249 research outputs found

    Channeler Ant Model: 3D segmentation of medical images through ant colonies

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    In this paper the Channeler Ant Model (CAM) and some results of its applications to the analysis of medical images are described. The CAM is an algorithm able to segment 3D structures with different shapes, intensity and background. It makes use of virtual ant colonies and exploits their natural capabilities to modify the environment and communicate with each other by pheromone deposition. Its performance has been validated with the segmentation of 3D artificial objects and it has been already used successfully in lung nodules detection on Computer Tomography images. This work tries to evaluate the CAM as a candidate to solve the quantitative segmentation problem in Magnetic Resonance brain images: to evaluate the percentage of white matter, gray matter and cerebrospinal fluid in each voxel

    Measuring the Impact of Nuclear Interaction in Particle Therapy and in Radio Protection in Space: the FOOT Experiment

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    In Charged Particle Therapy (PT) proton or 12C beams are used to treat deep-seated solid tumors exploiting the advantageous characteristics of charged particles energy deposition in matter. For such projectiles, the maximum of the dose is released at the end of the beam range, in the Bragg peak region, where the tumour is located. However, the nuclear interactions of the beam nuclei with the patient tissues can induce the fragmentation of projectiles and/or target nuclei and needs to be carefully taken into account when planning the treatment. In proton treatments, the target fragmentation produces low energy, short range fragments along all the beam path, that deposit a non-negligible dose especially in the first crossed tissues. On the other hand, in treatments performed using 12C, or other (4He or 16O) ions of interest, the main concern is related to the production of long range fragments that can release their dose in the healthy tissues beyond the Bragg peak. Understanding nuclear fragmentation processes is of interest also for radiation protection in human space flight applications, in view of deep space missions. In particular 4He and high-energy charged particles, mainly 12C, 16O, 28Si and 56Fe, provide the main source of absorbed dose in astronauts outside the atmosphere. The nuclear fragmentation properties of the materials used to build the spacecrafts need to be known with high accuracy in order to optimise the shielding against the space radiation. The study of the impact of these processes, which is of interest both for PT and space radioprotection applications, suffers at present from the limited experimental precision achieved on the relevant nuclear cross sections that compromise the reliability of the available computational models. The FOOT (FragmentatiOn Of Target) collaboration, composed of researchers from France, Germany, Italy and Japan, designed an experiment to study these nuclear processes and measure the corresponding fragmentation cross sections. In this work we discuss the physics motivations of FOOT, describing in detail the present detector design and the expected performances, coming from the optimization studies based on accurate FLUKA MC simulations and preliminary beam test results. The measurements planned will be also presented

    CMS physics technical design report : Addendum on high density QCD with heavy ions

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    Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

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    Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio

    Production and assembly of the ALICE silicon drift detectors

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    Abstract The ALICE experiment at the LHC will study collisions of heavy-ions at a centre-of-mass energy $5:5 TeV per nucleon. The main aim of the experiment is to study in detail the behaviour of nuclear matter at high densities and temperatures, in view of probing deconfinement and chiral symmetry restoration. Silicon Drift Detectors (SDDs) have been selected to equip the two intermediate layers of the ALICE Inner Tracking System (ITS) [ALICE Collaboration, Technical Design Report, CERN/LHCC 99-12], since they couple a very good multi-track capability with dE=dx information and excellent spatial resolution as described in [E. Gatti, P. Rehak, Nucl. Instr. and Meth. A 225 (1984) 608; S. Beole´, et al., Nucl. Instr. and Meth. A 377 (1996) 393; S. Beole´, et al., Il Nuovo Cimento 109A (9) (1996)]. In this paper we describe the different components of the SDD system as well as the different procedure of the system assembly.

    Production and assembly of the ALICE silicon drift detectors

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    The ALICE experiment at the LHC will study collisions of heavy-ions at a centre-of-mass energy similar to 5.5 TeV per nucleon. The main aim of the experiment is to study in detail the behaviour of nuclear matter at high densities and temperatures, in view of probing deconfinement and chiral symmetry restoration. Silicon Drift Detectors (SDDs) have been selected to equip the two intermediate layers of the ALICE Inner Tracking System (ITS) [ALICE Collaboration, Technical Design Report, CERN/LHCC 99-12], since they couple a very good multi-track capability with dE/dx information and excellent spatial resolution as described in [E. Gatti, P. Rehak, Nucl. Instr. and Meth. A 225 (1984) 608; S. Beole, et al., Nucl. Instr. and Meth. A 377 (1996) 393; S. Beole, et al., Il Nuovo Cimento 109A (9) (1996)]. In this paper we describe the different components of the SDD system as well as the different procedure of the system assembly. (c) 2006 Elsevier B.V. All rights reserved

    Production and assembly of the ALICE Silicon Drift Detectors

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    none23The ALICE experiment at the LHC will study collisions of heavy-ions at a centre-of-mass energy 5.5TeV per nucleon. The main aim of the experiment is to study in detail the behaviour of nuclear matter at high densities and temperatures, in view of probing deconfinement and chiral symmetry restoration. Silicon Drift Detectors (SDDs) have been selected to equip the two intermediate layers of the ALICE Inner Tracking System (ITS) [ALICE Collaboration, Technical Design Report, CERN/LHCC 99–12], since they couple a very good multi-track capability with dE/dx information and excellent spatial resolution as described in [E. Gatti, P. Rehak, Nucl. Instr. and Meth. A 225 (1984) 608; S. Beolé, et al., Nucl. Instr. and Meth. A 377 (1996) 393; S. Beolé, et al., Il Nuovo Cimento 109A (9) (1996)]. In this paper we describe the different components of the SDD system as well as the different procedure of the system assembly.http://dx.doi.org/10.1016/j.nima.2006.09.027noneS.ANTINORI; S.COLI; E.CRESCIO; D.FALCHIERI; R.ARTECHE DIAZ; S. DI LIBERTO; GABRIELLI A.; G.GIRAUDO; P.GIUBELLINO; S.MARTOIU; G.MASETTI; G.MAZZA; M.A.MAZZONI; F.MEDDI; A.RASHEVSKY; L.RICCATI; A.RIVETTI; L.SIMONETTI; L.TOSCANO; F.TOSELLO; G.M.URCIUOLI; A.VACCHI; R.WHEADONS.ANTINORI; S.COLI; E.CRESCIO; D.FALCHIERI; R.ARTECHE DIAZ; S. DI LIBERTO; GABRIELLI A.; G.GIRAUDO; P.GIUBELLINO; S.MARTOIU; G.MASETTI; G.MAZZA; M.A.MAZZONI; F.MEDDI; A.RASHEVSKY; L.RICCATI; A.RIVETTI; L.SIMONETTI; L.TOSCANO; F.TOSELLO; G.M.URCIUOLI; A.VACCHI; R.WHEADO

    The foot experiment: fragmentation measurements in particle therapy

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    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

    Charge identification of nuclear fragments with the FOOT Time-Of-Flight system

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    FOOT (FragmentatiOn Of Target) is an applied nuclear physics experiment conceived to conduct high-precision cross section measurements of nuclear fragmentation processes relevant for particle therapy and radiation protection in space. These measurements are important to estimate the physical and biological effects of nuclear fragments, which are produced when energetic particle beams penetrate human tissue. A component of the FOOT experiment is the ΔE-TOF system. It is designed to measure energy loss and time-of-flight of nuclear fragments produced in particle collisions in thin targets in order to extract their charge and velocity. The ΔE-TOF system is composed of a start counter, providing the start time for the time-of-flight, and a 40 × 40 cm2 wall of thin plastic scintillator bars, providing the arrival time and energy loss of the fragments passing through the detector. Particle charge discrimination can be achieved by correlating the energy loss in the scintillator bars with the measured time-of-flight. Recently, we have built a full-size ΔE-TOF detector. In this work, we describe the energy and time-of-flight calibration procedure and assess the performance of this system. We use data acquired during beam tests at CNAO with proton and 12C beams and at GSI with 16O beams in the energy range relevant for particle therapy, i.e., from 60 to 400 MeV/u. For heavy fragments (C and O), we obtain energy and time resolutions ranging from 4.0 to 5.2% and from 54 to 76 ps, respectively. The procedure is also applied to a fragmentation measurement of a 400 MeV/u 16O beam on a 5 mm carbon target, showing that the system is able to discriminate the charges of impinging fragments
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