rPET Detectors Design and Data Processing

Vaquero, J.J.; Lage, Eduardo; Ricon, L; Abella, Mónica; Vicente, E.; Desco, Manuel

doi:10.1109/nssmic.2005.1596934

Cited by 36 publications

(45 citation statements)

References 23 publications

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“…To illustrate how the procedure works with real data, a multiframe acquisition of a decaying FDG phantom was performed with the rPET (SUINSA Medial Systems) [4] small animal high resolution scanner. Results for PMT XY positioning and energy spectrum are shown in Figs.…”

Section: Methodsmentioning

confidence: 99%

Improved image reconstruction in small animal PET using a priori estimates of single-pixel events

Espaa

Herraiz²,

Vicente³

et al. 2007

2007 IEEE Nuclear Science Symposium Conference Record

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Most small animal PET scanners are based on arrays of pixelated scintillators crystals. As the read-out of individual pixels would be too expensive, identification of the crystal of interaction is usually made by center of energy methods based for instance on Anger logic. This allows for a reduction in the number of signals to be acquired, but prevents the identification of multi-hit events, that is, events in that one (or several) photon produces several hits in the detector, thus blurring the correct positioning of the interaction. Improving the identification of the pixel of interaction is pursued in this work by combining all the information acquired by the scanner without increasing the number of signals. The probability for every individual event for being single or multi-pixel is estimated from the XY positioning and energy information. This probability is fed into a 3D-OSEM iterative statistical reconstruction method. Every coincidence event detected may be analyzed combining information such as deposited energy, PMT XY location, time difference between both singles of the coincidence and coincidence and single rates, if available. With the proposed method, improved peak/noise ratio and better resolution are obtained without the introduction of additional hardware.

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Section: Methodsmentioning

confidence: 99%

Improved image reconstruction in small animal PET using a priori estimates of single-pixel events

Espaa

Herraiz²,

Vicente³

et al. 2007

2007 IEEE Nuclear Science Symposium Conference Record

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“…All physical effects are simulated with respect to a water médium, which approximates the majority of biological tissues, and 18 F sources. Geometrical and detector characteristics of the small animal rPET scanner [15] were used in the Monte Cario modeling. Monte Cario simulation is also used to determine the most probable points of detection for every pair of scintillating crystals, which define the ideal LOR.…”

Section: A Monte Cario Simulationmentioning

confidence: 99%

Projector model for efficient list-mode reconstruction in PET scanners with parallel planar detectors

Ortuño

Sportelli

Guerra

et al. 2011

2011 IEEE Nuclear Science Symposium Conference Record

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Abstrcwt-We have developed a new projector model speciflcally tailored for fast list-mode tomographic reconstructions in Positrón emission tomography (PET) scanners with parallel planar detectors. The model provides an accurate estimation of the probability distribution of coincidence events defined by pairs of scintillating crystals. This distribution is parameterized with 2D elliptical Gaussian functions defined in planes perpendicular to the main axis of the tube of response (TOR). The parameters of these Gaussian functions have been obtained by fitting Monte Cario simulations that include positrón range, acolinearity of gamma rays, as well as detector attenuation and scatter effects. The proposed model has been applied efficiently to list-mode reconstruction algorithms. Evaluation with Monte Cario simulations over a rotating high resolution PET scanner indicates that this model allows to obtain better recovery to noise ratio in OSEM (ordered-subsets, expectationmaximization) reconstruction, if compared to list-mode reconstruction with symmetric circular Gaussian TOR model, and histogram-based OSEM with precalculated system matrix using Monte Cario simulated models and symmetries.

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“…Discarding the pixelated crystals at the borders of each detector is based on the assumption that real mounted systems hardly resolve the frontier pixelated scintillators (Vaquero et al 2005b).…”

Section: Scanner Geometrymentioning

confidence: 99%

Efficient methodologies for system matrix modelling in iterative image reconstruction for rotating high-resolution PET

Ortuño¹,

Kontaxakis²,

Rubio³

et al. 2010

Phys. Med. Biol.

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A fully 3D iterative image reconstruction algorithm has been developed for high-resolution PET cameras composed of pixelated scintillator crystal arrays and rotating planar detectors, based on the ordered subsets approach. The associated system matrix is precalculated with Monte Carlo methods that incorporate physical effects not included in analytical models, such as positron range effects and interaction of the incident gammas with the scintillator material. Custom Monte Carlo methodologies have been developed and optimized for modelling of system matrices for fast iterative image reconstruction adapted to specific scanner geometries, without redundant calculations. According to the methodology proposed here, only one-eighth of the voxels within two central transaxial slices need to be modelled in detail. The rest of the system matrix elements can be obtained with the aid of axial symmetries and redundancies, as well as in-plane symmetries within transaxial slices. Sparse matrix techniques for the non-zero system matrix elements are employed, allowing for fast execution of the image reconstruction process. This 3D image reconstruction scheme has been compared in terms of image quality to a 2D fast implementation of the OSEM algorithm combined with Fourier rebinning approaches. This work confirms the superiority of fully 3D OSEM in terms of spatial resolution, contrast recovery and noise reduction as compared to conventional 2D approaches based on rebinning schemes. At the same time it demonstrates that fully 3D methodologies can be efficiently applied to the image reconstruction problem for high-resolution rotational PET cameras by applying accurate pre-calculated system models and taking advantage of the system's symmetries.

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rPET Detectors Design and Data Processing

Cited by 36 publications

References 23 publications

Improved image reconstruction in small animal PET using a priori estimates of single-pixel events

Improved image reconstruction in small animal PET using a priori estimates of single-pixel events

Projector model for efficient list-mode reconstruction in PET scanners with parallel planar detectors

Efficient methodologies for system matrix modelling in iterative image reconstruction for rotating high-resolution PET

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