Patent classifications
G01T1/1647
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 .sub.3(x,y,z) image of the ration of two-quantum and three-quantum annihilations without the necessity to measure the deexcitation quanta.
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.
Photon scatter imaging
One embodiment provides a method, including: receiving a dataset associated with a plurality of photon emission events interacting with a detector array of an imaging device; identifying a first subset of the dataset associated with a plurality of unscattered photon emission events from the plurality of photon emission events; identifying a second subset of the dataset associated with at least one scattered photon event from the plurality of photon emission events; determining, for a scattered photon event, a likely location of emission of the scattered photon event using data from the first subset of the dataset associated with the plurality of unscattered photon events; and correcting the dataset by associating the scattered photon event with the determined likely location of emission. Other aspects are described and claimed.
SCATTER ESTIMATION METHOD, SCATTER ESTIMATION PROGRAM, AND POSITRON CT DEVICE HAVING SAME INSTALLED THEREON
In the scatter estimation method of the present invention, Step S1 (first TOF projection data generation) and Step S4 (non-TOF scatter estimation algorithm) are performed, and Step S2 (second TOF projection data generation) and Step S3 (calculation of TOF direction distribution ratio) are performed, and Step S5 (calculation of TOF scatter projection data) is performed. A distribution ratio is obtained from the second TOF projection data measured in a scattered radiation energy window (low energy window). Since the target of distribution is non-TOF scatter projection data in a reconstruction data energy window (standard energy window), post-distribution TOF scatter projection data is obtained as approximate TOF scatter projection data in the reconstruction data energy window (standard energy window), and scatter estimation can be accurately performed.
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.
Histogram smoothing in positron emission tomography (PET) energy histograms
A medical nuclear imaging system (10) and method (100) generate smooth energy histograms. Radiation events are detected by a plurality of detectors (14), the radiation events localized to a plurality of pixels of the detectors (14). The energy levels of the detected radiation events are estimated and the estimated energy levels are scaled with scaling parameters that scale the energy centroids of the plurality of pixels to target values differing by offsets around a common target value, the target values differing with spatial location of the plurality of pixels. Target value offsets are removed from the scaled energy levels and the detected radiation events are combined into an energy histogram using the energy levels with the target value offsets removed.
PHOTON SCATTER IMAGING
One embodiment provides a method, including: receiving a dataset associated with a plurality of photon emission events interacting with a detector array of an imaging device; identifying a first subset of the dataset associated with a plurality of unscattered photon emission events from the plurality of photon emission events; identifying a second subset of the dataset associated with at least one scattered photon event from the plurality of photon emission events; determining, for a scattered photon event, a likely location of emission of the scattered photon event using data from the first subset of the dataset associated with the plurality of unscattered photon events; and correcting the dataset by associating the scattered photon event with the determined likely location of emission. Other aspects are described and claimed.
Compton camera system and method for detecting gamma radiation
A Compton camera system and method for detecting gamma radiation, comprising a gamma radiation source, at least one fast scintillator plate P1 of which the rise time to peak light is less than 1 ns, having a thickness greater than or equal to 5 mm, equipped with an array of segmented photodetectors (5) and a dedicated fast-reading microelectronic means. The system is characterised in that it is capable of measuring the spatial and temporal coordinates (X, Y, Z, T) and energy E at at least two successive positions of a gamma photon when said photon undergoes Compton scattering at a first point A before being absorbed at a second point B, by recognising circles of non-scattered photons corresponding to each scintillation interaction. The system has a module for estimating a valid Compton event. The detection system has two scintillator plates P1 and P2.
Normalization correction for multiple-detection enhanced emission tomography
A method and system for acquiring a series of medical images includes acquiring imaging data, identifying double coincidence events and multiple detection (MD) coincidence events from the imaging data, and storing the double coincidence events and the MD coincidence events in a first dataset and a second dataset, respectively. The method also includes applying a normalization correction to the first dataset and/or the second dataset using normalization values based on double coincidence events and/or MD coincidence events to obtain at least one normalized dataset, and reconstructing a series of medical images of the subject from the at least one normalized dataset.
SYSTEM AND METHOD FOR IMAGE DATA PROCESSING IN POSITRON EMISSION TOMOGRAPHY
The present disclosure relates to systems and methods for reconstructing a PET image. The systems may execute the methods to acquire PET data of a subject. The PET data may include position information of a plurality of coincident events. The plurality of coincident events may include scattering events and random events. The systems may execute the methods to select a portion of the PET data from the PET data based on the position information. The systems may execute the methods to reconstruct a first preliminary image of the subject based on the selected portion of the PET data, and project the first preliminary image. The systems may execute the methods to may determine, based on the PET data and the projection of the first preliminary image, preliminary correction data relating to the scattering events and the random events.