46 results on '"Paolo Randaccio"'
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2. A DVB-T Based System for the Diffusion of Tele-Home Care Practice.
- Author
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Gianmarco Angius, Danilo Pani, Luigi Raffo, Stefano Seruis, and Paolo Randaccio
- Published
- 2008
3. A pervasive telemedicine system exploiting the DVB-T technology.
- Author
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Gianmarco Angius, Danilo Pani, Luigi Raffo, Stefano Seruis, and Paolo Randaccio
- Published
- 2008
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4. Measurements of Indoor Radon Levels and Gamma Dose Rates
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Stefania DaPelo, Alessandra Bernardini, Valentina Dentoni, Daniele Chiriu, Mirsina Mousavi Aghdam, Viviana Fanti, and Paolo Randaccio
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Indoor air quality ,chemistry ,Gamma dose ,chemistry.chemical_element ,Environmental science ,Radon ,Atmospheric sciences - Published
- 2019
5. Natural radioactivity and radon exhalation rate of Sardinian dimension stones
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Mirsina Mousavi Aghdam, Alessandra Bernardini, Valentina Dentoni, Stefania Da Pelo, Nicola Careddu, Paolo Randaccio, and Alfredo Loi
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Basalt ,Geochemistry ,chemistry.chemical_element ,Exhalation ,Pyroclastic rock ,Radon ,Building and Construction ,Radium ,Petrography ,Igneous rock ,chemistry ,Environmental science ,General Materials Science ,Natural radioactivity ,Civil and Structural Engineering - Abstract
Due to the ever-growing public concern about radon risk arising from building materials, the radon exhalation rates and the natural radioactivity of eighteen dimension stones mostly used in Sardinia and widely exported worldwide have been estimated by means of laboratory tests. Some of the quarrying companies that operate within the Sardinian territory provided the samples to be tested, which include twelve granitoids, four pyroclastic rocks and two basalts. The Activity Concentration Index (Iɤ), the External Radiation Hazard Index (Hex) and the Radium equivalent activity (Raeq) were calculated for each rock sample under investigation, based on the estimated values of 222Rn exhalation rate and 226Ra, 232Th and 40K radioactivity concentration. A poor correlation between radon release rates and 226Ra radioactivity concentrations was found. The contribution to indoor radon accumulation was also simulated for the stone with the highest 222Rn exhalation rate and the resulting concentration compared with the limit value establish by the 2013/59/Euratom Directive. These findings can be extended to rocks formed in similar geodynamic settings that are likely to produce igneous rocks with similar petrographic and geochemical features.
- Published
- 2020
6. The <scp>GEANT4</scp> toolkit for microdosimetry calculations: Application to microbeam radiation therapy (MRT)
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Alberto Bravin, J. Spiga, E.A. Siegbahn, Paolo Randaccio, and Elke Bräuer-Krisch
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Physics ,Photon ,business.industry ,Monte Carlo method ,Compton scattering ,General Medicine ,Microbeam ,Radiation ,Computational physics ,Superposition principle ,Dosimetry ,Nuclear medicine ,business ,Beam (structure) - Abstract
Theoretical dose distributions for microbeam radiation therapy (MRT) are computed in this paper using the GEANT4 Monte Carlo (MC) simulation toolkit. MRT is an innovative experimental radiotherapy technique carried out using an array of parallel microbeams of synchrotron-wiggler-generated x rays. Although the biological mechanisms underlying the effects of microbeams are still largely unknown, the effectiveness of MRT can be traced back to the natural ability of normal tissues to rapidly repair small damages to the vasculature, and on the lack of a similar healing process in tumoral tissues. Contrary to conventional therapy, in which each beam is at least several millimeters wide, the narrowness of the microbeams allows a rapid regeneration of the blood vessels along the beams' trajectories. For this reason the calculation of the "valley" dose is of crucial importance and the correct use of MC codes for such purposes must be understood. GEANT4 offers, in addition to the standard libraries, a specialized package specifically designed to deal with electromagnetic interactions of particles with matter for energies down to 250 eV. This package implements two different approaches for electron and photon transport, one based on evaluated data libraries, the other adopting analytical models. These features are exploited to cross-check theoretical computations for MRT. The lateral and depth dose profiles are studied for the irradiation of a 20 cm diameter, 20 cm long cylindrical phantom, with cylindrical sources of different size and energy. Microbeam arrays are simulated with the aid of superposition algorithms, and the ratios of peak-to-valley doses are computed for typical cases used in preclinical assays. Dose profiles obtained using the GEANT4 evaluated data libraries and analytical models are compared with simulation results previously obtained using the PENELOPE code. The results show that dose profiles computed with GEANT4's analytical model are almost indistinguishable from those obtained with the PENELOPE code, but some noticeable differences appear when the evaluated data libraries are used.
- Published
- 2007
7. A Portable Acquisition System Based on USB Standard for the Medipix2 X-Ray Detector
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R. Marzeddu, Viviana Fanti, G. Piredda, and Paolo Randaccio
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Nuclear and High Energy Physics ,Engineering ,Pixel ,Serial communication ,business.industry ,Interface (computing) ,Detector ,USB ,Chip ,law.invention ,Microcontroller ,Data acquisition ,Nuclear Energy and Engineering ,law ,Nuclear electronics ,Personal computer ,Hardware_INTEGRATEDCIRCUITS ,Electronic engineering ,Electrical and Electronic Engineering ,business ,Computer hardware - Abstract
We describe a portable readout system for an X-ray hybrid detector based on the Medipix2 pixel readout chip. The Medipix2 chip (256times256 square pixels with 55 mum pitch) is bump-bonded with a pixellated Silicon sensor 300-micron thick. The readout system consists of a simple small size electronic card based on a single powerful microcontroller and can be connected to a PC through the widespread Universal Serial Bus (USB) interface. The reduced size of the final card (3.8 cmtimes4.8 cm) makes it suitable for special applications like dental radiology
- Published
- 2006
8. PCI card with DMA capabilities for digital imaging detectors
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R. Marzeddu, Paolo Randaccio, and Viviana Fanti
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Physics ,Nuclear and High Energy Physics ,business.industry ,M.2 ,PCI configuration space ,PCI hole ,Conventional PCI ,Local bus ,Hardware_ARITHMETICANDLOGICSTRUCTURES ,business ,Field-programmable gate array ,Instrumentation ,Direct memory access ,Computer hardware ,PCI Express - Abstract
A readout card based on the standard PCI 32-bit/33 MHz bus has been developed for the fast readout of digital systems. The PCI card exploits a PCI bridge chip with Direct Memory Access (DMA) capabilities which permits to obtain a measured throughput up to 90 Mbytes/s. The PCI card has two high-density 80-pin connectors for data I/O; an external system acquisition card can be connected through two flat cables. A powerful programmable logic FPGA provides the management of the I/O lines; by default, 32 input and 32 output single-ended lines (CMOS) plus six LVDS lines are provided, but the FPGA allows several different I/O configurations depending on the specific application requirements. Another programmable device manages the control and status signals of the local bus and the Synchronous Static RAM available for data storage. Due to its main features like the configurable I/O patterns and the high throughput, this PCI card is suitable for applications like the fast readout of imaging acquisition systems.
- Published
- 2006
9. Design and test of data acquisition systems for the Medipix2 chip based on PC standard interfaces
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Paolo Randaccio, R. Marzeddu, Giuseppina Piredda, and Viviana Fanti
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Physics ,Nuclear and High Energy Physics ,business.industry ,Serial communication ,Interface (computing) ,USB ,Chip ,Photon counting ,law.invention ,Data acquisition ,law ,Medipix ,business ,Parallel port ,Instrumentation ,Computer hardware - Abstract
We describe two readout systems for hybrid detectors using the Medipix2 single photon counting chip, developed within the Medipix Collaboration. The Medipix2 chip (256×256 pixels, 55 μm pitch) has an active area of about 2 cm 2 and is bump-bonded to a pixel semiconductor array of silicon or other semiconductor material. The readout systems we are developing are based on two widespread standard PC interfaces: parallel port and USB (Universal Serial Bus) version 1.1. The parallel port is the simplest PC interface even if slow and the USB is a serial bus interface present nowadays on all PCs and offering good performances.
- Published
- 2005
10. Medipix2 parallel readout system
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Viviana Fanti, Paolo Randaccio, and R. Marzeddu
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Physics ,Nuclear and High Energy Physics ,Motherboard ,business.industry ,Chip ,Data acquisition ,Software ,Interfacing ,Transfer (computing) ,Medipix ,business ,Instrumentation ,Computer hardware ,Data transmission - Abstract
A fast parallel readout system based on a PCI board has been developed in the framework of the Medipix collaboration. 1 The readout electronics consists of two boards: the motherboard directly interfacing the Medipix2 chip, and the PCI board with digital I/O ports 32 bits wide. The device driver and readout software have been developed at low level in Assembler to allow fast data transfer and image reconstruction. The parallel readout permits a transfer rate up to 64 Mbytes/s. r 2003 Elsevier Science B.V. All rights reserved. PACS: 07.05.Hd; 87.59.Hd
- Published
- 2003
11. PHAROS: a spectrometer-on-a-chip for digital radiology systems with spectral detection
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Paolo Randaccio, A. Lai, M. Caria, S. Cadeddu, and D Caredda
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Very-large-scale integration ,Physics ,Nuclear and High Energy Physics ,medicine.medical_specialty ,Photon ,Spectrometer ,Spectral power distribution ,business.industry ,Detector ,Integrated circuit ,Chip ,law.invention ,Optics ,law ,medicine ,Medical physics ,business ,Instrumentation ,Effective atomic number - Abstract
When a beam of X-rays crosses an object, its spectrum is modified depending on both the density and effective atomic number of the material. We describe an integrated (VLSI) spectrometer used in a digital radiology system for performing spectral analysis of the detected X-rays. It integrates 16 independent channels and gives seven bits of energy resolution. This permits the distinction between tissues featuring small differences in effective atomic number, e.g. micro-calcifications and fat cysts, which have the same contrast in a normal radiography. The integrated circuit services a row of solid-state detectors that can travel along the specimen in the radiology system in perpendicular directions, so that bi-dimensional images can be recorded. The circuit performs pulse height analysis and stores the spectral distribution of the detected photons. The circuit is described and its performance analyzed.
- Published
- 2002
12. Comprehensive measurements of GaAs pixel detectors capacitance
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Luigi Barberini, Paolo Randaccio, Saverio D'Auria, S. Cadeddu, M. Caria, and A. Lai
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Physics ,Nuclear and High Energy Physics ,Differential capacitance ,Physics::Instrumentation and Detectors ,business.industry ,Detector ,Schottky diode ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Capacitance ,Gallium arsenide ,Crystal ,chemistry.chemical_compound ,Semiconductor ,chemistry ,Optoelectronics ,Wafer ,business ,Instrumentation - Abstract
We have studied GaAs pixel detectors on semi-insulating wafers with Schottky contacts. We performed comprehensive measurements on the inter-pixel and capacitance to back plane. Being semi-insulating, the behaviour is totally different with respect to other common semiconductors, such as high resistivity silicon. Non-homogeneities are also an issue, due to both the contacts and the crystal bulk. In order to detect them and their influence on capacitance, we undertook systematic measurements with different configurations of the measuring electrodes.
- Published
- 2002
13. Validation of a computed radiography device to monitor the HIV-1 RNase H activity
- Author
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Luca Zinzula, Paolo Randaccio, Francesca Esposito, R. Marzeddu, Viviana Fanti, and Enzo Tramontano
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Physics ,Acid derivative ,Gel electrophoresis ,Nuclear and High Energy Physics ,Chromatography ,biology ,Human immunodeficiency virus (HIV) ,medicine.disease_cause ,Reverse transcriptase ,RNase H activity ,medicine ,biology.protein ,Signal intensity ,Computed radiography ,RNase H ,Instrumentation - Abstract
A commercially available computed radiography (CR) system for dental radiography was used to produce images from radiolabeled polyacrilamide gel electrophoresis (PAGE) assays. Typically, similar investigations require specific and expensive autoradiography devices. The CR unit was characterized in terms of sensitivity and fading by means of a 90 Sr source that well simulates the experimental conditions, and then used for quantitative analyses of the human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) polymerase-independent ribonuclease H (RNase H) activity monitored by PAGE analysis. The results showed that the present methodology allows quantifying effectively the RNase H catalyses and that the obtained data are in good agreement with previous reference works. Finally, in order to further validate the present method in terms of relationship between enzyme activity, the rate of products formation and signal intensity, a PAGE analyses of the HIV-1 RNase H inhibition by the known diketo acid derivative RDS1643 was carried out.
- Published
- 2009
14. A VLSI chip set for digital radiology with energy selection
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D. Lo Presti, S. Reito, M. Caria, P. Porcu, C. Petta, S. Cadeddu, Paolo Randaccio, A. Lai, C. Caligiore, G.V. Russo, and Nunzio Randazzo
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Physics ,Nuclear and High Energy Physics ,medicine.medical_specialty ,Photon ,Selection (relational algebra) ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Radiation ,Photon counting ,Set (abstract data type) ,Range (mathematics) ,Physical information ,medicine ,Electronic engineering ,Medical physics ,Instrumentation ,Energy (signal processing) - Abstract
We present a compact acquisition system for digital radiology, based on GaAs detectors. The system is based on a custom VLSI circuit set, with analog and digital functions for the acquisition of radiological images in a wide range of applications. The circuit architectures and the operating principles are presented. We use a broad spectrum X-ray tube and try to exploit the full physical information contained in the incident radiation by means of both single photon counting and energy measurement of each photon.
- Published
- 1999
15. The design of a system for coloured digital radiology with VLSI circuits and GaAs pixel detectors
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S. Cadeddu, C. Petta, C. Caligiore, Nunzio Randazzo, M. Caria, P. Porcu, A. Lai, S. Panebianco, G.V. Russo, D. LoPresti, S. Reito, and Paolo Randaccio
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Very-large-scale integration ,Physics ,Nuclear and High Energy Physics ,medicine.medical_specialty ,Pixel ,business.industry ,Detector ,Process (computing) ,Digital imaging ,Chip ,medicine ,Medical physics ,business ,Instrumentation ,Computer hardware ,Energy (signal processing) ,Electronic circuit - Abstract
WedescribethedesignofadigitalradiologysystemwithGaAspixeldetectors,basedontheenergyselectionofthenonabsorbedX-ray spectrum.We present ageneral layout; we show that simulationand experimentaldatacorroboratetheidea for the feasibility of the system. ( 1998 Elsevier Science B.V. All rights reserved. 1. IntroductionTheuseof GaAsasahigh-eƒciencyX-rayimag-ing detector is now well known [1].An idea for a novel digital radiology device withinherent high spatial and energy resolution hasbeen proposed [2]. It is based on a GaAs pixeldetector and two custom-made VLSI electroniccircuits which process each photon pulse and clas-sify it according to its energy.The circuits store the counting and the energyinformation, allowing the acquisition of coloured X-ray images. The artiÞcial elaboration of colourcan be performedon line in a scale proportionaltotheenergyofthedetectedphoton.Thescaleresolu-tionwillbelimitedbytheelectroniccircuitsdesign.The method,generallyapplicable,has beenillus-trated before [3]. Here we describe the design fora digital imaging system with an X-ray source,a GaAs pixel detector and the VLSI circuits. Thepaperconcentratesonthegenerallayoutinarealis-tic conÞguration. We address the compromises be-tween the performances of the system, versus thefabrication technologies risks and the costs.WehaveatpresentaÞrstversionofthedetectorswith 32 pixels and the new chip with 8 energyintervals.We show data and compare with the simulationproving that the design idea is well based.2. The basic principleIn radiology, the use of the energy and count-ing information is performed simultaneously in
- Published
- 1998
16. Characterisation of an X-Ray System with GaAs Detector for Composite Material Analysis
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Filippo Bertolino, Gianluca Gatto, Francesco Ginesu, and Paolo Randaccio
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Materials science ,Mechanics of Materials ,Mechanical Engineering ,Detector ,X-ray ,General Materials Science ,Composite material - Published
- 1997
17. Autoradiography with silicon strip detectors
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Angelo Taibi, M. Caria, Mauro Gambaccini, E. Mancini, Valeria Rosso, Maria Giuseppina Bisogni, Paolo Russo, A. M. Stefanini, Maria Evelina Fantacci, Michele Marziani, G. Madonna, A. Del Guerra, E. Bertolucci, Paolo Randaccio, Salvator Roberto Amendolia, Marcello Rossetti Conti, R. Beccherle, G. Grossi, U. Bottigli, Raffaele Tripiccione, R Marchesini, E., Bertolucci, M., Conti, Grossi, Gianfranco, G., Madonna, E., Mancini, Russo, Paolo, M., Caria, P., Randaccio, A., DEL GUERRA, M., Gambaccini, R., Marchesini, M., Marziani, A., Taibi, R., Beccherle, M. G., Bisogni, U., Bottigli, M. E., Fantacci, V., Rosso, A., Stefanini, R., Tripiccione, and S. R., Amendolia
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Physics ,Nuclear and High Energy Physics ,Activity measurements ,Silicon ,chemistry ,Detector ,Radiochemistry ,chemistry.chemical_element ,Mammary cells ,Linearity ,Active surface ,Instrumentation - Abstract
A digital autoradiography system based on double sided silicon strip detectors (1.6 × 1.6 mm2 active surface with 100 μm pitch) has been developed and successfully tested with beta-emitting tracers. It is shown here that the system is able to perform imaging of organic material with specific sensitivity as small as 0.002 nCi/mm2, and to record activity measurements with good linearity in the range 0.002–20 nCi/mm2. Autoradiographic images of clusters of mammary cells marked with ortho-(32P)phosphate, obtained with an exposure time of about 10 min are presented.
- Published
- 1996
18. MPRS: Medipix parallel readout system for angiography digital imaging
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Paolo Randaccio, R. Marzeddu, and Viviana Fanti
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Nuclear and High Energy Physics ,Engineering ,Pixel ,business.industry ,Motherboard ,Chip ,Photon counting ,Data acquisition ,Nuclear Energy and Engineering ,CMOS ,Transfer (computing) ,Electronic engineering ,Medipix ,Electrical and Electronic Engineering ,business ,Computer hardware - Abstract
A fast readout system for a low noise CMOS pixel chip, working in single photon counting mode (Medipix2) has been developed for digital angiography applications. Each chip has an active area of about 2 cm/sup 2/, with 256/spl times/256 square pixels 55 /spl mu/m side size, and can be bump bonded to Si or GaAs for direct charge conversion of incoming photons. The system permits the parallel readout of up to 8 chips at a rate of at least 25 frames/s, to allow real time X-ray imaging of contrast medium flowing in blood vessels. The readout electronics is PCI bus-based and consists of two boards, the motherboard directly interfacing the chip for settings and data flow, and the PCI board linking the motherboard to the bus. Dedicated software has been developed to test each single pixel, set configuration patterns and perform data transfer. With parallel readout transfer rate up to 64 MByte/s has been achieved.
- Published
- 2003
19. A dedicated processor for Monte Carlo computations in radioteraphy
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Callisto Pili, Paolo Randaccio, Artur Szostak, Viviana Fanti, Giovanna Rosa Fois, R. Marzeddu, Jenny Spiga, and S. Siddhanta
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Physics ,Photon ,business.industry ,Physics::Medical Physics ,Monte Carlo method ,Compton scattering ,Monte Carlo method for photon transport ,Electron ,Computational science ,Optics ,Real-time simulation ,Dosimetry ,business ,Energy (signal processing) - Abstract
A dedicated processor for Monte Carlo computation in radiotherapy treatment planning on FPGA based hardware is being developed at INFN, Cagliari. When performing Monte Carlo simulations of the radiation dose delivered to the human body, the Compton interaction of a photon with an electron is simulated. A fast, pipelined, cost effective design for real time simulation of the Compton interaction had been implemented. The inputs to the system are the energy and the normalized direction vectors of the incoming photon. The energy and the direction vectors of the scattered photon and the scattered electron are calculated. The energy distribution by the scattered electron along its path in a voxel space is then calculated which can be used to construct maps of dose distribution in real time.
- Published
- 2012
20. KeepInTouch: A telehealth system to improve the follow-up of chronic patients
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Paolo Randaccio, Danilo Pani, Luigi Raffo, and Gianmarco Angius
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Telemedicine ,Multimedia ,business.industry ,Computer science ,Interface (computing) ,education ,Certification ,Telehealth ,computer.software_genre ,Health care ,The Internet ,User interface ,business ,computer ,Telehomecare - Abstract
With the progressive ageing of the western people, the number of chronic patients requiring a continuous follow-up by the physicians increases. Even though telehealth solution can be potentially effective in such a scenario, both the age factor and often the cost of the systems hamper the diffusion of telehealth systems. KeepInTouch is a low cost system for telehomecare conceived for the daily off-line monitoring of diabetic and cardiac patients. It exploits a mixed approach offering a simple TV-based front-end from the patient side, and a web-based one from the physician side. The web-based approach enables the authorized medical professionals to access the patient data from the web, exchanging useful information and providing textual feedback to the patient, all within the system interface. The patient's front-end is based on the Digital Video Broadcasting Terrestrial (DVB-T) technology, exploiting an acquisition unit connected to the patient's certified biomedical devices (sphygmomanometer, glucometer, body weight scale) and with the interactive DVB-T set-top box in order to provide a user-friendly interface on the TV for people not accustomed with computers. The system is going to be used for a first clinical trial in Italy.
- Published
- 2011
21. Characterization of the response of a double side mu -strip silicon detector to X-rays in the diagnostic energy range
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U. Bottigli, Paolo Russo, Marcello Rossetti Conti, A. Bandettini, Paolo Randaccio, Maria Evelina Fantacci, Valeria Rosso, Walter Bencivelli, E. Bertolucci, A. Del Guerra, A. M. Stefanini, A., Bandettini, W., Bencivelli, E., Bertolucci, U., Bottigli, M., Conti, A., Del Guerra, M. E., Fantacci, P., Randaccio, V., Rosso, Russo, Paolo, A., Stefanini, Bandettini, A, Bencivelli, W, Bertolucci, Ennio, Bottigli, U, Conti, Maurizio, Del Guerra, A, Fantacci, Me, Randaccio, P, Rosso, V, and Stefanini, A.
- Subjects
Physics ,Nuclear and High Energy Physics ,Silicon ,Physics::Instrumentation and Detectors ,business.industry ,Detector ,X-ray detector ,Microstrip silicon detector ,chemistry.chemical_element ,Cat's-whisker detector ,Capacitance ,Particle detector ,Semiconductor detector ,Monocrystalline silicon ,Optics ,Nuclear Energy and Engineering ,chemistry ,Silicon microstrip detector ,Digital radiography ,Electrical and Electronic Engineering ,business - Abstract
The use of a double sided mu -strip silicon crystal for X-ray detection is being investigated. The detector is 300 mu m thick and the read-out pitch is 100 mu m for both sides. It operates in capacitance charge division mode by means of floating strips between read-out strips. The detector has been irradiated by /sup 241/Am and /sup 109/Cd sources. Different zones within the 100- mu m read-out pitch have been individually exposed. The following characteristics have been studied as a function of the impact point of the photon: (a) the charge collection mechanism; (b) the relative detection efficiency; (c) the energy resolution; and (d) the spatial resolution. The absolute efficiency of the detector has been measured at three energy values. >
- Published
- 1993
22. The effect of beam polarization in Microbeam Radiation Therapy (MRT): Monte Carlo simulations using Geant4
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J. Spiga, Viviana Fanti, Elke Bräuer-Krisch, Paolo Randaccio, Yolanda Prezado, Alberto Bravin, Yu B, Spiga, J, Prezado, Y, Brauer-Krisch, E, Fanti, V, Randaccio, P, and Bravin, A
- Subjects
Physics ,business.industry ,medicine.medical_treatment ,Monte Carlo method ,Beam polarization ,Dose distribution ,Microbeams, radiotherapy ,Radiation therapy ,Conventional radiotherapy ,Planar ,Optics ,Microbeam radiation therapy ,medicine ,Dosimetry ,business ,Nuclear medicine - Abstract
Microbeam Radiation Therapy (MRT) is an innovative experimental technique potentially able to overcome the limitations of conventional radiotherapy for infantile brain tumors. Its effectiveness seems to be related to the ability of normal tissues to tolerate a very high radiation dose in small volumes, resulting in the preservation of the tissues' architecture. The effectiveness of MRT is well represented by peak-to-valley dose ratios (PVDRs), which are one of the crucial parameters associated with the outcome of the treatment. We present Geant4 Monte Carlo calculations of the dose distribution deposited by planar polarized microbeams with micrometric resolution. The simulation of the beam polarization, made possible by different libraries included in Geant4, is a crucial step in enhancing the comparability of experimental data and simulation results.
- Published
- 2009
23. Dose calculation for radiotherapy treatment planning using Monte Carlo methods on FPGA based hardware
- Author
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Artur Szostak, Paolo Randaccio, S. Siddhanta, Callisto Pili, Viviana Fanti, Jenny Spiga, and R. Marzeddu
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Physics ,Photon ,business.industry ,Physics::Medical Physics ,Monte Carlo method ,Compton scattering ,Dosimetry ,Monte Carlo method for photon transport ,Photon energy ,business ,Electromagnetic radiation ,Energy (signal processing) ,Computer hardware - Abstract
This work describes a fast Monte Carlo Machine for dose calculation in radiotherapy treatment planning on FPGA based hardware. When performing Monte Carlo simulations of the radiation dose delivered to the human body, the Compton interaction is simulated. The inputs to the system are the energy and the normalized direction vectors of the incoming photon. The energy and the direction vectors of the scattered photon and the scattered electron are calculated. The energy distribution by the scattered electron along its path in a voxel space is then calculated which can be used to construct maps of dose distribution in real time.
- Published
- 2009
24. A DVB-T framework for the remote monitoring of cardiopathic and diabetic patients
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Luigi Raffo, Paolo Randaccio, Danilo Pani, and Gianmarco Angius
- Subjects
Telemedicine ,business.industry ,Remote patient monitoring ,media_common.quotation_subject ,medicine.disease ,Cost savings ,Digital Video Broadcasting ,Health care ,Medicine ,Elderly people ,DVB-T ,Quality (business) ,Medical emergency ,business ,media_common - Abstract
Tele-home care systems enable patients with chronic diseases to be remotely and constantly monitored by the healthcare staff reducing the need for frequent visits to the hospital. Besides the advantages for patients, this solution could also provide significant cost savings through the exploitation of low-cost equipment for simple physiological measurements to be performed at home, sending the recorded data to the healthier staff placed elsewhere. Tile aim of this work is the development of a low-cost tele-home care system based on the digital video broadcasting terrestrial (DVB-T) technology for the remote monitoring of cardiopathic and diabetic patients. Easy to use even by untrained or elderly people, such tele-home care system could represent the best solution in terms of simplicity, quality and costs.
- Published
- 2008
25. A pervasive telemedicine system exploiting the DVB-T technology
- Author
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Paolo Randaccio, Danilo Pani, S. Seruis, Luigi Raffo, and Gianmarco Angius
- Subjects
Telemedicine ,Ubiquitous computing ,Multimedia ,Exploit ,Computer science ,business.industry ,Usability ,computer.software_genre ,law.invention ,Base station ,law ,Digital Video Broadcasting ,DVB-T ,business ,computer ,Remote control ,Computer network - Abstract
Telemedicine is a form of remote assistance to patients unable to easily reach the hospitals. The diffusion of such systems depends both on the availability of widespread low-cost platforms and on the ease of use. In this paper, a DVB-T based platform for telemedicine is presented. The proposed system enables to perform simple routine exams through a low-cost Base Station connected to the patientpsilas DVB-T set-top box, using the remote control and the TV screen as I/O interfaces for the user. The uplink connection is used to send the results to a remote care center. The practice with such home-entertainment equipment allows even elderly people to easily exploit the proposed platform.
- Published
- 2008
26. Experimental study of beam hardening artifacts in photon counting breast computed tomography
- Author
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A. Del Guerra, M. Quattrocchi, Paolo Russo, Adele Lauria, Giovanni Mettivier, Daniele Panetta, Maria Giuseppina Bisogni, Valeria Rosso, Roberto Pani, Nico Lanconelli, Paolo Randaccio, Maria Cristina Montesi, Bisogni, Mg, DEL GUERRA, A, Lanconelli, N, Lauria, Adele, Mettivier, Giovanni, Panetta, D, Pani, R, Quattrocchi, Mg, Randaccio, P, Rosso, V, Russo, Paolo, Montesi, MARIA CRISTINA, M.G. Bisogni, A. Del Guerra, N. Lanconelli, A. Lauria, G. Mettivier, M.C. Montesi, D. Panetta, R. Pani, M.G. Quattrocchi, P. Randaccio, V. Rosso, and P. Russo
- Subjects
Physics ,Nuclear and High Energy Physics ,medicine.medical_specialty ,Artifact (error) ,Single photon counting detector ,Pixel ,business.industry ,Detector ,beam hardening artifact ,chemistry.chemical_element ,Tungsten ,beam hardening artifacts ,breast ct ,single photon counting detector ,Photon counting ,Anode ,Charge sharing ,Optics ,chemistry ,medicine ,BEAM HARDENING ARTIFACTS ,Breast CT ,Beam Hardening Artifact ,Medical physics ,business ,Instrumentation - Abstract
We are implementing an X-ray breast Computed Tomography (CT) system on the gantry of a dedicated single photon emission tomography system for breast Tc-99 imaging. For the breast CT system we investigated the relevance of the beam hardening artifact. We studied the use of a single photon counting silicon pixel detector (0.3 mm thick, 256 � 256 pixel, 55mm pitch, bump-bonded to the Medipix2 photon counting readout chip) as detector unit in our X-ray CT system. We evaluated the beam hardening ‘‘cupping’’ artifact using homogeneous PMMA slabs and phantoms up to 14 cm in diameter, used as uncompressed breast tissue phantoms, imaged with a tungsten anode tube at 80 kVp with 4.2 mm Al filtration. For beam hardening evaluation we used a bimodal energy model. The CT data show a ‘‘cupping’’ artifact going from 4% (4-cm thick material) to 18% (14-cm thick material). This huge artifacts is influenced by the low detection efficiency and the charge sharing effect of the silicon pixel detector. r 2007 Published by Elsevier B.V. PACS: 85.57.cp; 87.57.Q
- Published
- 2007
27. Optical link based read out system for medipix2 quad x-ray detector
- Author
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Nico Lanconelli, Maria Cristina Montesi, A. Del Guerra, A. Aloisio, Roberto Pani, Viviana Fanti, Paolo Russo, Giovanni Mettivier, Paolo Randaccio, R. Marzeddu, V., Fanti, R., Marzeddu, P., Randaccio, Aloisio, Alberto, A., DEL GUERRA, N., Lanconelli, Mettivier, Giovanni, Montesi, MARIA CRISTINA, R., Pani, Russo, Paolo, V. Fanti, R. Marzeddu, P. Randaccio, A. Aloisio, A. Del Guerra, N. Lanconelli, G. Mettivier, M.C. Montesi, R. Pani, and P. Russo
- Subjects
Physics ,Nuclear and High Energy Physics ,medicine.medical_specialty ,Pixel ,business.industry ,Optical link ,Optical Link ,data acquisition ,optical link ,pci interface ,x-ray imaging ,Detector ,X-ray imaging ,X-ray detector ,Data acquisition ,Frame rate ,Photon counting ,PCI interface ,Application-specific integrated circuit ,medicine ,Medical physics ,business ,Instrumentation ,Computer hardware - Abstract
An imaging system based on the Medipix2, a single photon counting pixel readout ASIC for X-ray hybrid detectors, has been developed for tomography imaging applications. The “quad assembly” houses four Medipix2 chips placed in a 2×2 array with an active area of about 3×3 cm 2 . The readout system we present consists of four electronic cards and exploits the Medipix2 parallel readout mode and a fast optical link based on the Glink standard, giving high flexibility and EM interference immunity over long distance connections. A PCI board interfaces the imaging system to a standard PC. We expect a frame rate of 25 frame/s which allows real-time X-ray imaging acquisitions and fast computed tomography (CT) scanning. In this paper, we describe the DAQ project and the status of development.
- Published
- 2007
28. Geant4 simulations for microbeam radiation therapy (MRT) dosimetry
- Author
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Jenny Spiga, Alberto Bravin, Paolo Randaccio, Elke Bräuer-Krisch, E.A. Siegbahn, Spiga, J, Siegbahn, E, Brauer-Krisch, E, Randaccio, P, and Bravin, A
- Subjects
Materials science ,business.industry ,medicine.medical_treatment ,microbeam radiation therapy, dosimetry, X-rays ,FIS/07 - FISICA APPLICATA (A BENI CULTURALI, AMBIENTALI, BIOLOGIA E MEDICINA) ,Dose distribution ,Radiation ,equipment and supplies ,Radiation therapy ,Planar ,Optics ,Microbeam radiation therapy ,medicine ,Dosimetry ,Irradiation ,Nuclear medicine ,business ,Beam (structure) - Abstract
Radiation therapy is one of the techniques most commonly used in the treatment of various types of tumors. The microbeam radiation therapy (MRT) is a very promising variant, which exploits the property that tissues can tolerate high doses of radiation in small volumes. The effectiveness of MRT is well represented by the peak-to-valley dose ratios (PVDRs), which are one of the crucial parameters associated with the outcome of the treatment. In this study, we investigate on the factors that influence PVDRs, such as different beam energies and geometries. MRT experiments typically employ rectangular (planar) microbeams of different sizes, but, for convenience of analysis, preliminary computations have been performed also using arrays of cylindrical microbeams. This work shows that the shape of the impinging irradiation field largely influences the dose distribution. It highlights that a bundle of larger microbeams, with a small separation, produces more scattered radiation and therefore lower PVDRs. The study of how dose distributions vary with different setups and irradiation parameters is an essential step in enhancing the comparability of experimental data and simulation results.
- Published
- 2007
29. Microdosimetry for Microbeam Radiation Therapy (MRT): theoretical calculations using the Monte Carlo toolkit
- Author
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Elke Bräuer-Krisch, Paolo Randaccio, Alberto Bravin, E.A. Siegbahn, J. Spiga, Spiga, J, Siegbahn, E, Brauer-Krisch, E, Randaccio, P, and Bravin, A
- Subjects
Physics ,business.industry ,medicine.medical_treatment ,Monte Carlo method ,FIS/07 - FISICA APPLICATA (A BENI CULTURALI, AMBIENTALI, BIOLOGIA E MEDICINA) ,Microdosimetry, Monte Carlo, Geant ,Microbeam ,equipment and supplies ,Imaging phantom ,Radiation therapy ,Optics ,Beamline ,Microbeam radiation therapy ,medicine ,Dosimetry ,Radiation treatment planning ,business ,Nuclear medicine - Abstract
Radiation therapy is widely used in the treatment of very different types of cancer. Recent developments in this field are aiming at delivering high doses to the target volume while sparing the surrounding healthy tissues. The Microbeam Radiation Therapy (MRT) is a new kind of radiotherapy which could be used for treating infantile brain tumors, as other kinds of radiotherapy would be extremely dangerous to the normal brain development. MRT is carried out using an array of parallel microbeams of synchrotron-wiggler-generated X-rays. In this work, Monte Carlo simulations using the Geant4 toolkit are carried out to estimate the dose deposition on a 20-cm-diameter, 20-cm-long cylindrical PMMA phantom, mimicking an infantile head. A set of physics processes is implemented in Geant4 to extend the range of validity of electromagnetic interactions down to 250 eV. The dose distribution in MRT is computed to prepare the treatment planning of preclinical trials. Primary photon histories are simulated for the different experimental setups, scoring the dose in cylindrical shells. We used cylindrical monoenergetic microbeams of 50, 100 and 150 keV and one microbeam with energies sampled from the measured spectrum at the ESRF ID17 beamline. The depth- and lateral-dose profiles have been studied, and for a few typical cases, the simulation results have been compared with those obtained with other codes.
- Published
- 2006
30. Monte Carlo Computations for Radiotherapy with the use of Dedicated Processors
- Author
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Paolo Randaccio, Callisto Pili, Jenny Spiga, R. Marzeddu, and Viviana Fanti
- Subjects
Programmable logic device ,Speedup ,Computer engineering ,Computer science ,Computation ,Monte Carlo method ,Real-time computing ,Hardware circuits ,Radiotherapy treatment planning ,Radiation treatment planning ,Field-programmable gate array - Abstract
The project we present foresees the development of a hardware processor dedicated to real time Monte Carlo computations for radiotherapy treatment planning. Treatment planning systems are nowadays based on empirical methods which can lead to errors in the localization of the area to be irradiated of the order of centimeters. The use of Monte Carlo techniques permits to reach a more adequate precision but with the drawback of a computing time which is too high with respect to the requirements of a radiotherapy center. We propose to implement time consuming algorithms directly in hardware circuits based on programmable logic devices in order to speed up the computation. The hardware is based on a `Configurable Computer', a PCI master board housing one or more high performance fPGA and a RAM large enough for the application.
- Published
- 2006
31. Optimization of the acquisition parameters for a SPET system dedicated to breast imaging
- Author
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Maria Nerina Cinti, L. Spontoni, Paolo Randaccio, Renato Campanini, Nicola Belcari, Paolo Russo, Roberto Pani, M. Camarda, Sara Vecchio, Nico Lanconelli, Paolo Bennati, Emiro Iampieri, Alberto Del Guerra, Bernard Phlips, N., Lanconelli, R., Campanini, E., Iampieri, R., Pani, M. N., Cinti, P., Bennati, N., Belcari, M., Camarda, L., Spontoni, S., Vecchio, P., Randaccio, Russo, Paolo, A., Del Guerra, N. Lanconelli, R. Campanini, E. Iampieri, R. Pani, M. N. Cinti, P. Bennati, N. Belcari, M. Camarda, L. Spontoni, S. Vecchio, P. Randaccio, P. Russo, and A. Del Guerra
- Subjects
Physics ,medicine.diagnostic_test ,Breast imaging ,business.industry ,media_common.quotation_subject ,Visibility (geometry) ,Collimator ,Iterative reconstruction ,law.invention ,Optics ,law ,Positron emission tomography ,SPECT ,medicine ,Contrast (vision) ,Mammography ,Nuclear medicine ,business ,Image resolution ,media_common - Abstract
This work is developed within the framework of a larger project, which aims to develop a multimodal CT-SPET system dedicated to breast imaging. The goal of this paper is to optimize the choice of the various parameters involved in the design of a SPET system dedicated to breast imaging. In particular, we simulated different collimators, different tumor to background (T/B) ratios for two different spherical tumors with diameters of 5 mm and 8 mm. The performance of the explored cameras were analyzed in terms of SNR and image contrast (IC) values, calculated on the reconstructed images. In addition, we investigated the visibility limits of the system, by modifying the tumor size, the T/B value, and the diameter of the breast phantom (8 cm, 10 cm, and 13 cm). As a general tendency, we found out that a high-resolution camera is preferable, in terms of image contrast. On the other hand, the General Purpose collimator seems to give a smoother image, giving rise to SNR values comparable to those obtained with the High-Resolution collimator, even with a reduced contrast. High-sensitivity collimators seem to give a worse response on the reconstructed images. The 8 mm tumor is clearly visible for all the simulated conditions, even if it could be very close to the visibility limit for the High-Sensitivity collimator. The 5 mm tumor is close to the visibility limit for General Purpose and High-Resolution collimators, for a T/B ratio equal to 10:1 and is not visible with High-Sensitivity collimator. The smaller tumor is almost obscured by the background with the thickest breast (13 cm diameter).
- Published
- 2006
32. A simulation tool for X-ray imaging systems
- Author
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G. Massazza, Viviana Fanti, Paolo Randaccio, R. Marzeddu, and A. Bemardini
- Subjects
Physics ,business.industry ,Orientation (computer vision) ,Image quality ,Detector ,X-ray ,computer.software_genre ,Optics ,Voxel ,Point (geometry) ,Tube (container) ,business ,computer ,Beam (structure) - Abstract
We present a software tool for the simulation of X-ray imaging systems. It consists of three virtual objects: the X-ray source, the human body and the detector. The X-ray source is modeled as a radiological tube for which the user can modify the tube potential, the anode material, the tube load, the filtration and some geometric parameters such as source-skin distance, orientation, and field size. The virtual body consists of a 3D voxel matrix in which CT numbers for each point of the body are stored, obtained from tomographic slices. The interactions of X-rays passing through the body are evaluated using pencil beam technique. The image is obtained computing the dose absorbed by the detector and converting it into optical density by the use of a proper response function. The dose absorbed in each point of the body is also computed and can be visualized both in 2D and 3D representations. The influence of each parameter on the beam spectrum, on the image quality and on the dose to the patient can be observed interactively
- Published
- 2005
33. A Simulator for X-ray images
- Author
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Bruno Golosio, Giovanna Massazza, Paolo Randaccio, R. Marzeddu, Antonio Brunetti, and Viviana Fanti
- Subjects
Models, Anatomic ,Tomography Scanners, X-Ray Computed ,Image quality ,Physics::Medical Physics ,Image processing ,computer.software_genre ,Radiation Dosage ,Optics ,Voxel ,Image Processing, Computer-Assisted ,Humans ,Radiology, Nuclear Medicine and imaging ,Computer Simulation ,Image resolution ,Simulation ,Physics ,Radiation ,Models, Statistical ,Radiological and Ultrasound Technology ,Orientation (computer vision) ,business.industry ,Phantoms, Imaging ,Radiotherapy Planning, Computer-Assisted ,X-Rays ,Detector ,Public Health, Environmental and Occupational Health ,General Medicine ,Radiographic Image Enhancement ,Radiographic Image Interpretation, Computer-Assisted ,Tomography ,business ,Tomography, X-Ray Computed ,computer ,Monte Carlo Method - Abstract
A simulator for X-ray images is presented based on a virtual X-ray source and a virtual human body obtained from tomographic slices. In the simulator it is possible to modify the tube potential, the anodic current, the exposure time, the filtration and some geometric parameters such as source-skin distance, orientation and field size. The virtual body consists of a three-dimensional voxel matrix in which CT numbers for each point of the body are stored. The interactions of X rays passing through the body are evaluated using the pencil beam technique. The image is obtained by computing the dose absorbed by the detector and converting it into optical density using a proper response function. The image spatial resolution is limited by the voxel size. The influence of each parameter on the image quality can be observed interactively. The dose absorbed in each point of the body is an important parameter obtained as output of the simulator.
- Published
- 2005
34. A simulation tool to support teaching and learning the operation of X-ray imaging systems
- Author
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Viviana Fanti, Giovanna Massazza, Paolo Randaccio, and R. Marzeddu
- Subjects
Computer science ,Image quality ,Acoustics ,Biophysics ,Biomedical Engineering ,Environment ,computer.software_genre ,Matrix (mathematics) ,User-Computer Interface ,Voxel ,Education, Professional ,Point (geometry) ,Computer vision ,Computer Simulation ,Tube (container) ,Internet ,Orientation (computer vision) ,business.industry ,Detector ,Models, Theoretical ,Radiography ,Italy ,Artificial intelligence ,Curriculum ,business ,Radiology ,computer ,Beam (structure) ,Computer-Assisted Instruction - Abstract
We present a software tool for the simulation of an X-ray imaging systems. It consists of three virtual objects: the X-ray source, the human body and the detector. The X-ray source is modeled as a radiological tube for which the user can modify the tube potential, the anode material, the tube load, the filtration and some geometric parameters, such as source-skin distance, orientation and field size. The virtual body consists of a 3D voxel matrix in which CT numbers for each point of the body are stored, obtained from tomographic slices. The interactions of X-rays passing through the body are evaluated using pencil beam technique. The image is obtained computing the dose absorbed by the detector and converting it into optical density by the use of a proper response function. The dose absorbed in each point of the body is also computed and can be visualized both in 2D and 3D representations. The influence of each parameter on the beam spectrum, on the image quality and on the dose to the patient can be observed interactively.
- Published
- 2004
35. Voxel-based Monte Carlo simulation of X-ray imaging and spectroscopy experiments
- Author
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Simone Stumbo, Pierre Bleuet, Bruno Golosio, Ubaldo Bottigli, Paolo Randaccio, Piernicola Oliva, Alexandre Simionovici, Andrea Somogyi, Laszlo Vincze, and Antonio Brunetti
- Subjects
Physics ,Monte Carlo method ,X-ray imaging ,spectroscopy experiment ,Inelastic scattering ,computer.software_genre ,Atomic and Molecular Physics, and Optics ,Analytical Chemistry ,Regular grid ,Computational physics ,Hybrid Monte Carlo ,Chemistry ,Voxel ,Dynamic Monte Carlo method ,Monte Carlo simulation ,Variance reduction ,Statistical physics ,Spectroscopy ,Instrumentation ,computer - Abstract
A Monte Carlo code for the simulation of X-ray imaging and spectroscopy experiments in heterogeneous samples is presented. The energy spectrum, polarization and profile of the incident beam can be defined so that X-ray tube systems as well as synchrotron sources can be simulated. The sample is modeled as a 3D regular grid. The chemical composition and density is given at each point of the grid. Photoelectric absorption, fluorescent emission, elastic and inelastic scattering are included in the simulation. The core of the simulation is a fast routine for the calculation of the path lengths of the photon trajectory intersections with the grid voxels. The voxel representation is particularly useful for samples that cannot be well described by a small set of polyhedra. This is the case of most naturally occurring samples. In such cases, voxel-based simulations are much less expensive in terms of computational cost than simulations on a polygonal representation. The efficient scheme used for calculating the path lengths in the voxels and the use of variance reduction techniques make the code suitable for the detailed simulation of complex experiments on generic samples in a relatively short time. Examples of applications to X-ray imaging and spectroscopy experiments are discussed. (C) 2004 Elsevier B.V. All rights reserved.
- Published
- 2004
36. A Tele-home Care System Exploiting the DVB-T Technology and MHP
- Author
-
Gianmarco Angius, S. Seruis, Luigi Raffo, Paolo Randaccio, and Danilo Pani
- Subjects
Telemedicine ,Computer science ,Interface (computing) ,Video Recording ,Pilot Projects ,Health Informatics ,computer.software_genre ,Personalization ,Upload ,Base station ,Software ,Health Information Management ,Telecommunications link ,Humans ,DVB-T ,Advanced and Specialized Nursing ,Multimedia ,business.industry ,Home Care Services ,Italy ,Embedded system ,business ,Delivery of Health Care ,computer - Abstract
Summary Objectives: The aim of this research work is the development of a low-cost system for telemedicine based on the DVB-T technology. The diffusion of DVB-T standard and the low cost of DVB-T set-top boxes bring the vision of a capillary distribution of tele-home care monitoring systems with easy-to-use patient’s interface. Methods: Exploiting the potentiality of the DVB-T settop box, we transformed it into an “on-demand telehome care interface”. The Xlet we developed is able to govern the functionality of an external microcontrollerbased unit for the acquisition of the bio-signals of interest. The uplink connection is used to send the exam results to a remote care center. Results: The Xlet providing the patient interface on the set-top box is uploaded by a DVB-T broadcaster without any intervention in the patient’s home. A prototypal low-cost base station for the acquisition of the patient’s signals (1-lead ECG) has been developed. It is able to be connected to the set-top box via an infrared link. A smart-card-based system is in charge for the customization of the Xlet for every patient. Conclusions: The proposed system, based on a currently widespread infrastructure, is able to allow the patients monitoring from home without any installation procedure. Even untrained (or elderly) people can easily use such system due to their practice with the basic DVB-T home-entertainment equipments.
- Published
- 2008
37. Use of silicon and GaAs pixel detectors for digital autoradiography
- Author
-
R Marchesini, E. Bertolucci, N. Romeo, C. Da Via, E. Heijen, Valeria Rosso, G. Grossi, Val O'Shea, Paolo Russo, Paolo Randaccio, W. Snoeys, Salvator Roberto Amendolia, Saverio D'Auria, P. Middelkamp, Michael Campbell, E. Mancini, A. Del Guerra, Mauro Gambaccini, R. Beccherle, E. Chesi, A. M. Stefanini, Kevin M. Smith, Maria Evelina Fantacci, L. Scharfetter, Ubaldo Bottigli, Maria Agnese Ciocci, Maria Giuseppina Bisogni, Marcello Rossetti Conti, E., Bertolucci, M., Conti, Grossi, Gianfranco, E., Mancini, Russo, Paolo, M., Campbell, E., Chesi, E., Heijne, P., Middelkamp, L., Scharfetter, P., Randaccio, R., Beccherle, A., Del Guerra, M., Gambaccini, R., Marchesini, C., Da Via', S., D'Auria, V., O'Shea, K., Smith, W., Snoey, S. R., Amedolia, M. G., Bisogni, U., Bottigli, M. A., Ciocci, M. E., Fantacci, N., Romeo, V., Rosso, O. A., Stefanini, S. R., Amendolia, C., Davia, A., Delguerra, S., Dauria, V., Oshea, and A., Stefanini
- Subjects
Physics ,Nuclear and High Energy Physics ,Radioactive tracer ,Pixel ,Silicon ,Detector ,Analytical chemistry ,Solid-state ,chemistry.chemical_element ,Biomedical equipment ,hybrid pixel detector ,law.invention ,Electrophoresis ,Nuclear Energy and Engineering ,chemistry ,law ,Electronic engineering ,Silicon pixel detector ,Autoradiography ,GaA ,Electrical and Electronic Engineering ,Silicon radiation detectors - Abstract
Solid state detectors made of Si (4.8/spl times/8 mm/sup 2/) and GaAs (6.4/spl times/8 mm/sup 2/) pixel matrices bump-bonded to the Omega2 and Omega3 electronic read-out systems, developed at CERN for H.E.P. experiments, have been used to obtain autoradiographic images of clusters of human epithelial cells and DNA fragments separated via electrophoresis, both labeled with /sup 32/P. The system has shown a good minimum detectable activity per unit area of 2.10/sup -4/ cps mm/sup -2/, and has proved linear for a count rate in the range 0.2-20 cpa, typical of autoradiography. The pixel dimensions are 75/spl times/500 /spl mu/m/sup 2/ (Si-Omega2) and 50/spl times/500 /spl mu/m/sup 2/ (GaAs-Omega3), respectively. We are able to clearly localize clusters of cells which have incorporated the radioactive tracer and DNA fragments on an electrophoretic gel on paper (blots).
- Published
- 1997
38. COMPARISON OF DIFFERENT GAAS DETECTORS FOR X-RAY DIGITAL RADIOGRAPHY
- Author
-
E. Bertolucci, Valeria Rosso, C. Del Papa, U. Bottigli, R. Bertin, Walter Bencivelli, A. M. Stefanini, Paolo Randaccio, Maria Evelina Fantacci, and Saverio D'Auria
- Subjects
Physics ,Nuclear and High Energy Physics ,Photon ,business.industry ,Resolution (electron density) ,X-ray ,Charge (physics) ,Trapping ,Optics ,Electric field ,Irradiation ,business ,Instrumentation ,Digital radiography - Abstract
Two different GaAs crystals, one LEC and one LPE, have been irradiated with photons of various energies, to compare their response in view of a possible application for digital radiography. Experimental results include I–V curves, charge collection efficiency, detection efficiency and energy resolution as a function of bias. A comparison is made with a simulation program that takes into account X-ray interactions, electric field and charge trapping inside the material.
- Published
- 1994
39. X-ray-imaging Test of A micro-strip Silicon Detector With A Transputer DAQ
- Author
-
Maria Evelina Fantacci, M. Larobina, Paolo Russo, Valeria Rosso, Walter Bencivelli, A. Scarlatella, Paolo Randaccio, U. Bottigli, E. Bertolucci, Marcello Rossetti Conti, A. Del Guerra, Michele Marziani, Mauro Gambaccini, A. M. Stefanini, S. Russo, W., Bencivelli, E., Bertolucci, U., Bottigli, M., Conti, A., Delguerra, M. E., Fantacci, M., Gambaccini, M., Larobina, M., Marziani, P., Randaccio, V., Rosso, Russo, Paolo, Russo, Stefano, A., Scarlatella, and A., Stefanini
- Subjects
Physics ,Nuclear and High Energy Physics ,Photon ,Silicon ,business.industry ,Transputer ,Detector ,chemistry.chemical_element ,Image processing ,Particle detector ,DIGITAL RADIOGRAPHY ,Data acquisition ,Optics ,Nuclear Energy and Engineering ,chemistry ,Measuring instrument ,Electronic engineering ,Microstrip detector ,Electrical and Electronic Engineering ,business - Abstract
The authors have developed a TDC+Transputer-based acquisition system to study the X-ray imaging capabilities of a silicon /spl mu/-strip detector with 100 and 200 /spl mu/m read-out pitch. This system allows real-time image acquisition and display. The authors present images obtained with an X-ray mammography tube using sub-millimeter high contrast test objects on a 16*16 channels prototype. >
- Published
- 1994
40. DIGITAL IMAGING IN RADIOLOGY - PRELIMINARY-RESULTS OBTAINED WITH A HIGH-SPATIAL-RESOLUTION 2D SILICON DETECTOR
- Author
-
M. Larobina, Paolo Russo, A. M. Stefanini, Michele Marziani, Maurizio Conti, A. Del Guerra, U. Bottigli, Valeria Rosso, B. Alfano, A. Bandettini, Mauro Gambaccini, Maria Evelina Fantacci, Walter Bencivelli, E. Bertolucci, Paolo Randaccio, B., Alfano, A., Bandettini, W., Bencivelli, Bertolucci, Ennio, U., Bottigli, Conti, Maurizio, A., Del Guerra, M. E., Fantacci, M., Gambaccini, M., Larobina, M., Marziani, P., Randaccio, V., Rosso, Russo, Paolo, and A., Stefanini
- Subjects
Physics ,Nuclear and High Energy Physics ,Contrast transfer function ,business.industry ,Detector ,X-ray tube ,Particle detector ,Imaging phantom ,law.invention ,Semiconductor detector ,Optics ,Nuclear Energy and Engineering ,law ,Electronic engineering ,Electrical and Electronic Engineering ,business ,Image resolution ,Digital radiography - Abstract
Double-sided microstrip silicon crystals are being tested as detectors for X-rays in the diagnostic energy range (10-100 keV) for digital radiology. An analog-to-digital-converter and CAMAC based acquisition system has been developed to study the imaging capabilities of a silicon microstrip detector with 100 and 200 mu m read-out pitch. The authors present the first images of submillimeter high-contrast phantoms obtained with an X-ray mammography tube operating at high flux density. A preliminary contrast transfer function study was performed; a low frequency contrast of about 0.97 for a high-contrast phantom and a decrease of contrast at a frequency of 5 1p/mm corresponding to the detector intrinsic spatial resolution (100 mu m) were measured. >
- Published
- 1993
41. First x-ray images with a double-sided microstrips silicon crystal. A novel detector for digital radiography?
- Author
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Valeria Rosso, Paolo Russo, Maria Evelina Fantacci, Walter Bencivelli, E. Bertolucci, M Penkowski, Maurizio Conti, B. Alfano, A. Del Guerra, Paolo Randaccio, U. Bottigli, A. Bandettini, Alfano, B, Bandettini, A, Bencivelli, W, Bertolucci, Ennio, Bottigli, U, Conti, Maurizio, Del Guerra, A, Fantacci, Me, Penkowski, M, Randaccio, P, Rosso, V, and Russo, Paolo
- Subjects
Physics ,Silicon ,Photon ,Radiological and Ultrasound Technology ,Physics::Instrumentation and Detectors ,business.industry ,Astrophysics::High Energy Astrophysical Phenomena ,Detector ,Tantalum ,chemistry.chemical_element ,Photon energy ,Collimated light ,Monocrystalline silicon ,Radiographic Image Enhancement ,Optics ,chemistry ,Radiology, Nuclear Medicine and imaging ,business ,Ohmic contact ,Digital radiography - Abstract
In the framework of an experimental program to study the possibility of using a silicon crystal for X-ray detection in the diagnostic energy range (10-100 keV), the authors present the first experimental results obtained with a silicon detector (300 mu m thick, 1.4*1.4 cm2 surface) with microstrips deposited on each side: 25 mu m spacing on the junction side and 50 mu m spacing on the ohmic side: 25 mu m spacing on the junction side and 50 mu m spacing on the ohmic side; the read-out pitch is 100 mu m for both sides. Energy and spatial resolutions have been measured by means of collimated radioactive sources: 241Am (E gamma =60 keV) and 109Cd (E gamma =24 and 88 keV). A very good linearity in the response to the photon energy has been measured. Tantalum wires, i.e. high contrast objects, have been used as phantoms when exposing the detector to the 60 keV photons; the authors present the images thus obtained.
- Published
- 1992
42. An electronic coincidence system for 'in frame' DAQ from a double side mu -strip silicon detector exposed to X-rays
- Author
-
U. Bottigli, Walter Bencivelli, A. M. Stefanini, A. Bandettini, Paolo Russo, Maria Evelina Fantacci, Paolo Randaccio, Marcello Rossetti Conti, Valeria Rosso, A. Del Guerra, E. Bertolucci, A., Bandettini, W., Bencivelli, Bertolucci, Ennio, U., Bottigli, Conti, Maurizio, A., Del Guerra, M. E., Fantacci, P., Randaccio, V., Rosso, Russo, Paolo, and A., Stefanini
- Subjects
Physics ,Silicon ,business.industry ,Detector ,X-ray detector ,chemistry.chemical_element ,STRIPS ,Dead time ,Coincidence ,law.invention ,Optics ,Data acquisition ,chemistry ,law ,business ,Digital radiography - Abstract
In the framework of an experimental study of the possibility of using a double-sided silicon strip detector for digital radiography, and electronic system has been developed to make the signals coming from the two sides of the crystal coincide and hence to define the impact point of X-rays, giving an image matrix as final output. It is based on commercial PALs, and has been built and tested for 32×32 channels. In this configuration the dead time between two subsequent events is ⩽34 ns. Its logic is easily extendable to a large number of channels with a limited increase of the overall dead time and its various stages have been devised in view of a future integration as VLSI
- Published
- 1992
43. USE OF THE EGS4 MONTE-CARLO CODE TO EVALUATE THE RESPONSE OF HGI2 AND CDTE DETECTORS FOR PHOTONS IN THE DIAGNOSTIC ENERGY-RANGE
- Author
-
W.R. Nelson, Walter Bencivelli, D. Mazzei, Maurizio Conti, E. Bertolucci, U. Bottigli, Paolo Russo, Paolo Randaccio, A. Del Guerra, S. Stefanini, Valeria Rosso, Alberto Messineo, Conti, Maurizio, A., Delguerra, D., Mazzei, Russo, Paolo, W., Bencivelli, Bertolucci, Ennio, A., Messineo, V., Rosso, A., Stefanini, U., Bottigli, P., Randaccio, and W. R., Nelson
- Subjects
Physics ,Nuclear and High Energy Physics ,Range (particle radiation) ,Photon ,positron emission tomography ,Astrophysics::High Energy Astrophysical Phenomena ,HgI2 ,Monte Carlo method ,Physics::Optics ,Monte Carlo method for photon transport ,CdTe ,Photon energy ,Cadmium telluride photovoltaics ,Computational physics ,Crystal ,X-ray ,Semiconductor crystal ,Monte Carlo simulation ,Digital radiography ,Statistical physics ,Instrumentation ,Energy (signal processing) - Abstract
We present the results of the detailed simulation of the response of a HgI 2 crystal in terms of efficiency, energy and space resolutions versus photon energy in the diagnostic energy range 20–100 keV. Some configurations of CdTe crystals for positron emission tomography are also evaluated.
- Published
- 1992
44. EVALUATION OF ELEMENTAL AND COMPOUND SEMICONDUCTORS FOR X-RAY DIGITAL RADIOGRAPHY
- Author
-
Paolo Randaccio, Valeria Rosso, E. Bertolucci, Walter Bencivelli, A. M. Stefanini, P. Russo, Alberto Messineo, A. Del Guerra, W.R. Nelson, U. Bottigli, W., Bencivelli, Bertolucci, Ennio, U., Bottigli, A., Del Guerra, A., Messineo, W. R., Nelson, P., Randaccio, V., Rosso, Russo, Paolo, and A., Stefanini
- Subjects
Physics ,Nuclear and High Energy Physics ,Range (particle radiation) ,Astrophysics::High Energy Astrophysical Phenomena ,Resolution (electron density) ,solid state ,X-ray digital radiography ,Analytical chemistry ,X-ray ,Solid-state ,General purpose ,Compound semiconductor ,Instrumentation ,Energy (signal processing) ,Digital radiography - Abstract
We present a comparative study of the performance of elemental and compound solid state crystals of possible use in X-raY digital radiography. The general purpose EGS4 code was used to simulate photon-electron transport in the energy range 20 to 60 keV. The efficiency and the energy resolution, as a function of X-ray energy, are calculated and correlated to the different physical characteristics of the crystals considered.
- Published
- 1991
45. USE OF EGS4 FOR THE EVALUATION OF THE PERFORMANCE OF A SILICON DETECTOR FOR X-RAY DIGITAL RADIOGRAPHY
- Author
-
Walter Bencivelli, E. Bertolucci, A. Del Guerra, Paolo Randaccio, A. M. Stefanini, W.R. Nelson, D. Mazzei, U. Bottigli, Alberto Messineo, Paolo Russo, Valeria Rosso, W., Bencivelli, Bertolucci, Ennio, U., Bottigli, A., Del Guerra, D., Mazzei, A., Messineo, W. R., Nelson, P., Randaccio, V., Rosso, Russo, Paolo, and A., Stefanini
- Subjects
Physics ,Nuclear and High Energy Physics ,Range (particle radiation) ,medicine.medical_specialty ,Physics::Instrumentation and Detectors ,business.industry ,mammography ,Physics::Medical Physics ,Detector ,X-ray ,Monocrystalline silicon ,Optics ,silicon detectors ,medicine ,Medical physics ,business ,Instrumentation ,Single crystal ,Image resolution ,Beam (structure) ,Digital radiography - Abstract
The general-purpose EGS4 code has been used to evaluate the efficiency, the energy and the spatial resolution of a silicon crystal with double-side microstrips readout to detect X-rays in the diagnostic energy range (10–100 keV). A single crystal configuration, a sandwich arrangement with a high- Z converter foil in between two crystals and a multicrystal configuration have been investigated. The simulation with a low energy spectrum X-ray beam and a breast phantom has shown that this type of detector would be of valuable use in mammography applications: breast calcification with a diameter smaller than 500 μm can be easily identified.
- Published
- 1991
46. A probabilistic approach to the statistical analysis of experiments on helminth parasites
- Author
-
Gianfranco Ferretti, Ludovico Piccinato, and Paolo Randaccio
- Subjects
Probabilistic method ,Bayesian probability ,Statistics ,Probabilistic logic ,Helminths ,Probability distribution ,Animal Science and Zoology ,Statistical analysis ,Biology - Abstract
A probabilistic method, based on a Bayesian approach, is proposed for the evaluation of results obtained in experimental infections induced by microscopic eggs (or larvae) whose exact number is not directly known. The statistical analysis leads to the evaluation of the probability that the eggs (or larvae) develop “normally”; the results are represented by normalized likelihood functions (NLF) or, more generally, through final probability distributions. Any difference in the various experiments that possibly emerged may be judged on the NLF graphs. Some real and fictional cases are discussed as examples. In particular, the unreliability of the usual method that considers only the number of recovered parasites but not the number of eggs used may be easily verified.
- Published
- 1980
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