A multifocal collimator with circularly distributed focal points for SPECT imaging

Conference · Mon Aug 01 00:00:00 EDT 1994 · IEEE Transactions on Nuclear Science (Institute of Electrical and Electronics Engineers); (United States)

OSTI ID:6838684

Guillemaud, R; Grangeat, P ^[1]

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1. CEA - Technologies Avancees, Grenoble (France)

The authors propose a new circular multifocal collimator which has multiple axial focal points distributed on a transverse circle. This distribution provides a strong focusing at the center of the detector like a cone-beam collimator, with a good sensitivity, and a weak transverse focusing at the periphery, to ensure acquisition of sufficient data, in order to prevent truncation artifacts. For a circular acquisition trajectory, each projection set of the multifocal geometry is equivalent to a virtual cone-beam projection set with a larger detector. Due to this equivalence, the authors derive a first solution for an analytical multifocal reconstruction algorithm: to rebin the projection set from multifocal to cone-beam geometry, then to use a 3D cone-beam reconstruction algorithm. The authors propose to use the Grangeat algorithm in order to deal with a large cone-beam aperture. Finally, the authors present results on simulated data for heart phantom, for a Defrise phantom and for a MTF study. The conclusion is that, from a multifocal projection set, objects are reconstructed without truncation artifacts, with a good precision at their center and with a loss of resolution at the periphery. In addition, the 3D cone-beam artifacts are reduced with the use of the Grangeat algorithm for the reconstruction step.

• OSTI ID: 6838684
• Report Number(s): CONF-931051--
• Journal Information: IEEE Transactions on Nuclear Science (Institute of Electrical and Electronics Engineers); (United States), Journal Name: IEEE Transactions on Nuclear Science (Institute of Electrical and Electronics Engineers); (United States) Vol. 41:4PT1; ISSN 0018-9499; ISSN IETNAE
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
BODY
BRAIN
CAMERAS
CENTRAL NERVOUS SYSTEM
COLLIMATORS
COMPUTERIZED TOMOGRAPHY
DESIGN
DIAGNOSTIC TECHNIQUES
EMISSION COMPUTED TOMOGRAPHY
GAMMA CAMERAS
IMAGE PROCESSING
NERVOUS SYSTEM
ORGANS
PROCESSING
RESOLUTION
SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY
SPATIAL RESOLUTION
TOMOGRAPHY