Search results for " Resolution"
showing 10 items of 1159 documents
SU-E-T-508: Monte Carlo Dosimetric Study of the CSM40 Low Dose Rate Source
2013
Purpose: There is a LDR 137Cs brachytherapy source, CSM40, developed by Eckert & Ziegler BEBIG. Fundamental dosimetric datasets to be used on treatment planning systems do not exist for this source. This study aims to obtain quality dosimetric data for this source for its use in clinical practice as required by AAPM and ESTRO. Methods: Penelope2008 and GEANT4 Monte Carlo codes were used to characterize this source dosimetry. Water composition and mass density was that recommended by AAPM. Due to the typical energies of the 137 Cs, dose for small distances can be approximated by collisional kerma. Therefore, we have considered collisional kerma for r<20 cm. To provide adequate spatial resolu…
An approach to using conventional brachytherapy software for clinical treatment planning of complex, Monte Carlo-based brachytherapy dose distributio…
2009
Certain brachytherapy dose distributions, such as those for LDR prostate implants, are readily modeled by treatment planning systems (TPS) that use the superposition principle of individual seed dose distributions to calculate the total dose distribution. However, dose distributions for brachytherapy treatments using high-Z shields or having significant material heterogeneities are not currently well modeled using conventional TPS. The purpose of this study is to establish a new treatment planning technique (Tufts technique) that could be applied in some clinical situations where the conventional approach is not acceptable and dose distributions present cylindrical symmetry. Dose distributi…
MO-D-AUD B-08: Treatment Planning for Complex Brachytherapy Dose Distributions Using High-Z Shields and Conventional Software
2008
Purpose: Certain brachytherapydose distributions, like for LDR prostate implants, are readily modeled by treatment planningsoftware using the superposition principle of individual seeds to replicate the total dose distribution. However, dose distributions for brachytherapy treatments using high‐Z shields are currently not well‐modeled using conventional software.Method and Materials:Dose distributions from complex brachytherapy plaques determined using Monte Carlo methods were used as input data, and included COMS‐based eye plaques using 125 I , 103 Pd , and 131 Cs ; 4–8cm diameter AccuBoost peripheral breast brachytherapy applicators from Advanced Radiation Therapy; and the 2 and 3cm diame…
The optical blocking filter for the ATHENA wide field imager: Ongoing activities towards the conceptual design
2015
ATHENA is the L2 mission selected by ESA to pursue the science theme "Hot and Energetic Universe" (launch scheduled in 2028). One of the key instruments of ATHENA is the Wide Field Imager (WFI) which will provide imaging in the 0.1-15 keV band over a 40'x40' large field of view, together with spectrally and time-resolved photon counting. The WFI camera, based on arrays of DEPFET active pixel sensors, is also sensitive to UV/Vis photons. Optically generated electron-hole pairs may degrade the spectral resolution as well as change the energy scale by introducing a signal offset. For this reason, the use of an X-ray transparent optical blocking filter is needed to allow the observation of all …
22nd Colloquium on High Resolution Molecular Spectroscopy: Special Issue dedicated to Gianfranco Di Lonardo
2011
This issue, together with a second issue to appear in early 2012, consists of contributions submitted by participants attending the Colloquium on High Resolution Molecular Spectroscopy (HRMS), held in Dijon, France from 29 August to 2 September 2011. This is the 22nd in a biannual series of international conferences, which in recent years have taken place alternately in Dijon, France (1999, 2003, 2007, 2011) and in another European Country (1997 in Glasgow, Scotland; 2001 in Nijmegen, The Netherlands; 2005 in Salamanca, Spain, 2009 in Castellammare di Stabia, Italy). This series has a longstanding tradition as one of the most important conferences worldwide on all aspects of high resolution…
Transversal superresolution with noncontact axial movement of periodic structures
2007
We present an innovative approach that allows superresolved images to be obtained by axial moving of two gratings and time integrating in the detector plane. The two gratings do not have to be in contact with either the object or the detector, and both are positioned between the object and the image planes. One of the main applications for the proposed approach in contrast to previously discussed time multiplexing superresolving methods is that it may fit well to superresolved imaging of remote objects, since both gratings are not in contact with either the object or the detector planes.
Based on Compton Camera
2016
Compton Cameras have been proposed as an alternative to SPECT imaging with Gamma Camera, mainly due to factors such as the electronic collimation, which allows a bigger field of view and provides further information from the acquired events if compared to devices with mechanical collimation. By contrast, this involves a higher amount of data to be processed. In medical devices this leads to waiting times that are generally higher than desirable by the health-care professionals. In this work we have assessed the reconstruction of Compton images by making use of iterative and non-iterative techniques, and also evaluated its performances as a SPECT imaging technique.
Stray light characterization in a high-resolution imaging spectrometer designed for solar-induced fluorescence
2019
New commercial-off-the-shelf imaging spectrometers promise the combination of high spatial and spectral resolution needed to retrieve solar induced fluorescence (SIF). Imaging at multiple wavelengths for individual plants and even individual leaves from low-altitude airborne or ground-based platforms has applications in agriculture and carbon-cycle science. Data from these instruments could provide insight into the status of the photosynthetic apparatus at scales of space and time not observable with tools based on gas exchange, and could support the calibration and validation activities of current and forthcoming space missions to quantify SIF. High-spectral resolution enables SIF retrieva…
Recent results on heavy-ion direct reactions of interest for 0νββ decay at INFN - LNS
2020
Abstract Neutrinoless double beta decay of nuclei, if observed, would have important implications on fundamental physics. In particular it would give access to the effective neutrino mass. In order to extract such information from 0νββ decay half-life measurements, the knowledge of the Nuclear Matrix Elements (NME) is of utmost importance. In this context the NUMEN and the NURE projects aim to extract information on the NME by measuring cross sections of Double Charge Exchange reactions in selected systems which are expected to spontaneously decay via 0νββ. In this work an overview of the experimental challenges that NUMEN is facing in order to perform the experiments with accelerated beams…
Relativistically Smeared Iron Lines in the Spectra of Bright NS LMXB
2009
We present preliminary results of a study on three bright accreting low-mass X-ray binaries hosting a neutron star, based on XMM-Newton observations. These sources (GX 340+0, GX 349+2 and SAX J1808.4-3658) show a broad Fe K alpha iron line in their spectra. This feature can be well described by relativistic line profile in each case; the good spectral resolution of the EPIC/PN and the high statistics spectra allow to put very good constraints on the disk geometry and ionization stage of the reflecting matter.