Abstract: Described herein is an approach for analyzing perfusion characteristics of heterogeneous tissues in 4D data set (i.e., a time series of contrast enhanced 3D volumes) in which spatially entangled tissue components are separated into individual tissue components and perfusion maps for the individual tissue components are generated and visually presented. In one instance, the approach includes obtaining the 4D data set in electronic format, generating a different time activity curve point for each of the different tissue components for each voxel being evaluated for each time frame being evaluated, and generating a signal indicative of a different parameter map for each of the different tissue components based at least on the time activity curves. Optionally, relations between parameters of the different components are determined and presented in relation maps.

Abstract: A gantry control panel for positioning a patient with respect to a gantry includes at least one contour of at least a portion of a figure representing a patient to be positioned with respect to a gantry, and at least one control button positioned in association with the at least one contour or as part of the at least one contour. The at least one control button controls positioning of the patient with respect to the gantry.

Abstract: The present disclosure discloses a spiral CT system and a reconstruction method thereof. In some embodiments, it is proposed that data missing due to a large pitch is compensated by weighting the complementary projection data of the projection data obtained using the spiral CT system. After the data is complemented, the projection data is rebinned as cone parallel beam data, cone-angle cosine weighting and one-dimensional filtering are implemented on the rebinned data, and parallel beam back projection is finally implemented on the filtered data, to obtain the reconstructed images. In some embodiments, with the above method, the speed of the belt can be increased by more than one time in a case that the existing area of the detectors and the existing speed of the slip ring are unchanged, thereby improving the pass rate of the luggage and maintaining the quality of the reconstructed images unchanged.

Abstract: Systems, devices and methods of reconstructing an image from a positron emission tomography scan that may include detecting a plurality of photons selected from scattered photons and unscattered photons by a plurality of detectors, identifying a time interval for each of the plurality of photons by a processing device, matching each of the plurality of photons into a plurality of pairs of coincident photons based upon a substantially simultaneous time interval identified by the processing device, measuring an energy produced by each of the plurality of photons by the plurality of detectors, determining a scattering angle for each pair of coincident photons from an annihilation point relative to the position of the plurality of detectors by the processing device based on the energy produced and reconstructing an image using a reconstruction algorithm, wherein the reconstruction algorithm uses the scattering angle of each pair of coincident photons.

Abstract: A diagnostic device for morpho-functional investigations includes a plurality of measuring elements (5, 6, 7, 8, 9) of the scintillation type, positioned around a receiving area (3) for performing relative three-dimensional investigations on different parts of a patient (P) positioned in the receiving area, the first ring (5) having an internal diameter (d) less than the internal diameter (D) of the second ring (6).

Abstract: An imaging system is provided including a plurality of detector units and a controller. The plurality of detector units are distributed about a bore. The bore is configured to accept an object to be imaged, and the detector units are radially articulable within the bore. The controller is operably coupled to the plurality of detector units and configured to control the positioning of the detector units. The controller is configured to position an external group of the plurality of detector units at a predetermined intermediate position corresponding to a ring having a radius corresponding to a total number of detector units, and to position an internal group of the plurality of detector units radially inside the ring.

Abstract: A medical imaging system is provided that includes a first gantry having a plurality of first detector units coupled within a bore of the first gantry such that the first detector units form a first field of view (FOV) of the first gantry. The first detector units are configured to acquire SPECT data. Further, the medical imaging system includes a second gantry having a plurality of second detector units coupled within a bore of the second gantry such that the second detector units form a second FOV of the second gantry. The second detector units are configured to acquire x-ray CT data. The second gantry is positioned adjacent to the first gantry. The medical imaging system also includes a patient table movable through the bores and a controller unit configured to control a rotation speed of the first detector units and the second detector units around the examination axis.

Abstract: The technical solution as put forth by the present invention comprises a computer imaging system and detectors arranged around the detected object for collecting gamma photons from positron annihilation events. The key is a multi-pinhole plate placed between the detected object and the detectors, and the multi-pinhole plate can be a coded aperture mask coded by using a function h(x,y). The gamma photons generated from the annihilation events inside the detected object are absorbed by the detector after being collimated by the multi-pinhole plate. Accordingly, after the detectors have performed detection at multiple angles, the result is transmitted to the computer imaging system, and quasi three-dimensional images are generated after being processed by the disclosed algorithm. Furthermore, the quasi three-dimensional images generate secondary projection images and, after adjustment, generate sinograms, and finally three-dimensional tomographic images are reconstructed from multiple sinograms.

Abstract: The present invention discloses a method for performing CT imaging on a region of interest of an object under examination, comprising: acquiring the CT projection data of the region of interest; acquiring the CT projection data of region B; selecting a group of PI line segments covering the region of interest, and calculating the reconstruction image value for each PI line segment in the group; and combining the reconstruction image values in all the PI line segments to obtain the image of the region of interest. The present invention further discloses a CT imaging device using this method and a data processor therein. Since the 2D/3D slice image of the region of interest can be exactly reconstructed and obtained as long as the X-ray beam covers the region of interest and the region B, it is possible to use a small-sized detector to perform CT imaging on the region of interest at any position of a large-sized object, which reduces to a great extent the radiation dose of the X-ray during the CT scanning.

Abstract: Apparatus and methods comprising a positron emission tomography detector having a first rectangular cross-section crystal block positioned between a first pentagonal cross-section crystal block and a second pentagonal cross-section crystal block.

Abstract: A method of determining the degree of uptake of a PET maker in an individual candidate PET scan, the method including the steps of: (a) calculating a series of representative matched controlled PET and MRI templates for a series of controlled sample scans of individuals; (b) computing a series of brain surfaces from the matched templates; (c) aligning the individual candidate PET scan with the candidate templates; (d) aligning the candidate PET images with the series of brain surfaces; (e) selecting a predetermined (M) best candidate templates for each surface location based on a similarity measure between the candidate PET values and the corresponding controlled PET scans; (f) computing M weights for each surface location, utilizing a corresponding MRI tissue map; (g) utilizing the M weights to combine a corresponding M template tissue indicators from corresponding MRI templates into an average brain surface indicator.

Abstract: A PET apparatus and a timing correction method of this invention select two target gamma-ray detectors which count coincidences, select a reference detector which is one detector out of the two selected gamma-ray detectors, select a gamma-ray detector different from the other, opposite detector, and when repeating the selection, make a time lag histogram concerning two gamma-ray detectors selected in the past a reference, and correct a time lag histogram concerning gamma-ray detectors selected this time based on the reference. By repeating an operation to make the corrected time lag histogram concerning the two gamma-ray detectors a new reference, an optimal time lag histogram can be obtained without repeating many measurements and computations.

Abstract: In Positron Emission Tomography, a time window (260) and an energy window (225) are dynamically adjusted, based on an attenuation map, count rate, clinical application, discrimination tailoring, and/or offline discrimination tailoring. Detected radiation events are filtered using the dynamically adjusted energy and time windows into scattered events, random events, and true events. The true events are input to image reconstruction, correction, and error analysis.

Abstract: Systems and methods are disclosed for identifying image acquisition parameters. One method includes receiving a patient data set including one or more reconstructions, one or more preliminary scans or patient information, and one or more acquisition parameters; computing one or more patient characteristics based on one or both of one or more preliminary scans and the patient information; computing one or more image characteristics associated with the one or more reconstructions; grouping the patient data set with one or more other patient data sets using the one or more patient characteristics; and identifying one or more image acquisition parameters suitable for the patient data set using the one or more image characteristics, the grouping of the patient data set with one or more other patient data sets, or a combination thereof.

Abstract: A positron emission tomography (PET) scanner, including a first detector portion arranged circumferentially around a patient pallet, the first detector portion having a predetermined axial extent and transaxially subtending less than 360 degrees with respect to a central axis of the scanner defined by the first detector portion, wherein the first detector portion includes a plurality of first detector elements; and a second detector portion arranged separately from and opposing the first detector section, the second detector portion including a plurality of second detector elements, the second detector elements being of a different type than the first detector elements, wherein each of the first detector elements includes photomultiplier tubes (PMTs); and each of the second detector elements includes photosensors of a different type from the PMTs of the first detector elements.

Abstract: A pixel circuit includes a single photon avalanche diode (SPAD) and a measurement circuit including a capacitance. The circuit is operable to discharge a known portion of the charge on the capacitance upon each detection of a SPAD event within a time period, such that the charge remaining on the capacitance at the end of the time period corresponds to the number of SPAD events detected within the time period. A time resolved imaging apparatus includes an array of such pixel circuits. A method of counting photon detection includes sensing photons with a SPAD device and discharging a known portion of the charge on a capacitance upon each detection of a SPAD event within a time period.

Abstract: A method and apparatus for reducing random events in positron emission tomography (PET) list mode data, the method including the steps of obtaining, for a PET scanner having a given reconstruction field of view (FOV), time-of-flight (TOF) prompt list-mode count data that includes TOF information, the TOF prompt list-mode count data including a plurality of entries; and filtering the obtained prompt list-mode count data by removing those entries in the obtained prompt list-mode count data that represent emission points lying outside a tangential TOF mask to obtain filtered list-mode count data.

Abstract: Methods and systems for processing data for medical imaging are disclosed. The method includes obtaining a set of continuous bed motion (CBM) data from a first imaging modality. The set of CBM data includes a plurality of gating signals. A CBM normalization matrix is calculated. The CBM normalization matrix calculation includes the plurality of gating signals. An image is reconstructed from the CBM data and the CBM normalization matrix. The first imaging modality can be a PET imaging device.

Abstract: A system and method is provided for imaging a region of interest (“ROI”) including a breast having received a reduced dose of radionuclide using an imaging system including at least two gamma detectors. The acquired imaging data is analyzed respect to an energy characteristic and divided into subsets of data based on the analysis. A plurality of images is generated using the subsets of data, wherein the plurality of images include a primary image corresponding to subsets of data having energy including the energy characteristic and multiple secondary images corresponding to subsets of data having energy not including the energy characteristic. Each of the plurality of images is processed using energy information associated with each of the plurality of images and the processed plurality of images is combined to form a composite image of the ROI.

Abstract: A detector maintains thermal stability between two different operating modes. The detector includes at least one controller which sets the detection sensitivity of the detector to a level disabling the detection of gamma photons. The controller further controls a heat generator to maintain the temperature of the detector at a predetermined temperature. The predetermined temperature is the steady state temperature of the detector when the detection sensitivity of the detector is set to a level enabling the detection of gamma photons. A method for maintaining thermal stability of a detector between two different operating modes is also provided. Approaches are also disclosed for normalize acquired imaging data during image reconstruction using dark current-dependent normalization factors.

Abstract: The invention provides a system for reusing triple event data of PET. The system includes an input unit, a determining unit, and an output unit. A plurality of data is generated by an object undergoing the PET scan, and the input unit is used to receive the data. The determining unit is used to determine the data and pick out data corresponding to triple event from the data and according to a formula to pick out data corresponding to coincident event from the data corresponding to triple event. In other words, the determining unit picks out data corresponding to true triple event from the data to reuse and analyze the data corresponding to coincident event and further to generate an analysis result. The output unit is used to output the analysis result.

Abstract: Scintillator and semiconductor based materials incorporating radioactive materials and their method of manufacture are disclosed. The disclosed materials are integrated with energy conversion devices and structures to provide nuclear battery assemblies which exhibit increased power densities.

Abstract: A system and method for producing MR images in which bone and soft tissue are identified. The method includes applying a pulse sequence that includes a first stage configured to acquire a radially-encoded FID and radially-encoded echoes performed after a non-selective RF excitation pulse and before a second stage, which is configured to acquire additional echoes. The radially-encoded MR data acquired during the first stage is substantially representative of bone, while the MR data acquired during the second stage is substantially representative of soft tissues. MR images in which bone and soft tissue are identified are reconstructed from these MR data sets.

Abstract: A positron emission tomography (PET) scanner, including a first detector portion arranged circumferentially around a patient pallet, the first detector portion having a predetermined axial extent and transaxially subtending more than 180 degrees, but less than 360 degrees with respect to a central axis of the scanner defined by the first detector portion; and a second detector portion arranged separately from and opposing the first detector section, the second detector portion having a radius of curvature smaller than a radius of curvature of the first detector portion, wherein the second detector portion transaxially subtends less than 180 degrees with respect to the central axis of the scanner.

Abstract: Methods and systems for a light sensor for a gamma ray detector of a positron emission tomography (PET) imaging system is provided. The methods and systems include a plurality of micro-cells forming a micro-cell array. The methods and systems include a set of signal traces electrically coupling the plurality of micro-cells to the pin-out. The set of signal traces are configured to define a non-orthogonal signal path from each of the micro-cells to the pin-out.

Abstract: In a coincidence determination of a PET device, the PET device uses a scintillator of radioactive isotope containing background noise due to intrinsic radioactivity as a radiation detector. The PET device counts a pair of annihilation radiations that is assumed to occur from a same nuclide. The annihilation radiations are detected within a predetermined coincidence time window by a plurality of radiation detectors. The method includes determining a coincidence with a wide energy window that allows detecting the background noise due to intrinsic radioactivity as multiple coincidences; removing the multiple coincidences; and using an energy window narrower than the wide energy window to limit a coincidence event to a coincidence event in a photopeak from a positron nuclide only.

Abstract: An optical source capable of enhanced scaling of pulse energy and brightness utilizes an ensemble of single-aperture fiber lasers as pump sources, with each such fiber laser operating at acceptable pulse energy levels. Beam combining involves stimulated Raman scattering using a Stokes' shifted seed beam, the latter of which is optimized in terms of its temporal and spectral properties. Beams from fiber lasers can thus be combined to attain pulses with peak energies in excess of the fiber laser self-focusing limit of 4 MW while retaining the advantages of a fiber laser system of high average power with good beam quality.

Abstract: In a method to operate an image-generating medical modality in order to avoid harm to a patient caused by an electromagnetic field, an adjustment process is implemented in which the electromagnetic field is radiated by the modality and preliminary image data are acquired using the electromagnetic field; and a clearance between the patient and a wall of the modality is determined from the image. The determined clearance forms the basis of a check process to determine an adaptation of the electromagnetic field for a diagnostic examination of the patient that follows. During the diagnostic examination, that also includes radiation of the electromagnetic field, movement monitoring of the patient takes place and the adjustment process is restarted as soon as a movement of the patient is registered.

Abstract: A neutron detector circuit for a neutron detector is disclosed that includes a scintillator having a plurality of wavelength shifting optical fibers. A first detection circuit is connected with a first PMT output that is configured to generate a first detection circuit output in response to a first neutron event. A second detection circuit is connected with a second PMT output that is configured to generate a second detection circuit output in response to a second neutron event. A coincidence detection circuit is included that has inputs connected with the first and second detection circuit outputs that is configured to generate a neutron event count output pulse in response to coincident signals being received by the coincidence detection circuit from the first and second detection circuit outputs.

Abstract: A pixellated detector with an enhanced structure enables easy pixel identification even with high light output at crystal edges. A half-pixel shift between scintillator crystals (50) and detector pixels (12) enables the identification of a crystal (50) from four detector pixels (12) instead of nine pixels in case of optical crosstalk. Glass plates without any mechanical structuring may be used as a common substrate (60) for detectors and scintillators.

Abstract: A method for reducing noise in a medical diagnostic image includes acquiring an initial three-dimensional (3D) volume of projection data, generating a projection space noise estimate using the 3D volume of projection data, generating an initial 3D volume of image data using the 3D volume of projection data, generating an image space noise estimate using the 3D volume of image data, generating a noise projection estimate using the projection space noise estimate and the image space noise estimate, and reconstructing an image using the generated noise estimate. A system and non-transitory computer readable medium are also described.

Abstract: A system and method are provided for determining the onset of gamma interactions for positron emission tomography (PET) imaging more accurately than with existing techniques. The timing of a sequence of primary trigger events is obtained and used to determine a weighted combination, which mixes the timing information from the various primary trigger events to compute an overall event trigger timing with improved time resolution. Numerical simulations demonstrate that the invention improves time resolution by approximately 10% over state-of-the-art methods. This improved time resolution directly benefits the imaging performance of the PET scanner, especially in time-of-flight (TOF) mode, where a high time resolution directly translates to a reduction in image noise at the same dose—or, alternatively, a reduction of dose to the patient or scan time for the same image quality.

Abstract: Even when areas delimited by delimiting points are not appropriate and area division has failed, success or failure of area division in such areas can easily be determined by applying a map determination condition in the map determining step (step S50). And since the areas delimited by the delimiting points are changed and the map determining step (step S50), including also steps S22 and S23 and steps S30 and S40, is repeated until the map determination condition is satisfied, the areas satisfying the map determination condition are determined appropriate and the area division in such areas can be carried out accurately. Even when there is distortion, a two-dimensional position map can be corrected accurately.

Abstract: According to one embodiment, a radiation therapy apparatus includes a radiation irradiation device, a detector included in a PET scanner, a control unit, and a PET image reconstruction unit. The radiation irradiation device emits a therapeutic radiation. The detector counts light derived from gamma rays, and is provided with a gap portion through which the therapeutic radiation passes on a plane of rotation about the body axis of a subject. The control unit controls the radiation irradiation device and the detector so as to rotate in synchronization with each other in a state capable of emitting the therapeutic radiation to the gap portion. The PET image reconstruction unit reconstructs a PET image based on position information at the time of counting of the detector that nearly coincidentally counts pair annihilation gamma rays in a state where the control unit performs rotation control.

Abstract: According to one embodiment, a nuclear medicine imaging apparatus includes a detector, a calibrator, and an image reconstruction unit. The detector includes a plurality of detector modules, each counting light originating from a gamma ray. The calibrator unit calibrates time information of all of the plurality of detector modules by calibrating time information for determining each detection time of a pair of detector modules based on each detection time of the pair of the detector modules which approximately coincidentally count annihilation gamma rays and a distance between the pair of detector modules in a state in which a point radiation source including a positron emitting nuclide is installed in each position near a plurality of predetermined detector modules. The image reconstruction unit reconstructs a nuclear medicine image using a time difference between detection times of annihilation gamma rays corrected based on time information calibrated by the calibrator.

Abstract: In an open PET device including a plurality of detector rings that are arranged apart in the direction of the body axis of a subject and having a physical open field of view area, at least one of the detector rings or another imaging device arranged in parallel is configured to be movable by simple device moving means in order to change the configuration of the PET device. This improves the versatility of the open PET device for easier introduction to facilities.

Abstract: A smart sensor for maintaining constant gain in a photosensor despite temperature is disclosed. The smart sensor receives temperature data from a temperature sensor, then compares the temperature data to a lookup table of temperatures corresponding to voltages which, when applied to a photosensor at that temperature, will produce a desired gain. The smart sensor then applies the voltage from the lookup table to the photosensor, to yield a desired gain from the photosensor. The smart sensor is particularly applicable to SiPMs used in PET/MRI imaging systems.

Abstract: A helmet-type PET device includes a helmet portion (hemispherical detector) and an added portion (jaw portion detector, an ear portion detector, or a neck portion detector). The helmet portion includes a PET detector so as to cover a parietal region of an examination target. The added portion is positioned to dispose a PET detector at a part other than the parietal region of the examination target. PET measurement is performed using both an output from the PET detector at the helmet portion and an output from the PET detector at the added portion.

Abstract: The present invention relates to a positron tomography imaging apparatus for a multiphase flow in an oil pipeline, which apparatus utilizes positron and electron annihilation generating a pair of coincidence gamma-rays of 511 keV energy as tomography imaging means and provides an on-line tomography imaging function for metering a multiphase flow in an oil pipeline of an oil field. The apparatus comprises a plurality of sets of parallel high-precision gamma-ray detector arrays with a particular space structure arrangement, a positron radioactive source and a shield, and can acquire a phase fraction of such multiphase flow mixture as oil, gas and water under a condition of a single radioactive source by combining an image processing function. The design of a plurality of sets of high-precision detector arrays also greatly improves accuracy of a multiphase flow metering and its applicability in multiphase flows of different flow patterns.

Abstract: A method for attenuation correction of a phantom image in a PET imaging system includes obtaining raw scan data of a scanned phantom, a non attenuation corrected template image of a stock phantom of like type to the scanned phantom, and an attenuation map of the stock phantom. The method further includes generating a non-attenuation corrected raw image of the scanned phantom based on the raw scan data, registering the template image and attenuation map to the raw image through a rigid image transform, and applying the registered attenuation map to the raw scan data to enable reconstruction of an attenuation corrected final image.

Abstract: A method for extracting photon depth of interaction information in a positron emission tomography system is provided. A pulse is detected in a photodetector. A height of the pulse is measured. A determination of whether the pulse height is within a set range is made. Photon depth of interaction is extracted from the pulse height. An energy of interaction is calculated from the pulse height and calibration data. The extracted photon depth and calculated energy spectrum are used in image reconstruction.

Abstract: A detector arrangement of an imaging system detector detecting ionizing radiation includes a detector carrier, a plurality of detector modules attached to the detector carrier, and a collimator disposed in the radiation direction in front of the detector modules which are disposed on the incident radiation measurement side. In at least one embodiment, at least one air gap is included for conveying cooling air is disposed between the collimator and the measurement sensors of the detector modules. A method is also disclosed for cooling a detector arrangement of a detector rotating around a system axis with a plurality of measurement sensors disposed next to one another and a collimator arranged in the radiation direction in front of the measurement sensors, wherein cooling air is conveyed in or against the system axis direction between the collimator and the measurement sensors which directly cools the surface of the measurement sensors.

Abstract: When calibrating a positron emission tomography (PET) scanner, a radioactive calibration phantom is scanned over a period of several half lives to acquire a plurality of frames of scan data. Interlaced timing windows are employed to facilitate acquiring coincidence data for a plurality of coincidence timing windows and energy windows during a single calibration scan. Coincident events are binned according to each of a plurality of selected coincidence windows, and the PET scanner is calibrated for each of the plurality of coincidence timing windows using data acquired from the single calibration scan.

Abstract: Timing pick-off is provided in time-of-flight positron emission using digital output photo sensors (e.g., SPAD or dSiPM). The timing-to-digital converter (TDC) is replaced for timing detection with a mixed analog and digital timing pick-off (MTP) where a processor determines the timing from an output of the MTP. The digital SPAD or dSiPM output is summed into an analog waveform, allowing for triggering based on signal statistics or other than at a particular number of discrete detections. The trigger is used by the processor to extrapolate the time of occurrence without an integrated TDC.

Abstract: When calculating a system matrix (detection probability), adjustment is made by fitting a point spread function (PSF) expressed by a Gauss function to a profile of count values of radiation with respect to a distance from a point source which emits radiation of the same type as the positron-emitting drug, and a distance range of the above PSF is adjusted for each layer in a depth direction of gamma-ray detectors indicating an incident direction in which the radiation strikes. By calculating the system matrix (detection probability) after adjusting the distance range of the function for each layer, improvement can be made in image quality of a reconstructed image.

Abstract: An optical device (102) configured for concentrating light towards a target element (104) is provided. The optical device (102) comprises a waveguide element (106) configured for guiding light towards the target element (104), and a wavelength conversion element (108) configured for converting incoming light of a first wavelength into outgoing light of a second wavelength. The wavelength conversion element (108) extends adjacent to the waveguide element (106). An interface (114) between the waveguide element (106) and the wavelength conversion element (108) comprises a surface roughness. The latter may provide for an in creased efficiency and low manufacturing costs of the optical device (102).

Abstract: An integrated magnetic resonance (MR) and positron emission tomography (PET) system includes an MR scanner including a magnet that defines an opening in which a subject is positioned, a set of PET detectors disposed about the opening, a plurality of data processing units each electrically connected with a respective one or more of the PET detectors of the set of PET detectors, and a plurality of power supply modules, each power supply module being operable to generate a DC power supply for different groups of one or more of the data processing units. Each power supply module is discrete from the other power supply modules.

Abstract: A printed circuit board (PCB) assembly of a data processing unit for an integrated magnetic resonance (MR) and positron emission tomography (PET) system, the PCB assembly includes a plurality of PCB layers disposed in a stacked arrangement, first and second PET signal processing circuits carried by a first layer of the plurality of PCB layers, first and second ground plane structures carried by a second layer of the plurality of PCB layers and configured relative to the first and second PET signal processing circuits, respectively, and a ground partition that separates the first PET signal processing circuit from the second PET signal processing circuit on the first layer. The ground partition extends through the first layer to provide electromagnetic interference (EMI) shielding between the first and second PET signal processing circuits.

Abstract: The subject matters of the invention is a matrix device and method for determining the place and time of the gamma quanta interaction as well as the use of the device for determining the place and time of the gamma quanta interaction in positron emission tomography.

Abstract: The present invention provides systems, methods, and devices for improved computed tomography (CT) and, more specifically, to methods for improved single photon computed tomography (SPECT) using exact and stable region of interest (ROI) reconstructions. This technology can be extended across all tomographic modalities. Embodiments provide a method and a system for reconstructing an image from projection data provided by a single photon emission computed tomography scanner comprising: identifying a region of interest in an object; defining an attenuation coefficient and object boundary; computing the generalized Hilbert transform of the data through the defined region of interest and a known subregion; and reconstructing the image with improved temporal resolution at lower radiation doses, wherein the reconstructing comprises performing a reconstruction method that yields an exact and stable reconstruction.