Speaker
Mr
Sandor Attila Kis
(PET Center, University of Debrecen, Debrecen, Hungary)
Description
In-vivo imaging of small laboratory animals is a valuable tool in the development of
new drugs. For this purpose miniPET, an easy to scale modular PET camera, has been
developed at our institutes. The detector module comprises Hamamatsu R8520 position
sensitive PMT and LSO crystal matrix (8 x 8 array of 2 x 2 x 10 mm size). The current
system has 4 modules, which makes it possible to rotate the whole detector system
around the axis of the field of view. Detector signals are processed by digital
signal processing and programmed FPGA boards. Data collection and image
reconstruction are performed using a data acquisition (DAQ) module with Ethernet
communication facility and a computer cluster of commercial PCs.
In order to allow flexibility and easy management of various configurations,
coincidence conditions were analyzed using digitized detector signals. This signal
processing philosophy allowed us to completely avoid any hardware coincidence
circuits. The architecture of DAQ system software of the miniPET is like a client-
server network, which makes it easy to scale up the instrument and ensures
flexibility in building scanners of different diameter and axial field of view (FOV)
using identical signal processing boards and DAQ software.
Performance tests were carried out to determine system parameters, such as energy
resolution, spatial resolution, sensitivity and noise equivalent count rate. Energy
resolution proved to be 19.6 % on average while spatial resolution in radial
direction ranged between 1.5 and 2.3 mm. Using a small volume source the sensitivity
of the miniPET was found to be 1.08 cps/kBq.
GEANT4 based GATE Monte Carlo software package was used to simulate PET data
analogous to those of the performance measurements. GATE was run on a Linux cluster
of 10 processors (64 bit, Xeon with 3.0 GHz) and controlled by a SUN grid engine.
The application of this special computer cluster reduced the time necessary for the
simulations by an order of magnitude. The simulated energy spectra, maximum rate of
true coincidences and sensitivity of the camera were in good agreement with the
measured parameters.
Author
Mr
Sandor Attila Kis
(PET Center, University of Debrecen, Debrecen, Hungary)
Co-authors
Dr
Balkay László
(PET Center, University of Debrecen, Debrecen, Hungary)
Dr
Bükki Tamas
(MEDISO Ltd, Budapest, Hungary)
Dr
Emri Miklós
(PET Center, University of Debrecen, Debrecen, Hungary)
Dr
Hegyesi Gyula
(Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen, Hungary)
Mr
Imrek József
(Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen, Hungary)
Dr
Kalinka Gábor
(Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen, Hungary)
Dr
Kerek András
(Royal Institute of Technology, Stockholm, Sweden)
Dr
Molnár József
(Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen, Hungary)
Dr
Opposits Gábor
(PET Center, University of Debrecen, Debrecen, Hungary)
Prof.
Trón Lajos
(PET Center, University of Debrecen, Debrecen, Hungary)
Mr
Valastyán Iván
(Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen, Hungary)
Dr
Végh József
(Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen, Hungary)
