Patent classifications
G01T1/1647
Collimators for medical imaging systems and image reconstruction methods thereof
A method of imaging reconstruction includes providing a detector and a collimator, operating the detector to acquire a measured image of a target object from photons passing through the collimator, partitioning the collimator such that the collimator can be represented by a first matrix, providing an initial estimated image of the target object, and calculating an estimated image of the target object based on the measured image and the first matrix. The calculating of the estimated image includes an iteration using the initial estimated image as a starting point. The method also includes partitioning the collimator such that the collimator can be represented by a second matrix larger than the first matrix, and calculating a refined estimated image of the target object based on the measured image and the second matrix. The calculating of the refined estimated image includes an iteration using the estimated image as a starting point.
Calibration Method and System for Photon or Particle Counting Detectors
The present invention provides a method of calibrating gamma-ray and photon counting detectors, including, but not limited to, monolithic crystal detectors. The method of the present invention is based on the observation that measurement of fan beam datasets allows the synthesis of collimated beam data to derive MDRFs by use of an algorithm that finds the common or intersecting data subsets of two or more orthogonal calibration datasets. This makes the calibration process very efficient while still allowing the full benefits of maximum-likelihood event-parameter estimation that incorporates the statistical nature of the light sensor measurements.
Silicon photomultiplier based TOF-PET detector
A scintillation block detector employs an array of optically air coupled scintillation pixels, the array being wrapped in reflector material and optically coupled to an array of silicon photomultiplier light sensors with common-cathode signal timing pickoff and individual anode signal position and energy determination. The design features afford an optimized combination of photopeak energy event sensitivity and timing, while reducing electronic circuit complexity and power requirements, and easing necessary fabrication methods. Four of these small blocks, or “miniblocks,” can be combined as optically and electrically separated quadrants of a larger single detector in order to recover detection efficiency that would otherwise be lost due to scattering between them. Events are validated for total energy by summing the contributions from the four quadrants, while the trigger is generated from either the timing signal of the quadrant with the highest energy deposition, the first timing signal derived from the four quadrant time-pickoff signals, or a statistically optimum combination of the individual quadrant event times, so as to maintain good timing for scatter events. This further reduces the number of electronic channels required per unit detector area while avoiding the timing degradation characteristic of excessively large SiPM arrays.
RADIATION DETECTION SYSTEM AND METHOD
A method of processing radiation from a source is described comprising: positioning a detector to receive radiation from the source; positioning a collimator between the source and the detector, wherein the collimator has a plurality of apertures; allowing radiation from the source to pass through the collimator and be incident upon the detector; receiving a plurality of responses each being a response to an interaction with incident radiation occurring within the detector; determining, for each of the plurality of responses, a characteristic of the interaction, wherein the characteristic comprises at least a position and depth of the interaction within the detector; processing the said plurality of responses by simultaneously processing position and depth of interaction data in such manner as to accommodate the effect of multiplexing due to overlap of the projected radiation pathways from multiple apertures in the collimator at the detector on the detected position on the detector. A radiation detection system for the detection of radiation from a source, in particular to perform the method, is also described.
IMAGE RECONSTRUCTION METHOD FOR COLLIMATOR AND DETECTOR BASED MEDICAL IMAGING SYSTEMS
A method includes providing a target object and acquiring measured images of the target object. Each of the measured images is acquired by filtering radiation from the target object by a mask having multiple holes and detecting filtered radiation by a detector. The method further includes providing an estimated image of the target object and calculating an updating factor for each of the measured images. The calculating of the updating factor includes partitioning a mathematical representation of the mask into multiple first regions; for each of the first regions, deriving a separate forward projection from the estimated image of the target object and the respective first region; and comparing the respective measured image of the target object with the forward projections. The method further includes updating the estimated image of the target object based on the updating factors.
MRI with improved segmentation in the presence of susceptibility artifacts
A system for generating MR images for segmentation and/or use in correcting attenuation in subsequent images using other modalities (e.g., PET, SPECT, etc.) is described. A surrogate soft tissue device is provided and positioned on the patient near the artifact source to provide a surrogate soft tissue boundary that can be imaged and interpreted during segmentation to mitigate the deleterious effects of a local susceptibility artifact in the MR image.
NUCLEAR MEDICINE DIAGNOSIS APPARATUS
A nuclear medicine diagnosis apparatus according to an embodiment includes a scintillator configured to emit self-radiation, storage, and processing circuitry. The storage stores first detection efficiency correction data that is generated based on an external radiation source or a simulation and first detection efficiency data per scintillator that is calculated based on radiation that is emitted from the scintillator. The processing circuitry calculates second detection efficiency data per scintillator that is calculated based on radiation that is emitted from the scintillator and generates second detection efficiency correction data based on the first detection efficiency correction data, the first detection efficiency data, and the second detection efficiency data.
Estimating Background Radiation from Unknown Sources
Embodiments include a method, comprising: receiving measured radiation obtained from a radiation detector that received radiation through an object; simulating the measured radiation obtained from the radiation detector that received radiation through the object; generating an offset based on the measured radiation and the simulated measured radiation; estimating scatter radiation based on the offset; and estimating primary radiation based on the estimated scatter radiation
Method for medical imaging in TOF-PET tomography
The invention relates to a method for reconstruction of an image of a morphometric parameter being a ratio of the frequency of annihilation of an electron with a positron to three and two quanta. The device for imaging the interior of the studied object comprises a series of TOF-PET detection modules (110), a data acquisition subsystem (111), a data selection subsystem (113) configured so as to record and identify all types of quanta emitted from the studied object after administration of an isotopic marker, the data processing system being characterised in that it allows for reconstructing (121, 123, 131, 133, 141) and visualising (143) of a δ.sub.3γ(x,y,z) image of the ration of two-quantum and three-quantum annihilations without the necessity to measure the deexcitation quanta.
Radiation detection device and nuclear medicine diagnosis apparatus including the same
A radiation detection device (300) is used in a nuclear medicine diagnosis apparatus, and includes a plurality of scintillators (44), a semiconductor light-receiving device (SiPM), a position detection circuit (214), and a timing detection circuit (216). Each of the scintillators converts a gamma ray emitted from a subject (15) into fluorescence. The semiconductor light-receiving device is provided corresponding to each of the scintillators and converts the fluorescence converted by a corresponding one of the scintillators into an electrical signal. The position detection circuit specifies a gamma ray detection position in the scintillators based on the electrical signal from the semiconductor light-receiving device. The timing detection circuit is connected to an anode of the semiconductor light-receiving device, and specifies time information corresponding to a time of occurrence of an event in which the gamma ray is detected.