Abstract: 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.

Abstract: 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.

Abstract: A sensor device, in particular a PET detector, for operation in the time-varying magnetic field of a magnetic resonance tomograph. In at least one embodiment, a sensor circuit is for generating a sensor signal, as well as an induction circuit in which a compensation signal is induced. These signals are combined with one another so as to compensate for noise signals in the sensor signal, which are induced in the sensor circuit by the time-varying magnetic field. The invention furthermore concerns a method of compensating for such noise signals.

Abstract: A method is disclosed for determining radiation attenuation as a result of an object in a positron emission tomography scanner. In at least one embodiment, a phantom object is arranged in the positron emission tomography scanner during the method. First raw radiation data of the phantom object is acquired while the object is not arranged in the positron emission tomography scanner. A first image of the phantom object is calculated from the first raw radiation data. The object then is arranged in the positron emission tomography scanner (2) and preliminary radiation attenuation of the object is identified. Second raw radiation data of the phantom object is acquired while the object is arranged in the positron emission tomography scanner. A second image of the phantom object is calculated from the second raw radiation data taking into account the preliminary radiation attenuation. The radiation attenuation is determined on the basis of the first image and the second image.

Abstract: A combined PET/MRT unit is disclosed that includes a PET detector which is reduced by comparison with the prior art, and that consists, for example, of a PET detector with a polygonal arrangement of the detector elements or with a PET detector ring. The PET detector is reduced in an axial direction by comparison with the detectors of the prior art, as a result of which the costs for producing the expensive PET detectors are lowered. The reduction of the PET detector is possible because the MR measurement usually lasts longer than the PET measurement, and so a reduced PET detector can be used for the temporally sequential recording of a number of PET tomograms by mechanical displacement of the PET detector. Since the MR measurement lasts substantially longer, this mechanical displacement does not lead to a lengthening of the measuring time. The invention also relates to methods for simultaneously recording MR and PET tomograms in which the PET/MRT units according to the invention are used.

Abstract: A method is disclosed for determining a location of a subarea of an area under examination in a magnetic resonance system. The subarea is arranged at the edge of a field-of-view of the magnetic resonance system. In at least one embodiment of the method, at least one slice position is determined for an MR image in which the B0 field at the edge of the MR image satisfies a homogeneity value. For the slice position determined an MR image is acquired which contains the subarea at the edge of the field-of-view and the location of the subarea of the object under examination is determined through the location of the subarea in the MR image.

Abstract: A method is disclosed for recording and evaluating PET data recorded at the same time as magnetic resonance data using a combined magnetic resonance/PET apparatus, wherein in the context of a pulse sequence for recording the magnetic resonance data a magnetic resonance recording facility, including at least one gradient coil and at least one high-frequency coil, is activated. In at least one embodiment, the method includes recording the PET data and assigning the recorded PET data after the recording time point to at least two data groups assigned to a predetermined operating state of the magnetic resonance recording facility; for each data group, determining a measure of similarity of the PET data contained therein to the PET data as a whole and/or to PET data of at least one further data group, whereby if the measure of similarity is below a threshold value, the PET data of the data group is rejected and/or further evaluated separately.

Abstract: A method is disclosed for producing an attenuation map for a component of an MR/PET system. In at least one embodiment, the method includes ascertaining attenuation values of the component, producing a basic map from the attenuation values, ascertaining a position of the component relative to an examination volume of the MR/PET system, and producing the attenuation map by correcting the basic map using the ascertained position. This enables the actual position of the components to be taken into account in the attenuation correction.

Abstract: A patient positioning couch for a combined medical examination device is disclosed. In at least one embodiment, at least one opening is provided in a support plate of the patient positioning couch and the patient positioning couch includes at least one conveyor belt in order to move a patient on the support plate in the longitudinal direction.

Abstract: A magnetic resonance system is disclosed, with a tunnel for accommodating an object under investigation and at least one local coil array. In at least one embodiment, the local coil array is arranged in a fixed position within the tunnel and in the longitudinal direction of the magnetic resonance system, where the geometry of the local coil array, in particular its diameter, can be altered. In at least one embodiment, for the purpose of arranging the local coil array on the patient's body, at least a proportion of the coils of the local coil array is attached to a fixture the volume of which can be altered, either hydraulically or pneumatically. The fixture is subdivided into chambers, the volumes of which can be altered separately in order to realize a bending of the fixture.

Abstract: 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.

Abstract: 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(?, ?body, ?coils{p}) as a log-likelihood of measured PET data, where ? is an emitter distribution (image), ?body is a known linear attenuation coefficient (LAC) distribution of the body from MRI, ?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 ?coils is assumed, then ? 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.

Abstract: 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.

Abstract: An apparatus is disclosed for combined magnetic resonance tomography and positron emission tomography imaging which is designed for recording PET image data of a person under examination from an examination area. In at least one embodiment, the apparatus includes a scanning unit, embodied to scan a prespecified area of the person under examination and based on the scanning, to determine a contour of the person under examination for the prespecified area; and a processing unit, embodied, based on the contour determined, to carry out an absorption correction of PET data which has been recorded from the prespecified area of the person under examination. A method is also disclosed.

Abstract: A device is disclosed for superposed MRI and PET imaging and includes an MRI tube that has a first field of view along its longitudinal direction, and a multiplicity of PET detection units arranged opposite one another in pairs about the longitudinal direction. In at least one embodiment the many PET detection units define a second field of view along the longitudinal direction, and their arrangement density along the longitudinal direction is optimized such that the second field of view substantially corresponds to the first field of view.

Abstract: A method and an system are disclosed for reconstructing an emission tomography image in a combined MR (magnetic resonance) and emission tomography imaging system. In at least one embodiment, the method includes obtaining an MR image of a subject, the subject being clipped in the MR image; obtaining raw emission tomography scan data of the subject; determining a missing part of the subject clipped in the MR image; using information of the MR image and the determined missing part to obtain a final attenuation model of the subject; and reconstructing the emission tomography image using the raw data and the final attenuation model.

Abstract: A method for stabilizing the gain of a PET detection system with a cooling unit includes: determining the temperature of at least one component of the PET detection system, comparing the actual gain with a reference value, and actuating the cooling unit to influence the temperature such that the gain tends to the reference value. In at least one embodiment, the reference value is determined by determining the temperature of the at least one component during a test measurement, determining the gain during the test measurement, determining a functional dependence of the gain on the temperature, and selecting the reference value based on the gain to be stabilized. Advantageously, in at least one embodiment the gain can be kept constant using the described method in a simple manner, with the influence of the temperature of the components being taken into account.

Abstract: In a method for designing a gradient coil composed of multiple sub-coils, parameters representing the structure of the gradient coil are varied, and the variation that produces an optimized electrical field generated by the gradient coil is determined. The final design of the gradient coil embodies those parameters that produced the optimal electrical field. In a method for manufacturing a gradient coil, the gradient coil is manufactured according to the final design. A gradient coil manufactured according to the invention has a gradient conductor configuration that optimizes the electrical field generated by the gradient coil. A magnetic resonance apparatus, and a combined positron emission tomography/magnetic resonance apparatus, embodies such a gradient coil.

Abstract: 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.

Abstract: A method and a transmission system are disclosed for the transmission of wanted signals between a sensor and an evaluation unit. In order to suppress interference to the sensor signals due to external interference sources as far as possible, at least one embodiment of the inventive system has at least one signal receiver with the sensor for detecting a wanted signal and a signal processing device for conditioning the wanted signal, at whose output a mixed signal with a wanted signal component and an interference signal component from at least one interference source are present; an interference source signal input for detecting at least one interference source signal of the at least one interference source; a filter device for reconstructing the interference signal component as a function of the at least one interference source signal; and a subtractor for eliminating interference superimposed on the wanted signal.