Siemens Medical Solutions Usa, Inc.

Siemens Aktiengesellschaft

Cti Pet Systems, Inc.

Christian J Michel

Larry Byars

Michael E Casey

Ralf Ladebeck

Vladimir Y Panin

Charles C Watson

Maurizio Conti

David Faul

Ronald Grazioso

A Andrew Carey

Frank Kehren

Johan Nuyts

Michel Defrise

Thorsten Speckner

Matthias J Schmand

Matthias Fenchel

James Luke Corbeil

Ziad Burbar

Volker Matschl

Peter Carl Cohen

Inki Hong

Piotr Szupryczynski

Harold E Rothfuss

Kirstin Jattke

Mark W Lenox

Danny F Newport

Rainer Paul

Girish Bal

Charles H Hayden, Jr

Merence Sibomana

Apparatuses, computer-readable mediums, and methods are provided. In one embodiment, a positron emission tomography ('PET') detector array is provided which includes a plurality of crystal elements arranged in a two-dimensional checkerboard configuration. In addition, there are empty spaces in the checkerboard configuration. In various embodiments, the empty spaces are filled with passive shielding, transmission source assemblies, biopsy instruments, surgical instruments, and/or electromagnetic sensors. In various embodiments, the crystal elements and the transmission source assemblies simultaneously perform emission/transmission acquisitions.

PET scanner with emission and transmission structures in a checkerboard configuration

The DCC (Data Consistency Condition) algorithm is used in combination with MLAA (Maximum Likelihood reconstruction of Attenuation and Activity) to generate extended attenuation correction maps for nuclear medicine imaging studies. MLAA and DCC are complementary algorithms that can be used to determine the accuracy of the mu-map based on PET data. MLAA helps to estimate the mu-values based on the biodistribution of the tracer while DCC checks if the consistency conditions are met for a given mu-map. These methods are combined to get a better estimation of the mu-values. In gated MR/PET cardiac studies, the PET data is framed into multiple gates and a series of MR based mu-maps corresponding to each gate is generated. The PET data from all gates is combined. Once the extended mu-map is generated the central region is replaced with the MR based mu-map corresponding to that particular gate. On the other hand, in dynamic PET studies the uptake in the patient's arms reaches a steady state only after the tracer distributes throughout the body. Hence, for dynamic scans, the projection data of all frames is summed and used to generate the MLAA based extended mu-map for all frames.

Generating attenuation correction maps for combined modality imaging studies and improving generated attenuation correction maps using MLAA and DCC algorithms

The present invention is a method of generating a best estimate of an image attenuation map derived from a truncated image attenuation map and PET emissions data for the object being imaged by a morphological imaging modality. The method involves a plurality of steps beginning with the recordation and processing of PET emissions data. Next, the morphological imaging modality records image data which is processed to determine an attenuation map. The attenuation map, for image modalities such as CT and MR scanning systems integrated with PET, is truncated, resulting in a truncated attenuation map image. Pixels for which attenuation data needs to be determined are identified and attenuation coefficients for these pixels are estimated and combined with the truncated attenuation map to generate a full initial attenuation map for the image, which is iteratively processed together with the PET emission data until the improvement change in the emission image reaches a defined threshold improvement level.

Completion of truncated attenuation maps using maximum likelihood estimation of attenuation and activity (MLAA)

An apparatus and method for expanding the FOV of a truncated computed tomography (CT) scan. An iterative calculation is performed on the original CT image to produce an estimate of the image. The calculated estimate of the reconstructed image includes the original image center and a estimate of the truncated portion outside the image center. The calculation uses an image mask with the image center as one boundary.

Extension of truncated CT images for use with emission tomography in multimodality medical images

Using complementary reconstruction, images from short time frames may be generated for positron emission tomography. Detected events are gathered over a long period, such as three minutes. The detected events from a short period, such as one or two seconds, are removed. Reconstruction is performed on the detected events from the long period and another reconstruction is performed on the detected events from the long period without the detected events from the short period. The second reconstruction is subtracted from the first, providing data representing the short period. The data may result in better image quality than merely reconstructing an individual frame for the short period.

Complementary PET reconstruction

A method is disclosed for at least partly determining and/or adapting an attenuation map used for attenuation correction of Positron Emission Tomography image data sets in a combined Magnetic Resonance-Positron Emission Tomography device. In at least one embodiment of the method, at least one one-dimensional magnetic resonance data set of a patient is recorded along one imaging direction; the boundaries of at least one part of the body of the patient intersected by the imaging direction are determined from the one-dimensional magnetic resonance data set; and the attenuation map is determined and/or adapted at least partly as a function of the boundaries determined.

Method for at least partly determining and/or adapting an attenuation map used for correcting attenuation of positron emission tomography image data sets in a combined magnetic resonance-positron emission tomography device

Example embodiments are directed to a method of correcting attenuation in a magnetic resonance (MR) scanner and a positron emission tomography (PET) unit. The method includes acquiring PET sinogram data of an object within a field of view of the PET unit. The method further includes producing an attenuation map based on a maximum likelihood expectation maximization (MLEM) of a parameterized model instance and the PET sinogram data.

Model based estimation of a complete or partial positron emission tomography attenuation map using maximum likelihood expectation maximization

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 method for co-registering attenuation data of MR coils in a MR/PET imaging system with PET emission data includes computing a likelihood of PET emission data on a grid in a parameter space based on an algorithm, wherein the algorithm defines L(&#x3bb;, &#x3bc;body, &#x3bc;coils{p}) as a log-likelihood of measured PET data, where &#x3bb; is an emitter distribution (image), &#x3bc;body is a known linear attenuation coefficient (LAC) distribution of the body from MRI, &#x3bc;coils is a linear attenuation coefficient map of MRI coils, and {p} is a set of parameters governing the position of each coil, wherein if &#x3bc;coils is assumed, then &#x3bb; can be reconstructed and forward projected and L can be computed. The method includes adjusting the estimated position of the MR coils to maximize the likelihood of emission data based on the computed L.

Co-registering attenuation data and emission data in combined magnetic resonance/positron emission tomography (MR/PET) imaging apparatus

A method for interpolating at least one oblique line of response ray representing nuclear image projection data through a rectangular volume and a system for using the method. The method consists of steps of interpolating all the direct rays in a rectangular volume, making a projected ray by projecting the oblique ray onto a surface of the rectangular volume, matching the projected ray to a coinciding interpolated direct ray, shearing the rectangular volume to match the projected ray, and interpolating the oblique ray in the sheared volume.

Acceleration of Joseph's method for full 3D reconstruction of nuclear medical images from projection data

Axial rebinning methods are provided for 3D time-of-flight (TOF) positron emission tomography (PET), based on 2D data rebinning. Rebinning is performed separately for each axial plane parallel to the axis of the PET scanner. An analytical approach is provided that is based on a consistency condition for TOF-PET data with a gaussian profile. A fully discrete approach is also provided, wherein each 2D TOF-PET data is calculated as a linear combination of 3D TOF-PET data having the same sinogram coordinates s and &#x3c6;.

Discrete axial re-binning of time-of-flight positron emission tomography data

A phantom and method are provided for co-registering a magnetic resonance image and a nuclear medical image. The phantom includes a first housing defining a first chamber configured to receive a magnetic resonance material upon which magnetic resonance imaging can be performed in order to produce the magnetic resonance image. The phantom also includes three or more second housings configured to be attached to the first housing, where the second housings each define a second chamber configured to receive a radioactive material upon which nuclear imaging can be performed in order to produce the nuclear medical image and upon which the magnetic imaging can be performed in order to produce the magnetic resonance image. The first chamber has a volumetric capacity that is larger than a volumetric capacity of each second chamber.

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Lenoir City, TN, United States of America

Christian J Michel