Perspectives of Nuclear Physics in Europe: NuPECC Long Range Plan 2010

The goal of this European Science Foundation Forward Look into the future of Nuclear Physics is to bring together the entire Nuclear Physics community in Europe to formulate a coherent plan of the best way to develop the field in the coming decade and beyond.<p></p> The primary aim of Nuclear Physics is to understand the origin, evolution, structure and phases of strongly interacting matter, which constitutes nearly 100% of the visible matter in the universe. This is an immensely important and challenging task that requires the concerted effort of scientists working in both theory and experiment, funding agencies, politicians and the public.<p></p> Nuclear Physics projects are often “big science”, which implies large investments and long lead times. They need careful forward planning and strong support from policy makers. This Forward Look provides an excellent tool to achieve this. It represents the outcome of detailed scrutiny by Europe’s leading experts and will help focus the views of the scientific community on the most promising directions in the field and create the basis for funding agencies to provide adequate support.<p></p> The current NuPECC Long Range Plan 2010 “Perspectives of Nuclear Physics in Europe” resulted from consultation with close to 6 000 scientists and engineers over a period of approximately one year. Its detailed recommendations are presented on the following pages. For the interested public, a short summary brochure has been produced to accompany the Forward Look.<p></p&gt

Study of the track reconstruction in the FOOT experiment for Hadrontherapy

In adroterapia vengono utilizzati fasci di ioni (protoni e ioni carbonio) per il trattamento di tumori profondi; queste particelle possiedono molti vantaggi rispetto ai fotoni utilizzati nella radioterapia convenzionale. Il profilo dose-profondità di questi ioni è caratterizzato da una bassa dose nel canale di entrata e da un massimo molto pronunciato situato alla fine del loro range, chiamato picco di Bragg, la cui profondità dipende dall'energia del fascio. Inoltre gli ioni più pesanti del protone, come il carbonio o l'ossigeno, mostrano un'efficacia biologica maggiore nella regione del picco di Bragg, aprendo così alla possibilità di trattare anche tumori ipossici. Tuttavia il problema più grande nell'utilizzo di questi ioni è la loro frammentazione nucleare che causa una dose non nulla oltre il picco di Bragg. Nei trattamenti con fasci di protoni invece, è la frammentazione del bersaglio ad essere un problema: una conoscenza corretta e approfondita di questo fenomeno sarebbe davvero importante per valutare la reale efficacia biologica dei protoni. L'esperimento FOOT (FragmentatiOn Of Target) è stato proposto proprio per fare luce su questi aspetti: il suo obiettivo finale è quello di misurare la sezione d'urto dei frammenti pesanti, con Z>2, con un'incertezza massima del 5% e il loro spettro energetico con una risoluzione dell'ordine di 1-2 MeV/u, così da ottenere una migliore caratterizzazione radiobiologica dei protoni. In questa tesi si intende studiare come si determinano i momenti dei frammenti ricostruendo le loro tracce in campo magnetico usando il filtro di Kalman. Inoltre vengono sviluppati e discussi due algoritmi che hanno lo scopo di assegnare correttamente le hit con le tracce

Range uncertainty and dose uniformity in proton therapy in the presence of inhomogeneities in tissue and phantom materials

Proton therapy is an emerging modality for providing radiation treatment to cancer pa-tients. The principal advantages of proton therapy are the reduced total dose deposited into the patient as compared to conventional photon therapy and the finite range of the proton beam. It is considered as a more favorable option for optimum treatment outcomes in terms of maximising tumor control probability and minimising normal tissue complications. The depth dose distribution of the proton beam adds an additional degree of freedom to treat-ment planning. The range in tissue is associated with substantial uncertainties triggered by imaging, patient set-up, beam delivery and dose calculations. Therefore, reduction in uncer-tainties would allow to minimise the treatment volume and thus allow a better usage of the protons. However, the presence of sub-millimeter sized heterogeneities, such is pronounced in trabecular bone and lung parenchyma, in the path of the proton beam can cause the Bragg peak degradation with a widening to the distal fall-o˙. Additionally, the restricted resolution of a classic CT scan used in treatment planning cannot fully resolve such fine structures, potentially leading to inaccuracy in determination of the range.This work aims to investigate the presence of range uncertainties in proton therapy beams when they penetrate through the sub-millimeter sized heterogeneities. The e˙ect of Bragg peak degradation has been demonstrated in bone models with the FLUKA Monte Carlo code and experimental measurements with a 36 MeV proton beam. The bone-substitute material, SAWBONES®, ranging in density from 0.088 to 0.48 g/cc, was used to simulate bone heterogeneities. Micro-CT images were obtained of the SAWBONES® material and used to construct Monte Carlo models of realistic proton radiotherapy treatments and to benchmark experimental studies. Broadening of the Bragg peak and shifts in the range, as defined by the d20% depth-dose parameter were observed both experimentally and in Monte Carlo models, indicating that such e˙ects are in principle, clinically relevant in certain circumstances.Furthermore, a FLUKA Monte Carlo model is benchmarked against the Eclipse treatment planning system (TPS) golden data for proton beam therapy. This project is designed to obtain the proton dose distributions from TPS for a 10 ×10 × 10 cm3 water-filled box. A Monte Carlo analytical model is developed by utilising the information from the TPS to recalculate the dose distribution which are then compared to find any di˙erences (if present) for di˙erent phantom materials. Due to the lack of any experimental information to measure the normalized depth dose as a function of energy, considering the general behaviour of a monitor chamber, it has been assumed that the treatment planning system has a built-in relationship between the monitor units (MU) and dose delivered. A mathematical formula is developed to find the relationship between monitor units (MU) and dose (E). MU α 1/Ea.The value of a is varied from 0 to 1. It has been observed that the beam non-uniformity calculated by using the relationship " MU = E−0.5 " is only 0.15 % for water and 0.43 % for graphite. This non-uniformity in graphite is not severe and it is actually clinically acceptable. This modeling has suggested that the planned dose distributions for water can also be replaced by graphite to a reasonably acceptable standard

DESIGN, SIMULATION AND PERFORMANCES STUDY OF THE FOOT EXPERIMENT

Nuclear fragmentation processes induced by the interaction of hadrons and nuclei with matter are of great interest not only in fundamental physics research but also in applied physics, particularly in particle therapy and space radioprotection. Particle therapy is a novel technique in which solid tumors are treated with charged light ions beams by reason of their favorable depth-dose deposition profile. As a consequence of nuclear interactions between the beam particles and the patient tissues, during irradiation a large amount of secondary fragments is produced. Both projectile (if Zbeam>1) and target fragmentation can occur. Space radioprotection, instead, aims to develop effective shields to preserve astronauts from the harmful effects of ionizing space radiation. In long duration and far from Earth space missions, the exposure to galactic cosmic rays leads to an abundant production of neutrons and other nuclear fragments originating from the interactions with the spaceship shields which must be considered. In both cases, nuclear fragmentation can highly affect the particle yields and the energy spectrum, which are mandatory for the calculation of the particle transport and the estimation of the dose. The main goal of the FOOT (FragmentatiOn Of Target) experiment is to measure fragment production cross sections for energies, beams and targets of interest for therapy and for radioprotection in space. In addition, these results will help the further development of Monte Carlo models. To this aim, a dedicated experimental setup is currently under development. The main purpose of this work is the construction and the maintenance of an accurate and reliable Monte Carlo simulation of the setup, on basis of the FLUKA code, focusing especially on the study of design and expected performances of the electronic setup. Also the fragment reconstruction capabilities of the setup are investigated by means of a dedicated analysis software developed within the collaboration

Review of BLM thresholds at tertiary LHC collimators

The Large Hadron Collider is designed to accelerate protons at the unprecedented energy of 7 TeV. With a total stored energy of 360 MJ, even tiny losses can cause machine downtime or induce damage to sensitive accelerator components. The Beam Loss Monitors (BLMs) are an important component of the complex LHC protection system. They consist of a series of ionisation chambers located all around the ring to detect secondary particle showers induced by beam losses. The monitors are assigned thresholds such that if the radiation generated by the loss is too high, the BLM triggers a beam dump, preventing the loss to grow excessively. BLM signals are recorded for different integration windows, in order to detect losses on very different time scales, ranging from the extremely short ones (taking place over half a turn) to those very close to steady state (i.e. lasting for more than a minute). The LHC is equipped with a complex collimation system, to provide the machine with passive protection in case of transient losses. Among the different families populating the system, the tertiary collimators (TCTs) are located close to the experiments to protect the magnets needed to squeeze the colliding beams. These collimators are made of tungsten to maximise absorption capabilities at the expenses of robustness. Thresholds at collimator BLMs, aimed at preventing damage to the jaws, have been first set based on simulations and empirical scaling laws, and then optimized based on operational experience as a trade-off between the required protection of the metallic collimators and the rate of spurious beam abort triggers. This work reviews and proposes further optimisation of the current thresholds of the BLMs at the TCTs. The review is accomplished by means of numerical simulations, where a single TCT collimator is set as aperture bottleneck and the losses concentrate there. Two steps are carried out; in the first one, the population of protons hitting the collimator is evaluated by means of cleaning simulations, where single-particle beam dynamics and particle-matter interactions are taken into account. The second step consists of the actual energy deposition calculations carried out by means of a Monte Carlo transport code, for the evaluation of the peak energy deposition in the collimator jaw and the corresponding BLM signal. Thanks to these two quantities, and knowing the maximum energy deposition that a TCT can stand before experiencing damage in different time domains, it is then possible to compute the BLM thresholds on the different integration windows. The work is complemented by a benchmark of the simulation results against measurements gathered in 2016 and 2017. This allows to verify experimentally the BLM response per hitting proton, for a couple of scenarios of controlled losses on different collimators

Integrative multimodal image analysis using physical models for characterization of brain tumors in radiotherapy

Therapy failure with subsequent tumor progress is a common problem in radiotherapy of high grade glioma. Definition of treatment volumes with CT and MRI is limited due to uncertainties concerning tumor outlines. The goal of the presented work was to enable assessment of tumor physiology and prediction of progression patterns using multi-modal image analysis and thus, improve target delineation. Physiological imaging modalities, such as 18F-FET PET, diffusion and perfusion MRI were used to predict recurrence patterns. The Medical Imaging Interaction ToolKit together with own software implementation enabled side-by-side evaluation of all image modalities. These included tools for PET analysis and a module for voxel wise fitting of dynamic data with pharmacokinetic models. Robustness and accuracy of parameter estimates were studied on synthetic perfusion data. Parameter feasibility for progression prediction was investigated on DCE MRI and 18F-FET PET data. Using the developed software tools, a pipeline for prediction of tumor progression patterns based on multi-modal image classification with a random forest machine learning algorithm was established. Exemplary prediction analysis was applied on a small patient set for illustration of workflow functionality and classification results