727 research outputs found
A liquid Xenon Positron Emission Tomograph for small animal imaging : first experimental results of a prototype cell
A detector using liquid Xenon (LXe) in the scintillation mode is studied for
Positron Emission Tomography (PET) of small animals. Its specific design aims
at taking full advantage of the Liquid Xenon scintillation properties. This
paper reports on energy, time and spatial resolution capabilities of the first
LXe prototype module equipped with a Position Sensitive Photo- Multiplier tube
(PSPMT) operating in the VUV range (178 nm) and at 165 K. The experimental
results show that such a LXe PET configuration might be a promising solution
insensitive to any parallax effect.Comment: 34 pages, 18 pages, to appear in NIM
Experimental study of a liquid Xenon PET prototype module
A detector using liquid Xenon in the scintillation mode is studied for
Positron Emission Tomography (PET). The specific design aims at taking full
advantage of the liquid Xenon properties. It does feature a promising
insensitive to any parallax effect. This work reports on the performances of
the first LXe prototype module, equipped with a position sensitive PMT
operating in the VUV range (178 nm).Comment: Proc. of the 7th International Workshops on Radiation Imaging
Detectors (IWORID-7), Grenoble, France 4-7 July 200
GePEToS : A Geant4 Monte Carlo simulation package for Positron Emission Tomography
GePEToS is a simulation framework developed over the last few years for
assessing the instrumental performance of future PET scanners. It is based on
Geant4, written in Object-Oriented C++ and runs on Linux platforms. The
validity of GePEToS has been tested on the well-known Siemens ECAT EXACT HR+
camera. The results of two application examples are presented : the design
optimization of a liquid Xe micro-PET camera dedicated to small animal imaging
as well as the evaluation of the effect of a strong axial magnetic field on the
image resolution of a Concorde P4 micro-PET camera.Comment: 5 pages, 12 figures, submitted to IEEE Transactions on Nuclear
Scienc
MPGDs in Compton imaging with liquid-xenon
The interaction of radiation with liquid xenon, inducing both scintillation
and ionization signals, is of particular interest for Compton-sequences
reconstruction. We report on the development and recent results of a
liquid-xenon time-projection chamber, dedicated to a novel nuclear imaging
technique named "3 gamma imaging". In a first prototype, the scintillation is
detected by a vacuum photomultiplier tube and the charges are collected with a
MICROMEGAS structure; both are fully immersed in liquid xenon. In view of the
final large-area detector, and with the aim of minimizing dead-zones, we are
investigating a gaseous photomultiplier for recording the UV scintillation
photons. The prototype concept is presented as well as preliminary results in
liquid xenon. We also present soft x-rays test results of a gaseous
photomultiplier prototype made of a double Thick Gaseous Electron Multiplier
(THGEM) at normal temperature and pressure conditions.Comment: presented at MPGD09, CRETE, June 2009; to be published in JINST
Proceedings, PDF, 10 pages, 11 figure
Development of a TDC to equip a Liquid Xenon PET prototype
A Time to Digital Converter was designed (CMOS 0.35 $\mum) in order to be
used in Liquid Xenon PET prototype. The circuit proved to be able to work at
-120 degrees C, while showing a resolution of 250 ps. The circuit enables a low
readout dead time (<90 ns) and provides a fully synchronous digital interface
for easy data retrieval.Comment: 4 pages, submitted to IEEE Transactions on Nuclear Scienc
Experimental results and first 22Na source image reconstruction by two prototype modules in coincidence of a liquid xenon positron emission tomograph for small animal imaging
International audienceA detector with a very specific design using liquid Xenon (LXe) in the scintillation mode is studied for Positron Emission Tomography (PET) of small animals. Two prototype modules equipped with Position Sensitive Photo Multiplier Tubes (PSPMTs) operating in the VUV range (178 nm) and at 165 K were built and studied in coincidence. This paper reports on energy, time and spatial resolution capabilities of this experimental test bench. Furthermore, these experimental results were used to perform the first image reconstruction of a 22Na source placed in the experimental setup
Sub-millimeter nuclear medical imaging with high sensitivity in positron emission tomography using beta-gamma coincidences
We present a nuclear medical imaging technique, employing triple-gamma
trajectory intersections from beta^+ - gamma coincidences, able to reach
sub-millimeter spatial resolution in 3 dimensions with a reduced requirement of
reconstructed intersections per voxel compared to a conventional PET
reconstruction analysis. This '-PET' technique draws on specific beta^+
- decaying isotopes, simultaneously emitting an additional photon. Exploiting
the triple coincidence between the positron annihilation and the third photon,
it is possible to separate the reconstructed 'true' events from background. In
order to characterize this technique, Monte-Carlo simulations and image
reconstructions have been performed. The achievable spatial resolution has been
found to reach ca. 0.4 mm (FWHM) in each direction for the visualization of a
22Na point source. Only 40 intersections are sufficient for a reliable
sub-millimeter image reconstruction of a point source embedded in a scattering
volume of water inside a voxel volume of about 1 mm^3 ('high-resolution mode').
Moreover, starting with an injected activity of 400 MBq for ^76Br, the same
number of only about 40 reconstructed intersections are needed in case of a
larger voxel volume of 2 x 2 x 3~mm^3 ('high-sensitivity mode'). Requiring such
a low number of reconstructed events significantly reduces the required
acquisition time for image reconstruction (in the above case to about 140 s)
and thus may open up the perspective for a quasi real-time imaging.Comment: 17 pages, 5 figutes, 3 table
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