A VLSI chip set for digital radiology with energy selection Cadeddu, S; Caligiore, C; Caria, M ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
1999, Volume:
422, Issue:
1
Journal Article
Peer reviewed
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.
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IJS, IMTLJ, KILJ, KISLJ, NUK, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
23.
Autoradiography with silicon strip detectors Bertolucci, E.; Conti, M.; Grossi, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/1996, Volume:
381, Issue:
2
Journal Article
Peer reviewed
A digital autoradiography system based on double sided silicon strip detectors (1.6 × 1.6 mm
2 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/mm
2, and to record activity measurements with good linearity in the range 0.002–20 nCi/mm
2. Autoradiographic images of clusters of mammary cells marked with ortho-(
32P)phosphate, obtained with an exposure time of about 10 min are presented.
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IJS, IMTLJ, KILJ, KISLJ, NUK, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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).
Optical link based readout system for Medipix2 quad X-ray detector Fanti, V.; Marzeddu, R.; Randaccio, P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2007, Volume:
576, Issue:
1
Journal Article
Peer reviewed
Open access
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.
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IJS, IMTLJ, KILJ, KISLJ, NUK, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Objective: To summarize current excellent research and trends in the field of Health and Clinical management. Methods: Synopsis of the articles selected for the IMIA Yearbook 21014 Results: A ...comprehensive review of papers published in 2013 was performed by querying PubMed. 1079 were reviewed as papers without authors, without abstract or smaller than 4 pages were excluded from the selection. The editors reviewed all papers and 15 papers selected and provided to to international reviewers. Four papers from international peer-reviewed journals were finally selected for the Health and Clinical Management section. Conclusion: Many telemedicine applications are tested nowadays in medical situation, but the challenges emphasized by the best papers selection focus on the ability of proposing integrative frameworks for applications or data in order to handle efficiency of health and clinical management.
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 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.
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.
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.
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