Abstract: A method for training of a process for generating an image of an object from measurement data modified by scatter radiation. Individual sets of measured data are each made up of matrix elements. Each matrix element corresponds to an individual detector element that detects ionizing radiation. Signals measured by the individual detector elements in an energy bin are assigned as values for each matrix element. The individual sets of measured data and a template image are used as input for a procedure for determining a correction image for correcting a modification of the measured data by the scatter radiation. The preliminary image obtained using the individual sets of measured data is adjusted to the template. These steps are repeated until the deviation between the preliminary image and the template image is below a threshold. The procedure is used to generate the image of the object from the measurement data.

Abstract: A method for training of a process for generating an image of an object from measurement data modified by scatter radiation. Individual sets of measured data are each made up of matrix elements. Each matrix element corresponds to an individual detector element that detects ionizing radiation. Signals measured by the individual detector elements in an energy bin are assigned as values for each matrix element. The individual sets of measured data and a template image are used as input for a procedure for determining a correction image for correcting a modification of the measured data by the scatter radiation. The preliminary image obtained using the individual sets of measured data is adjusted to the template. These steps are repeated until the deviation between the preliminary image and the template image is below a threshold. The procedure is used to generate the image of the object from the measurement data.

Abstract: The invention relates to a system for generating an estimate of a photon attenuation map for an object on the basis of single-scattered coincidences measured in a PET scanner. The system comprises a simulation module configured to calculate single-scattered coincidences by a numerical model calculation based on a preliminary attenuation map, where the estimate of the photon attenuation map is generated by adapting at least some attenuation values. The model calculation is made on the basis of a grid covering the object, the grid comprising grid elements (61) to which attenuation values are assigned, and the simulation module is further configured to determine at least one set of adjacent grid elements (61) in order to form a merged image element (63) including the set of adjacent grid elements (61) and to assign a single attenuation value to the merged image element in the model calculation.

Abstract: A lung segmentation processor (40) is configured to classify magnetic resonance (MR) images based on noise characteristics. The MR segmenatation processor generates a lung region of interest (ROI) and detailed structure segmentation of the lung from the ROI. The MR segmentation processor performs an iterative normalization and region definition approach that captures the entire lung and the soft tissues within the lung accurately. Accuracy of the segmentation relies on artifact classification coming inherently from MR images. The MR segmentation processor (40) correlates segmented lung internal tissue pixels with the lung density to determine the attenuation coefficients based on the correlation. Lung densities are computed using MR data obtained from imaging sequences that minimize echo and acquisition times. The densities differentiate healthy tissues and lesions, which an attenuation map processor (36) uses to create localized attenuation maps for the lung.

Abstract: A combined PET/MR system includes an MR subsystem including a main field magnet (14) which generates a stationary magnetic field through an examination region (16), a gradient magnetic field system (18, 20, 22, 24) which applies magnetic field gradients across the examination region, and an RF system (26, 28, 32, 34, 36, 38) that applies RF excitation pulses to excite resonance in a subject in the examination region and receive magnetic resonance signals from the subject. A PET detector module (70) which is permanently or removably fixed in the examination region (16) to detect radiation from radiopharmaceuticals injected into the subject causes distortions in the magnetic field gradients. A plurality of probes (90) which are mounted in a fixed relationship to the PET detector module (70) measure magnetic field strength. A gradient magnetic field distortion correction system (110) determines distortions caused in the gradient magnetic fields and corrects the magnetic resonance signals accordingly.

Abstract: The invention relates to a system for generating an estimate of a photon attenuation map for an object on the basis of single-scattered coincidences measured in a PET scanner. The system comprises a simulation module configured to calculate single-scattered coincidences by a numerical model calculation based on a preliminary attenuation map, where the estimate of the photon attenuation map is generated by adapting at least some attenuation values. The model calculation is made on the basis of a grid covering the object, the grid comprising grid elements (61) to which attenuation values are assigned, and the simulation module is further configured to determine at least one set of adjacent grid elements (61) in order to form a merged image element (63) including the set of adjacent grid elements (61) and to assign a single attenuation value to the merged image element in the model calculation.

Abstract: A method for determining the position of a scintillation event in a radiation particle detector with multiple scintillator element locations which are configured to emit a burst of photons responsive to a radiation particle being absorbed at the scintillator element location and with a plurality of photosensors (5.1, 5.2, 5.3, 5.4) optically coupled to said scintillator element locations, comprising the steps of determining, for each of the photosensors (5.1, 5.2, 5.3, 5.4), a triggering probability indicative of the probability of said photosensor (5.1, 5.2, 5.3, 5.4) measuring a number of photons that exceeds a predetermined triggering threshold; measuring a photon distribution with the photosensors (5.1, 5.2, 5.3, 5.4) indicative of the number of photons incident on the individual photosensors (5.1, 5.2, 5.3, 5.

Abstract: A method for determining the position of a scintillation event in a radiation particle detector with multiple scintillator element locations which are configured to emit a burst of photons responsive to a radiation particle being absorbed at the scintillator element location and with a plurality of photosensors (5.1, 5.2, 5.3, 5.4) optically coupled to said scintillator element locations, comprising the steps of determining, for each of the photosensors (5.1, 5.2, 5.3, 5.4), a triggering probability indicative of the probability of said photosensor (5.1, 5.2, 5.3, 5.4) measuring a number of photons that exceeds a predetermined triggering threshold; measuring a photon distribution with the photosensors (5.1, 5.2, 5.3, 5.4) indicative of the number of photons incident on the individual photosensors (5.1, 5.2, 5.3, 5.

Abstract: An imaging system (36) includes a Positron Emission Tomography (PET) scanner (38) and one or more processors (52). The Positron Emission Tomography (PET) scanner (38) which generates event data including true coincident events and scatter events, the event data includes each end point of a line of response (LOR) and an energy of each end point. The one or more processors (52) are programmed to generate (72) a plurality of activity map and attenuation map pairs based on the true coincident events, and select (76) an activity map and an attenuation map from the plurality of activity and attenuation map pairs based on the scattered events.

Abstract: A lung segmentation processor (40) is configured to classify magnetic resonance (MR) images based on noise characteristics. The MR segmenatation processor generates a lung region of interest (ROI) and detailed structure segmentation of the lung from the ROI. The MR segmentation processor performs an iterative normalization and region definition approach that captures the entire lung and the soft tissues within the lung accurately. Accuracy of the segmentation relies on artifact classification coming inherently from MR images. The MR segmentation processor (40) correlates segmented lung internal tissue pixels with the lung density to determine the attenuation coefficients based on the correlation. Lung densities are computed using MR data obtained from imaging sequences that minimize echo and acquisition times. The densities differentiate healthy tissues and lesions, which an attenuation map processor (36) uses to create localized attenuation maps for the lung.

Abstract: A combined PET/MR system includes an MR subsystem including a main field magnet (14) which generates a stationary magnetic field through an examination region (16), a gradient magnetic field system (18, 20, 22, 24) which applies magnetic field gradients across the examination region, and an RF system (26, 28, 32, 34, 36, 38) that applies RF excitation pulses to excite resonance in a subject in the examination region and receive magnetic resonance signals from the subject. A PET detector module (70) which is permanently or removably fixed in the examination region (16) to detect radiation from radiopharmaceuticals injected into the subject causes distortions in the magnetic field gradients. A plurality of probes (90) which are mounted in a fixed relationship to the PET detector module (70) measure magnetic field strength. A gradient magnetic field distortion correction system (110) determines distortions caused in the gradient magnetic fields and corrects the magnetic resonance signals accordingly.

Abstract: The present invention relates to a method for determining the distribution of an imaging agent in a volume. The method comprises the acquisition of at least one three-dimensional functional image of the volume; the segmentation of the volume into one or more compartments; the representation of the three-dimensional imaging agent activity from the functional image by the product of a scaling factor and a non-affine transformation of a template imaging agent activity; the calculation of a projected imaging agent activity from the thus represented imaging agent activity on a planar surface; the acquisition of a planar image of the imaging agent activity in the volume; the registration of the projected imaging agent activity with the planar image; the comparison of the acquired planar image with the calculated projected imaging agent activity; and the modification of the representation of the three-dimensional imaging agent activity.

Abstract: The present invention relates to a method for determining the distribution of an imaging agent in a volume. The method comprises the acquisition of at least one three-dimensional functional image of the volume; the segmentation of the volume into one or more compartments; the representation of the three-dimensional imaging agent activity from the functional image by the product of a scaling factor and a non-affine transformation of a template imaging agent activity; the calculation of a projected imaging agent activity from the thus represented imaging agent activity on a planar surface; the acquisition of a planar image of the imaging agent activity in the volume; the registration of the projected imaging agent activity with the planar image; the comparison of the acquired planar image with the calculated projected imaging agent activity; and the modification of the representation of the three-dimensional imaging agent activity.

Abstract: An imaging system (36) includes a Positron Emission Tomography (PET) scanner (38) and one or more processors (52). The Positron Emission Tomography (PET) scanner (38) which generates event data including true coincident events and scatter events, the event data includes each end point of a line of response (LOR) and an energy of each end point. The one or more processors (52) are programmed to generate (72) a plurality of activity map and attenuation map pairs based on the true coincident events, and select (76) an activity map and an attenuation map from the plurality of activity and attenuation map pairs based on the scattered events.