Il presente programma si articola in due linee di ricerca, dedicate allo sviluppo di sistemi di i... more Il presente programma si articola in due linee di ricerca, dedicate allo sviluppo di sistemi di imaging del tumore alla mammella, rispettivamente nel campo della Medicina Nucleare e della Tomografia Assiale Computerizzata. L'obiettivo primario del programma di ricerca consiste nello sviluppo di una nuova tecnica per imaging ad emissione di fotone singolo in grado di superare gli attuali limiti di sensibilita' clinica nella rivelazione di tumori di piccole dimensioni nella mammella. Lo sviluppo tecnologico che questo obiettivo comporta consiste nella realizzazione di un anello SPECT compatto ottimizzato ad alta efficienza di rivelazione che si adatti all'anatomia della mammella della paziente, in modo da ottenere un'elevata risoluzione spaziale. L'obiettivo sar\ue0 conseguito attraverso l'analisi della cinetica di radiofarmaci con 99mTc. Tale dinamica si ipotizza essere legata alla neoangiogenesi generata dalla presenza della lesione. L'anello avr\ue0 un diametro di circa 15 cm e l'imaging della mammella avverr\ue0 attraverso cinque "teste" di rivelazione di dimensione pari a circa 5 x10 cm^2 ciascuna, secondo una struttura pentagonale. La paziente sar\ue0 posizionata in posizione prona con la mammella pendula. L'anello ruoter\ue0 attorno alla mammella, consentendo una ricostruzione tomografica secondo l'asse verticale (VaoR). Una volta completato, l'anello SPECT sar\ue0 testato su sorgenti e sar\ue0 trasferito, per la sua validazione, presso la Divisione di Medicina Nucleare dell'Azienda Ospedaliera Universitaria di Pisa. Un secondo obiettivo di questo programma di ricerca \ue8 il confronto tra tre differenti metodologie di tomografia TAC della mammella. Verranno confrontati tre tipi di rivelatori: una matrice lineare di CCD+CsI, un rivelatore a semiconduttore di piccola area con capacit\ue0 di "single-photon-counting" e un rivelatore Flat Panel di grande area. In questa parte del programma le Unit\ue0 di ricerca collaboreranno con l'Istituto di Fisica Medica dell'Universit\ue0 di Erlangen-Nurnberg (Germania). La prima metodica TAC che verr\ue0 studiata \ue8 basata su una TAC, precedentemente sviluppata presso l'unit\ue0 di ricerca di Pisa per studi su piccoli animali. La micro-TAC \ue8 costituita da un tubo a raggi X microfuoco, una CCD (Hamamatsu S7199) accoppiata ad uno scintillatore di Cs(Tl), 6.144 mm x 147.456 mm, suddivisa in 128 x 3076 con pixel quadrati delle dimensioni di 48 micron^2 ciascuno. La seconda tipologia di TAC che sar\ue0 valutata \ue8 basata sull'uso di rivelatori a semiconduttore pixellati dotati di elettronica di lettura con capacit\ue0 di "single-photon counting". Il rivelatore consiste in una matrice di silicio cristallino, con pixel di 50 micron, e con un'area attiva di 2.8 cm x 2.8 cm. Questa matrice sar\ue0 letta da quattro circuiti integrati in tecnologia CMOS , Medipix2. I chip dell'elettronica saranno saldati al rivelatore con una tecnica di "bump-bonding". Questo rivelatore rappresenta l'evoluzione di prototipi di rivelatori di piccola area (1.4 cm x 1.4 cm), gi\ue0 sviluppati dall'unit\ue0 di Pisa. Inoltre verranno valutate le capacit\ue0 di imaging di soluzioni a pi\uf9 moduli. Le prestazioni di entrambi i rivelatori saranno confrontati con il sistema TAC, sviluppato presso l'Universit\ue0 di Erlangen- Nurnberg (Germania), composto da un rivelatore Flat Panel di grande area e da un tubo a raggi X a microfuoco. Il confronto tra le tre modalit\ue0 verr\ue0 effettuato in termini di capacit\ue0 di imaging, impatto diagnostico e dose impartita al tessuto mammario
A very large-use optimization technique for radiation treatment planning is presented. Very few i... more A very large-use optimization technique for radiation treatment planning is presented. Very few input data are sufficient to enable the program to work out an optimized dose distribution; optimization is obtained by modifying the intersection point of beams and the size, the wedge and the time of each beam. The technique may be extended to moving beam teletherapy. A memorized collection of typical geometric arrangements allows a good saving in operator's time especially during data preparation.
Il progetto nazionale RadioLab dell\\u2019INFN rappresenta un\\u2019azione efficace di diffusione... more Il progetto nazionale RadioLab dell\\u2019INFN rappresenta un\\u2019azione efficace di diffusione della cultura scientifica, e in particolare di Fisica nucleare, attraverso il coinvolgimento attivo di studenti delle scuole superiori in misure di radioattivit\\ue0 ambientale. Comunicazione scientifica, didattica e ricerca si integrano attuando azioni di orientamento formativo mediante un processo che ricalca le fasi attraverso cui evolve un lavoro di ricerca. Il coinvolgimento degli studenti avviene con sessioni di lavoro in laboratorio, con l\\u2019assemblaggio dei rivelatori, la loro esposizione nelle scuole e nelle abitazioni e di nuovo in laboratorio per la lettura dei dosimetri e l\\u2019elaborazione dei dati acquisiti. Ci\\uf2 comporter\\ue0 una partecipazione attiva anche dei docenti in un percorso di aggiornamento, particolarmente opportuno, soprattutto in vista delle nuove direttive ministeriali che prevedono l\\u2019insegnamento della fisica moderna nell\\u2019ultimo anno della scuola superiore. Al progetto partecipano attualmente le sezioni INFN di Cagliari, Catania, Laboratori Nazionali del Sud-CT, Milano, Napoli, Torino, Trieste, di cui verr\\ue0 riportata una panoramica delle attivit\\ue0 realizzate
In this paper, we present nMOVE, a project aimed at investigating and finding methods and solutio... more In this paper, we present nMOVE, a project aimed at investigating and finding methods and solutions for the reconstruction of accessibility models to archaeological nuragic settlements and the creation of possible old road networks. The main goal is to map a model of ancient road system through digital cartographic bases. We hereby present the archaeobotanical studies carried out on plant remains found in different archaeological sites dated from Bronze Age to investigate the movements of the past communities for supply of wild food resources. The processing of all plant remains (cleaning, preservation, storage, identification and study) are being realized at the Laboratory of Archaeobotany, which was recently established at the CCB and BG-SAR (Sardinian Germplasm Bank). The archaeo-seeds are being analysed using macroscopic, microscopic and morpho-colorimetric techniques. This study will allow to understand the relationship between human and environment in prehistoric times, as wel...
Summary A preliminary climatology of atmospheric ozone over Western Mediterranean Sea is given b... more Summary A preliminary climatology of atmospheric ozone over Western Mediterranean Sea is given by analysis of the upper observations of O3 carried out at Cagliari-Elmas station from 1968 to 1976. Some peculiarities are here illustrated and discussed.
2011 International Conference on Collaboration Technologies and Systems (CTS), 2011
With the progressive ageing of the western people, the number of chronic patients requiring a con... more With the progressive ageing of the western people, the number of chronic patients requiring a continuous followup 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
Proceedings of the First International Conference on Health Informatics, 2008
Typical telemedicine systems are usually PC based and in some cases they use expensive custom dev... more Typical telemedicine systems are usually PC based and in some cases they use expensive custom devices to satisfy the system requirements. For tele-home care uses by elderly or untrained people, these type of solutions are impracticable. As an example of user-friendly tele-home care system, in this paper we present the first telehome care application of DVB-T technology over standard home entertainment equipments and a prototypal low cost microcontroller-based acquisition unit for 1-lead ECG. The usability and low cost of the system show the potentiality of the approach.
The optics of the LHC beams in the insertion regions, where the ZDCs have to be placed, is rather... more The optics of the LHC beams in the insertion regions, where the ZDCs have to be placed, is rather complicated; it includes, apart from the separation dipoles, other magnetic elements, mainly quadrupole triplets, which can distort to a considerable extent the trajectories of charged particles, such as spectator protons, as they have a different magnetic rigidity than that of the beam. Furthermore, the geometry foreseen for the magnets and the beam pipes includes elements which could generate a non-negligible background for spectator neutron detection. Therefore, in order to finalize the study of the geometry of the detectors, a detailed simulation of the ALICE insertion region must be performed. As the LHC optics, as well as the design of the various elements connected with the vacuum systems (beam pipes, flanges) is still evolving at the time of drawing up this TDR, the most up-to-date information (corresponding to version 6 of LHC optics) has been used whenever possible.
Bu araştırmanın amacı okul öncesi eğitim alan çocukların okul öncesi eğitim programına kaynaştırı... more Bu araştırmanın amacı okul öncesi eğitim alan çocukların okul öncesi eğitim programına kaynaştırılan çevre eğitimi programının çocukların çevre kavramı hakkındaki zihinsel model gelişimine etkisini belirlemektir. Araştırma kapsamında 52, 48-66 aylık çocuklarla çalışılmıştır. Araştırma karma desen modelinde yürütülmüştür. Araştırmanın verilerini çocukların çizimleri oluşturmaktadır. Çizimler Draw An Environment Test-Rubric (DAET-R) aracılığıyla puanlanmıştır. Araştırma sonucunda okul öncesi eğitim programına kaynaştırılan çevre eğitiminin çocukların çevre kavramına yönelik zihinsel modellerinde istendik değişiklikler sağladığı tespit edilmiştir. Bu sonuçtan yola çıkılarak, çevre eğitiminin mümkün olan en erken yaşta verilmesinin önemli olduğu düşünülmektedir.
to within 0.5% both for 3 × 3 and 10 × 10 cm 2 fields. As dose-rate dependence regards, the micro... more to within 0.5% both for 3 × 3 and 10 × 10 cm 2 fields. As dose-rate dependence regards, the microchamber readings showed the maximum variation from the reference condition at the lowest dose rate value; relative standard deviation of measurements was within 0.3%. The polarity effect is within 0.5% for field size greater than 2 × 2 cm 2 ; for field size less than 2 × 2 cm 2 the effect increases, still remaining within 1%. No energy and angular dependence were observed. A26 IC PDD measurements agreed with those obtained with the EDGE diode. FWHM values show a better agreement with the EDGE diode values than A1SL. The penumbra values were greater than those obtained with the EDGE diode. OF values showed a good agreement with EDGE diode ones. Conclusions: A26 IC meets the requirements to be a class reference chamber and it could consequently represent a reference detector for PDD and OAR measurements.
The project we present foresees the development of a hardware processor dedicated to real time Mo... more 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
IEEE Nuclear Science Symposuim & Medical Imaging Conference, 2010
A dedicated processor for Monte Carlo computation in radiotherapy treatment planning on FPGA base... more 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.
A Monte Carlo code for the simulation of X-ray imaging and spectroscopy experiments in heterogene... more 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, voxelbased 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.
A simulator for X-ray images is presented based on a virtual X-ray source and a virtual human bod... more 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.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2006
A readout card based on the standard PCI 32-bit/33MHz bus has been developed for the fast readout... more A readout card based on the standard PCI 32-bit/33MHz 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 90Mbytes/s. The PCI card has two high-density 80-pin connectors for data I/O; an external system acquisition card
Preclinical Microbeam Radiation Therapy (MRT) research programs are carried out at the European S... more Preclinical Microbeam Radiation Therapy (MRT) research programs are carried out at the European Synchrotron Radiation Facility (ESRF) and at a few other synchrotron facilities. MRT needs an accurate evaluation of the doses delivered to biological tissues for carrying out pre-clinical studies. This point is crucial for determining the effect induced by changing any of the physical irradiation parameters. The doses
The authors have developed a TDC+Transputer-based acquisition system to study the X-ray imaging c... more The authors have developed a TDC+Transputer-based acquisition system to study the X-ray imaging capabilities of a silicon μ-strip detector with 100 and 200 μm 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
Il presente programma si articola in due linee di ricerca, dedicate allo sviluppo di sistemi di i... more Il presente programma si articola in due linee di ricerca, dedicate allo sviluppo di sistemi di imaging del tumore alla mammella, rispettivamente nel campo della Medicina Nucleare e della Tomografia Assiale Computerizzata. L'obiettivo primario del programma di ricerca consiste nello sviluppo di una nuova tecnica per imaging ad emissione di fotone singolo in grado di superare gli attuali limiti di sensibilita' clinica nella rivelazione di tumori di piccole dimensioni nella mammella. Lo sviluppo tecnologico che questo obiettivo comporta consiste nella realizzazione di un anello SPECT compatto ottimizzato ad alta efficienza di rivelazione che si adatti all'anatomia della mammella della paziente, in modo da ottenere un'elevata risoluzione spaziale. L'obiettivo sar\ue0 conseguito attraverso l'analisi della cinetica di radiofarmaci con 99mTc. Tale dinamica si ipotizza essere legata alla neoangiogenesi generata dalla presenza della lesione. L'anello avr\ue0 un diametro di circa 15 cm e l'imaging della mammella avverr\ue0 attraverso cinque "teste" di rivelazione di dimensione pari a circa 5 x10 cm^2 ciascuna, secondo una struttura pentagonale. La paziente sar\ue0 posizionata in posizione prona con la mammella pendula. L'anello ruoter\ue0 attorno alla mammella, consentendo una ricostruzione tomografica secondo l'asse verticale (VaoR). Una volta completato, l'anello SPECT sar\ue0 testato su sorgenti e sar\ue0 trasferito, per la sua validazione, presso la Divisione di Medicina Nucleare dell'Azienda Ospedaliera Universitaria di Pisa. Un secondo obiettivo di questo programma di ricerca \ue8 il confronto tra tre differenti metodologie di tomografia TAC della mammella. Verranno confrontati tre tipi di rivelatori: una matrice lineare di CCD+CsI, un rivelatore a semiconduttore di piccola area con capacit\ue0 di "single-photon-counting" e un rivelatore Flat Panel di grande area. In questa parte del programma le Unit\ue0 di ricerca collaboreranno con l'Istituto di Fisica Medica dell'Universit\ue0 di Erlangen-Nurnberg (Germania). La prima metodica TAC che verr\ue0 studiata \ue8 basata su una TAC, precedentemente sviluppata presso l'unit\ue0 di ricerca di Pisa per studi su piccoli animali. La micro-TAC \ue8 costituita da un tubo a raggi X microfuoco, una CCD (Hamamatsu S7199) accoppiata ad uno scintillatore di Cs(Tl), 6.144 mm x 147.456 mm, suddivisa in 128 x 3076 con pixel quadrati delle dimensioni di 48 micron^2 ciascuno. La seconda tipologia di TAC che sar\ue0 valutata \ue8 basata sull'uso di rivelatori a semiconduttore pixellati dotati di elettronica di lettura con capacit\ue0 di "single-photon counting". Il rivelatore consiste in una matrice di silicio cristallino, con pixel di 50 micron, e con un'area attiva di 2.8 cm x 2.8 cm. Questa matrice sar\ue0 letta da quattro circuiti integrati in tecnologia CMOS , Medipix2. I chip dell'elettronica saranno saldati al rivelatore con una tecnica di "bump-bonding". Questo rivelatore rappresenta l'evoluzione di prototipi di rivelatori di piccola area (1.4 cm x 1.4 cm), gi\ue0 sviluppati dall'unit\ue0 di Pisa. Inoltre verranno valutate le capacit\ue0 di imaging di soluzioni a pi\uf9 moduli. Le prestazioni di entrambi i rivelatori saranno confrontati con il sistema TAC, sviluppato presso l'Universit\ue0 di Erlangen- Nurnberg (Germania), composto da un rivelatore Flat Panel di grande area e da un tubo a raggi X a microfuoco. Il confronto tra le tre modalit\ue0 verr\ue0 effettuato in termini di capacit\ue0 di imaging, impatto diagnostico e dose impartita al tessuto mammario
A very large-use optimization technique for radiation treatment planning is presented. Very few i... more A very large-use optimization technique for radiation treatment planning is presented. Very few input data are sufficient to enable the program to work out an optimized dose distribution; optimization is obtained by modifying the intersection point of beams and the size, the wedge and the time of each beam. The technique may be extended to moving beam teletherapy. A memorized collection of typical geometric arrangements allows a good saving in operator's time especially during data preparation.
Il progetto nazionale RadioLab dell\\u2019INFN rappresenta un\\u2019azione efficace di diffusione... more Il progetto nazionale RadioLab dell\\u2019INFN rappresenta un\\u2019azione efficace di diffusione della cultura scientifica, e in particolare di Fisica nucleare, attraverso il coinvolgimento attivo di studenti delle scuole superiori in misure di radioattivit\\ue0 ambientale. Comunicazione scientifica, didattica e ricerca si integrano attuando azioni di orientamento formativo mediante un processo che ricalca le fasi attraverso cui evolve un lavoro di ricerca. Il coinvolgimento degli studenti avviene con sessioni di lavoro in laboratorio, con l\\u2019assemblaggio dei rivelatori, la loro esposizione nelle scuole e nelle abitazioni e di nuovo in laboratorio per la lettura dei dosimetri e l\\u2019elaborazione dei dati acquisiti. Ci\\uf2 comporter\\ue0 una partecipazione attiva anche dei docenti in un percorso di aggiornamento, particolarmente opportuno, soprattutto in vista delle nuove direttive ministeriali che prevedono l\\u2019insegnamento della fisica moderna nell\\u2019ultimo anno della scuola superiore. Al progetto partecipano attualmente le sezioni INFN di Cagliari, Catania, Laboratori Nazionali del Sud-CT, Milano, Napoli, Torino, Trieste, di cui verr\\ue0 riportata una panoramica delle attivit\\ue0 realizzate
In this paper, we present nMOVE, a project aimed at investigating and finding methods and solutio... more In this paper, we present nMOVE, a project aimed at investigating and finding methods and solutions for the reconstruction of accessibility models to archaeological nuragic settlements and the creation of possible old road networks. The main goal is to map a model of ancient road system through digital cartographic bases. We hereby present the archaeobotanical studies carried out on plant remains found in different archaeological sites dated from Bronze Age to investigate the movements of the past communities for supply of wild food resources. The processing of all plant remains (cleaning, preservation, storage, identification and study) are being realized at the Laboratory of Archaeobotany, which was recently established at the CCB and BG-SAR (Sardinian Germplasm Bank). The archaeo-seeds are being analysed using macroscopic, microscopic and morpho-colorimetric techniques. This study will allow to understand the relationship between human and environment in prehistoric times, as wel...
Summary A preliminary climatology of atmospheric ozone over Western Mediterranean Sea is given b... more Summary A preliminary climatology of atmospheric ozone over Western Mediterranean Sea is given by analysis of the upper observations of O3 carried out at Cagliari-Elmas station from 1968 to 1976. Some peculiarities are here illustrated and discussed.
2011 International Conference on Collaboration Technologies and Systems (CTS), 2011
With the progressive ageing of the western people, the number of chronic patients requiring a con... more With the progressive ageing of the western people, the number of chronic patients requiring a continuous followup 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
Proceedings of the First International Conference on Health Informatics, 2008
Typical telemedicine systems are usually PC based and in some cases they use expensive custom dev... more Typical telemedicine systems are usually PC based and in some cases they use expensive custom devices to satisfy the system requirements. For tele-home care uses by elderly or untrained people, these type of solutions are impracticable. As an example of user-friendly tele-home care system, in this paper we present the first telehome care application of DVB-T technology over standard home entertainment equipments and a prototypal low cost microcontroller-based acquisition unit for 1-lead ECG. The usability and low cost of the system show the potentiality of the approach.
The optics of the LHC beams in the insertion regions, where the ZDCs have to be placed, is rather... more The optics of the LHC beams in the insertion regions, where the ZDCs have to be placed, is rather complicated; it includes, apart from the separation dipoles, other magnetic elements, mainly quadrupole triplets, which can distort to a considerable extent the trajectories of charged particles, such as spectator protons, as they have a different magnetic rigidity than that of the beam. Furthermore, the geometry foreseen for the magnets and the beam pipes includes elements which could generate a non-negligible background for spectator neutron detection. Therefore, in order to finalize the study of the geometry of the detectors, a detailed simulation of the ALICE insertion region must be performed. As the LHC optics, as well as the design of the various elements connected with the vacuum systems (beam pipes, flanges) is still evolving at the time of drawing up this TDR, the most up-to-date information (corresponding to version 6 of LHC optics) has been used whenever possible.
Bu araştırmanın amacı okul öncesi eğitim alan çocukların okul öncesi eğitim programına kaynaştırı... more Bu araştırmanın amacı okul öncesi eğitim alan çocukların okul öncesi eğitim programına kaynaştırılan çevre eğitimi programının çocukların çevre kavramı hakkındaki zihinsel model gelişimine etkisini belirlemektir. Araştırma kapsamında 52, 48-66 aylık çocuklarla çalışılmıştır. Araştırma karma desen modelinde yürütülmüştür. Araştırmanın verilerini çocukların çizimleri oluşturmaktadır. Çizimler Draw An Environment Test-Rubric (DAET-R) aracılığıyla puanlanmıştır. Araştırma sonucunda okul öncesi eğitim programına kaynaştırılan çevre eğitiminin çocukların çevre kavramına yönelik zihinsel modellerinde istendik değişiklikler sağladığı tespit edilmiştir. Bu sonuçtan yola çıkılarak, çevre eğitiminin mümkün olan en erken yaşta verilmesinin önemli olduğu düşünülmektedir.
to within 0.5% both for 3 × 3 and 10 × 10 cm 2 fields. As dose-rate dependence regards, the micro... more to within 0.5% both for 3 × 3 and 10 × 10 cm 2 fields. As dose-rate dependence regards, the microchamber readings showed the maximum variation from the reference condition at the lowest dose rate value; relative standard deviation of measurements was within 0.3%. The polarity effect is within 0.5% for field size greater than 2 × 2 cm 2 ; for field size less than 2 × 2 cm 2 the effect increases, still remaining within 1%. No energy and angular dependence were observed. A26 IC PDD measurements agreed with those obtained with the EDGE diode. FWHM values show a better agreement with the EDGE diode values than A1SL. The penumbra values were greater than those obtained with the EDGE diode. OF values showed a good agreement with EDGE diode ones. Conclusions: A26 IC meets the requirements to be a class reference chamber and it could consequently represent a reference detector for PDD and OAR measurements.
The project we present foresees the development of a hardware processor dedicated to real time Mo... more 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
IEEE Nuclear Science Symposuim & Medical Imaging Conference, 2010
A dedicated processor for Monte Carlo computation in radiotherapy treatment planning on FPGA base... more 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.
A Monte Carlo code for the simulation of X-ray imaging and spectroscopy experiments in heterogene... more 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, voxelbased 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.
A simulator for X-ray images is presented based on a virtual X-ray source and a virtual human bod... more 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.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2006
A readout card based on the standard PCI 32-bit/33MHz bus has been developed for the fast readout... more A readout card based on the standard PCI 32-bit/33MHz 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 90Mbytes/s. The PCI card has two high-density 80-pin connectors for data I/O; an external system acquisition card
Preclinical Microbeam Radiation Therapy (MRT) research programs are carried out at the European S... more Preclinical Microbeam Radiation Therapy (MRT) research programs are carried out at the European Synchrotron Radiation Facility (ESRF) and at a few other synchrotron facilities. MRT needs an accurate evaluation of the doses delivered to biological tissues for carrying out pre-clinical studies. This point is crucial for determining the effect induced by changing any of the physical irradiation parameters. The doses
The authors have developed a TDC+Transputer-based acquisition system to study the X-ray imaging c... more The authors have developed a TDC+Transputer-based acquisition system to study the X-ray imaging capabilities of a silicon μ-strip detector with 100 and 200 μm 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
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Papers by P. Randaccio