Siemens Medical Solutions Usa, Inc.

Siemens Aktiengesellschaft

Other

Cti Pet Systems, Inc.

Charles C Watson

Michael E Casey

Ralf Ladebeck

Bernard Bendriem

Christian J Michel

William F Jones

John Thomas Pawlak

David Faul

Elmar Rummert

Jun Bao

Ronald Nutt

Ralph Ladebeck

Stephen David Miller

Matthias Fenchel

Vladimir Y Panin

James J Hamill

Richard L Clark

J Clifton Moyers

Harold E Rothfuss

Jicun Hu

Larry Byars

David Navone

Charles H Hayden, Jr

Chuanyu Zhou

Johannes Pauli

Howard Hoyt

Diane Kewley-Port

Carl V Miller

Methods for simulating, and correcting for, doubly scattered annihilation gamma-ray photons in both time-of-flight (TOF) and non-TOF positron emission tomography scan data are disclosed.

Double scatter simulation for improved reconstruction of positron emission tomography data

In beta emission imaging, magnetic lensing allows a lower resolution detector to detect the spatial distribution of emissions at a higher resolution. The sample is placed in a magnetic field with field lines at a given density, and the detector is placed away from the sample where the magnet field lines diverge, resulting in a lesser density. Since the beta emissions travel along the field lines, the divergence of the field lines from the sample to the detector result in lensing or magnification. Using positron attenuation tomography to detect annihilation in the detector allows for correction due to self-absorption by the sample. The correction and lensing are used together or may be used independently.

Magnetic lensing for beta emission imaging

Positron attenuation is estimated. Positrons attenuate differently than x-rays, so measuring positron attenuation may assist in diagnosis or material study. To measure positron attenuation, a positron beam is formed using a magnetic field. The annihilations along the beam within an object are measured using positron emission tomography. The rate of annihilation and integration of the rate of annihilation along the positron beam may be used to determine positron attenuation.

Positron attenuation tomography

A phantom for co-registering a magnetic resonance image and a nuclear medical image is disclosed. The phantom includes a longitudinal member having a first end cap and a second end cap and a chamber contained within the longitudinal member. The chamber contains a fluid for producing a first image using a first imaging modality. The phantom further includes a first rod disposed within the chamber of the longitudinal member. The first rod contains a radioactive substance for producing a second image using a second imaging modality.

Alignment phantom for MR/PET system

Supplemental transmission information is used in PET imaging with a hybrid PET/MR system. The magnetic field of the MR portion is used to direct positrons from one or more sources outside or inside the PET field of view to within the PET field of view. An oblique target or targets create an annihilation source within the PET field of view from the positron beam or beams. The resulting radiation may be detected. In combination with measurements made with the sources shielded (e.g., no positron beam-target annihilation sources), the attenuation or other characteristics outside the uniform region of the MR field of view is determined, such as calculating attenuation of arms of a patient for attenuation correction in PET imaging.

Supplemental transmission information for attenuation correction in positron emission tomography imaging

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

A method and a system are disclosed for calibrating an emission tomography subsystem in a combined MR (magnetic resonance) and emission tomography imaging system. In at least one embodiment, the method includes providing a phantom that is configured such that the phantom is visible on a MR image, providing an attenuation map of the phantom, wherein the attenuation map includes an attenuation of the phantom, obtaining the MR image of the phantom, obtaining a position of the phantom from the MR image, mapping the attenuation map with the position of the phantom, and calibrating the emission tomography subsystem using the attenuation map mapped with the position of the phantom.

Calibration of an emission tomography subsystem

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 improving clinical data quality in Positron Emission Tomography (PET). The method provides for the processing of PET data to accurately and efficiently determine a data signal-to-noise (SNR) corresponding to each individual clinical patient scan, as a function of a singles rate in a PET scanner. The method relates an injected dose to the singles rate to determine SNR(D), and provides an accurate estimate of quantity proportional to SNR, similar in function to SNR(D). Knowledge of SNR(D) permits determination of peak SNR, optimal dose, SNR deficit, dose deficit, and differential dose benefit. The patient dose is fractionated, with a small calibration dose given initially. After a short uptake, the patient is pre-scanned to determine T, S, and R. An optimal dose is then determined and the remainder is injected.

Method for improving clinical data quality in positron emission tomography

A method for reducing randoms variance in a Positron Emission Tomograph (PET) or Positron Emission Tomograph combined with another Medical Imaging device is disclosed. An average of an element of the randoms event (delayeds) sinogram may be estimated by dividing fan sums in delayeds sinogram by singles rates taken from headers of the delayeds sinogram.

Hybrid method for randoms variance reduction

A method for correcting PET emission data for prompt gamma emission background components present in non-pure positron-emitting isotopes uses a two component fit of modeled scatter and modeled prompt gamma emission in the area of scatter tails in a normalized emission sinogram. The method allows a PET scan using non-standard PET isotopes to be quantitative and thus more clinically useful.

Growing community of inventors

Knoxville, TN, United States of America

Charles C Watson