"L'evoluzione del mercato europeo: la portualità e gli scambi"

L’Unione Europea è nata dalla necessità di tutelare e favorire gli scambi e quindi il mercato. Al suo interno quelli marittimi, da sempre importanti, hanno recentemente conquistato il mercato per dimensioni e prospettive. Il porto costituisce allo stesso tempo una secolare tradizione ed un elemento fondamentale per l’economia europea. L’emergere di grandi realtà asiatiche quali Singapore, Shangai, Hong Kong ha tuttavia messo in evidenza i limiti, le carenze e le necessità della portualità europea, ulteriormente aggravata dall’enorme divario tra South e Northern Range. Cosa farà ed ha fatto lʼEuropa per riacquistare forza nei confronti dei grandi concorrenti mondiali? In che modo si propone di rimuovere gli ostacoli che impediscono il suo rilancio? Quali iniziative intendono attuare i vari paesi per ritagliarsi uno spazio sullo scenario internazionale? La creazione di un modello di governance comunitario, la crescente specializzazione dei traffici, lo sviluppo dell’intermodalità sono solo alcune delle proposte più avanzate per restituire al vecchio continente competitività in questo vitale settore. Il progetto di ricerca ha analizzato i più importanti aspetti della portualità in Europa tentando non solo di fornire un quadro esauriente del sistema, ma soprattutto di tratteggiarne le prospettive, avanzando contemporaneamente proposte e regole tese ad affrontare questioni che il mondo contemporaneo e l’economia globalizzata prospettano in modo drammatico

GEANT4 for breast dosimetry: parameters optimization study

Mean glandular dose (MGD) is the main dosimetric quantity in mammography. MGD evaluation is obtained by multiplying the entrance skin air kerma (ESAK) by normalized glandular dose (DgN) coefficients. While ESAK is an empirical quantity, DgN coefficients can only be estimated with Monte Carlo (MC) methods. Thus, a MC parameters benchmark is needed for effectively evaluating DgN coefficients. GEANT4 is a MC toolkit suitable for medical purposes that offers to the users several computational choices. In this work we investigate the GEANT4 performances testing the main PhysicsLists for medical applications. Four electromagnetic PhysicsLists were implemented: the linear attenuation coefficients were calculated for breast glandularity 0%, 50%, 100% in the energetic range 8-50 keV and DgN coefficients were evaluated. The results were compared with published data. Fit equations for the estimation of the G-factor parameter, introduced by the literature for converting the dose delivered in the heterogeneous medium to that in the glandular tissue, are proposed and the application of this parameter interaction-by-interaction or retrospectively is discussed. G4EmLivermorePhysicsList shows the best agreement for the linear attenuation coefficients both with theoretical values and published data. Moreover, excellent correlation factor ([Formula: see text]) is found for the DgN coefficients with the literature.The final goal of this study is to identify, for the first time, a benchmark of parameters that could be useful for future breast dosimetry studies with GEANT4

Optimization of the energy for Breast monochromatic absorption X-ray Computed Tomography

The limits of mammography have led to an increasing interest on possible alternatives such as the breast Computed Tomography (bCT). The common goal of all X-ray imaging techniques is to achieve the optimal contrast resolution, measured through the Contrast to Noise Ratio (CNR), while minimizing the radiological risks, quantified by the dose. Both dose and CNR depend on the energy and the intensity of the X-rays employed for the specific imaging technique. Some attempts to determine an optimal energy for bCT have suggested the range 22keV\u201334keV, some others instead suggested the range 50keV\u201360keV depending on the parameters considered in the study. Recent experimental works, based on the use of monochromatic radiation and breast specimens, show that energies around 32keV give better image quality respect to setups based on higher energies. In this paper we report a systematic study aiming at defining the range of energies that maximizes the CNR at fixed dose in bCT. The study evaluates several compositions and diameters of the breast and includes various reconstruction algorithms as well as different dose levels. The results show that a good compromise between CNR and dose is obtained using energies around 28keV