Abstract: A system and method for simultaneously acquiring PET and MR data from a subject of interest with a hybrid PET-MR scanner includes monitoring transmission times of RF and gradient coils of the MR equipment and blanking segments of the PET data stream accordingly. By excluding PET data acquired during active MR transmissions, the remaining PET data used for image reconstruction will provide improved PET image quality.

Abstract: A system and method for simultaneously acquiring PET and MR data from a subject of interest with a hybrid PET-MR scanner includes monitoring transmission times of RF and gradient coils of the MR equipment and blanking segments of the PET data stream accordingly. By excluding PET data acquired during active MR transmissions, the remaining PET data used for image reconstruction will provide improved PET image quality.

Abstract: A method for converting digitized image pixel values from a first range to a second range including (a) determining a lower limit value of a relevant portion of the first range; (b) generating an intensity histogram representative of pixel populations having specified intensities, and transforming the histogram to generate a log-transformed histogram; (c) identifying a threshold value for an upper limit of log-transformed values from the log-transformed histogram; (d) identifying a population of pixels having log-transformed values having a desired relationship to the threshold value; (e) determining an upper limit value of the relevant portion of the first range based upon the identified population; (f) converting the pixel values to converted values over the second range based upon the lower and upper limit values; and (g) transmitting information relating to an image associated with the pixel values or sources thereof between a first location and a second location remote from the first location to provide

Abstract: A method and system for processing data in a PET scanner is provided, in which a projection plane data set is converted into a two-dimensional sinogram data set. The method includes (1) selecting a subset of projection plane data from the projection plane data set, (2) performing a set of Fourier transforms, respectively, on a plurality of data rows within the subset of projection plane data to obtain a transformed data set, and (3) performing an additional set of Fourier transforms on the transformed data set to obtain intermediate results. The additional set of Fourier transforms includes a plurality of individual Fourier transforms respectively corresponding to a plurality of combinations of at least two indices.

Abstract: A PET scanner is disclosed which includes a gantry, a plurality of sets of detectors supported by the gantry, and a plurality of septa that are supported by the gantry and are constructed of material which blocks photons. The detectors in each set are disposed in a plane and positioned around a central axis that intersects the plane, and the plurality of sets of detectors are spaced along the central axis. The septa are spaced along the central axis to separate groups of two or more detector sets and block external photons from reaching the detectors. The PET scanner further includes a processor means for receiving signals produced by the detectors and indicating annihilation events occurring within a central region around the central axis, and for reconstructing an image from indicated annihilation events.

Abstract: A method to be used with an imaging system, the system including two opposed cameras mounted for rotation among a plurality of acquisition angles about an imaging axis for acquiring imaging data throughout an arc about the axis, the cameras collecting data corresponding to an acquisition angle range including a plurality of flight path angles at each acquisition angle, the system also including a processor having a processor memory.

Abstract: A method for reducing required memory in a PET acquisition system processor wherein imaging data is collected and binned in a two dimensional histogram of coincident counts, the two dimensions being a flight path angle &thgr; and a distance R from the center of an imaging area, the method including the steps of determining when data acquired at a current acquisition angle will not include data corresponding to a specific flight angle and, when this is the case, storing the data corresponding to the specific flight angle on a secondary memory storage device independent of the processor memory. The method also includes a back projection method for using the stored data to construct an image and the invention includes an apparatus for performing the method.

Abstract: An algorithm for creating a normalization data array to use in generating a three-dimensional image is described. In one embodiment, the algorithm includes performing the steps of acquiring geometric factors from a two-dimensional normalization scan, determining the three-dimensional crystal sensitivities from a three-dimensional phantom acquisition scan, and using such geometric factors and crystal sensitivities, creating a three-dimensional normalization data array.

Abstract: A positron emission tomography scanner detects coincident annihilation events occurring in the field of view of a detector array and stores them as a two-dimensional sinogram array. Prior to image reconstruction, the sinogram transmission data is filtered along both dimensions (R, .theta.) to improve image quality. Row direction (R) filtering is manually selected, and column direction (.theta.) filtering is calculated automatically as a function of the amount of row direction filtering selected and the size of the object being imaged relative to the scanner's field of view.

Abstract: A PET scanner includes an orbiting source of positron emissions which is employed in an attenuation scan to collect attenuation data used to correct image data acquired during an emission scan. In addition, the orbiting source is used in a coincidence timing calibration scan to acquire timing information employed to calibrate the scanner electronics. Time-of-flight errors in the calibration timing information due to the use of an off-center emissions source are eliminated by a sorter which separates the timing data as a function of the position of the orbiting source.