on the radiopharmaceutical kinetics empirically derived from single-photon emission tomography/computed tomography (SPECT/CT) image analysis. The idea is to exploit a rough estimate of the time-integrated activity as has been suggested for SPECT/CT dosimetry but using planar images. The resulting further reduction in dose estimation accuracy is moderated by the use of a high-precision Monte-Carlo S-factor, such as those available within the OpenDose project. Results: We moved the problem of individualized dosimetry to a transformed space where comparing doses was imparted to the ICRP Average Male/Female computational phantom, resulting from an activity distribution related to patient’s pharmaceutical uptake. This is a fast method for the personalized dosimetric evaluation of radionuclide therapy, bearing in mind that the resulting doses are meaningful in comparison with thresholds calculated in the same framework. Conclusion: The simplified scheme proposed here can help the community, or even the single physician, establish a quantitative guide-for-the-eye approach to individualized dosimetry.

Space missions with humans expose the crews to ionizing radiation, mainly due to the galactic cosmic radiation (GCR). All radiation protection programs in space aim to minimize crews’ exposure to radiation. The radiation protection of astronauts can be achieved through the use of shields. The shields could serve as a suit to reduce GCR exposure and, in an emergency, as a radiation shelter to perform necessary interventions outside the space habitat in case of a solar proton event (SPE). A space radiation shielding that is suitable for exploration during space missions requires particular features and a proper knowledge of the radiation type. This study shows the results of numerical simulations performed with the Geant4 toolkit-based code DOSE. Calculations to evaluate the performance of Nomex, an aramidic fiber with high mechanical resistance, in terms of dose reduction to crews, were performed considering the interaction between protons with an energy spectrum ranging from 50 to 1100 MeV and a target slab of 20 g/cm2. This paper shows the properties of secondary products obtained as a result of the interaction between space radiation and a Nomex target and the properties of the secondary particles that come out the shield. The results of this study show that Nomex can be considered a good shield candidate material in terms of dose reductions. We also note that the secondary particles that provide the greatest contribution to the dose are protons, neutrons and, in a very small percentage, α-particles and Li ions.

Humans are mostly exposed to ionizing radiation through radon and its decay products. The results of indoor radon measurements in 39 kindergartens and primary schools in the Campania region of southern Italy are presented in this paper. The survey was carried out with CR-39 solid-state nuclear track detectors (SSNTDs). Radon concentrations were measured and ranged from 11 to 1416 Bq/m3, with a geometric mean of 77 Bq/m3 and a geometric standard deviation of 2. The findings revealed that 70% of the measures were below the WHO recommended level of 100 Bq/m3 and that 97 percent of the measurements were below the 300 Bq/m3 level set by Italian law.

The population is continuously exposed to a background level of ionizing radiation due to the natural radioactivity and, in particular, with radon (222Rn). Radon gas has been classified as the second leading cause of lung cancer after tobacco smoke [1]. In the confined environment, radon concentration can reach harmful level and vary accordingly to many factors. Since the primary source of radon in dwellings is the subsurface, the risk assessment and reduction cannot disregard the identification of the local geology and the environmental predisposing factors. In this article, we propose a new methodology, based on the computation of the Gini coefficients at different spatial scales, to estimate the spatial correlation and the geographical variability of radon concentrations. This variability can be interpreted as a signature of the different subsurface geological conditions. The Gini coefficient computation is a statistical tool widely used to determine the degree of inhomogeneity of different kinds of distributions. We generated several simulated radon distributions, and the proposed tool has been validated by comparing the variograms based on the semi-variance computation with those ones based on the Gini coefficient. The Gini coefficient variogram is shown to be a good estimator of the inhomogeneity degree of radon concentration. Indeed, it allows to better constrain the critical distance below which the radon geological source can be considered as uniform at least for the investigated length scales of variability; it also better discriminates the fluctuations due to the environmental predisposing factors from those ones due to the random spatially uncorrelated noise.

Radon is the main source of exposure to ionizing radiation for the general population. In Italy, very little has been investigated to determine occupational radon exposure in workers. In this study, radon concentrations of various workplaces type were measured for 1 year using SSNTD CR-39. Q–Q plot and Shapiro–Wilks statistical test showed that radon concentrations are not log-normally distributed. The geometric mean of radon concentration was found to be 97 Bq/m3 with a geometric standard deviation of 3. The mean effective dose to workers has been calculated and found to be 1.4 mSv/y. Finally, for estimation of cancer risks, the lifetime risk and lung cancer cases per year per million have been calculated.

This article provides a review of the role of stochastic approaches, in particular Monte Carlo calculations, in the study of aviation-induced contrails at different characteristic lengths, ranging from micrometers to the planetary scale. Pioneered in the 1960s by Bird, Direct Simulation Monte Carlo has for long time been considered unfeasible in extended dispersed-phase systems as clouds. Due to the impressive increase in computational power, Lagrangian Monte Carlo approaches are currently available, even for studying cloud formation and evolution. Some aspects of these new approaches are reviewed after a detailed introduction to the topic of aircraft-induced cloudiness. The role of Monte Carlo approaches in reducing the different source of uncertainty about the contribution of aviation contrails to climate change is introduced. Perspectives on their role in future experimental and theoretical studies are discussed throughout the paper.

In confined spaces such as living environments and workplaces, the concentration levels of radon (Rn222) can be very high as compared to the external environment. Since Rn has been classified as the second leading cause of lung cancer after cigarette smoking, to apply efficient locally based risk reduction actions, dense maps of indoor radon concentration are needed. These maps would provide information about the areas prone to high radon concentrations and therefore more dangerous to human health. The soil is the primary source of the Rn, hence the risk assessment and reduction for the radon exposure cannot disregard the identification of the local geology. In this regard, we propose an innovative method, based on the Gini index computation, for the realization of interpolated maps (kriging) to describe the distribution of concentration of Rn. To validate the method, a tool that simulates sets of radon concentrations is used, whose variability is, to the first order, controlled by a priori imposed different lithologies. A systematic comparison is made between the results achieved by means of a classically used geostatistical method and the proposed Gini-based tool. We show how, by using this latter tool, the kriging solutions appear to be more robust to resolve the different geogenic radon sources independently from the number of the available measurements.

In recent years, stereotactic body radiation therapy (SBRT) has gained popularity among clinical methods for the treatment of medium and low risk prostate cancer (PCa), mainly as an alternative to surgery. The hypo-fractionated regimen allows the administration of high doses of radiation in a small number of fractions; such a fractionation is possible by exploiting the different intrinsic prostate radiosensitivity compared with the surrounding healthy tissues. In addition, SBRT treatment guaranteed a better quality of life compared with surgery, avoiding risks, aftermaths, and possible complications. At present, most stereotactic prostate treatments are performed with the CyberKnife (CK) system, which is an accelerator exclusively dedicated for stereotaxis and it is not widely spread in every radiotherapy centre like a classic linear accelerator (LINAC). To be fair, a stereotactic treatment is achievable also by using a LINAC through Volumetric Modulated Arc Therapy (VMAT), but some precautions must be taken. The aim of this work is to carry out a dosimetric comparison between these two methodologies. In order to pursue such a goal, two groups of patients were selected at Instituto Nazionale Tumori—IRCCS Fondazione G. Pascale: the first group consisting of ten patients previously treated with a SBRT performed with CK; the second one was composed of ten patients who received a hypo-fractionated VMAT treatment and replanned in VMAT-SBRT flattening filter free mode (FFF). The two SBRT techniques were rescaled at the same target coverage and compared by normal tissue sparing, dose distribution parameters and delivery time. All organs at risk (OAR) constraints were achieved by both platforms. CK exhibits higher performances in terms of dose delivery; nevertheless, the general satisfying dosimetric results and the significantly shorter delivery time make VMAT-FFF an attractive and reasonable alternative SBRT technique for the treatment of localized prostate cancer.

Introduction: Radiotherapy is increasingly used for the treatment of cancer patients and more and more personalized treatments are being developed to improve the patient’s quality of life. Today, the medical community is moving toward VMAT plans, which allow to deliver the prescription dose to the tumor and to spare surrounding healthy tissues. In this context the development of autoplanning system is desirable. Method and results: In this work we report the implementation, in the TPS RayStation, of the autoplanning algorithm that creates high quality plans, when brain metastases are involved. Conclusion: At the state of the art, the AP codes can be intended to lighten the work of the medical physicist so that he can refine the plan previously elaborated in AP modality or devote himself to more delicate situations.

Introduction: For the first time, the Council Directive 2013/59/Euratom focuses on the risk to human health deriving from exposure to radon in homes, promoting the adoption of more stringent actions for the public awareness about indoor radon risk. Although the directive has not been transposed in Italy yet, some regions e.g. Campania, independently have issued a regional decree (n.13 of 2019) to comply with this lack. Method and results: In this study, the results of a survey on the public's knowledge about the risks associated with exposure to radon collected during two scientific dissemination events “Researchers' Night” (September 2019) and “Futuro Remoto” (November 2019) in Naples, South Italy, are reported.

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.

Radiation metrology is crucial in space, for instance in monitoring the conditions on-board space vehicles. The energy released in matter by ionizing radiation is due to the atomic and molecular ionization processes, which have been investigated for several decades from both a theoretical and an experimental point of view. Electronic excitation and ionization cross-section are of particular interest in radiation physics, because of their role in the radiation–matter interaction process. Recently, experimental findings have shown that the interplay with a laser field can strongly modify the electronic interaction probabilities and emission spectra. These phenomena are still not completely understood from a theoretical point of view, and the available empirical data concern a few, simple atomic species. We represent a possible dosimetric effect of the interaction with laser light, inferring from experiments the characteristics of laser-assisted cross-sections. Using a Monte-Carlo calculation for simulating the micro-dosimetric aspects of the irradiation of a simple geometry, we show the need of new experimental data and more detailed theoretical approaches to these phenomena in complex molecular systems.

Indoor radon activity concentrations were measured in seven Museums of University of Naples, very old buildings of great historical value. The measurements were performed using a time-integrated technique based on LR-115 solid-state nuclear track detectors. The annual average concentrations were found to range from 40 up to 1935 Bq m(-3) and in 26 % of measurement sites, the values were higher than 500 Bq m(-3) which is the limit value of Italian legislation for workplace. Moreover, we analysed the seasonal variations of radon concentrations observing the highest average in cold weather than in warm.

It has been widely shown that nuclear fallout includes substances, which accumulate in organisms such as crustaceans, fish, mushrooms and lichens, helping to evaluate the activity concentration of contaminants accumulated on a long time. In this context, radiocaesium deposited in soil following the Chernobyl accident on 26 April 1986 is known to have remained persistently available for plant uptake in many areas of Europe. Studies on the lichen Stereocaulon vesuvianum show the plant's high capacity to retain radionuclides from the substrate and the air. After the Chernobyl accident, starting from September 1986, at the Radioactivity Laboratory (LaRa) of the University of Naples Federico II, four monitoring campaigns to evaluate the activity concentration of four isotopes of the two elements caesium and ruthenium ( 134 Cs, 137 Cs, 103 Ru and 106 Ru) were carried out until 1999. This study allowed the effective half-life of 134 Cs and 137 Cs to be estimated. Twenty-eight years after the accident, in December 2014, a further sampling was carried out; only 137 Cs was revealed beyond the detection limits, measuring activity concentrations ranging from 20 to 40 Bq/kg, while the other radionuclides were no longer observed due to their shorter half-life. The last sampling allowed more precise determination of the effective half-life of 137 Cs (6.2 ± 0.1 year), due to the larger dataset on a large time period.

In the study of the effectiveness of shielding materials against radiations, one of the main steps concerns with the validation of models describing the interaction processes of the radiation of interest with the material chosen for the shielding. This paper shows the results of the validation of electromagnetic and hadronic processes with the aim to contribute to the study of protection for astronauts against the radiations due to the Solar Particle Events, in particular to the selection of the optimal material for radiation shielding. The physics case deals with the interaction of a proton beam with an aluminum slab about 20 g/cm 2 thick. Two specific applications, STP and DOSE, were developed by using Geant4 package. STP computes the radiations produced in the interaction and their stopping power; DOSE computes the absorbed dose from the stopping power calculated by STP. The validation process was performed in two steps. In the first one, the output of the STP code is compared to data available on NIST database; in the second one, the absorbed dose computed with DOSE is compared to the dose gathered during an experiment performed at the NASA Space Radiation Laboratory involving the bombardment of an aluminum slab with a 1 GeV proton beam. The computing model has allowed us to correlate the size of the impinging beam profile to the dose measured before and after an Al slab. The sharp increase of the dose in the position right after the slab might be due to the stochastic nature of the trajectories of charged ions in matter which makes the radiation to emerge with non-zero transverse linear momentum. From the case examined here, we conclude that aluminum is not an efficient material for Solar Particle Event shielding.

HiDOSE (Heavy ion DOSimetry Experiment) and nDOSE (neutron DOSimetry Experiment) experiments conducted as a part of BIOKIS (Biokon in Space) payload were designed to measure the dose equivalent due to charged particles and to neutron field, on the entire energy range, during STS-134 mission. Given the complexity of the radiation field in space environment, dose measurements should be considered an asset of any space mission, and for this reason HiDOSE and nDOSE experiments represent an important contribution to the radiation environment assessment during this mission, a short duration flight. The results of these experiments, obtained using Thermo Luminescence Dosimeters (TLDs) to evaluate the charged particles dosimetry and neutron bubbles dosimeters and stack bismuth track dosimeters for neutron dosimetry, indicate that the dose equivalent rate due to space radiation exposure during the STS-134 mission is in accordance with the results obtained from long duration flights.

In this study, the indoor radon concentrations have been measured in 93 dwellings of the Penisola Sorrentina, using LR115 detectors. The detectors were placed in the bedrooms and living rooms for two consecutive semesters starting from December 2010 to December 2011. The annual average indoor radon concentrations vary from 25 to 722 Bq m(-3), with a mean value of 132 ± 114 Bq m(-3). Correlation between indoor radon measurements and same building characteristics was also studied. Based on the obtained results, the mean annual effective dose of 2.4 mSv y(-1) received by inhabitants was estimated.

Indoor radon concentrations were measured in dwellings of the Puglia region in Southern Italy using LR-115 passive detectors. The results show that the radon concentrations varied from 15 ± 2 to 2166 ± 133 Bq/m3 with a geometric mean of 114 Bq/m3 and a geometric standard deviation of 2.3. An analysis on the factors affecting radon concentration such as age of the dwellings, floors, and stories, was performed. The mean effective dose to inhabitants has been calculated and found to be 8.2 mSv/y. Finally, for estimation of cancer risks, the lifetime risk and lung cancer cases per years per million have been calculated.