Siemens Medical Solutions Usa, Inc.

University of Tennessee Research Foundation

Harold E Rothfuss

Dieter Ritter

Vladimir Y Panin

Charles L Melcher

Paul Schleyer

Deepak Bharkhada

Mohammadreza Teimoorisichani

Charles C Watson

Ronald Grazioso

Christian J Michel

Merry A Koschan

Andrew Philip Moor

Lars Aldon Eriksson

John W Young

Larry Byars

Florian Bauer

Lars A Erikkson

A framework for gantry alignment of a multimodality medical scanner. First image data of a non-radioactive structure is acquired by using intrinsic radiation emitted by scintillator crystals of detectors in a first gantry of the multimodality medical scanner. Second image data of the non-radioactive structure is acquired using a second gantry for another modality of the multimodality medical scanner. Image reconstruction may be performed based on the first and second image data of the non-radioactive structure to generate first and second reconstructed image volumes. A gantry alignment transformation that aligns the first and second reconstructed image volumes may then be determined.

Gantry alignment of a medical scanner

A process for operating a PET scanner includes acquiring, at a plurality of detector blocks of the PET scanner, emission data of gamma photons of a first energy level originating from annihilation events associated with radioactivity of a phantom in a field of view of the PET scanner. Based on the emission data, an emission block-pair scattering model is generated. The process includes acquiring counts of gamma photons of a second energy level originating from intrinsic background radiation of scintillator crystals of the detector blocks, without any phantom in the field of view, to provide blank scan data for the second energy level. A sinogram is generated based on the blank scan data for the second energy level. The emission block-pair scattering model is added to a scaled version of the sinogram to yield a composite model.

Method and apparatus for compensating for scattering of emission gamma photons for PET imaging

Gain values of PMTs of a PET scanner's detectors are balanced based on detected radiation from a radioactive calibration source placed in an FOV of the scanner. A time alignment is performed for scintillator crystals of the detectors based on TOF computations based on gamma photons associated with the radioactive calibration source. Baseline data is acquired using intrinsic background radiation of the scintillator crystals, without any object in the FOV. A first set of data, based on the baseline data, is stored in a memory of the scanner. After the acquisition of the baseline data, test data is acquired using intrinsic background radiation of the scintillator crystals, without any object in the FOV. A calibration status of the scanner or of an environment surrounding the scanner is automatically checked based on a comparison between the stored first set of data and a second set of data.

Method and apparatus for automatic calibration check of PET scanner using intrinsic background radiation of scintillator crystals

Crystals with improved scintillation and optical properties are achieved by codoping with a trivalent dopant and a divalent and/or a monovalent dopant. Embodiments include codoping LSO, YSO, GSO crystals and LYSO, LGSO, and LYGSO crystals. Embodiments also include codoped crystals with a controlled monovalent or divalent:trivalent dopant ratio of from about 1:1 for increased light yield to about 4:1 for faster decay time.

Use of codoping to modify the scintillation properties of inorganic scintillators doped with trivalent activators

A method and system is provided for performing medical imaging. The method and system includes at least one radiation detector to detect radiation from a subject, and an image processor which determines attenuation paths for an image point, groups substantially similar attenuation path lengths for the same image point to form a modified subset group, and processing image data using the modified subset group in order to provide a reconstructed image substantially similar to an original image.

Method and system for using a modified ordered subsets scheme for attenuation weighted reconstruction

In positron emission tomography (PET), a detector's response to scattered radiation may be different from its response to unscattered (true coincidence) photons. This difference should be accounted for during normalization and scatter correction. The disclosure shows that only a knowledge of the ratio of the scatter to trues efficiencies is necessary, however. A system and method are disclosed for measuring the scatter/trues detection efficiency ratio, as well as for applying this compensation during the scatter correction of PET emission data. PET detector efficiencies are measured in two steps, the first using a plane radiation source, and the second using a plane radiation source in combination with a scattering medium. A ratio of the scatter and trues detection efficiency is obtained from this data for each detector/crystal, and is applied as a correction factor to PET data obtained during medical imaging processes.

System and method for scatter normalization of PET images

A phoswich device for determining depth of interaction (DOI) includes a first scintillator having a first scintillation decay time characteristic, a second scintillator having a second scintillation decay time characteristic substantially equal to the first scintillation decay time, a photodetector coupled to the second scintillator, and a wavelength shifting layer coupled between the first scintillator and the second scintillator, wherein the wavelength shifting layer modifies the first scintillation decay time characteristic of the first scintillator to enable the photodetector to differentiate between the first decay time characteristic and the second decay time characteristic. The phoswich device is particularly applicable to positron emission tomography (PET) applications.

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Knoxville, TN, United States of America

Harold E Rothfuss