Outils logiciels et algorithmiques de reconstruction pour les données nucléaires en hadronthérapie

La hadronthérapie est une modalité de traitement du cancer utilisant des ions pour irradier les tumeurs. L’utilisation de ces ions apporte des propriétés balistiques supérieures par rapport à la radiothérapie conventionnelle, qui utilise des rayons X. Cependant, elle n’est pas sans contrepartie : les interactions entre les ions du faisceau et les noyaux du milieu ciblé peuvent produire des fragments qui vont altérer le dépôt de dose envisagé pour le traitement. Ainsi, il est crucial d’être capable de prendre en compte l’impact de ce processus de fragmentation lors d’un traitement, afin de réaliser le potentiel latent de cette technologie. Pour cela, la détermination des sections efficaces de ces réactions est nécessaire. C’est en effet la tâche entreprise par la collaboration FOOT. Le travail effectué lors de cette thèse a constitué en l’élaboration d’un algorithme de reconstruction globale nécessaire à la détermination de ces données. Le contrôle du traitement en hadronthérapie est difficile : malgré de nombreuses équipes de recherche travaillant sur le sujet, les méthodes envisagées doivent faire face à la faible statistique disponible pour établir un contrôle fiable. Une expérience autour du développement d’une nouvelle méthode de contrôle, basée sur le dopage de tumeurs avec des éléments caractérisés par leur profil d’émission gamma, a permis le développement d’algorithmes de déconvolution nécessaire à l’étude des spectres ainsi produits.Hadrontherapy is a cancer treatment modality using ions to irradiate tumors. The use of those ions brings superior balistical properties over conventional radiotherapy, which uses x-rays. However, this modality also has a few downsides: the interactions between the ions and the target nuclei can produce fragments which will alter the dose deposition. Thus, it is crucial to be able to consider the impact the fragmentation process during a treatment, in order to fully exploit the advantages of the modality. To do so, the determination of the fragmentation cross sections is mandatory. It is indeed the task undertaken by the FOOT collaboration. The work done during this thesis lead to the elaboration of a global reconstruction algorithm, necessary in order to extract this information. Treatment monitoring in hadrontherapy is difficult : despite extensive work done by several research teams around the world, the methods developed have to face intrinsically low available statistics in order to establish range verification. An experiment focused on the development of a novel method, based on the enhancement of tumoral volume with elements selected according to their gamma emission profile, allowed for the development of unfolding algorithms mandatory in order to study the produced spectra

Outils logiciels et algorithmiques de reconstruction pour les données nucléaires en hadronthérapie

Hadrontherapy is a cancer treatment modality using ions to irradiate tumors. The use of those ions brings superior balistical properties over conventional radiotherapy, which uses x-rays. However, this modality also has a few downsides: the interactions between the ions and the target nuclei can produce fragments which will alter the dose deposition. Thus, it is crucial to be able to consider the impact the fragmentation process during a treatment, in order to fully exploit the advantages of the modality. To do so, the determination of the fragmentation cross sections is mandatory. It is indeed the task undertaken by the FOOT collaboration. The work done during this thesis lead to the elaboration of a global reconstruction algorithm, necessary in order to extract this information. Treatment monitoring in hadrontherapy is difficult : despite extensive work done by several research teams around the world, the methods developed have to face intrinsically low available statistics in order to establish range verification. An experiment focused on the development of a novel method, based on the enhancement of tumoral volume with elements selected according to their gamma emission profile, allowed for the development of unfolding algorithms mandatory in order to study the produced spectra.La hadronthérapie est une modalité de traitement du cancer utilisant des ions pour irradier les tumeurs. L’utilisation de ces ions apporte des propriétés balistiques supérieures par rapport à la radiothérapie conventionnelle, qui utilise des rayons X. Cependant, elle n’est pas sans contrepartie : les interactions entre les ions du faisceau et les noyaux du milieu ciblé peuvent produire des fragments qui vont altérer le dépôt de dose envisagé pour le traitement. Ainsi, il est crucial d’être capable de prendre en compte l’impact de ce processus de fragmentation lors d’un traitement, afin de réaliser le potentiel latent de cette technologie. Pour cela, la détermination des sections efficaces de ces réactions est nécessaire. C’est en effet la tâche entreprise par la collaboration FOOT. Le travail effectué lors de cette thèse a constitué en l’élaboration d’un algorithme de reconstruction globale nécessaire à la détermination de ces données. Le contrôle du traitement en hadronthérapie est difficile : malgré de nombreuses équipes de recherche travaillant sur le sujet, les méthodes envisagées doivent faire face à la faible statistique disponible pour établir un contrôle fiable. Une expérience autour du développement d’une nouvelle méthode de contrôle, basée sur le dopage de tumeurs avec des éléments caractérisés par leur profil d’émission gamma, a permis le développement d’algorithmes de déconvolution nécessaire à l’étude des spectres ainsi produits

Outils logiciels et algorithmiques de reconstruction pour les données nucléaires en hadronthérapie

Hadrontherapy is a cancer treatment modality using ions to irradiate tumors. The use of those ions brings superior balistical properties over conventional radiotherapy, which uses x-rays. However, this modality also has a few downsides: the interactions between the ions and the target nuclei can produce fragments which will alter the dose deposition. Thus, it is crucial to be able to consider the impact the fragmentation process during a treatment, in order to fully exploit the advantages of the modality. To do so, the determination of the fragmentation cross sections is mandatory. It is indeed the task undertaken by the FOOT collaboration. The work done during this thesis lead to the elaboration of a global reconstruction algorithm, necessary in order to extract this information. Treatment monitoring in hadrontherapy is difficult : despite extensive work done by several research teams around the world, the methods developed have to face intrinsically low available statistics in order to establish range verification. An experiment focused on the development of a novel method, based on the enhancement of tumoral volume with elements selected according to their gamma emission profile, allowed for the development of unfolding algorithms mandatory in order to study the produced spectra.La hadronthérapie est une modalité de traitement du cancer utilisant des ions pour irradier les tumeurs. L’utilisation de ces ions apporte des propriétés balistiques supérieures par rapport à la radiothérapie conventionnelle, qui utilise des rayons X. Cependant, elle n’est pas sans contrepartie : les interactions entre les ions du faisceau et les noyaux du milieu ciblé peuvent produire des fragments qui vont altérer le dépôt de dose envisagé pour le traitement. Ainsi, il est crucial d’être capable de prendre en compte l’impact de ce processus de fragmentation lors d’un traitement, afin de réaliser le potentiel latent de cette technologie. Pour cela, la détermination des sections efficaces de ces réactions est nécessaire. C’est en effet la tâche entreprise par la collaboration FOOT. Le travail effectué lors de cette thèse a constitué en l’élaboration d’un algorithme de reconstruction globale nécessaire à la détermination de ces données. Le contrôle du traitement en hadronthérapie est difficile : malgré de nombreuses équipes de recherche travaillant sur le sujet, les méthodes envisagées doivent faire face à la faible statistique disponible pour établir un contrôle fiable. Une expérience autour du développement d’une nouvelle méthode de contrôle, basée sur le dopage de tumeurs avec des éléments caractérisés par leur profil d’émission gamma, a permis le développement d’algorithmes de déconvolution nécessaire à l’étude des spectres ainsi produits

The foot experiment: fragmentation measurements in particle therapy

M. Sitta; R. Spighi; E. Spiriti; G. Sportelli; A. Stahl; V. Tioukov; S. Tommasini; F. Tommasino; G. Traini; S. M. Valle; M. Villa; U. Weber; A. ZoccoliInternational audienceCharged Particle Therapy (CPT) is a powerful radiotherapy technique for the treatment of deep-seated tumours characterized by a large dose released in the Bragg peak area (corresponding to the tumour region) and a small dose delivered to the surrounding healthy tissues. The precise measurement of the fragments produced in the nuclear interactions of charged particle beams with patient tissues is a crucial task to improve the clinical treatment plans. The FOOT (FragmentatiOn Of Target) experiment is an international project, funded by the Istituto Nazionale di Fisica Nucleare (INFN), aimed to study the dose released by the tissues and particle beams fragmentation. The target (16O, 12C) fragmentation induced by 150-400 MeV/n proton beams will be studied via the inverse kinematic approach, where 16O and 12C therapeutic beams collide on graphite and hydrocarbon target to provide the cross section on Hydrogen. A table-top detector is being developed and it includes a drift chamber as a beam monitor upstream of the target to measure the beam direction, a magnetic spectrometer based on silicon pixel and strip detectors, a scintillating crystal calorimeter able to stop the heavier produced fragments, and a ΔE detector, with TOF capability, for the particle identification. A setup based on the concept of the “Emulsion Cloud Chamber”, coupled with the interaction region of the electronic FOOT setup, will complement the physics program by measuring lighter charged fragments to extend the angular acceptance up to about 70 degrees. In this work, the experimental design and the requirements of the FOOT experiment will be discussed and preliminary results on the emulsion spectrometer tests will be presented

The Drift Chamber detector of the FOOT experiment: Performance analysis and external calibration

The study that we present is part of the preparation work for the setup of the FOOT (FragmentatiOn Of Target) experiment whose main goal is the measurement of the double differential cross sections of fragments produced in nuclear interactions of particles with energies relevant for particle therapy. The present work is focused on the characterization of the gas-filled drift chamber detector composed of 36 sensitive cells, distributed over two perpendicular views. Each view consists of six consecutive and staggered layers with three cells per layer. We investigated the detector efficiency and we performed an external calibration of the space–time relations at the level of single cells. This information was then used to evaluate the drift chamber resolution. An external tracking system realized with microstrip silicon detectors was adopted to have a track measurement independent on the drift chamber. The characterization was performed with a proton beam at the energies of 228 and 80 MeV. The overall hit detection efficiency of the drift chamber has been found to be 0.929±0.008 , independent on the proton beam energy. The spatial resolution in the central part of the cell is about 150±10 μ m and 300±10 μ m and the corresponding detector angular resolution has been measured to be 1.62±0.16 mrad and 2.1±0.4 mrad for the higher and lower beam energies, respectively. In addition, the best value on the intrinsic drift chamber resolution has been evaluated to be in the range 60−100 μ m. In the framework of the FOOT experiment, the drift chamber will be adopted in the pre-target region, and will be exploited to measure the projectile direction and position, as well as for the identification of pre-target fragmentation events

Characterization of 150 μm thick silicon microstrip prototype for the FOOT experiment

International audienceThe goals of the FOOT (FragmentatiOn Of Target) experiment are to measure the proton double differential fragmentation cross-section on H, C, O targets at beam energies of interest for hadrontherapy (50–250 MeV for protons and 50–400 MeV/u for carbon ions), and also at higher energy, up to 1 GeV/u for radioprotection in space. Given the short range of the fragments, an inverse kinematic approach has been chosen, requiring precise tracking capabilities for charged particles. One of the subsystems designed for the experiment will be the MSD (Microstrip Silicon Detector), consisting of three x-y measurement planes, each one made by two single sided silicon microstrip sensors. In this document, we will present a detailed description of the first MSD prototype assembly, developed by INFN Perugia group and the subsequent characterization of the detector performance. The prototype is a wide area(∼ 100 cm$^{2}$) single sensor, 150 μm thick to reduce material budget and fragmentation probability along the beam path, with 50 μm strip pitch and 2 floating strip readout approach. The pitch adapter to connect strips with the readout channels of the ASIC has been implemented directly on the silicon surface. Beside the interest for the FOOT experiment, the results in terms of cluster signal, signal-to-noise ratio, dynamic range of the readout chips, as well as long-term stability studies in terms of noise, are relevant also for other experiments where the use of thin sensors is crucial

Characterization of 150 μm\mu m thick silicon microstrip prototype for the FOOT experiment

International audienceThe goals of the FOOT (FragmentatiOn Of Target) experiment are to measure the proton double differential fragmentation cross-section on H, C, O targets at beam energies of interest for hadrontherapy (50–250 MeV for protons and 50–400 MeV/u for carbon ions), and also at higher energy, up to 1 GeV/u for radioprotection in space. Given the short range of the fragments, an inverse kinematic approach has been chosen, requiring precise tracking capabilities for charged particles. One of the subsystems designed for the experiment will be the MSD (Microstrip Silicon Detector), consisting of three x-y measurement planes, each one made by two single sided silicon microstrip sensors. In this document, we will present a detailed description of the first MSD prototype assembly, developed by INFN Perugia group and the subsequent characterization of the detector performance. The prototype is a wide area(∼ 100 cm$^{2}$) single sensor, 150 μm thick to reduce material budget and fragmentation probability along the beam path, with 50 μm strip pitch and 2 floating strip readout approach. The pitch adapter to connect strips with the readout channels of the ASIC has been implemented directly on the silicon surface. Beside the interest for the FOOT experiment, the results in terms of cluster signal, signal-to-noise ratio, dynamic range of the readout chips, as well as long-term stability studies in terms of noise, are relevant also for other experiments where the use of thin sensors is crucial