173 research outputs found
A novel method for calibration and monitoring of time synchronization of TOF-PET scanners by means of cosmic rays
All of the present methods for calibration and monitoring of TOF-PET scanner
detectors utilize radioactive isotopes such as e.g. Na or Ge,
which are placed or rotate inside the scanner. In this article we describe a
novel method based on the cosmic rays application to the PET calibration and
monitoring methods. The concept allows to overcome many of the drawbacks of the
present methods and it is well suited for newly developed TOF-PET scanners with
a large longitudinal field of view. The method enables also monitoring of the
quality of the scintillator materials and in general allows for the continuous
quality assurance of the PET detector performance.Comment: 10 pages, 7 figure
J-PET analysis framework for the prototype TOF-PET detector
Novel TOF-PET scanner solutions demand, apart from the state of the art
detectors, software for fast processing of the gathered data, monitoring of the
whole scanner and reconstruction of the PET image. In this article we present
an analysis framework for the novel STRIP-PET scanner developed by the J-PET
collaboration in the Institute of Physics of the Jagiellonian University. This
software is based on the ROOT package used in many particle physics
experiments.Comment: 4 pages, 2 figure
Novel method for hit-position reconstruction using voltage signals in plastic scintillators and its application to Positron Emission Tomography
Currently inorganic scintillator detectors are used in all commercial Time of
Flight Positron Emission Tomograph (TOF-PET) devices. The J-PET collaboration
investigates a possibility of construction of a PET scanner from plastic
scintillators which would allow for single bed imaging of the whole human body.
This paper describes a novel method of hit-position reconstruction based on
sampled signals and an example of an application of the method for a single
module with a 30 cm long plastic strip, read out on both ends by Hamamatsu
R4998 photomultipliers. The sampling scheme to generate a vector with samples
of a PET event waveform with respect to four user-defined amplitudes is
introduced. The experimental setup provides irradiation of a chosen position in
the plastic scintillator strip with an annihilation gamma quanta of energy
511~keV. The statistical test for a multivariate normal (MVN) distribution of
measured vectors at a given position is developed, and it is shown that signals
sampled at four thresholds in a voltage domain are approximately normally
distributed variables. With the presented method of a vector analysis made out
of waveform samples acquired with four thresholds, we obtain a spatial
resolution of about 1 cm and a timing resolution of about 80 p
Test of a single module of the J-PET scanner based on plastic scintillators
Time of Flight Positron Emission Tomography scanner based on plastic
scintillators is being developed at the Jagiellonian University by the J-PET
collaboration. The main challenge of the conducted research lies in the
elaboration of a method allowing application of plastic scintillators for the
detection of low energy gamma quanta. In this article we report on tests of a
single detection module built out from BC-420 plastic scintillator strip (with
dimensions of 5x19x300mm^3) read out at two ends by Hamamatsu R5320
photomultipliers. The measurements were performed using collimated beam of
annihilation quanta from the 68Ge isotope and applying the Serial Data Analyzer
(Lecroy SDA6000A) which enabled sampling of signals with 50ps intervals. The
time resolution of the prototype module was established to be better than 80ps
(sigma) for a single level discrimination. The spatial resolution of the
determination of the hit position along the strip was determined to be about
0.93cm (sigma) for the annihilation quanta. The fractional energy resolution
for the energy E deposited by the annihilation quanta via the Compton
scattering amounts to sigma(E)/E = 0.044/sqrt(E[MeV]) and corresponds to the
sigma(E)/E of 7.5% at the Compton edge.Comment: 12 pages, 6 figures; Updated with editorial corrections related to
publication in NIM
System Response Kernel Calculation for List-mode Reconstruction in Strip PET Detector
Reconstruction of the image in Positron Emission Tomographs (PET) requires
the knowledge of the system response kernel which describes the contribution of
each pixel (voxel) to each tube of response (TOR). This is especially important
in list-mode reconstruction systems, where an efficient analytical
approximation of such function is required. In this contribution, we present a
derivation of the system response kernel for a novel 2D strip PET.Comment: 10 pages, 2 figures; Presented at Symposium on applied nuclear
physics and innovative technologies, Cracow, 03-06 June 201
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