Patent ID: 8971991
Filing Date: 2015-03-03
Classification: A61B

Abstract:
1. 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; determining attenuation correction factors as a function of the detected gamma radiation; retracting the positron source into a shield; and detecting, with the PET detectors, gamma radiation while the positron source is retracted into the shield; wherein determining comprises subtracting data representing the gamma radiation detected while the positron source is retracted from data representing the gamma radiation detected while the target intersects the positron beam.