摘要:
A method is disclosed for performing a combined magnetic resonance/positron emission tomography scan of an examination object in an MR/PET system. An embodiment of the method entails acquiring first magnetic resonance data using a first readout gradient field. The first readout gradient field is chosen such that, at a location of the field of view of the magnetic resonance system, a distortion caused by a nonlinearity of the first readout gradient field and a distortion caused by a B0 field inhomogeneity substantially cancel each other out. First magnetic resonance images for planning the combined magnetic resonance/positron emission tomography session and determining an attenuation correction map for a positron emission tomography scan are determined on the basis of the first magnetic resonance data. Positron emission data and second magnetic resonance data are acquired using a second readout gradient field.
摘要:
According to an embodiment of a method, a first readout gradient field is determined in such a way that a distortion caused by a non-linearity of the first readout gradient field and a distortion caused by a B0 field inhomogeneity are essentially cancelled at a first location of a field of view of the magnetic resonance facility. Moreover, a second readout gradient field is determined in such a way that a distortion caused by a non-linearity of the second readout gradient field and a distortion caused by a B0 field inhomogeneity are essentially cancelled at a different second location of the field of view. Finally, a multiecho sequence is performed, wherein first magnetic resonance data is captured using the first readout gradient field after a 180° pulse and second magnetic resonance data is captured using the second readout gradient field after a further 180° pulse.
摘要:
A phantom, particularly for use in MR- or PET-based imaging methods, includes a hollow base body that delimits an interior volume, wherein the interior volume is subdivided into at least two volume portions by at least one separation element, and wherein the separation element or a section thereof consists of foam.
摘要:
A method is disclosed for imaging a portion of an examination object in a magnetic resonance scanner. The portion is arranged at the edge of a field of view of the magnetic resonance scanner. During at least one embodiment of the method, a gradient field is produced such that a nonlinearity in the gradient field and a B0-field inhomogeneity cancel at a predetermined point at the edge of the field of view. Magnetic resonance data, which contains the predetermined point at the edge of the field of view, is acquired with the aid of the gradient field. An image of the portion of the examination object at the predetermined point is determined from the magnetic resonance data.
摘要:
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.
摘要:
According to an embodiment of a method, a first readout gradient field is determined in such a way that a distortion caused by a non-linearity of the first readout gradient field and a distortion caused by a B0 field inhomogeneity are essentially cancelled at a first location of a field of view of the magnetic resonance facility. Moreover, a second readout gradient field is determined in such a way that a distortion caused by a non-linearity of the second readout gradient field and a distortion caused by a B0 field inhomogeneity are essentially cancelled at a different second location of the field of view. Finally, a multiecho sequence is performed, wherein first magnetic resonance data is captured using the first readout gradient field after a 180° pulse and second magnetic resonance data is captured using the second readout gradient field after a further 180° pulse.
摘要:
A phantom, particularly for use in MR- or PET-based imaging methods, includes a hollow base body that delimits an interior volume, wherein the interior volume is subdivided into at least two volume portions by at least one separation element, and wherein the separation element or a section thereof consists of foam.
摘要:
A method and a facility are disclosed for imaging a PET spectrum with a PET detector, especially a PE-MR tomograph, and evaluation of the PET spectrum. To improve the correction of the base line in PET and thereby to improve the energy resolution for the PET images, at least one embodiment of the facility includes: a sampling facility for sampling the output signal of the PET detector at a predetermined sampling rate; an edge discriminator for recognizing at least one edge of a PET pulse; a background signal discriminator for estimating a background signal under the PET pulse; and an integrator device for determining the energy of the PET pulse in the PET spectrum above of the background signal from the sample values of the sampling facility.
摘要:
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.
摘要:
A method for determining attenuation values of an object is disclosed. In at least one embodiment, the method includes stationary positioning of the object, irradiation of the object via a radiation source, measurement of the object's transmission data via a detection system, determination of at least one geometric property of the object on the basis of the transmission data, and assignment of attenuation values to the object on the basis of the geometric property.