Supplemental Transmission Information for Attenuation Correction in Positron Emission Tomography Imaging
AssigneeSiemens Medical Solutions USA, Inc.
InventorCharles C. Watson
Life of this patent
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Abstract
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.
Claims20
A method for attenuation correction for positron emission tomography (PET) in a combined PET and magnetic resonance (MR) imaging system, the method comprising:
- generating, with a positron source in a magnetic field, a positron beam extending into a field of view of PET detectors of the combined PET and MR system;
- intersecting the positron beam with a target within the field of view of the PET detectors;
- detecting, with the PET detectors, gamma radiation resulting from the intersection of the positron beam with the target;
- and
- determining attenuation correction factors as a function of the detected gamma radiation.
A hybrid magnetic resonance (MR) and positron emission tomography (PET) system comprising:
- a MR magnet for generating a magnetic field in a bore;
- PET detectors within the magnetic field;
- a plurality of positron sources spaced apart within the magnetic field;
- and
- a plurality of targets positionable obliquely to positron beams generated by the positron sources in the magnetic field.
A method for determining a characteristic of tissue or other materials for positron emission tomography (PET) in a region where an MR image is distorted, truncated, or otherwise inaccurately represents attenuating tissues or materials within the PET FOV, the method comprising:
- producing a transmission line source within a PET field of view in the region of the distorted, truncated, or inaccurate magnetic field with a positron beam guided by the distorted magnetic field;
- and
- determining the characteristic of the tissue in the region as a function of emissions generated by the transmission line source.
Dependencies are inferred from the claim text.